土壤Nmin在南疆棉花氮肥推荐中的应用研究

结合6个施氮水平下土壤Nmin速测值分析了土壤Nmin与施肥量和棉花产量关系,对应用土壤Nmin进行棉花氮肥推荐进行了研究。分析结果表明:土壤Nmin与棉花产量和施氮量均呈正相关关系,与土壤深度呈负相关关系;其中0~20cm土层土壤与施氮量和棉花产量相关性最强,可以很好的表征土壤初始供氮能力,因而可以利用它作为棉花氮肥推荐的指标。在考虑土壤初始供氮能力下,供试棉花品种达到最高产量时的最佳施肥量为226kghm-2,此时0~20cm土层土壤Nmin临界值为为20mgkg-1,并结合最佳施肥量和0~20cm土层土壤Nmin临界值计算出了棉花苗期、蕾期、花铃期的氮肥追施量。

The Study of Applying Soil Nmin to Cotton Nitrogen Recommendation

The relationship between soil Nmin and nitrogen application rate and cotton yield was analyzed based on soil Nmin value under 6 different nitrogen application levels,and applying soil Nmin to cotton nitrogen recommendation was studied. The results showed that the relationship between soil Nmin and cotton yield, and nitrogen application rate was positive, and the relationship between soil Nmin and soil depth was negative. The correlation between Nmin value in 0-20cm soil depth and nitrogen application rate, and cotton yield was most significant, which could denote the soil’ s N supply capability. So, Nmin in 0-20cm soil layer could be as an available index for cotton nitrogen recommendation. The best nitrogen application rate when cotton yield was the highest was 226kg hm-2, including the 0~20cm soil Nmin. And here, the critical Nmin value in 0-20cm soil depth was 20mg kg-1. The nitrogen application rate at seedling stage, bud stage, blossoming and boll-forming stage of zhong 35 were calculated based on the best nitrogen application rate and the critical Nmin value of 0-20cm soil depth.