长期施用有机肥下稻田土壤磷素累积与迁移机理研究-以莲塘层母质发育的土壤为例

Soil phosphorous (P) accumulation and transport are closely correlated with soil P availability and P loss. In our past research based on a long-term fertilization experiment, organic manures increased more soil Olsen-P and P assimilation for rice compared to inorganic P fertilizers with the equal dose of P, but the soil total P in the plots treated with organic manures was higher than that with inorganic P fertilizers. This implies that the mechanism of soil P accumulation and transport affected by organic manures may be different from that affected by inorganic P fertilizers. Aiming at this unclear scientific problem, this project will be based on a long-term fertilization experiment to study the mechanism of P accumulation and transport in paddy soil derived from “Liantang layer” parent material under organic fertilization. Through combining research methods of the field observation, indoor culture, nuclear magnetic resonance detection and microbial diversity analysis, we will study the mechanism of P accumulation and transport in paddy soil under organic fertilization. Paddy soil, rice plant, water samples, and historical samples will be determined for P content and P form classification. Experiments of P adsorption and desorption will be carried out. Effects of soil organic matter, iron and aluminum oxide, pH, phosphatase activity, and rice field surface actual conditions on P accumulation and transport will be studied. Through NMR detection of  soil P micro molecular structure, analysis of soil microbial diversity in applications such as NGS, qPCR technology, the mechanism of soil P accumulation and transport caused by organic manures will be discovered. This study will provide theoretical and technical support for applying P fertilizers and manures in paddy soil and reducing non-point agricultural pollution.

土壤磷累积及迁移与土壤磷有效性及磷流失损失密切相关。申请者研究发现，在等磷量条件下，施用有机肥作物产量和吸磷量增加，而土壤全磷却比施用无机磷肥的高,暗示着有机肥对土壤磷累积和迁移机理与无机磷肥可能不同。针对这尚不十分清楚的科学问题，本项目以莲塘层母质发育的稻田长期（30多年）试验为基础，通过大田观测、室内培养、核磁共振检测与微生物多样性分析相结合方法，研究施用有机肥下稻田土壤磷素累积及迁移机理。结合历史样品并采集土壤、植株和水样，测定土壤磷素及形态分级；植株总磷；水样总磷、颗粒态磷。进行磷吸附解吸试验。研究土壤有机质、铁铝氧化物、pH、磷酸酶活性、稻田田面实际状况等对磷素累积及迁移的影响。通过NMR微观检测土壤磷素分子结构，应用NGS、qPCR技术分析土壤微生物多样性等，以期探索长期施用有机肥下莲塘层母质发育的稻田土壤磷素累积及迁移机理，为稻田合理施磷和减控农业面源污染提供理论和技术支持。

土壤磷累积及迁移与土壤磷有效性及磷流失损失密切相关。申请者前期研究发现，在等磷量条件下，施用有机肥作物产量和吸磷量增加，而土壤全磷却比施用无机磷肥的高,暗示着有机肥对土壤磷累积和迁移机理与无机磷肥可能不同。针对这尚不十分清楚的科学问题，本项目以莲塘层母质发育的稻田长期（30多年）试验为基础，结合历史样品并采集土壤、植株和水样，测定土壤磷素及形态分级；植株总磷;水样总磷、颗粒态磷。进行磷吸附解吸试验。研究土壤有机质、铁铝氧化物、pH、磷酸酶活性、稻田田面实际状况等对磷素累积及迁移的影响。通过NMR微观检测土壤磷素分子结构，应用NGS、qPCR技术分析土壤微生物多样性等，探索长期施用有机肥下莲塘层母质发育的稻田土壤磷素累积及迁移机理。.研究发现，施用磷肥提高耕层土壤全磷2-3倍、Olsen-P 5 -10倍、磷酸酶活性，施用有机肥提高更多，并随有机肥用量增加而增加，导致土壤磷素累积，NMR微观检测印证这结果。这增加了土壤磷流失风险。由于稻田田面实际状况包括植株下部触水部分、杂草及藻类生长等影响，施用有机肥和化学磷肥处理的种植水稻季磷流失相差不大，流失量665-713 mg P ha-1，流失率1.07%-1.15%。土壤有机质对增加土壤磷素累积与提高磷迁移的作用都有。土壤有机质既可封闭氧化铁铝表面磷吸附点位而减少磷的吸附，又可形成稳定的“Al-有机质-P络合物”及“Fe-有机质”络合物从而增加土壤吸附磷能力。本研究发现，土壤有机质利于磷素累积。施用有机肥提高土壤微生物多样性，也提高了聚磷菌功能基因丰度，有利于土壤磷素累积。土壤有机质含量提高，活化了土壤磷素供作物利用，同时又固持土壤磷素少受流失。.研究结果可为稻田合理施磷和减控农业面源污染提供理论和技术支持。