Agronomy Journal Grow Your Career With ASA
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Abstract Freely available
Right arrow Figures Only
Right arrow Full Text (PDF) Free
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Web of Science (55)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Miller, P. R.
Right arrow Articles by Neill, K. E.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Miller, P. R.
Right arrow Articles by Neill, K. E.
Agricola
Right arrow Articles by Miller, P. R.
Right arrow Articles by Neill, K. E.
Related Collections
Right arrow Other Legumes
Right arrow Dryland Cropping Systems
Agronomy Journal 94:261-272 (2002)
© 2002 American Society of Agronomy

SYMPOSIUM PAPERS

Pulse Crop Adaptation in the Northern Great Plains

Perry R. Miller*,a, Brian G. McConkeyb, George W. Claytonc, Stewart A. Brandtd, James A. Starickae, Adrian M. Johnstonf, Guy P. Lafondg, Blaine G. Schatzh, David D. Baltenspergeri and Karnes E. Neillj

a Dep. of Land Resour. and Environ. Sci., Montana State Univ., P.O. Box 173120, Bozeman, MT 59717-3120
b AAFC–Semiarid Prairie Agric. Res. Cent., P.O. Box 1030, Swift Current, SK, Canada S9H 3X2
c Agric. and Agri-Food Can., Lacombe Res. Cent., 6000 C&E Trail, Lacombe, AB, Canada T4L 1W1
d AAFC–Scott Res. Farm, Box 10, Scott, SK, S0K 4A0 Canada
e North Dakota State Univ., Williston Res. Ext. Cent., 14120 Hwy 2, Williston, ND 58801
f Potash and Phosphate Inst. of Can., Suite 704–CN Tower, Midtown Plaza, Saskatoon, SK, Canada S7K 1J5
g AAFC–Indian Head Res. Farm, Box 760, Indian Head, SK, Canada S0G 2K0
h North Dakota State Univ., Carrington Res. Ext. Cent., P.O. Box 219, Carrington, ND 58421-0219
i Univ. of Nebraska, Panhandle Res. and Ext. Cent., Scottsbluff, NE 69361
j Montana State Univ., Cent. Agric. Res. Cent., HC90-Box 20, Moccasin, MT 59462

* Corresponding author (pmiller{at}montana.edu)

Received for publication February 11, 2000.

   ABSTRACT
TOP
 ABSTRACT
INTRODUCTION
 ADAPTATION
 NOTES
 REFERENCES
 
Pulse crops discussed in this review include soybean (Glycine max L.), dry pea (Pisum sativum L.), lentil (Lens culinaris Medik.), dry bean (Phaseolus vulgaris L.) and chickpea (Cicer arietinum L.). Basic maturity requirements, yield relationships with rainfall and temperature, relative yield comparisons, water relationships, water use efficiency (WUE), crop management, tillage systems, and the rotational impact of these crops on productivity were considered. With the exception of soybean, maturity requirements for pulse crops are met in most locations within the northern Great Plains. Yield was more closely related to growing season precipitation than maximum temperature for all pulse crops except dry bean and lentil. The inability to effectively relate weather parameters to dry pea and lentil yield may indicate broad adaptation of these two pulse crops within the northern Great Plains. Correlation analyses showed the productivity of chickpea, dry pea, and lentil to be most closely associated with each other and for dry bean productivity to be most closely associated with that of soybean, effectively grouping pulse crops into their respective cool- and warm-season classifications. Dry pea and chickpea had high WUE values, similar to spring wheat (Triticum aestivum L.). Examination of plant water relations of these crops revealed an ability for chickpea and dry pea to grow at lower relative water contents than spring wheat. Increased wheat grain yield and/or protein following pulse crops under widely different N-limiting growth conditions indicated a consistent N benefit provided by pulse crops to wheat. Four general research needs were identified. First, comparative adaptation among pulse crops remains poorly understood. Second, best management practices and key production risks remain incompletely characterized. Thirdly, the knowledge of rotational effects of pulse crops in the northern Great Plains remains imprecise and inadequate. Fourth, genetic improvement for early maturity, increased yield, improved harvestability, and disease resistance requires attention. Pulse crops are poised to play a much greater role in diversifying cropping systems in the northern Great Plains but require that these key research areas be addressed so that their production potential can be realized.

Abbreviations: DD5, growing degree days with a base temperature of 5°C • Tmax, daily maximum temperature • WUE, water use efficiency


   INTRODUCTION
TOP
 ABSTRACT
 INTRODUCTION
ADAPTATION
 NOTES
 REFERENCES
 
INCREASED CROP DIVERSIFICATION remains an important step toward the goal of increasing the profitability and sustainability of agriculture (Hatfield and Karlen, 1994). A review team consisting of researchers with extensive knowledge of pulse crop production practices in the Canadian and U.S. northern Plains region was charged with discussing the potential of pulse crops for diversifying wheat-based cropping systems. This task represented a special challenge, given the scarcity of published information regarding the adaptation of pulse crops within this region. As a result, the review team relied on the contribution of original data on pulse crop agronomy, specifically from completed studies designed to compare two or more pulse crops within the same experimental protocol.

The area sown to pulse crops in the Canadian prairies has increased steadily in the last two decades, with 1999 hectarage equal to 15% of that for wheat (SAFSB, 2000). The most notable area increase has been in semiarid regions due to increased adoption of dry pea, chickpea, and lentil for intensifying wheat–fallow crop rotations, especially in no-till management systems. In the driest prairie soil–climatic zone (Aridic Haploborolls), the pulse crop area expanded from 2% of the wheat area in 1991 to 11% in 1999 (SAFSB, 2000). In the primary northern Great Plains states, as defined in Table 1, pulse crop area is equal to 35% of the wheat area due to the dominant presence of soybean in the subhumid regions of the eastern Dakotas (Farm Service Agency, State Office, Fargo, ND). However, pulse crops have retained a minor role in semiarid regions of the U.S. northern Great Plains, unlike the adjacent Canadian prairies. For example, in 1999, pulse crops equaled only 1% of the wheat acreage in Montana (Farm Service Agency, State Office, Bozeman, MT). The low inclusion of pulse crops in the U.S. northern Great Plains is of interest to agronomic researchers, leading us to ask questions about the relative adaptation of pulse crops and their effective role in cropping systems in this water-limited region. A comprehensive review of the role of pulse crops in the northern Great Plains has never been conducted.


