平衡施肥对马铃薯-大豆套作系统中作物产量的影响

根据西北一熟制灌区土壤养分条件以及马铃薯-大豆系统中作物养分吸收互补的特点,选用马铃薯品种费乌瑞它和大豆品种冀豆12作为试验材料,设置3重复随机区组试验,小区处理最优施肥(OPT:N、P、K分别为180、135、135 kg hm~(–2))、最优减N(OPT-N)、最优减P(OPT-P)、最优减K(OPT-K)、最优减1/3N(OPT-1/3N)、最优增1/3N(OPT+1/3N)、最优减1/3P(OPT-1/3P)、最优增1/3P(OPT+1/3P)、最优减1/3K(OPT-1/3K)和不施肥(CK)10个处理。通过2012—2013连续2年大田试验,系统分析N、P、K对套作马铃薯及套作大豆产量及产量构成因素的影响。结果表明,OPT-N处理与OPT处理套作马铃薯产量差异最大(11 653.86 kg hm~(–2));OPT-P处理与OPT处理套作大豆产量差异最大(751.55 kg hm~(–2)),差异均达到显著水平(P0.05),说明影响套作马铃薯、套作大豆产量的最大的因素分别是N和P。随N水平递增,套作马铃薯产量呈现递增的趋势,OPT+1/3N处理产量最高为50 231.85 kg hm~(–2);套作大豆产量则呈现先增后减的趋势,OPT处理产量最高为3373.55 kg hm~(–2),方差分析表明,OPT和OPT+1/3N各处理套作马铃薯产量差异不显著,OPT-1/3N、OPT、OPT+1/3N各处理套作大豆产量差异不显著。随P素水平增加,套作马铃薯和套作大豆产量均呈现增加趋势,OPT+1/3P处理下套作马铃薯、套作大豆产量均最高,分别为52 430.03 kg hm~(–2)和3637.13 kg hm~(–2),同样在OPT+1/3P处理下,套作马铃薯平均单薯最重,套作大豆有效荚数、每荚粒数及单株粒数均最高,2年平均分别为185.13、74.24、1.87和139.15 g。综合考虑薯豆套作产量效应及养分利用效率,OPT施肥方案中,N适宜,P偏低,K偏高。

Effect of Balanced Fertilizer Application on Crop Yield in Potato-Soybean Relay-Cropping System

The treatments of optimum fertilization (OPT:N 180, P 135, K 135 kg ha–1), OPT-N, OPT-P, OPT-K, OPT-1/3N, OPT +1/3N, OPT-1/3P, OPT +1/3P, OPT-1/3K, and CK were designed according to soil condition and uptake characteristics of nitrogen, phosphorus and potassium of potato/soybean relay-cropping system in Northwest irrigation districts. A field experiment was conducted in two consecutive seasons (from 2012 to 2013) to verify the yield response to balanced fertilization. The relay-cropping potato yield of OPT was significantly higher than that of OPT-N, OPT-P, and OPT-K, with obvious difference of 11 653.86 kg ha–1 between OPT and OPT-N, the relay-cropping soybean yield of OPT was significantly higher than that of OPT-N, OPT-P, and OPT-K, with obvious difference of 751.55 kg ha–1 between OPT and OPT-P. Therefore, nitrogen and phosphorus were the first limiting factors in relay-cropping potato and soybean production. Under certain phosphorus and potassium fertilizer, the relay-cropping potato yield increased with increasing N application, reaching the highest of 50 231.85 kg ha–1 under 240 kg ha–1 treatment (OPT+1/3N), but there was no significant difference between OPT and OPT+1/3N. And the relay-cropping soybean yield increased firstly and decreased then with increasing nitrogen fertilizer application, with the highest yield of 3373.55 kg ha–1 under 180 kg ha–1 treatment (OPT), there was no significant difference between OPT, OPT-1/3N, and OPT+1/3N. Under certain nitrogen and potassium fertilizer, the yield of relay-cropping potato and soybean increased with the increase of phosphorus fertilizer application, and reaching the highest yield of 52 430.03 kg ha–1 and 3637.13 kg ha–1 under 180 kg ha–1 treatment (OPT+1/3P), respectively. For relay-cropping potato, average fresh-weight of individual tuber reached the highest under 180 kg ha–1 treatment (OPT+1/3P), which was 185.13 g. For relay-cropping soybean, the average of pods per plant, seeds per plant and seeds per pod reached the highest under OPT+1/3P, which were 74.24, 1.87, and 139.15 respectively. Therefore, nitrogen (N 180 kg ha–1) fertilizer was adequate, phosphorus (P 135 kg ha–1) fertilizer a little lacking, and potassium (K 135 kg ha–1) fertilizer on the high side in OPT treatment.