Dry matter accumulation,yield and nitrogen use efficiency of crops rotation and intercropping systems in Sichuan | 四川轮套作体系的干物质积累、产量及氮素利用效率研究

chinois. 以“小麦／玉米／大豆”、“小麦／玉米／甘薯”2种三熟套作体系和“小麦-大豆”、“小麦-甘薯”、“蚕豆玉米”3种两熟轮作体系为研究对象，通过2011和2012年2年的田间试验，探讨了不同种植模式下小麦、玉米干物质积累分配、产量、氮素利用效率和体系产量产值的变化。结果表明：套作小麦各时期地上部干物质积累量从拔节期后均显著高于单作小麦，套作玉米各时期干物质积累量与对应单作相比略有降低，但差异不显著；2种三熟套作模式中小麦／玉米、玉米／大豆和玉米／甘薯套作体系的土地当量比（I．ER）均大于l，具有明显的产量优势；与相应单作相比，玉米／大豆套作提高了体系的氮素利用效率（△NUEms〉0），平均提高38．5％，玉米/甘薯套作降低了体系的氮素利用效率（△NUEms〈0），平均降低46．0％；全年总收益2年平均以三熟套作“麦／玉/薯”体系最高，比三熟套作“麦／玉／豆”体系高13．1％，比两熟轮作体系小麦一甘薯、小麦大豆和蚕豆一玉米分别高14．7％、2．4％和41．2％。综上，三熟套作相对两熟轮作能提高体系产量和产值，与大豆套作能提高体系氮素吸收利用效率。

anglais. Crop intercropping or relay province, The wheat/maize/sweet pot systems. To assess the effect of differ and nitrogen use efficiency, two field -cropping is very popular and there are dozens of planting patterns in Sichuan ato and wheat/maize/soybean relay-cropping systems are two main intercropping ent planting patterns on crops grain yield, dry matter accumulation,output value experiments were conducted in 2011 and 2012 at SCAU experimental base in Sichuan,the experiment treatments included two triple-harvest ＂wheat/maize/sweet potato＂ and three double-harvest crop potato＂ and ＂faba bean-maize＂. The results showed that significantly higher than that of monoculture wheat after the intercropping systems as ＂wheat/maize/soybean＂ and rotation systems as ＂wheat-soybean＂, ＂wheat-sweet Dry matter accumulation of intercropping wheat was ointing stage, while dry matter accumulation of relay- cropping maize slightly decreased comparing to monoculture maize but with no significant difference during the whole growth period. The wheat/maize, maize/soybean and maize/sweet potato intercropping systems in the wheat/maize/ soybean and wheat/maize/sweet potato relaYTcropping systems had obvious production advantages with a LER （Land equivalent ratio）D1. Comparing to the relevant sole cropping, nitrogen use efficiency of the maize/soybean intercropping system increased （△NUEms〉0） by 38. 5% but nitrogen use efficiency of the maize/sweet potato intercropping system decreased （△NUEms〈0） by 46.0%. The highest average annual revenue for 2011 and 2012 was obtained from wheat/maize/sweet potato triple-harvest intercropping system. Comparing to the other four systems （wheat/maize/soybean triple-harvest intercropping system, and the wheat-sweet potato, wheat-soybean, faba bean-maize double-harvest rotation systems）, it added values by 13. 1%, 14.7%, 2.4% and 41.2% respectively. In conclusion, triple-harvest intercropping systems was much better than double-harvest rotation systems since it could improve yield and output value,and intercropping system with soybean could enhance nitrogen absorption and use efficiency.