湖北省油菜氮肥效应及推荐用量研究

通过15个田间试验研究湖北省油菜主产区氮肥效应和适宜用量。结果表明适量施用氮肥对油菜具有明显的增产增收效果，施氮比不施氮对照增收油菜籽402~2759kg/hm2，平均增产1270kg/hm2，平均增产率达133.0%；施氮纯利润平均为3403元/hm2，产投比平均达6.00；氮肥偏生产力和农学利用率平均分别为17.6kg/kg N和8.0kg/kg N。根据肥料效应方程，在当前生产条件下，油菜生产的氮肥最佳经济用量为120.1~325.4kg N/hm2，平均用量为199.6kg N /hm2。土壤碱解氮含量与油菜氮肥最佳经济推荐用量呈极显著负相关性（r﹦﹣0.7734**，n﹦12），根据土壤碱解氮含量（x，单位为mg/kg）水平，湖北省目前油菜生产适宜用氮量（y，单位为kg/hm2）可通过公式y﹦553.72﹣74.699Ln（x）求得。

Study on effect of nitrogen application and recommendation of optimal N application for rapeseed in Hubei

15 field trials were carried out to study the response to nitrogen (N) and the optimal result from N application were recommended for rapeseed in Hubei province. The results showed that N application significantly increased both rapeseed yield and profit. Yield increment ranged from 402kg/hm2 to 2759kg/hm2, the average increment was 1270kg/hm2. This was a 133.0 percent increase compared with the control which has no N application. The average net profit of N application was 3403Yuan/hm2 and the value cost ratio (VCR) was 6.00. The average partial factor productivity of applied N (PFPN) and agronomic N use efficiency (ANUE) were 17.6kg/kg N and 8.0kg/kg N respectively. According to fertilizer response equations, the economical N application rates were 120.1kg/hm2 to 325.4 kg/hm2, with the average rates 199.6kg/hm2. The result indicated that the economical N application rates had significant negative correlation with soil available N level and the correlation coefficient (r) was 0.7734 (n=12). The economical N application rates of rapeseed can be obtained through the equation y=553.72- 74.699Ln(x) (y is applied rate of N and x is soil available N content.) in Hubei Province.