绿肥与施氮量对土壤理化性质的影响

Effects of Green Manure and Nitrogen Application on Soil Physical and Chemical Properties

免耕覆盖直播技术是近年来发展起来的一种新型农业种植技术系统,以传统的绿肥施用为基础。本文主要研究DMC(direct seeding mulch-based cropping systems,免耕覆盖直播)技术系统下绿肥和施氮量对土壤理化性质的影响。绿肥选择紫云英(L1)、黄花苜蓿(L2)、蚕豆(L3)、百脉根(L4)及冬季休闲(L0)作对照的5个种植模式,稻田施氮量设为低(N1)、中(N2)、高(N3)3个水平,共15个处理组合。结果表明种植绿肥能够降低土壤容重,增加土壤有机质,提高土壤碱解氮、速效磷和速效钾含量。其中在L3模式下,土壤容重在覆盖作物季和水稻季分别比L0模式降低8.16%和6.37%,土壤有机碳含量在覆盖作物季和水稻全生育期比L0模式高8.20%～22.45%,差异有逐渐增大的趋势,碱解氮含量在覆盖作物季和水稻全生育期比L0高15.10%～25.82%。L2模式下土壤速效磷含量在水稻播种期最高达到了39.63mg/kg。施氮肥(N2)能显著提高土壤有机质和碱解氮含量,但多增施氮肥(N3)提高并不显著。

No tillage direct seeding mulch technique is a new planting system in recent years.Based on the traditional green manure,the effecst of green manure and nitrogen application on the soil physical and chemical properties in DMC（direct seeding mulch-based cropping systems） were investigated.Astragalus sinicus Linn（L1）,Medicago falcata L.（L2）,Vicia faba Linn（L3）,Lotus cornioulatus L.（L4） and the control were chosen as the green manure treatments.Rice nitrogen application amounts were set low（N1）,middile（N2） and high（N3） levels with 15 treatments and combinations.The results showed that the green manure could decrease the soil bulk density,increase the soil carbon and improve the levels of alkali hydrolyzable nitrogen,available phosphorus and potassium.Compared with L0 treatment,during green manure season and rice season,In L3 treatment,the soil bulk density decreased by 8.16% and 6.37%,soil organic carbon increased by 8.2% and 22.45%,alkali hydrolyzable nitrogen increased by 15.10% and 25.82%,respectively.In L2 treatment,soil available phosphorus level reached highest value of 39.63 mg/kg.Nitrogen application can significantly increase the soil organic carbon and alkali hydrolyzable nitrogen,But more nitrogen manure won′t definitely have more significant effects.