Nouri Maman

Nitrogen Rate Influence on Pearl Millet Yield, Nitrogen Uptake, and Nitrogen Use Efficiency in Nebraska

Abstract Pearl millet is a potential dryland crop for Nebraska. Experiments were conducted in eastern Nebraska in 2000, 2001, and 2002, and in western Nebraska in 2000 and 2001. The objectives were to determine optimum nitrogen (N) rate, N uptake, and N use efficiency (NUE) for pearl millet. The hybrids “68×086R” and “293A×086R” and N rates of 0, 45, 90, and 135 kg N ha−1 were used. Hybrids had similar yield, N uptake and NUE responses. In western Nebraska in 2000, pearl millet yield response to N rate was linear, but the yield increase was only 354 kg ha−1 to application of 135 kg N ha−1. In eastern Nebraska, pearl millet response to N rate was quadratic with maximum grain yields of 4040 in 2001 and 4890 kg ha−1 in 2002 attained with 90 kg N ha−1. The optimum N rate for pearl millet was 90 kg N ha−1 for eastern Nebraska. For western Nebraska, drought may often limit pearl millets response to N fertilizer.

PEARL MILLET PRODUCTION PRACTICES IN SEMI-ARID WEST AFRICA: A REVIEW

Pearl millet ( Pennisetum glaucum L.) is an important grain crop for millions of poor farmers and consumers in the semi-arid region of West Africa. During the past 40 years, much research on pearl millet production practices and adoption in this region has been conducted, but an attempt to summarize these results has not been previously completed and these research results are not readily available to many West African scientists. This review was completed to address this need and integrate knowledge, and at the same time identify research needs for the future and extension priorities for semi-arid West African agro-ecological zones. Research has shown that selection of improved varieties and cropping systems, appropriate cultural practices, and recommended integrated soil, nutrient, residue and pest management can greatly increase grain and stover yields of pearl millet. However, adoption by farmers has been minimal due to limited profitability, high risk and labour demand, limited input supply, market availability and appropriate public policy. This review has 196 articles included as in-text citations ( Table 1 ) compared to 149 articles in the reference list, indicating that only one in four articles integrated two or more topics in the research. The obvious conclusion is that most of the past research has not addressed the ‘system’ but rather one or two management practices. In addition, most studies have interpreted responses in terms of yield without addressing other important considerations for farmer adoption. Recent conservation agriculture research moves closer to addressing the larger integrative types of research needed. Such research is complex and requires sustained funding for field and laboratory activities, but also for computer simulation modelling and economic assessment.

Optimizing Fertilizer Use by Smallholder Farmers and Economic Returns to Maize in Semi-arid Niger

Maize (Zea mays L.) is an important food crop in Niger, but low and irregular rainfall combined with sandy soils having low fertility level limit productivity. A two-year study was conducted at Institut National de Recherche Agronomique du Niger (INRAN) stations in Tarna/Maradi and Bengou/Gaya in 2014 and 2015 in order to evaluate maize agronomic and economic fertilizer use efficiency. The experimental design was a randomised complete block design (RCBD) with three replications. Results indicate higher effect of fertilizer in 2015 compared to 2014. At low N rates 20 kg N/ha and 40 kg N/ha, application of 20 kg P/ha increased maize grain yield across locations and years. The highest agronomic efficiency of N (AEN) was recorded with 60 kg N/ha in 2015 at Bengou and Tarna with 9.65 kg and 14.05 kg grain yield per kg of applied N, respectively. At Tarna, the low N rates of 20 kg N/ha and 40 kg N/ha recorded important AEN of more than 12 kg yield increases per kg of applied N. The highest rainfall use efficiency (RUE) of 6.13 kg/year/mm was obtained with application of 80 kg/ha N, 0 kg/ha P and 40 kg/ha N, 20 kg/ha P in 2015 at Tarna. Without P, the highest value cost ratio (VCR) value of 4.31 was recorded at Tarna in 2015 with 60 kg/ha N, and the lowest value of 0.08 at Bengou in 2014 with 20 kg/ha N. Based on VCR and RUE derived from this study, the optimal fertilizer recommendation for maize in the semi-arid conditions of Niger could be 40 kg/ha N, 20 kg/ha P and 0 kg/ha K.