星云湖径流区施肥对洋葱产量及不同土层养分残余量的影响

针对星云湖径流区蔬菜面积扩大、过量施肥,导致土壤养分残余量加大,对湖水质量产生影响的实际问题,采用田间试验研究不同施肥技术对洋葱产量的影响,探讨了试验前后不同土层养分变化情况。结果表明:不同施肥技术对洋葱产量影响不明显,以每公顷施N450kg、P2O50kg、K2O150kg,并采用10%氮肥及50%钾肥作基肥施于移栽沟中、20%氮肥移栽后15天兑水追施、70%氮肥及50%钾肥鳞茎膨大初期兑水追施的施肥技术产量最高。0～35cm层及35～50cm层的土壤速效N残余量随着施N量的增加而显著提高,而50～75cm层的土壤速效N残余量则略有降低;0～35cm层的土壤有效P及速效K的残余量相应地随着P2O5、K2O施用量的增加而显著提高,但耕作层以下的各层土壤有效P及速效K的残余量只是略有提高。

Effects of Onion Fertilization on Its Yield and Residual Amount of Soil Nutrient Among Different Soil Layers in Runoff Area of Xingyun Lake

In the light of realistic problem of lake water quality influenced by the increasing residual amount of soil nutrient, arising from the vegetable growing area and excessive fertilization in runoff area of Xingyun Lake, filed experiment was conducted to study the effects of fertilization technologies on onion yield and the changes of nutrient among soil layers before and after experiment. The results showed that the fertilization technologies had no obvious effect on onion yield, and the maximum onion yield was occurred in this fertilization technology (total 450 kg/hm2 nitrogen(N), 0 kg/hm2 P2O5 and 150 kg/hm2 K2O; first using 10% nitrogenous fertilizer and 50% potash fertilizer as base fertilizer, then applying 20% nitrogenous fertilizer 15 days after transplanting, lastly applying 70% nitrogenous fertilizer and 50% potash fertilizer in the initial stage of onion bulb expansion). The residual amounts of soil available N in this layers(0-35 cm, 35-50 cm) were significantly raising with the increasing of application amount of N, however, the case was slightly decreasing in 50-75 cm. The residual amounts of soil available phosphorus and potassium in 0-35 cm were significantly raising with the increasing of respective application amount of P2O5 and K2O, however, the case were slightly increasing among layers located under the cultivated horizon.