醋酸酯淀粉及与抑制剂结合包膜尿素在棕壤中尿素溶出特征

Traits of Urea Nitrogen Release from Starch Acetate Coated Urea and amended with biological inhibitors in meadow brown soil

在室内恒温培养条件下,以普通大颗粒尿素为对照,研究4种醋酸酯淀粉(SA)包膜及与生化抑制剂结合尿素肥料在草甸棕壤中尿素态氮溶出特征,以确定不同种SA包膜尿素在土壤中缓/控释效果及释放特征。研究表明,4种SA包膜尿素在土壤中尿素累积溶出量在28 d后达到最大值,接近100%,SA+UTRA、SA+DCD+UTRA、SA+NBPT+UTRA和SA+DCD+NBPT+UREA分别在12、16、12和16 d养分累积溶出量超过80%,是水中释放期的2倍左右,SA+UREA时段平均溶出率最高峰值出现在0～4 d,达到9.11%d-1,另3种包膜肥料均出现在5～8 d,为8.57%d-1～9.97%d-1。SA与DCD或NBPT结合包膜尿素对控制尿素释放作用效果十分显著,SA与DCD及NBPT结合型包膜尿素肥料对抑制尿素释放作用最强。

Using a conventional granular urea as control,the release characteristics of four kinds of urea nitrogen,which amended with biological inhibitors and/or coated by acetate starch,were examined under constant temperature incubation with Meadow Brown Soil in laboratory.The result indicated that the maximum accumulative urea nitrogen release rates of four starch acetate coated urea fertilizers were all observed after 28 days,and their values were nearly 100% of urea-N.The nutrient release amounts of SA ＋ UTRA,SA ＋ DCD ＋ UTRA,SA ＋ NBPT ＋ UTRA and SA ＋ DCD ＋ NBPT ＋ UREA were over 80% separately on the 12 d,16 d,12 d and 16 d,which were almost two times of release time in water.The maximum of average release rates per unit time from urea coated by starch acetate was up to 9.11 %/d between 0 and 4 d,and those of the other three coated fertilizers were between 8.57% d-1 and 9.97% d-1 from 5 to 8 d.The urea amended with DCD or NBPT coated by acetate starch showed a significantly slow release,and urea amended with DCD,NBPT and coated by starch acetate had the most significant slow-release effect.