Ariel - Volume 4 Number 2

Editors David A. Jacoby Eugenia Miller Tom Williams Associate Editors Paul Bialas Terry Burt Michael Leo Gail Tenikat Editor Emeritus and Business Manager Richard J. Bonnano Movie Editor Robert Breckenridge Staff Richard Blutstein Mary F. Buechler Steve Glinks Len Grasman Alice M. Johnson J. D. Kanofsky Tom Lehman Dave Mayer Bernie Odd

Impact of tillage and fertility management options on selected soil physical properties and sorghum yield

Water and soil fertility are the most limiting biophysical factors affecting crop production in semi-arid West Africa. . This study was conducted in Nadion (south Sudan zone of Burkina Faso) to assess the impact of tillage practices (no-till, tied ridging; ripping and conventional tillage) combined with soil fertility management options (compost, NPK + Urea, crop residues, Compost+ NPK + Urea and a control) on soil moisture content and sorghum yield. The soil moisture was monitored weekly using the Time Domain Reflectometer (TDR) method and the soil bulk density was evaluated 30 days after planting. Zero tillage increased the soil water storage capacity compared to the other tillage practices at 0-30 cm depth. Sorghum straw residues application improved soil water content by 20%. Conventional tillage decreased surface soil (0-10 cm) bulk density. Compost + NPK + Urea application increased sorghum yield by 74% over the control while, NPK + urea and compost increased sorghum grain yield by 50% and 29%, respectively relative to the control (no soil amendment). Conventional tillage led to decrease in yield compared to zero tillage after two years of experimentation. The zero tillage combined with compost, NPK and urea increased sorghum yield by 28% compared to tied-ridging regardless of the fertility management options. Zero tillage is a promising option for sorghum production in the South Sudan agro-ecological zone of Burkina Faso.Keywords: Bulk density, fertility management, sorghum yield, South Sudan zone, tillage, water conservation

Integrated use of fertilizer micro-dosing and Acacia tumida mulching increases millet yield and water use efficiency in Sahelian semi-arid environment

Limited availability of soil organic amendments and unpredictable rainfall, decrease crop yields drastically in the Sahel. There is, therefore, a need to develop an improved technology for conserving soil moisture and enhancing crop yields in the Sahelian semi-arid environment. A 2-year field experiment was conducted to investigate the mulching effects of Acacia tumida pruning relative to commonly applied organic materials in Niger on millet growth, yields and water use efficiency (WUE) under fertilizer micro-dosing technology. We hypothesized that (1) A. tumida pruning is a suitable mulching alternative for crop residues in the biomass-scarce areas of Niger and (2) combined application of A. tumida mulch and fertilizer micro-dosing increases millet yield and water use efficiency. Two fertilizer micro-dosing options (20 kg DAP ha−1, 60 kg NPK ha−1) and three types of organic mulches (millet straw, A. tumida mulch, and manure) and the relevant control treatments were arranged in factorial experiment organized in a randomized complete block design with four replications. Fertilizer micro-dosing increased millet grain yield on average by 28 %. This millet grain yield increased further by 37 % with combined application of fertilizer micro-dosing and organic mulch. Grain yield increases relative to the un-mulched control were 51 % for manure, 46 % for A. tumida mulch and 36 % for millet mulch. Leaf area index and root length density were also greater under mulched plots. Fertilizer micro-dosing increased WUE of millet on average by 24 %, while the addition of A. tumida pruning, manure and millet increased WUE on average 55, 49 and 25 %, respectively. We conclude that combined application of micro-dosing and organic mulch is an effective fertilization strategy to enhance millet yield and water use efficiency in low-input cropping systems and that A. tumida pruning could serve as an appropriate mulching alternative for further increasing crop yields and water use efficiency in the biomass-scarce and drought prone environment such as the Sahel. However, the economic and social implications and the long-term agronomic effects of this agroforestry tree in Sahelian millet based system have to be explored further

Evaluation of early maturing cowpea (Vigna unguiculata) germplasm for variation in phosphorus use efficiency and biological nitrogen fixation potential with indigenous rhizobial populations

Cowpea genotypes that efficiently utilize phosphorus (P) with high potential for biological nitrogen (N) fixation (BNF) are vital to sustainable cropping systems in West Africa. A total of 175 early maturing cowpea genotypes were evaluated in 2010 and 2011 for P use efficiency (PUE) and BNF with an indigenous rhizobial population at Shika in the Northern Guinea savanna of Nigeria. There were significant genotypic variations for all 11 variables measured. The P utilization index, percentage N derived from the atmosphere and total N fixed ranged between 2·10–4·67, 31·3–61·86% and 11·86–50 kg/ha, respectively. The 175 early maturing cowpea genotypes were divided into five categories using principal component analysis (PCA), whereby total N fixed was associated with N and P uptake and plant biomass yield. Complete linkage cluster analysis revealed a total of three distinctive clusters having remarkable correspondence with the PCA. Some genotypes were identified as potential candidates for further breeding programmes using high PUE genotypes with relatively high capacity for BNF and indigenous rhizobial populations