水肥耦合对棉花产量、收益及水分利用效率的效应

研究滴灌施肥条件下水肥耦合对棉花籽棉产量、水分利用效率和净收益的影响,并运用多元二次回归与归一化及3种不同目标值组合方式相结合的方法,探索满足多目标综合效益最大化的滴灌水肥用量。采用田间试验的方法,于2012年和2013年棉花生长季,设置5个N-P2O5-K2O施肥水平150-60-30、200-80-40、250-100-50、300-120-60、350-140-70 kg/hm2(分别记为F150、F200、F250、F300、F350)和3个灌溉水平(60%ETC:W1、80%ETC:W2、100%ETC:W3,ETC是作物蒸发蒸腾量)。结果表明,籽棉产量、水分利用效率和净收益的水肥耦合效应明显,60%ETC灌水水平显著抑制籽棉产量并降低净收益,100%ETC灌水水平能够显著提高籽棉产量和净收益,但水分利用效率低于60%ETC灌水水平。2012年灌水量为100%ETC且施肥量300-120-60 kg/hm2(N-P2O5-K2O)时籽棉产量最高,但净收益并未增加,2 a灌水量为100%ETC且施肥量250-100-50 kg/hm2(N-P2O5-K2O)时的净收益最高。二次回归分析结果表明,3种组合方式均可用于水肥多目标优化,其中乘法组合方式2 a水肥投入量差异更小且各目标值变化也更小,2012年灌水量92%ETC、施肥量278-111-56 kg/hm2(N-P2O5-K2O)以及2013年灌水量90%ETC、施肥量268-107-53 kg/hm2(N-P2O5-K2O)可作为籽棉产量、水分利用效率和净收益综合效益最大化的水肥管理策略。

Effects of Water and Fertilizer Coupling on Cotton Yield, Net Benefits and Water Use Efficiency

The coupling effects of different water and fertilizer combinations on seed cotton yield, water use efficiency and net benefits under drip fertigation were studied in the field of Shihezi during the growing seasons in 2012 and 2013. Multivariate quadratic regression and normalization as well as three different target combinations were used and the optimal water and fertilizer combination that maximized the multi-objective benefits was explored. There were five N-P 2 O 5 -K 2 O fertilizer application rates (150- 60-30, 200-80-40, 250-100-50, 300-120-60, 350-140-70 kg/hm 2 ; denoted as F 150 , F 200 , F 250 , F 300 and F 350 , respectively) and three irrigation levels (W 1 : 60%ET C ; W 2 : 80%ET C ; W 3 : 100%ET C ; ET C represents crop evapotranspiration). The results showed that the coupling of water and fertilizer had significant effects on seed cotton yield, water use efficiency and net benefits. The treatment with low irrigation level (60%ET C ) significantly inhibited seed cotton yield and net benefits, while the treatment with high irrigation level (100%ET C ) significantly increased seed cotton yield and net benefits, but caused lower water use efficiency than that of the treatment with low irrigation level. The combination of irrigation with 100%ET C and fertilizer application rate of 300-120-60 kg/hm 2 (N-P 2 O 5-K 2O) in 2012 produced the highest seed cotton yield, but it did not increase the net benefits. Instead, the combination of irrigation with 100%ET C and fertilizer application rate of 250-100- 50 kg/hm 2 (N- P 2 O 5 - K 2O) produced the highest net benefits in 2012 and 2013. The quadratic regression analysis showed that the multiplication combination exhibited much smaller differences in water and fertilizer inputs in 2012 and 2013 than other combinations. The combination of irrigation with 92%ET C and fertilizer application rate of 278-111-56 kg/hm 2 (N-P 2 O 5 -K 2 O) in 2012, and the combination of irrigation with 90%ET C and fertilizer application rate of 268-107-53 kg/hm 2 (N-P 2 O 5 -K 2 O) in 2013 could maximize the overall multi-objective benefits of seed cotton yield, water use efficiency and net benefits. The results can provide new ideas for the multi-objective management of water and fertilizer in cotton fields under drip fertigation.