黄土丘陵区不同耕作措施下春小麦和豌豆轮作水肥协同效应

摘要

Research has been undertaken using the validated Agricultural Production System Simulator Model (APSIM)to explore the synergy effects of water and fertilizer supply on grain yields of crops under different tillage practices in the loess hilly region of Dingxi City,Gansu Province.The model was used to simulate yields of rotational systems of wheat (Triticum aestivum )and pea (Pisum sativum )under three different tillage prac-tices:traditional tillage (T),no tillage (NT)and no tillage mulched with straw within 35 years (NTS).Multi-ple regression analysis was used to investigate the synergy effects of precipitation at the growing stage (X 3 ), fallow period (X 2 )and when nitrogen was applied (X 1 ).Results showed that the order of relevance to grain yields was X 3 >X 2 >X 1 .For X 3 and X 2 ,the contribution rate differed in the order of NTS>NT>T.Nitrogen application has an oppositive U-shaped quadratic relation with wheat and pea yield.The optimum nitrogen quantities were 65.0,65.5 and 44.5 kg/ha for spring wheat and 17.9,18.5 and 23.8 kg/ha for peas under T, NT and NTS respectively.The contribution of nitrogen to the grain yields of each rotational system followed the order NTS>NT>T for spring wheat and NTS>NT>T for peas.Precipitation was therefore the key fac-tor for the grain yields of spring wheat and pea in this region,especially in the case of NTS.Nitrogen applica-tion had different effects on yield under the three different tillage practices.%为探索水肥协同作用对不同耕作措施下作物产量影响规律，运用在黄土丘陵区率订和验证后的 APSIM（ag-ricultural production system simulator）模型，模拟研究区近35年传统耕作（T）、免耕（NT）和免耕覆盖（NTS）措施下轮作小麦／豌豆产量，并采用多元回归分析施氮量（X 1）、休闲期降水量（X 2）和生育期降水量（X 3）对小麦／豌豆模拟产量的水肥协同效应。结果表明，自然降水条件下3因素对不同耕作措施小麦和豌豆产量的贡献率均为：X 3＞X 2＞X 1。生育期降水量和休闲期降水量对产量的贡献率均为：NTS＞NT＞T。T、NT 和 NTS 措施下小麦和豌豆的产量与施氮量均呈开口向下二次抛物线型变化，但小麦最佳施氮量分别为65．0，65．5和44．5 kg／hm2，豌豆的最佳施氮量分别为17．9，18．5和23．8 kg／hm2，并且施氮量对小麦产量的贡献率为：NT＞T＞NTS，而施氮量对豌豆产量的贡献率为：NTS＞NT＞T。在甘肃省定西黄土丘陵区，决定小麦和豌豆产量的关键因素是降水，降水量对免耕覆盖的增产效应最为显著，且3种耕作措施条件下小麦和豌豆对施氮效应有不同的表现。