View this table:
[in this window]
[in a new window]
  		Table 1. Wheat and pulse crop seeded area (x1000 ha) in the northern Great Plains region of Canada and the USA in 1999.{dagger}

 
Many factors affect cropping choices, including comparative crop prices, government policy, inherent climatic variability, and appropriate production knowledge and farm equipment. Grain legumes are inherently more difficult to produce than wheat and will not be grown unless a producer perceives important economic advantages. However, the underlying trend in the Canadian prairies is a steady increase in pulse crop area (average annual rate of increase was 30% between 1978 and 1999) that is occurring at the expense of fallow hectarage, which has declined dramatically; in 1998, it occupied the smallest proportion of cultivated land since 1931 (SAFSB, 2000). This may indicate that Canadian producers perceive that the economic value of pulse crops, especially in no-till systems, is as much related to increased cropping intensity (e.g., fewer years of fallow) as to increased cropping diversity (Johnson, 1999). Rotational benefits of pulse crops may be critical in facilitating greater intensification of cropping. Recently completed studies concluded that grain legumes provide a uniquely valuable option for producers in Canadian semiarid prairie cropping systems due to combined N and water use efficiency (WUE) (Miller et al., 1998a; Angadi et al., 1999). Demand for knowledge on pulse crop productivity and rotational impact is growing steadily as agricultural producers and federal agencies become increasingly aware of the vital role that these N-fixing crops can play in enhancing economic viability and environmental sustainability. However, soil–climatic conditions vary tremendously within the northern Great Plains (Padbury et al., 2002), and the comparative adaptation of pulse crops remains poorly understood.

Abundant moisture, optimal thermal conditions, adequate fertility, and freedom from pests allow crops to expand growth while limitations from one or more of these factors restrict growth. Crops, and cultivars within crop species, differ in their response to the magnitude, timing, sequencing, and combinations of these environmental factors. In any growing season, those crops that are best adapted to these environmental factors tend to be the most productive. Relative yield performance among different pulse crops, under a range of growing conditions that are expected in a particular location, is a useful indicator of the adaptation of those crops to that location. Relative yields can be highly variable because crops differ greatly in their responses to climatic conditions and climate varies widely over years within a location. For this reason, alternate crop comparisons need to be conducted for a relatively large number of years to develop a true indication of their relative yielding ability. These comparisons allow identification of the genetic, pest management, and agronomic improvements that can make such crops profitable and risk-efficient for producers.

Thus, our objectives were to compare the productivity and rotational effects of the five major pulse crops in the northern Great Plains by reviewing the results of agronomic studies and cultivar evaluations completed over the past 15 yr. Pulse crops discussed in this review include soybean, dry pea, lentil, dry bean, and chickpea. Other pulse crops were omitted due to the lack of research information or limited market potential. The focus of this review was constrained to grain production of annual legumes (i.e., pulse crops), excluding the role that annual legumes have when harvested for forage or used as green manure (Entz et al., 2002). Important additional goals were to identify gaps in agronomic knowledge about pulse crop management and to discuss the potential for broadening the focus for cropping systems research to be more regional in scope.


   ADAPTATION
TOP
 ABSTRACT
 INTRODUCTION
 ADAPTATION
NOTES
 REFERENCES
 
The climate of the northern Great Plains is typically continental, characterized by long, cold winters; short but warm summers; large diurnal ranges in temperature; frequent strong winds; and perhaps most importantly from an agricultural perspective, by uncertain and highly variable and unpredictable precipitation (Padbury et al., 2002). Extreme year-to-year variations in total precipitation, as well as the distribution, are common. Typifying semiarid regions, crop growth cannot be planned or managed the same from year to year (Stewart and Robinson, 1997). In the course of conducting this review, we have accessed data from agronomic studies and cultivar evaluations at selected locations spanning the northern Great Plains (Table 2). Long-term mean annual precipitation varies surprisingly little (330–460 mm) among the selected dryland locations, despite encompassing 17 degrees each of latitude and longitude. Conversely, pan evaporation varies widely, resulting in moisture deficits that range from 360 mm at Fort Vermilion, AB, to 670 mm at Swift Current, SK1 (Table 2). Heat unit accumulation during the growing season increases generally from northern to southern latitudes though it's modified substantially by elevation, hence the inclusion of data from the High Plains region of Nebraska. It is important to know how pulse crop productivity is affected by rainfall and temperature gradients to design cropping systems that effectively diversify production risk.


View this table:
[in this window]
[in a new window]
  		Table 2. Climatic attributes of selected locations throughout the northern Great Plains.{dagger}

 
Maturity Requirements
A basic question of crop adaptation is whether the thermal requirements (cumulative degree days) for crop maturity can be met in most growing seasons. Pulse crops can be categorized into cool- and warm-season crops based primarily on their ability to emerge in cool soil conditions and on frost tolerance. In particular, cool-season crops (dry pea, lentil, and chickpea) exhibit hypogeal emergence in contrast to warm-season crops (dry bean and soybean), which exhibit epigeal emergence. Crops that exhibit epigeal emergence are especially sensitive to frost damage because the cotyledonary node (shoot growing point) is exposed to ambient air temperatures after emergence. Further, minimum temperatures for seed germination and crop growth differ among pulse crops, with dry bean and soybean having base temperatures near 5°C and 10°C, respectively (Laing et al., 1984; Raper and Kramer, 1987), compared with base temperatures near 0°C for chickpea, dry pea, and lentil (Roberts et al., 1988; Summerfield et al., 1989; Ney and Turc, 1993). Consequently, dry bean and soybean typically require a delayed seeding date, mid-May to early June in most locations in the northern Great Plains, to reduce the risk of frost injury. Conversely, chickpea, dry pea, and lentil tolerate a moderate degree of frost, -2 to -18°C, depending on cultivar, degree of acclimation, and plant stage (Wery et al., 1993; Welbaum et al., 1997; Srinivasan et al., 1998). Associated with hypogeal emergence, if a severe frost kills the shoot, axillary nodes below the soil surface generate new shoots. The resultant loss of plant vigor reduces yield potential but typically does not require re-establishment of the field because a late seeding date also has a reduced yield potential. Early spring seeding for dry pea has been promoted as a method of improving crop productivity in the Canadian semiarid prairies (Johnston et al., 1999). In a spring seeding date study at Swift Current, SK (1993–1998), frost injury was never observed in dry pea, lentil, or desi chickpea despite seedling exposure to -5 to -6°C in 4 of 6 yr (Miller et al., 1998a), indicating that there is little risk to very early seeding of these cool-season pulse crops.

