HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Buerkert, A. Articles by Marschner, H. Search for Related Content PubMed Articles by Buerkert, A. Articles by Marschner, H. Agricola Articles by Buerkert, A. Articles by Marschner, H.

Post Stratification Clarifies Treatment Effects on Pearl Millet Growth in the Sahel

Inst. of Plant Nutrition, Univ. of Hohenheim, D-70593 Stuttgart, Germany
ICRISAT Sahelian Ctr., B.P. 12404, Niamey, Niger.
Inst. of Plant Nutrition, Univ. of Hohenheim, D-70593 Stuttgart, Germany

^* Corresponding author (buerkert{at}uni-hohenheim.de).

Spatial variation in the growth of pearl millet [Pennisetum glaucum (L.) R. Br.] over short distances is a problem in field experiments in the Sahel, but the causes are still poorly understood. Data from a 3-yr experiment with millet were used to compare four data types for their usefulness for reducing variation not related to treatment: (i) soil chemical data, (ii) residuals of the first year's yield data, (iii) a traditional fertility classification system, and (iv) plant vigor scores. The completely randomized experiment consisted of four factors combined to 48 treatments, replicated twice. There were three levels of millet crop residues (CR), two levels of broadcast P, and four genotypes; the fourth factor had two levels and varied over years. Whereas chemical analyses of the topsoil did not explain overall variation, residuals of plant scores used as covariates led to a reduction in residual variation of 32% for straw and 51% for grain yield in 1991. Most satisfactory, however, was the use of residuals of plant scores to classify plots into two strata of relatively low and high inherent soil productivity (a retrospective procedure called post stratification). In low-productivity plots, a CR application of 2000 kg ha^–1 (compared with 500 kg ha^–1) increased millet straw yield by an average of 42% and grain yield by 48% for the first 2 yr. In contrast, under high productivity, yields were barely influenced by treatments. The application of P, however, was equally effective in both productivity strata. The results show that vigor scores can be useful to clarify treatment effects on millet growth. The different responses of crop residues and P in the two productivity strata also indicate that nonchemical parameters such as soil mechanical resistance may contribute to soil microvariability in the Sahel.

Received for publication April 18, 1994.

This article has been cited by other articles:

				J.W. van Groenigen, M. Gandah, and J. Bouma Soil Sampling Strategies for Precision Agriculture Research under Sahelian Conditions Soil Sci. Soc. Am. J., September 1, 2000; 64(5): 1674 - 1680. [Abstract] [Full Text]

				A. Buerkert, A. Bationo, and K. Dossa Mechanisms of Residue Mulch-Induced Cereal Growth Increases in West Africa Soil Sci. Soc. Am. J., January 1, 2000; 64(1): 346 - 358. [Abstract] [Full Text]