Yield of Grain Legumes as Affected by Irrigation and Fertilizer Regimes1

Abstract Chickpeas, cowpeas, and dry beans were grown under different soil moisture levels with split plot treatments of no fertilizer, N, P, and NP. Irrigations were given when 1/3, 2/3, and approximately all of the available water in the root zone was depleted. These moisture stresses were applied during different stages of plant growth. High moisture stress reduced grain yields 18 to 26% below the maximum values. This yield depression was most pronounced when the moisture stress occurred during bloom and early maturity. Yields for the medium and high moisture levels were statistically equal. Response to phosphorus fertilization varied with the field sites. Where phosphorus resulted in sizeable yield increases, high soil moisture increased the response to phosphorus and vice versa. The effect of nitrogen fertilization was not significant.