In this review, pulse crop maturity requirements were estimated by pooling means from different location-years within the northern Great Plains (Table 3). A base temperature of 5°C was used for degree day (DD5) calculation, representing a compromise between the cool- and warm-season pulse crops where cardinal values near 0 and 10°C, respectively, may be considered more appropriate (McKenzie and Hill, 1989; Summerfield et al., 1989; Dumoulin et al., 1994). Values recorded for spring wheat were included to enable reference with a commonly grown crop and agree closely with previous reports of growing degree requirements to reach maturity (Cutforth et al., 1990).


View this table:
[in this window]
[in a new window]
  		Table 3. Cumulative degree day (base temperature = 5°C) requirements to reach maturity for grain legumes compared with spring wheat in the northern Great Plains and bordering re-gions.

 
The mean cumulative DD5 requirements for early maturing soybean (00 maturity group) were greater than all other pulse crops included in this review (Table 3) and exceeded the mean cumulative DD5 available at many locations in the northern Great Plains (Table 2). Most soybean cultivars are short-day plants, and thermal time to anthesis can be greatly extended at long daylength periods (Raper and Kramer, 1987). At the Saskatchewan locations, an early maturing 00 cultivar was used to represent soybean (‘Pioneer 9007’, daylength sensitive). At these latitudes of 50 to 52°N, maturity is expected to be related primarily to heat unit accumulation (M. Fabrizius, personal communication, 2000). Maturity group 00 soybean cultivars were used at the northwestern Nebraska location, and heat unit accumulations to reach maturity were similar to those for the Saskatchewan locations. Because a limited commercial interest exists for maturity group 000 (M. Fabrizius, personal communication, 2000), this maturity requirement limits soybean adaptation to southern regions in the northern Great Plains.

Dry bean required fewer DD5 than soybean but more than other pulses (Table 3). Considering the delayed seeding requirement for dry bean, failure to reach maturity presents production risk at some locations in the northern Great Plains. However, reported DD5 values varied strongly (i.e., >400 DD5) among the 12 location-years due to variation in the growth habit (determinate vs. indeterminate) among dry bean cultivars. In semiarid regions, substantial water deficits typically limit plant growth, reducing the DD5 required to reach maturity. Genetic advancement in dry bean is occurring at a steady rate, resulting in determinate early maturing dry bean cultivars being grown successfully as far north as Saskatoon (52°12' N lat), SK (A. Vandenberg, personal communication, 1998). Thus, maturity requirements are not a major limitation for dry bean production in the northern Great Plains.

The maturity requirements of dry pea, lentil, and chickpea are easily met at most locations in the northern Great Plains, with DD5 requirements reported very similar to hard red spring wheat. There are two types of chickpea grown in the northern Great Plains: small-seeded desi (e.g., {approx}200 mg seed-1) and large-seeded kabuli (e.g., 400–500 mg seed-1). Though it was out of the scope of this review to conduct a detailed investigation of genetic variation within chickpea, it is important to note that DD5 requirements for the kabuli cultivars available in the northern Great Plains are typically greater than those for the desi type by approximately 100 DD5. Further, due to its large seed size and thin seed coat, kabuli chickpea germination and emergence can be drastically reduced by imbibitional chilling injury and consequent infection by soil-borne pathogens (Balasubramanian et al., 1998). Thus, its seeding date is often delayed compared with the desi type. Seed treatment of kabuli chickpea with fungicide to control Pythium spp. has proven necessary to get reliable germination and emergence at early seeding dates (Matus et al., 1998). Strict commercial grading standards strongly limit the number of immature seeds in both desi and kabuli chickpea. Currently available chickpea cultivars have an indeterminate growth habit and required physiological stress (i.e., drought) to terminate flowering (Anonymous, 2000). This can result in significant risk for many locations in the northern Great Plains in years with wetter-than-normal growing conditions combined with an early fall frost.

The mean DD5 requirements were lowest for dry pea, though a wide range (>350 DD5) of values was reported, due to differences in cultivar growth habits and growing season moisture among locations. Matching crop phenology to growing season temperature and precipitation is considered a key drought tolerance mechanism (Ludlow and Muchow, 1990). When combined with the possibility for early seeding in cool seedbed conditions, the very early maturity of pea and, to a lesser extent, desi chickpea and lentil affords producers the opportunity to advance crop growth during the late-spring and early summer rainy season, which typifies the northern Great Plains. This permits these cool-season pulse crops to complete large portions of their growth cycle before the typical onset of summer drought, and thus minimize production risk (Miller et al., 1998b).

The financial risk of grain legumes failing to mature varies by crop type and market intention. Grain legumes intended for human edible markets (e.g., dry bean, chickpea, lentil, and soybean) maintain steep price premium–discount schedules attached to grain grading standards (U.S. Dry Pea and Lentil Council, 2000). Failing to reach maturity in these crops results in reduced quality (i.e., loss of grade), as well as yield, which can markedly reduce financial returns. For example, U.S. No. 1 lentil typically returns a farmgate price in the range of $265 to $375 t-1, but if discounted to feed grade due to severe frost damage, the value drops to $88 to $110 t-1 (G. Kiemele, personal communication, 1999). On the other hand, dry pea has a predominant feed market and may not suffer such drastic financial losses when grain quality is reduced by frost damage.

Yield Relationships across Climatic Gradients
By comparing pulse crop yields from locations spanning the northern Great Plains, we explored yield relationships with cumulative rainfall and average daily maximum air temperature (Tmax). Data were included from locations where multiple pulse crops had been grown in a common trial. In order to enable comparisons with the most well-known crop in this region, data for wheat were included where it was grown in a common trial with pulse crops. Rather than develop yield–climate models that were crop specific, the purpose of this method was to compare differential sensitivity among crops to growing season rainfall and Tmax. Dry matter grain yields were related to rainfall and Tmax during a 2-mo growth period, which was selected for each crop at each location to include the two calendar months that included the complete flowering period. Yield was related to mean rainfall and Tmax via all possible combinations of linear and quadratic models (Table 4), and the best-fitting model was set as the model with the lowest P value and then with the highest R2 value (Steel and Torrie, 1980).


View this table:
[in this window]
[in a new window]
  		Table 4. Comparison of equation parameters for regression models of pulse crop yield on climatic parameters (rainfall and average maximum temperature) during critical growth periods.

 
The data includes a broad range of climatic conditions (Table 2) and, in at least some instances, the most suitable cultivars and agronomic practices had not been well identified. Consequently, these factors placed limitations on our ability to identify those climatic factors having major influences on yield of the various alternative pulse crops. Despite these limitations, some relationships were evident.

