ENHANCING WATER PRODUCTIVITY WHILE IMPROVING PEANUT KERNEL QUALITY BY WATER REGULATION UNDER DIFFERENT NITROGEN LEVELS

In order to improve the water productivity and kernel quality of peanut, a lysimeter experiment was conducted from 2014 to 2015 to evaluate the effects of nitrogen (N1: 75 kg ha(-1), N2: 150 kg ha(-1), N3: 225 kg ha(-1)) and irrigation regimes (W1: severe deficit, W2: moderate deficit, W3: full irrigation) on the photosynthetic traits, water productivity and kernel quality of peanut. Results show that optimal N rates enhanced chlorophyll content, photosynthetic rate, transpiration and stomatal conductance, while these traits decreased with an increase of soil water stress. N2W2 treatment significantly (p < 0.05) increased water productivity by 52 and 45% relative to W3N3 over the 2 years respectively. Although the N2W2 and N2W3 treatments produced the highest yields, water consumption of the N2W3 treatment was significantly higher than that of N2W2. Protein content (PC), crude fat content (CF) and oleic acid content (OA) increased with N input. However, the N3 treatment significantly lessened the OA/LA (linoleic acid) compared with N1. CF, OA (in 2015) and OA/LA were significantly increased by alleviated W stress which was completely contrary to PC and LA. For maximum economic benefit ($5870 ha(-1)), W2N2 was recommended as comprehensively improving yield, kernel quality and water productivity of peanut. (c) 2020 John Wiley & Sons, Ltd.