紫色土氮素矿化作用和硝化作用对长期施肥的响应

Effects of Different Fertilization on Mineralization and Nitrification in Purple Soil

[目的]研究不同施肥方式对紫色土中氮素循环特性的影响。[方法]采用室内培养试验研究长期施肥对四川紫色土无机氮的动态变化、矿化作用和硝化作用的影响。[结果]与不施肥对照相比,长期施肥显著提高了紫色土的净矿化速率(P<0.05),不同施肥处理的平均净矿化速率分别为单施化学氮肥处理(NPK)≥猪粪处理(OM)>猪粪-化肥配施处理(OM-NPK)>秸秆-化肥配施处理(RSD-NPK)>秸秆处理(RSD)。秸秆处理(RSD)、RSD-NPK的平均净矿化速率为负值,表明长期施用秸秆促进了土壤无机氮的同化。与对照相比,长期不同施肥处理均显著刺激了紫色土的平均净硝化速率(P<0.05),其中以猪粪处理(OM)最高,为16.74mg/(kg·d),是CK(5.84mg/(kg·d))的2.87倍。与单施化学氮肥处理(NPK)相比,秸秆处理(RSD)显著抑制了硝化作用,平均净硝化速率下降了10.69%,但显著高于对照处理(P<0.05)。[结论]该研究为紫色土地区农业生产中肥料的合理施用提供科学依据。

[Objective]To analyze the effects of long-term different fertilization application on the nitrogen dynamic in the Sichuan purple soil.[Method]An in situ incubation experiment was conducted to investigate the effects of different N fertilizer regimes on mineralization and nitrification in purple soil.[Result]Long-term repeated applications of mineral or organic N fertilizer significantly stimulated soil net mineralization rates(P<0.05),which decreased in the order:mineral fertilizer NPK treatment(NPK)≥pig manure treatment(OM)>OM-NPK>RSD-NPK>crop straw treatment(RSD).However,the average net mineralization rate was-0.88,-0.39 mg/(kg·d),less than 0,in the crop straw(RSD),RSD-NPK treatment,indicating that addition of crop straw into soil promoted the immobilization of inorganic N.Compared with the unfertilized control(CK),long-term repeated applications of different fertilizer significantly stimulated soil net nitrification rates(P<0.05),with the highest value of 16.74 mg/(kg·d)in the pig manure treatment(OM)which was 2.87 times higher than that in the unfertilized control(CK)(5.84 mg/(kg·d)).In the crop straw treatment(RSD),the average net nitrification rate was 10.69%lower than that in the mineral fertilizer NPK treatment(NPK),but significant higher than that of the unfertilized control(CK).[Conclusion]The study can provide scientific basis for rational fertilization in the regions of purple soil.