The strongest relationship (R2 = 0.53) was reported for dry bean, in which both mean rainfall and Tmax were positively related to yield (Table 4). Given the wide range of mean rainfall and Tmax values, and yield values, a relationship of this magnitude is not surprising. Because several low dry bean yields were included from cool Canadian sites, the positive relationship with Tmax was also as expected. Rainfall during the critical growth phase for chickpea was related to yield, but yield was favored by both high and low rainfall during this period, with the lowest yield noted for moderate rainfall levels. This response by chickpea is difficult to interpret. It may be an indication that under moderate rainfall during this period, chickpea builds a yield potential exceeding that which can be maintained through final maturity. Under such conditions, yield is reduced rather than enhanced. Chickpea yield was not related to Tmax, which was surprising given the known relationships of flower fertility and temperature (Srinivasan et al., 1998). Among the pulse crops in this review, chickpea production practices are the least well understood, and cultivar development the least advanced, confounding factors that likely contributed to this unusual yield response. Soybean showed a positive relationship with rainfall only. Few Canadian sites were included in the analysis, so the range in Tmax did not extend as low as in dry bean (i.e., 23 vs. 20°C), which may have prevented detection of a Tmax function.

Dry pea showed only a weak relationship with rainfall while lentil had no relationship with either rainfall or Tmax, despite the greatest number of observations in these two crops. This may indicate a broad adaptation within the northern Great Plains region. Where actual water use was related to crop yield, the regression equations were stronger for chickpea, dry pea, and lentil though not as strong as that for wheat in the same study (Fig. 1) . In the case of lentil, the uncertain relationship with growing season rainfall is not surprising because lentil has been reported to show limited yield benefit from irrigation (McKenzie and Hill, 1990) and is known to require drought stress to induce seed set in the Canadian prairies (Anonymous, 2000). Further, lentil is susceptible to a number of foliar pathogens, which have increased prevalence during high-rainfall seasons (Martens et al., 1984), though lentil yield data with obvious disease concerns were omitted from this review to minimize confounding effects.



View larger version (19K):
[in this window]
[in a new window]
  		Fig. 1. Relationships between grain yield and water use (WU) for dry pea, desi chickpea, lentil, and spring wheat when grown in common studies at Swift Current, SK, during 1996–1998. **Significant at P < 0.01. (Adopted from Angadi et al., 1999.)

 
Based on these yield functions with climate during the critical growth phase, limited insight regarding pulse crop adaptation in the northern Great Plains is gained. Soybean adaptation is currently constrained mainly by long maturity requirements. Dry bean is best adapted to areas with relatively warm, wet growing seasons or to areas under irrigated production, excluding dryland production in semiarid regions of the northern Great Plains. No useful insight was provided for chickpea adaptation based on its unusual response to growing season rainfall. Pulse industry sources in Australia, Canada, and the USA consider climatic conditions that are favorable for the development of ascochyta blight [Ascochyta rabiei (Pass.) Lab.] (Wiese et al., 1995) to be the key factors limiting adaptation of chickpea (F. Muehlbauer, personal communication, 1998). As a result, chickpea may be considered best adapted to semiarid environments of the southern and western regions of the northern Great Plains where climatic conditions are least favorable for the development of ascochyta blight. The weak climatic relationships for dry pea and lentil may indicate broad adaptation to both semiarid and subhumid regions within the northern Great Plains.

To compare general yield potential among pulse crops, crop yields were reported as a function of dry pea, for which the greatest number of direct comparisons were possible (Table 5). More important than the mean of the comparisons is the wide range in values for all crops relative to dry pea. This is a strong indication that there remains much to learn about the comparative adaptation of pulse crops in the northern Great Plains region. In common trials, the yield of spring wheat varied from 52 to 188% of dry pea, with a mean of 111%. Because wheat generally has a longer growing season requirement than dry pea (Table 3), it would be expected to be more responsive to late-season precipitation. Campbell et al. (1988) reported that wheat is also sensitive to moisture stress at the five- to flag leaf stage (Zadoks 1.5–4.1) when grown on stubble. If pea were less sensitive to this early season moisture stress, it could yield relatively favorably. By comparison, all other pulse crops had lower average yields than dry pea though each exceeded dry pea yield at individual location-years. This wide range in relative crop yields may indicate differences in climatic adaptation among site-years though it may also indicate a lack of knowledge of optimal crop management practices, as is discussed later in this review. The variability in relative crop yield values indicates that there remains much to learn about the optimal fit for respective pulse crops within the northern Great Plains. For example, chickpea yields ranged widely, from 2 to 178% of dry pea. Chickpea is a relative new pulse crop option in the northern Great Plains, and as a result, its yield performance is likely compromised by inadequate knowledge of best management practices and a lack of well-adapted cultivars. However, in some production circumstances, the productivity of chickpea was markedly superior to dry pea, indicating good potential for diversifying production risk in cropping systems.


View this table:
[in this window]
[in a new window]
  		Table 5. Comparison of grain yield of pulse crops and hard red spring (HRS) wheat standardized to dry pea yield (i.e., dry pea = 1.00; range = 400 to 4120 kg ha-1) in multicrop trials in the northern Great Plains.

 
Economic diversification is defined as a stabilization of economic returns (Zentner et al., 2002). Zentner et al. (2002) reported that increased stability can derive from differences in crop yield responses to climatic conditions (production diversification) or from differences in crop prices due to changes in market conditions (market diversification). While market diversification is of critical importance, this review is focused on production diversification. In the northern Great Plains, producers are seeking increased diversification from wheat, the dominant crop produced in this region (Table 1). Correlation of yield values showed that spring wheat was not well correlated with dry pea or lentil but was moderately correlated (r = 0.72, P < 0.01) with the yield of chickpea (Table 6). The latter finding was unexpected and may be a result of a low number of wheat–chickpea comparisons (13), but it merits further investigation as it suggests that production diversification will be greater with dry pea or lentil than with chickpea (ignoring market diversification) under the economic definition presented above. Can such an observation be explained agronomically? Rooting depths of dry pea and lentil have been reported to be shallower than those of chickpea and spring wheat (Miller et al., 1998a; Angadi et al., 1999). Because all yield values in this review were obtained from crops grown on cereal stubble, the similar response of spring wheat and chickpea may be due to similarities in their ability to extract soil water in years with deep (i.e., 120 cm) soil water recharge. The yield values of the cool-season pulse crops (chickpea, dry pea, and lentil) correlated more strongly among themselves than with the warm-season pulse crops (dry bean and soybean) and vice-versa (Table 6). This may indicate that diversification will be increased by the addition of both cool- and warm-season pulse crops into cropping systems compared with the addition of only one or the other.


