Paired-row planting and furrow irrigation increased light interception, pod yield and water use efficiency of groundnut in a hot sub-humid climate

摘要

Increasing scarcity of irrigation water calls for enhancing water use efficiency (WUE) of crops, and improved planting method is a potential option. Field experiments were conducted for 3 years to evaluate effects of three planting methods of groundnut viz. flat-bed, ridge and furrow and paired-row at four irrigation regimes viz. 1, 2, 3 and 4 irrigations. Ridge and furrow, and paired-row methods resulted in an increase in pod yield by 13 and 17% and irrigation water saving by 26.7 and 41.7%, respectively compared with flat-bed method. Although highest yield level was similar in ridge and furrow and paired-row methods with four irrigations, irrigation water was 28.4% less in the latter than the former. In the three irrigation x paired-row method, pod yield reduced by only 3.8%, whereas water saving was 26.9% compared to the four irrigations x paired-row method. Better root dry weight, greater intercepted photosynthetically active radiation, chlorophyll fluorescence (Fv/Fm and Phi PS II) and rate of leaf photosynthesis contributed to higher yield and nutrient uptake under paired-row at higher irrigation regime than traditional flat-bed method. Although evapotranspiration (ET) increased with higher irrigation regimes; ridge and furrow and paired-row method decreased ET by 13 and 21%, and increased crop WUE by 32.6 and 48%, respectively over flat-bed. The pod yield (Y)-ET functions were found linear; it has been revealed that the crop will achieve maximum pod yield (2109 kg ha(-1)) with 359 mm ET under paired-row planting. Computed elasticity of water production and crop yield response factor could well be used for making irrigation decisions. This field study confirmed that paired-row planting and furrow irrigation had increased pod yield, saved water and enhanced WUE of groundnut under hot sub-humid conditions.