Lentil production under supplemental irrigation in a Mediterranean environment

Abstract

Lentil is a major winter-sown legume crop grown in the Mediterranean region, and has considerable importance as food, feed, and fodder. The crop’s high water demands coincide with the end of the rainy season. Thus, lentil often experiences considerable drought stress during reproductive development, which reduces yields. Limited supplemental irrigation (SI) can boost and stabilize productivity. The objective of this study was to elucidate the effect of limited irrigation and early sowing on yield and water productivity (WP) of lentil. An experiment was carried out over four cropping seasons (1996–2000) at ICARDA’s main station at Tel Hadya (Aleppo, northern Syria) where mean annual rainfall is 330 mm. A lentil cultivar (ILL 5883) was grown in rotation with wheat. The experiment included three sowing dates (early: mid November; normal: late December to mid January; and late: late January to mid February) and four levels of SI (full SI, 2/3 SI, 1/3 SI, and no SI). The results indicated that lentil grain and biomass yield increased with increased SI. Mean grain yield of 1.04 t ha −1 under rainfed conditions increased to 1.42 at 1/3 SI, 1.69 at 2/3 SI, and 1.81 t ha −1 at full SI, while mean water productivity was 0.44 kg grain m −3 water when rainfed, 0.54 at 1/3 SI, 0.6 at 2/3 SI, and 0.58 kg m −3 at full SI. Overall mean biomass production was 4.27 (rainfed), 5.35 (1/3 SI), 6.00 (2/3 SI), and 6.2 t ha −1 (full SI). The study’s results indicated that the 2/3 SI level gives the maximum water productivity for both grain and biomass under SI. Early sowing increased lentil biomass production by 0.47 and 1.56 t ha −1 over normal and late sowing dates. However, the highest grain yield of 1.60 t ha −1 was obtained at the normal sowing date. Grain water productivity with SI, however, increased when seeds were sown late in the season. Biomass water productivity, by contrast, increased with the earliness of sowing date—1.79 (late), 1.97 (normal), and 2.05 kg m −3 (early). Sowing date had the greatest impact on crop response under rainfed conditions. Finally, production functions relating lentil yield with field water supply under supplemental and rainfed conditions were proposed.