View this table:
[in this window]
[in a new window]
  		Table 6. Correlation coefficients for grain legume and hard red spring (HRS) wheat yield in the northern Great Plains.

 
Water Use Efficiency
Because WUE is the main limiting factor to crop production in the Great Plains (Farahani et al., 1998), crop WUE was calculated for pulse crops at a large number of location-years for this review (Table 7). In this review, WUE was calculated as the dry matter grain yield divided by soil water depletion plus the total sum of precipitation that occurred between the preseeding and postharvest sampling dates. For spring wheat, the range (and mean) of WUE values was generally consistent with that previously reported for the Great Plains region (Peterson et al., 1996). Though the mean WUE for dry pea appeared to exceed that for spring wheat, when only directly comparable values were included, the mean WUE of spring wheat was similar to that of dry pea. The mean WUE values for all other pulse crops appeared lower than that of spring wheat though the maximum values observed for chickpea and lentil were similar to that for spring wheat. The observation of chickpea and lentil WUE values approaching that of spring wheat indicates that there is much to learn about attaining optimal yield response in these two pulse crops because actual yields are often much lower than spring wheat yields (Table 5). The two warm-season pulse crops, dry bean and soybean, had the lowest mean (and range of) WUE values. This reflects a typically delayed seeding date and longer plant maturity, extending crop growth into the mid- and late-summer season when peak evapotranspiration demand occurs. As such, dry bean and soybean generally are not acceptable to include into dryland cropping systems in semiarid regions of the northern Great Plains, especially in western regions where rainfall is normally concentrated in the late spring and early summer.


View this table:
[in this window]
[in a new window]
  		Table 7. Comparison of water use efficiency (WUE; kg ha-1 mm-1) for grain legumes and hard red spring (HRS) wheat in the northern Great Plains.

 
Recognizing the good fit for cool-season pulse crops in semiarid regions of the northern Great Plains, Angadi et al. (1999) compared the plant water relations among chickpea, dry pea, and lentil at Swift Current, SK (1996–1998), and found that lentil and dry pea rooting systems only extracted water effectively in the upper 0.9 m of soil while chickpea (desi type) used soil water to 1.2 m. Under the same growing conditions, all three pulse crops used less water than spring wheat though the difference between chickpea and wheat was small, indicating that dry pea and lentil are well adapted to semiarid Plains regions where the soil profile is often not fully recharged with water. Measurements of relative leaf water content and leaf water potential revealed a remarkably similar physiological response to water stress among the pulse crops that was fundamentally different from spring wheat (Fig. 2) . In particular, as leaf water content decreased, the leaf water potential of the pulse crops did not decrease as rapidly as that of spring wheat. This suggests pulse cell walls have additional elasticity, which helps maintain turgor under water-stressed conditions. Of the three pulse crops, dry pea had the highest WUE (Fig. 1). However, water use explained a relatively low proportion of grain yield variation (i.e., R2 = 0.37) in pea compared with spring wheat (i.e., R2 = 0.72; Fig. 1). This difference may reflect differences in growth habit (determinate vs. indeterminate), a lack of pulse crop cultivars specifically adapted to the cool semiarid northern Plains, or a relatively poor understanding of best management practices for pulse crops.



View larger version (26K):
[in this window]
[in a new window]
  		Fig. 2. Relationship between relative leaf water potential and relative leaf water content for dry pea (•), chickpea ({blacktriangleup}), and spring wheat ({blacksquare}) grown under the same growing conditions. (Adopted from Angadi et al., 1999.)

 
Crop Management Effects on Yield
Aside from climatic influences, crop management practices often affect the apparent adaptation of pulse crops. Management factors under the direct control of producers include seeding date, seeding depth, seeding rate, cultivar, and seedbed conditions (Johnson, 1987; Auld et al., 1988; Ali-Khan and Kiehn, 1989; Townley-Smith and Wright, 1994). Other factors that contribute to the variability of pulse crop yields are the result of farm fields that lack a history of pulse crops, dry seedbed conditions, low soil pH, and poor competitive ability with weeds (Clayton et al., 1997). However, yield variability has mainly been attributed to the lack of N in the pulse crop due to ineffective nodulation. Factors that adversely affect crop nutrient supply will result in an apparent yield value that is lower than that due to climatic conditions. Pulse crops are unique because of their reliance on biological N2 fixation to supply plant N. As one example of how crop management can affect apparent adaptation, in the northern Great Plains there are several soil- and climate-related factors that prevent or retard the establishment of this biological relationship, and thus decrease pulse crop yields. Brockwell and Bottomley (1995) reviewed the inoculation of pulse crops and determined that solid forms of inoculant introduced separately into the seedbed represent a satisfactory alternative to seed-applied application of liquid or peat powder inoculants. Recent research in Alberta has shown that the use of soil-applied peat granular inoculant increased yield compared with seed-applied liquid or peat powder inoculants in dry pea, particularly in dry seedbed conditions and fields that lack a history of pulse crops (Table 8). In the dry seedbed condition, pea yield was highest with the soil-inoculated treatment while pea yield with seed-applied inoculant was similar to that of the uninoculated check. Thus, the conclusion reached by Brockwell and Bottomley (1995) is certainly justifiable, that the use of soil inoculant results in yields that are "often better, never worse," and consequently reduces the yield variability and stabilizes the production of pulse crops. We included this example to highlight the risks associated with comparing the adaptation of crops under adverse conditions. There are areas in the northern Great Plains that could benefit from soil inoculation of pulse crops by reducing the yield variability associated with adverse soil and climatic conditions.


View this table:
[in this window]
[in a new window]
  		Table 8. Relative dry pea yield (% of uninoculated) from soil (granular) and seed inoculation (liquid and peat powder) at Fort Vermilion (dry) and Beaverlodge (moist), AB, Canada in 1995.{dagger}

 
Tillage System Effects
Lentil, chickpea, and dry bean have low plant heights while lentil and some dry bean and dry pea cultivars are prone to severe lodging. As a result, pulse crops frequently require harvesting at or near ground level. Relative to cereal crops, harvesting pulse crops often increases harvesting costs in terms of labor (i.e., slow harvest operation speeds); damage to the harvesting equipment from excessive ground contact or collection of unwanted material such as soil, rocks, and other debris; and the requirement for specialized harvest equipment (e.g., under cutters, pickup or air-assisted reels, and floating cutter bars). Rocky soil surfaces are poorly suited to pulse production because of risk of damage to harvesting machinery unless rigorous removal of larger rocks and land rolling to push smaller rocks into the soil after seeding is practiced. Land rolling, either pre- or postemergence, with large-diameter (approx. 1 m) steel rollers is a common practice in some soil landscapes to leave a smooth soil surface for easier harvest by crushing large soil clods and flattening tillage ridges in addition to pushing rocks into the soil surface (Anonymous, 2000). In the case of hummocky land with steep relief, the production of pulses is possible, but the challenges at harvest can be substantial. It may be necessary to use narrow headers to more easily follow the contour of the land.

