Managing Yield and Water Use of Pearl Millet in the Sahel

Abstract

Drought occurs often in the West African Sahel, but studies have shown that soil water availability is not usually the limiting factor to pearl millet [Pennisetum glaucum (L.) R. Br.] production, and that field water‐use efficiency (WUE)—i.e., the ratio of yield to evapotranspiration (ET)—is almost always very low. The purpose of this study was to determine management effects on yield and water use of pearl millet for a range of climate conditions in the Sahel. Grain and aboveground dry matter yield, daily vapor pressure deficit, and soil water data were taken during four years of contrasting rainfall. Within any given year, genotype, plant population, and fertilizer had relatively small to no effect on ET, but large effects on yield. When high plant population (≥20 000 hill ha−1) was combined with high fertilizer application (≥40 kg N ha−1 and ≥18 kg P ha−1) during the wettest year, total ET was increased by ≈50 mm. High fertilizer application tended to slightly increase ET and thereby deplete soil water reserves, but this was not associated with yield decline. Yield and water‐use data refute the view that, by maintaining fields at low fertility and low plant populations, farmers reduce risk of crop failure during drought by reducing crop water use. Compared with traditional practices that use plant populations as low as 5000 hill ha−1 and zero fertilizer input, moderate plant population (10 000 hill ha−1) and fertilizer application (20 kg N ha−1 and 9 kg P ha−1) substantially increased yield and approximately tripled WUE even during 1984, the driest year on record. In general, grain yield was better predicted from ET within different management categories when corrections were made for mean daily vapor pressure deficit during the growing season (VPD). The study provides evidence for the need to moderately increase pearl millet plant population and fertilizer application in the Sahel to efficiently use available water without risk of crop failure through depletion of soil water reserves. It also provides a practical, albeit empirical, basis for predicting yield under different management systems from seasonal ET and VPD data.

Hill placement of manure and fertilizer micro-dosing improves yield and water use efficiency in the Sahelian low input millet-based cropping system

“…Viets (1962) explained that since the evapotranspiration is little affected by the management, as was the case in the current study (data not presented), any factor that increases yield will increase WUE. These results are consistent with the earlier studies which reported an increment of millet water use efficiency in response to soil fertility management options in the Sahelian zone due to increase in biomass production (Akponikpé et al, 2008;Manyame, 2006;Payne, 1997;Yamoah et al, 2002). The results of the present study are also in agreement with the findings of Wang et al (2013) for maize.…”

“…Access tubes were installed in all the plots to monitor weekly soil moisture with a calibrated neutron probe from 0.15 to 2 m depth at 0.15 m intervals. The change in soil water storage in the root zone was calculated from the equation used by Payne (1997) as follows:…”

Modeling hydraulic properties of sandy soils of Niger using pedotransfer functions

“…We directly estimated K at the maximum rooting depth, Z r (1.4 m) using the two stage method proposed by Klaij and Vachaud (1992). Knowledge of K for this depth is needed to calculate root zone drainage and other soil water balance terms (Payne, 1997). In Klaij and Vachaud (1992), stage one represents the beginning of the season when the soil is wetting and the wetting front has not yet passed the bottom of the soil profile (1.8 m).…”

Water resources and their use in food production systems

“…In the same environment drainage is, in many cases, almost equal to the water lost as soil evaporation and transpiration (Gaze et al, 1997;Rockstrom, 1977). Such findings have led many to conclude that the efficiency with which water is used to produce crops could be significantly improved in many rainfed environments (Payne, 1997).…”