鄂中地区油菜-水稻轮作制度中的氮肥适宜用量

Optimum Application Rate of Nitrogen Fertilizer in Rapeseed-rice Rotation System in Central Hubei

为明确鄂中地区油菜-水稻轮作条件下适宜的氮肥施用量,在水稻土上进行油菜-水稻轮作中不同氮肥施用量对作物产量及土壤碱解氮含量影响的田间试验。结果表明,在土壤碱解氮为125mg/kg的中等肥力水稻土,施氮肥后的增产率油菜为3.9%-41.5%,水稻为7.3%-42.5%,全年8.3%-41.3%;氮肥最高施用量为水稻78.1kg/hm^2,油菜62.3kg/hm^2,全期72.4kg/hm^2;氮肥最佳施用量为水稻75.8kg/hm^2,油菜58.0kg/hm^2,全期70.9kg/hm^2。土壤碱解氮与油菜、水稻施氮增产率符合二次曲线关系,土壤施氮前后碱解氮增量与施氮量符合线性关系。

To explore the optimum application rate of nitrogen fertilizer in rapeseed-rice rotation system in central Hubei,a field experiment was conducted in paddy soil to explore the effects of various N application amount on crop yield and soil alkali-hydrolyzable nitrogen content.Results：In medium-fertility paddy soil with soil available N 125 mg/kg,after applying N fertilizer the yield increasing rate was respectively 3.9%-41.5%（rape）,7.3%-42.5%（rice）and 8.3%-41.3%（whole year）;The maximum N application amount was separately 78.1 kg/hm^2 （rice）,62.3 kg/hm^2 （rape）and 72.4 kg/hm^2 （whole period）;The optimum N application amount was 75.8 kg/hm^2 （rice ）, 58.0 kg/hm^2 （rape ） and 70.9 kg/hm^2 （whole period）respectively.Soil available N was of conical relationship with rape and rice yield increasing rate. Soil available N increment before and after applying N fertilizer has linear relationship with N application amount.