The effects of tillage systems on pulse crops in the northern Great Plains have not been studied extensively. However, the few existing studies do show the benefits of using no-till management with pulse crops. At Indian Head, SK, the increase in yield of field pea with no-till was directly related to the extra moisture conserved from leaving standing stubble over the winter, increasing snow trapping and moisture conservation (Table 9). In addition to the snowtrap effect, at Swift Current, SK, pulse crops also had increased grain yields when direct-seeded into standing cereal stubble (McConkey et al., 1998) due to the improved microclimate during the growing season. Reduced wind speeds and evaporative demand for water near ground level was provided by standing cereal stubble (Cutforth and McConkey, 1997).


View this table:
[in this window]
[in a new window]
  		Table 9. The effects of tillage systems on soil water conserved, total water used, grain yield, and water use efficiency (WUE) in field pea for the period of 1987–1998 at Indian Head, SK, Canada.{dagger}

 
Dry pea cultivars having a semileafless canopy type are much less likely to lodge than traditional normal-leafed cultivars, thereby expanding the number of soil landscapes suitable for dry pea production (Anonymous, 2000). Also, seeding lentil, dry pea, or chickpea directly into standing cereal stubble raises the height of the plant and basal pods (McConkey et al., 1998). There are three likely reasons for this: (i) natural trellising on the stubble; (ii) natural elongation response to growing in the partial shade produced by the standing stubble; and (iii) more vigorous growth due to better water conservation, as shown in Table 9. Thus, direct seeding into tall cereal stubble can improve harvestability, thereby expanding the effective area of suitable soil landscapes for pulse production.

Soil erosion is a perennial concern in the northern Great Plains with conventional tillage–based systems, and when pulse crops are introduced into the cropping system, the lower residue production combined with rapid residue decomposition can make for disastrous situations. For example, measurements in southern Saskatchewan have shown that chickpea provides about one-half the amount of crop residue on the soil surface as spring wheat grown under the same conditions (McConkey, unpublished data, 1998). Consequently, soil landscapes that are prone to erosion because of poor soil aggregation and/or routine exposure to highly eroding conditions from wind or water may not have sufficient residue after a pulse crop to prevent excessive soil erosion if that residue is tilled. No-till practices that maximize conservation of the pulse residue and carryover residue from previous crops are necessary for sustainable production of pulse crops on highly erodible soil landscapes.

Impact of Pulse Crops in Wheat-Based Cropping Systems
The rotational effect of pulse crops on subsequent wheat yield appears to be a result of a series of complex interactions of the pulse crop on soil water (Angadi et al., 1999), soil nutrient supply (Grant et al., 2002; Beckie and Brandt, 1997), and interruption of pest cycles (Derksen et al., 2002; Krupinsky et al., 2002). Consequently, yield responses can vary considerably among pulse crops, years, and locations (Table 10). Where pulse crops use less stored soil water, or mature earlier, soil water can be conserved. The positive rotational benefit observed at Swift Current, SK (Table 10), has been attributed at least partially to soil water conservation (Miller et al., 1998a). Conversely, in years where snowmelt plays an important role in soil moisture recharge, short stubble associated with pulses is less effective than wheat stubble in trapping and retaining snow (Miller, unpublished data, 2000).


View this table:
[in this window]
[in a new window]
  		Table 10. Normalized{dagger} dry matter grain yield and protein response in hard red spring wheat uniformly recropped in grain legume stubbles in three studies in the northern Great Plains.{ddagger}

 
Where soil- or residue-borne diseases reduce wheat yield in wheat–wheat sequences, a pulse–wheat sequence can be beneficial in reducing such losses (Stevenson and Van Kessel, 1996; Beckie et al., 1997). However, even where levels of wheat disease inoculum are reduced on pulse crop stubble, wheat yield responses due to reduced disease only occur where disease pressure is sufficient to reduce yield on wheat stubble (Fernandez et al., 1998). Similarly, pulses can have positive, neutral, or even negative effects on subsequent yield due to weed competition, depending on how weed populations in the succeeding crop are affected by the previous pulse crop. In many cases, benefits associated with one of these factors can be masked by negative effects on another or simply by climatic conditions. Thus, it is not surprising to find conflicting reports of the effect of pulses on a subsequent wheat crop, such as is evident by the results in Table 10, with contrasting responses among the three studies. However, most reports do indicate positive effects on a succeeding wheat crop, but they also suggest that our knowledge of this important function of pulse crops in a crop rotation remains limited.

Discussion of four crop rotation studies, three of which occurred in North Dakota, serve to illustrate this point. Nitrogen fixation by a pulse crop often increases the supply of N and/or N use efficiency to a succeeding crop (Badaruddin and Meyer, 1994; Campbell et al., 1992). In a subhumid environment at Carrington, ND, pulse crops varied widely in N yield (shoot biomass x N concentration), with mean values of 60, 64, 76, 83, and 115 kg ha-1 for dry bean, soybean, lentil, chickpea, and dry pea, respectively (NDSU-CREC, 1993). These differences in N yield are presumably due to differences in N2 fixation and show strong correspondence with the unfertilized wheat yields grown on these different crop residues (Table 10). However, this N benefit only increases subsequent crop yield where moisture is sufficient to utilize the increased N and where N is yield limiting (Beckie and Brandt, 1997; Beckie et al., 1997). In an earlier study in eastern North Dakota (Badaruddin and Meyer, 1994), also in a subhumid environment, wheat grown in the high-N wheat residue control treatment had equal N uptake and grain yield compared with wheat grown on pulse crop residues. In the Carrington study (Table 10), wheat grown in the high N fertilizer control treatment exceeded the yield and protein levels for the wheat grown on all pulse crop stubbles. Because Badaruddin and Meyer (1994) did not report the N yield of the aboveground biomass in their earlier study and inadvertently removed the pulse crop residues in one year of the 2-yr study, it is unknown how differences in N2 fixation may have been related to subsequent wheat response. These differences between the two studies, relative to the high N fertilizer control treatment, may be due to the effect of non-N rotational effects, whereby wheat–wheat sequences suffered different yield limitations due to cereal diseases between the two studies (Stevenson and van Kessel, 1996; Fernandez et al., 1998). In both studies, the unfertilized wheat control treatment produced much lower yield and protein than that grown on the pulse crop residues, indicating a positive effect on soil N balance.

