控释氮肥对大白菜产量和品质的影响及其机理研究

Effects of controlled-release nitrogen fertilizers on yield and quality of Chinese cabbage and their related mechanisms

田间试验研究了控释氮肥不同品种及不同用量对大白菜产量和品质的影响,并从养分释放、包膜特性等方面探讨其作用机理。结果表明,控释氮肥能显著提高大白菜产量和品质。与同期追施等氮量尿素相比,施用控释氮肥可使大白菜产量提高8 2%～16 8%;莲座末期功能叶和收获期球叶NO-3-N含量分别降低14 3%～39 9%和12 1%～21 4%,收获期球叶Vc含量平均提高24 8%。控释氮肥用量减半后,大白菜产量及叶片NO-3-N与Vc含量都未受到显著影响。研究证实,由于控释氮肥中的氮素是缓慢地释放出来,在大白菜生育前期施用,仍能较充分满足生育中后期株体对氮素的需求,控释期不同的两个氮肥品种混合施用较单一施用的效果更好。不同控释氮肥品种氮素释放特征的差异与肥料包膜的厚度、膜断面及表面孔隙状况不同有关。

The effects of different controlled-release nitrogen fertilizers (CRNFs) supply on yield and quality of Chinese cabbage (Brassica campestris L. var. pekinensis) were studied in field experiment. Relationship between nitrogen release from CRNFs and nitrogen uptake by Chinese cabbage, and the characteristics of fertilizer coat were also discussed. The results showed that the yield of Chinese cabbage was significantly increased by 8.2%—16.8% with CRNFs application, compared to the urea supply. Vc content in the head leaves at harvest stage was 1.80(mg/kg) at average with CRNFs application, 24.8% higher than that of urea treatment. NO^-_3-N contents were significantly decreased by CRNFs treatments, which were 14.3%—39.9% lower in rosette leaves at rosette stage and 12.1%—21.4%in head leaves at harvest stage, compared to urea treatment. The yields, NO^-_3-N content and Vc content of Chinese cabbage leaf were almost changeless when CRNFs were half supplied. It was confirmed that nitrogen was released slowly and continuously from the inner part of CRNF granules. When CRNFs were applied at early stage, nitrogen was still supplied at medium and later stage for Chinese cabbage. The characteristics of nitrogen release of CRNF were apparently determined by thickness of granule coat, number and diameter of pores on coat surface.