稻田不同种植模式对土壤养分表观平衡和氮素生产效率的影响

Effects of different planting patterns on the apparent balance of soil nutrients and nitrogen production efficiency in paddy soil

通过在湖南长沙双季稻田开展的冬闲-双季稻(CK)、黑麦草-双季稻(Ry-R-R)、紫云英-双季稻(Mv-R-R)和油菜-双季稻(Ra-R-R)4个种植模式的长期定位试验,分析不同种植模式对土壤养分含量、水稻产量、氮素生产效率和土壤养分表观平衡的影响.结果表明:Ry-R-R、Mv-R-R和Ra-R-R的土壤全氮和碱解氮含量显著高于CK,而土壤速效钾含量显著低于CK.与CK相比,Ry-R-R、Mv-R-R和Ra-R-R的晚稻氮肥偏生产力显著提升.Ry-R-R、Mv-R-R和Ra-R-R晚稻穗部的氮积累量显著高于CK;Ry-R-R、Mv-R-R和Ra-R-R茎叶的氮积累量均高于CK.Ry-R-R、Mv-R-R的水稻产量显著高于CK;水稻产量与土壤氮含量呈显著正相关.Ry-R-R、Mv-R-R的氮、磷盈余量显著高于CK;Ry-R-R、Ra-R-R的钾素盈余量显著高于CK.冬作物-双季稻模式提高了土壤养分含量和氮素生产效率,改善了土壤缺钾的状况,有利于维持稻田养分平衡,但土壤氮素盈余较多,还需减少氮肥的过量施用.

To investigate the effects of different planting patterns on soil nutrient contents,rice yield,nitrogen production efficiency,and apparent nutrient balance,a long-term field experiment was conducted in Changsha,Hunan,China.Four planting patterns were examined,including winter fallow-double cropping rice(CK),ryegrass-double cropping rice(Ry-R-R),Chinese milk vetch-double cropping rice(Mv-R-R),rape-double cropping rice(Ra-R-R).Compared with CK,soil total nitrogen(N)and available N were significantly higher under Ry-R-R,Mv-R-R and Ra-R-R.However,soil available potassium(K)content in CK was significantly higher than that in the other treatments.In addition,the N partial factor productivity in the late rice cropping was significantly higher under Ry-R-R,Mv-R-R and Ra-R-R.The N accumulation in panicles,stems and leaves of late rice under Ry-R-R,Mv-R-R and Ra-R-R were significantly higher than that in CK.Furthermore,the rice yield in Ry-R-R and Mv-R-R were significantly higher in comparison to CK.A significant positive correlation between grain yield and soil N content was observed.Compared with CK,Ry-R-R and Mv-R-R significantly increased the surplus of soil N and phosphorus content,but Ry-R-R and Ra-R-R increased the surplus of K content.Overall,winter crop-double rice cropping system could improve soil nutrient contents and N production efficiency,alleviate K deficiency,which would be beneficial to soil nutrient balance of paddy soils.Given the high surplus of N in paddy soils,N fertilizers should be reduced.