In the most recent North Dakota study, conducted in a semiarid environment at Williston, pulse–wheat sequences caused no yield benefit but did cause gains in grain protein (P = 0.05) compared with the wheat–wheat sequence (Table 10). The high N fertilizer application rate (average was 86 kg ha-1) likely prevented N from limiting grain yield, in agreement with Beckie and Brandt (1997). Continued N release from the pulse crop residues provided additional N during the grain fill period, increasing grain protein, in agreement with Miller et al. (1998c). The contention that N did not limit wheat grain yield in the Williston study is supported by the observation that protein concentration of grain dry matter (mean = 142 g kg-1) was consistently near the yield threshold of 147 g kg-1 established for hard red spring wheat by Engel et al. (1999). However, in an earlier study in Saskatchewan, also in a semiarid environment, increases in both grain yield and protein were observed for wheat grown in pulse residues compared with wheat grown in wheat residues. In the Saskatchewan study, a mean N fertilizer application rate of 50 kg ha-1 was used, which created N-limiting yield conditions in four of eight site-years, using the established grain protein–yield threshold value from Engel et al. (1999). In the Saskatchewan study, N yield was determined only for the harvested seed (rather than total shoot biomass), with mean values of 7, 44, 46, and 96 kg ha-1 for dry bean, lentil, chickpea, and dry pea, respectively (Miller et al., 1998a). These N yield values did not correspond well with the grain yield and protein values of wheat grown on these crop residues (Table 10), indicating that factors other than N2 fixation were involved in conferring the observed rotational response. Because disruption of wheat pest cycles was not observed to vary among these pulse crop residues, differences in soil moisture use and conservation for the subsequent wheat crop were investigated and found to be significant in conferring non-N, in addition to N, rotational benefits in this study (Miller et al., 1998a).

Discussion of the different patterns of rotational effects observed in the four studies cited above illustrates the incomplete knowledge for describing the underlying causes of rotational effects. It is apparent that rotational benefits from pulse crops can be obtained in semiarid, as well as subhumid, regions though likely with less consistency in semiarid regions due to the strong interacting effect of soil moisture (Beckie and Brandt, 1997). Enhanced understanding of how pulse crops influence yield and quality of succeeding crops would allow producers to alter management to capitalize on beneficial effects while minimizing negative impacts.

Needs and Opportunities
Pulse crops appear to have enormous potential for increasing the sustainability of wheat-based dryland cropping systems in the northern Great Plains. The general ability to use atmospheric N to supply part or all of the N needs for pulse crops is a function that is likely to become increasingly important as energy-efficient cropping systems are developed (Drinkwater et al., 1998). For some pulse crops, acceptable drought and heat tolerance, efficient water use, and moisture-conserving growth habits are obvious adaptive advantages for this region. However, pulse crops range widely in growth habits, maturity requirements, and yield response to climatic conditions. Comparative adaptation among pulse crops within the highly variable geographic and interannual climatic gradients of the northern Great Plains remains poorly understood. The advent of no-till systems adds further confusion about climatic relationships with productivity by conserving greater amounts of precipitation for crop growth and by changing thermal patterns within the crop canopy.

Four general needs have been identified in the course of this review. First, comparative adaptation among pulse crops remains poorly understood. To fully utilize crop diversification opportunities, managers of cropping systems require this information. Relatively simple experimental designs including important pulse crops within single studies conducted at different locations throughout the northern Great Plains, with careful monitoring of water use and thermal patterns, could provide this information in a short time period. Combining this productivity information with climatic probabilities will provide risk profiles by geographic subregion of the northern Great Plains, important support for the development of pulse crop production models. Second, best management practices and key production risks remain incompletely characterized for all pulse crops in at least some portion of the northern Great Plains. This uncertainty increases production risk markedly because a single management flaw can be costly. To overcome this lack of key agronomic knowledge, future studies in crop management could be conducted with common protocols at several sites spanning the northern Great Plains. The informal network that has been assembled in the writing of this review paper may increase the possibility of this type of regional research approach in the near future. Thirdly, the knowledge of rotational effects of pulse crops in the northern Great Plains remains imprecise and inadequate. The functional soil and climatic principles of rotational effects must be researched in a comprehensive manner, integrating expertise across the northern Great Plains. It is likely that capturing the synergy of systems benefits will be increasingly important to sustaining the economic and environmental viability of grain production in the northern Great Plains. Lastly, genetic improvement through traditional methods for early maturity, increased yield, improved harvestability, and disease resistance remains a gap that requires continuous attention. Molecular marker technology would be beneficial to improve the probability of success in developing new genetic material for the northern Great Plains. Pulse crops are poised to play a much greater role in diversifying cropping systems but require that these key research areas be addressed so that their production potential can be realized.


   NOTES
TOP
 ABSTRACT
 INTRODUCTION
 ADAPTATION
 NOTES
REFERENCES
 
1 Representative pan evaporation values were not available for Williston, ND, but it is likely that the moisture deficit there is even greater than Swift Current. Back


   REFERENCES
TOP
 ABSTRACT
 INTRODUCTION
 ADAPTATION
 NOTES
 REFERENCES
 




This article has been cited by other articles:


Home page
 Agron. J.Home page
Y. Gan, T. D. Warkentin, R. Chandirasekaran, B. D. Gossen, T. Wolf, and S. Banniza
Effects of Planting Pattern and Fungicide Application Systems on Ascochyta Blight Control and Seed Yield in Chickpea
Agron. J., November 1, 2009; 101(6): 1548 - 1555.
[Abstract] [Full Text] [PDF]

Home page
 Agron. J.Home page
Y. T. Gan, T. D. Warkentin, C. L. McDonald, R. P. Zentner, and A. Vandenberg
Seed Yield and Yield Stability of Chickpea in Response to Cropping Systems and Soil Fertility in Northern Latitudes
Agron. J., September 1, 2009; 101(5): 1113 - 1122.
[Abstract] [Full Text] [PDF]

Home page
 Agron. J.Home page
U. M. Sainju, A. W. Lenssen, T. Caesar-TonThat, and R. G. Evans
Dryland Crop Yields and Soil Organic Matter as Influenced by Long-Term Tillage and Cropping Sequence
Agron. J., February 4, 2009; 101(2): 243 - 251.
[Abstract] [Full Text] [PDF]

