稻鸭生态种养系统直播水稻根表和根际土壤营养特性研究

采用田间小区试验对比分析了直播方式下稻鸭生态种养系统和水稻单一种植系统水稻根表和根际土壤的氮、磷、钾和有机碳含量及pH的变化。结果表明:与水稻单一种植系统相比,稻鸭生态种养系统水稻根表和根际pH分别升高4.41%、0.85%,全氮含量分别降低0.11g·kg-1、0.11g·kg-1,全磷和全钾含量变化不明显。水稻根表速效氮和速效钾含量分别增加30.80mg·kg-1、17.93mg·kg-1,速效磷含量降低8.66mg·kg-1;水稻根际速效氮和速效钾含量分别减少15.13mg·kg-1、7.61mg·kg-1,速效磷增加9.66mg·kg-1。稻鸭生态种养系统水稻根表活性有机碳和高活性有机碳分别增加2.17g·kg-1、0.56g·kg-1,全有机碳含量减少0.99g·kg-1;根际土壤全有机碳、活性有机碳和中活性有机碳含量分别减少2.39g·kg-1、2.64g·kg-1、0.72g·kg-1。稻鸭生态种养改变了速效磷、速效钾和活性有机碳在水稻根域土壤的相对富集部位,即速效钾和活性有机碳富集部位主要在根表土壤,速效磷则主要在根际土壤。表明稻鸭生态种养明显改善了水稻根表和根际土壤营养状况,这可能对水稻根系吸收和利用土壤养分具有积极意义。

Nutrition characteristics in root surface and rhizosphere soils of direct-seeding rice in rice-duck eco-farming system

Soil organic carbon, N, P, K contents and pH in root surface and rhizosphere soils of early season rice in rice-duck eco-farming system and mono-cropping rice system were investigated in a field plot experiment. The results show that the soil pH in root surface and rhizosphere of rice in rice-duck eco-farming system is increased by 4.41%, 0.85% and total N is decreased by 0.11 g·kg^-1, 0.11 g·kg^-1 compared with those in mono-cropping rice system, respectively, while changes in total P and total K contents are not statistically significant. Available N, available K in rice root surface soil in rice-duck eco-farming system are 30.80 mg·kg^-1, 17.93 mg·kg^-1 higher and available P is 8.66 mg·kg^-1 lower than those in mono-cropping rice system, however, available N and available K in rhizospere soil are 15.13 mg·kg^-1, 7.61 mg·kg^-1 lower and available P is 9.66 mg·kg^-1 higher than those in mono-cropping rice system. Compared with the mono-cropping rice system, in rice-duck eco-farming system, active organic carbon and high-active organic carbon in root surface soil are increased by 2.17 g·kg^-1 and 0.56 g·kg^-1 respectively, total organic carbon is deceased by 0.99 g·kg^-1, and total organic carbon, active organic carbon and mid-active organic carbon in rhizosphere soil are decreased by 2.39 g·kg^-1, 2.64 g·kg^-1 and 0.72 g·kg^-1, respectively. It is illustrated that in rice-duck eco-farming system, available K and active organic carbon are accumulated in root surface soil, and available P is accumulated in rhizosphere soil. Hence, soil nutrient status in root surface and rhizosphere in rice-duck eco-farming ecosystem are significantly improved, which probably have a good effect on nutrient absorption of rice.