西北灌区薯/豆连续套作对系统产量及土壤肥力的影响

探求马铃薯/大豆连续套作下复合群体产量优势,为实现持续高产的生产目标提供理论和技术依据。2011-2014年,在西北沿黄灌区会宁县郭城镇,选用马铃薯品种克新4号和大豆品种冀豆17作为试验材料,设置马铃薯连作(PM)、大豆连作(SM)、薯-豆轮作(P-S)、薯/豆套作连作(IC)和薯/豆套作轮作(IR)5种种植方式开展大田定位试验,研究不同种植模式连续种植4年对系统产量及产量构成的影响,分析系统生产力及土壤肥力的变化特点,进而揭示薯/豆套作系统的生产价值。结果表明,1)薯/豆套作具有明显的产量优势,4年间,IC和IR系统产量与连作相比,分别提高了28.54%~254.07%和39.39%~283.98%,与轮作相比,分别提高了57.51%和70.81%。2011和2012年,IC与IR系统产量间差异不显著,但IC和IR与PM、SM、P-S处理间系统产量差异达到显著水平(P0.05),2013和2014年IR系统产量均最高,分别达到9912.79和9589.90kg/hm2,较IC处理分别提高了15.38%和8.45%,且与其他处理间均差异达到显著水平(P0.05)。2)不同种植模式在年际间变化显著,对于PM,2012年(连作1年)与2011年(正茬)产量差异不显著,而2013年(连作2年)和2014年(连作3年)产量较2011年分别下降了22.07%和42.11%;SM和IC变化趋势与PM表现一致,连作2年后,降幅分别为31.15%~53.60%和13.91%~24.17%;对于P-S和IR而言,年际间系统产量无显著变化。3)不同种植模式对耕层土壤肥力性质指标的影响程度是:有效磷碱解氮全氮全磷速效钾有机质全钾pH。较PM、SM和P-M,IC和IR连续套作4年,耕层土壤全氮、全磷、全钾、碱解氮、有效磷和速效钾呈下降趋势,尤其是有效磷和速效钾,下降幅度分别达到26.24%~42.87%和18.48%~30.22%。马铃薯和大豆连作2年后产量显著下降,薯/豆连续套作4年(IC或IR),相对于连作或轮作具有明显的生产力优势,尤其是薯/豆套作轮作模式,基于养分吸收量的增加和养分利用效率的提高,连续4年系统产量相对稳定。

Crop yield and soil fertility affected by continuous potato/soybean intercropping systems along the Yellow River

The objective of this work was to explore the mechanisms for the yield advantage of a potato/soybean continuous intercropping system.Potato,variety Kexin 4 and soybean,variety Jidou 12 were used in a longterm field experiment undertaken from 2011 to 2014 in Guochen,Huining County,Gansu Province in the Northwest irrigation district.The treatments included potato monocropping (PM),soybean monocropping (SM),potato-soybean rotational system (P-S),potato/soybean continues intercropping (IC) and potato/soybean rotational intercropping (IR).The influences of different cultivation systems on crop yields and soil fertility were analyzed.Continuous intercropping systems produced higher yields;IC and IR treatments enhanced yield by 28.5％-254.1％ and 39.4％-284.0％ compared with PM and SM,respectively and by 57.5％ to 70.8％ compared with P-S.There was no difference in yield between IC and IR in 2011 and 2012 but in 2013 and 2014 IR yield was significantly higher than those of PM,SM,IC and P-S,achieving 9913 kg/ha and 9590 kg/ha,respectively.Cultivation system influenced yield over time.For PM,yield was stable after 1 year but declined significantly by 22.1 ％ and 42.1％ after two and three years of continuous cropping,respectively.The SM and IC treatments significantly reduced yields by 31.2％-53.6％ and 13.9％-24.2％ after two years,respectively.The P-M and IR treatments did not influence yield over the four years of the study.Topsoil fertility was improved to some extent by different cultivation systems;Olsen P＞available N＞total N＞total P＞available K＞organic carbon＞total K＞pH.Topsoil fertility in the IC and IR treatments decline after four years of continuous cropping compared with PM,SM and P-S;Olsen P and available K decreased by 26.2％-42.9％ and 18.5％-30.2％,respectively.The results of this study showed that potato/soybean intercropping systems (IC or IR) produced better yields after four years of continuous cropping compared with monocropping and rotational cropping with the potato/soybean rotational intercropping system clearly superior.