基于钾平衡和氮淋失风险的红壤猪粪安全用量

Safety amount of pig manure application based on potassium balance and nitrate leaching risk on red soil

我国红壤区土壤普遍缺钾。通过8a猪粪施用试验,研究了长期不施肥,长期施低量有机肥钾(59kg/(hm2·a)),高量有机肥钾(237kg/(hm2·a)),高量有机肥钾+石灰(有机肥钾237kg/(hm2·a)+石灰1000kg/(hm2·a))对红壤旱地钾平衡的影响,并结合氮淋失风险制定有机肥钾安全用量。研究表明,红壤旱地长期有机肥施用提高了土壤供钾能力,而不会增加钾淋失。施入土壤的有机肥钾超过69%被作物吸收,但低量有机肥处理导致土壤钾库不断耗竭,而高量有机肥和高量有机肥+石灰处理每年可向土壤补充钾48～57kg/hm2。针对单作玉米系统,保障作物钾需求和土壤钾库平衡的有机肥施钾量为180kg/hm2。若考虑有机肥施用的硝酸盐淋失风险,有机肥施钾量不能高于155kg/hm2,同时需补施25kg/hm2化肥钾满足作物生长、预防土壤钾库耗竭。

The effect of 8-year application of pig manure and lime addition on potassium balance was investigated on red soil（Udic Ferralsols） with maize monoculture in subtropical China.The content of soil available potassium,leaching and uptake of potassium were measured under different application rates of organic manure（0,59 and 237 kg/hm2 for CK,LM and HM treatment,respectively） and with lime addition（application rates of organic manure 237 kg/hm2 by lime addition 1 t/（hm2·a） for HML treatment）.The results showed that continuous manure application increased the content of soil available K and K supply capacity.The K leaching did not increase with increasing manure application rate.More than 69% of potassium from manure was taken up by crop and higher utilization efficiency was found in LM which ultimately resulted in depletion of soil potassium pool.On the contrary,high manure application（HM and HML） annually replenished 48-57 kg/hm2 with lower utilization efficiency.The manure application rate was 180 kg/hm2 when considering only crop K demand and soil K pool balance.Considering the nitrate contamination risk,the manure application should be controlled under 155 kg/hm2 with a supplement of 25 kg/hm2 by chemical fertilizer.