Home page
 Agron. J.Home page
P. M. Carr, Glenn. B. Martin, and R. D. Horsley
Wheat Grain Quality Response to Tillage and Rotation with Field Pea
Agron. J., October 21, 2008; 100(6): 1594 - 1599.
[Abstract] [Full Text] [PDF]

Home page
 Agron. J.Home page
F. J. Lopez-Bellido, R. J. Lopez-Bellido, S. K. Khalil, and L. Lopez-Bellido
Effect of Planting Date on Winter Kabuli Chickpea Growth and Yield under Rainfed Mediterranean Conditions
Agron. J., June 16, 2008; 100(4): 957 - 964.
[Abstract] [Full Text] [PDF]

Home page
 Agron. J.Home page
H. W. Cutforth, S. M. McGinn, K. E. McPhee, and P. R. Miller
Adaptation of Pulse Crops to the Changing Climate of the Northern Great Plains
Agron. J., November 6, 2007; 99(6): 1684 - 1699.
[Abstract] [Full Text] [PDF]

Home page
 Agron. J.Home page
N. Z. Lupwayi and A. C. Kennedy
Grain Legumes in Northern Great Plains: Impacts on Selected Biological Soil Processes
Agron. J., November 6, 2007; 99(6): 1700 - 1709.
[Abstract] [Full Text] [PDF]

Home page
 J ANIM SCIHome page
T. C. Gilbery, G. P. Lardy, S. A. Soto-Navarro, M. L. Bauer, and V. L. Anderson
Effect of field peas, chickpeas, and lentils on rumen fermentation, digestion, microbial protein synthesis, and feedlot performance in receiving diets for beef cattle
J Anim Sci, November 1, 2007; 85(11): 3045 - 3053.
[Abstract] [Full Text] [PDF]

Home page
 Agron. J.Home page
S. P. Singh
Drought Resistance in the Race Durango Dry Bean Landraces and Cultivars
Agron. J., August 10, 2007; 99(5): 1219 - 1225.
[Abstract] [Full Text] [PDF]

Home page
 Agron. J.Home page
R. E. Blackshaw, L. J. Molnar, G. W. Clayton, K. N. Harker, and T. Entz
Dry Bean Production in Zero and Conventional Tillage
Agron. J., January 1, 2007; 99(1): 122 - 126.
[Abstract] [Full Text] [PDF]

Home page
 Agron. J.Home page
P. R. Miller, R. E. Engel, and J. A. Holmes
Cropping Sequence Effect of Pea and Pea Management on Spring Wheat in the Northern Great Plains
Agron. J., October 31, 2006; 98(6): 1610 - 1619.
[Abstract] [Full Text] [PDF]

Home page
 Agron. J.Home page
D. G. Felter, D. J. Lyon, and D. C. Nielsen
Evaluating Crops for a Flexible Summer Fallow Cropping System
Agron. J., October 3, 2006; 98(6): 1510 - 1517.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
C. G. Munoz-Perea, H. Teran, R. G. Allen, J. L. Wright, D. T. Westermann, and S. P. Singh
Selection for Drought Resistance in Dry Bean Landraces and Cultivars
Crop Sci., September 8, 2006; 46(5): 2111 - 2120.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
J. Wang, Y. T. Gan, F. Clarke, and C. L. McDonald
Response of Chickpea Yield to High Temperature Stress during Reproductive Development
Crop Sci., September 8, 2006; 46(5): 2171 - 2178.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
R. Ben-David, S. Lev-Yadun, C. Can, and S. Abbo
Ecogeography and Demography of Cicer judaicum Boiss., a Wild Annual Relative of Domesticated Chickpea
Crop Sci., April 25, 2006; 46(3): 1360 - 1370.
[Abstract] [Full Text] [PDF]

Home page
 Agron. J.Home page
J. W. White, G. Hoogenboom, and L. A. Hunt
A Structured Procedure for Assessing How Crop Models Respond to Temperature
Agron. J., March 1, 2005; 97(2): 426 - 439.
[Abstract] [Full Text] [PDF]

Home page
 Agron. J.Home page
P. R. Miller and J. A. Holmes
Cropping Sequence Effects of Four Broadleaf Crops on Four Cereal Crops in the Northern Great Plains
Agron. J., January 1, 2005; 97(1): 189 - 200.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
Y. Gan, P. Liu, and C. McDonald
SEVERITY OF ASCOCHYTA BLIGHT IN RELATION TO LEAF TYPE IN CHICKPEA
Crop Sci., November 1, 2003; 43(6): 2291 - 2294.
[Abstract] [Full Text] [PDF]

Home page
 Agron. J.Home page
P. R. Miller, Y. Gan, B. G. McConkey, and C. L. McDonald
Pulse Crops for the Northern Great Plains: I. Grain Productivity and Residual Effects on Soil Water and Nitrogen
Agron. J., July 1, 2003; 95(4): 972 - 979.
[Abstract] [Full Text] [PDF]

Home page
 Agron. J.Home page
P. R. Miller, Y. Gan, B. G. McConkey, and C. L. McDonald
Pulse Crops for the Northern Great Plains: II. Cropping Sequence Effects on Cereal, Oilseed, and Pulse Crops
Agron. J., July 1, 2003; 95(4): 980 - 986.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
P.-h. Liu, Y. Gan, T. Warkentin, and C. McDonald
Morphological plasticity of chickpea in a semiarid environment
Crop Sci., January 1, 2003; 43(1): 426 - 429.
[Abstract] [Full Text] [PDF]

Home page
 Agron. J.Home page
A. M. Johnston, D. L. Tanaka, P. R. Miller, S. A. Brandt, D. C. Nielsen, G. P. Lafond, and N. R. Riveland
Oilseed Crops for Semiarid Cropping Systems in the Northern Great Plains
Agron. J., March 1, 2002; 94(2): 231 - 240.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Figures Only
Right arrow Full Text (PDF) Free
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Web of Science (55)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Miller, P. R.
Right arrow Articles by Neill, K. E.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Miller, P. R.
Right arrow Articles by Neill, K. E.
Agricola
Right arrow Articles by Miller, P. R.
Right arrow Articles by Neill, K. E.
Related Collections
Right arrow Other Legumes
Right arrow Dryland Cropping Systems

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
The SCI Journals Crop Science Vadose Zone Journal
Journal of Natural Resources
and Life Sciences Education		 Soil Science Society of America Journal
Journal of Plant Registrations Journal of
Environmental Quality		 The Plant Genome