绿肥压青下粉垄水稻土壤的水肥迁移及生态效应研究

Guangxi is the main production area of double cropping rice. In order to increase output nowadays over-reliance on chemical fertilizers for increase multiple cropping index has caused soil compaction，low fertilizer efficiency， habitat worsening problems which can not be ignored. Method of the winter green manure dressing is the the effective way of paddy field conservation in the southern rice region. Smash-ridging cultivation increase the rice yield, but there are rare research about water and fertilizer migration ecological effect of smash-ridging rice yield under green manure dressing. Our research plan to combine agricultural machinery and agronomic, use different soil type as research object, based on smash-ridging rice location test under green manure dressing, the project will show the results :(1)soil water and fertilizer combine migration and transformation law of smash-ridging rice under green manure dressing; (2)soil organic compounds migration and transformation law of smash-ridging rice under green manure dressing; (3)soil environmental change law and ecological effect of smash-ridging rice under green manure dressing. Briefly introduce the water and fertilizer migration law and ecological effect of rice paddies under green manure dressing and smash-ridging cultivation. Also the research reveal smash-ridging rice yield soil mechanism under green manure dressing. Our research provide the use of green manure under smash-ridging rice cultivation condition. Realization reducing fertilizer and synergism. Our research also provide theoretical basis and practical basis of sustainable rice cropping.

广西是双季稻主产区，过分依赖化肥提高复种指数增加产出，引发稻田土壤板结、肥效低、生境恶化不容忽视。南方稻区冬绿肥压青还田是稻田保育的有效手段，粉垄耕作技术促进水稻增产，但有关绿肥压青下粉垄水稻增产的水肥迁移生态效应鲜有研究。本项目拟通过农机与农艺结合，以不同土壤类型为研究对象，绿肥压青下粉垄水稻定位试验为基础，研究（1）绿肥压青下粉垄水稻土壤水肥迁移和转化规律；（2）绿肥压青下粉垄水稻土壤有机物迁移和转化规律；（3）绿肥压青下粉垄水稻土壤的环境变化规律与生态效应。初步阐明绿肥压青与粉垄耕作对水稻土壤的水肥迁移规律和生态学效应，揭示绿肥压青下粉垄水稻增产的土壤机理，为粉垄水稻栽培条件下绿肥利用、农田减肥增效、稻作可持续发展提供理论基础和实践依据。

绿肥压青还田是调控现代集约化稻田的重要手段。粉垄耕作是近年来发展起来的一种新型农田深旋耕技术，采用螺旋型钻头刀片横向切割土壤，可实现绿肥、秸秆同步还田，是对传统耕作模式的重大变革。开展绿肥压青与粉垄耕作优化研究具有重要意义。本研究采用粉垄耕作与常规耕作2 种耕作模式，不施肥和同等肥力条件下施化肥、单倍绿肥配施化肥和双倍绿肥配施化肥4 种施肥处理，晚稻免耕常规施用化肥，开展双季稻周年大田定位应用试验。评估和揭示绿肥还田对粉垄稻田水肥分布、土壤耕层结构及土壤环境效应及耕层土壤碳库的影响机制。获得的主要结论如下：.（1）绿肥压青下粉垄耕作影响当季及后季稻田土壤紧实度和稳定入渗率，利于提高土壤耕层纳水和通气性，后延效应明显。.（2）粉垄耕作在绿肥压青腐解初期就可以降低田面水和渗漏液氮素浓度，对磷素浓度影响不显著，绿肥压青下粉垄耕作能减少稻田氮、磷流失。.（3）粉垄耕作可显著降低当季整季稻田土壤脲酶、磷酸酶活性，绿肥化肥配施处理提高粉垄稻田土壤脲酶、磷酸酶活性。 .（4）绿肥还田增加了粉垄耕作稻田耕层土壤微生物量碳的环境复杂性和生物多样性，绿肥压青下粉垄耕作显著提高了土壤微生物量碳含量，但对土壤微生物量氮影响不明显。.（5）垄耕作降低了耕层土壤砂粒含量，单倍绿肥粉垄耦合稳定了稻田不同耕层土壤团粒形成，绿肥粉垄耦合提高了0~15 cm土壤颗粒含量，单倍绿肥提高了土壤黏粒含量，双倍绿肥对粉粒含量的提升更为明显。.（6）绿肥还田影响粉垄稻田土壤微形态特征，粉垄耕作下土壤超显微呈现立式蓬松状，单倍绿肥粉垄耦合呈旋转态，双倍绿肥粉垄耦合呈絮状伸展状。.（7）绿肥粉垄耦合促进了土壤团聚体的形成，单倍绿肥粉垄耦合下稻田的土壤微团聚体、中团聚体含量高于双倍绿肥。.（8）粉垄耕作降低了稻田耕层土壤有机碳含量，绿肥还田可降低粉垄稻田温室气体综合增温潜势，有效提高土壤碳库管理指数，绿肥粉垄耦合有助于推进双季稻田土壤有机碳的稳效利用。