【作者】 通乐嘎；

【导师】 曹凑贵；

【作者基本信息】 华中农业大学 ， 生态学， 2010， 硕士

【摘要】 免耕是实现低碳经济的一项重要农业措施；水稻是湖北省主要粮食作物之一,稻田免耕已得到了大面积的推广,但对于稻田免耕磷素养分循环的研究还不完善,本研究旨在探究该地区免耕稻田的磷素转化特征,为免耕技术的进一步优化提出理论依据。于2008年与2009年,选取湖北省武穴市油菜-水稻轮作制度下稻田为研究对象,通过大田试验与室内分析研究了免耕稻田水体与土壤的磷素转化特点及对环境的影响。试验共设4个处理,分别是免耕+不施肥(NTO)、翻耕+不施肥(CTO)、免耕+复合肥(NTC)和翻耕+复合肥(CTC)。主要研究了田面水、渗漏水的磷素动态与渗漏损失,施肥与耕作对土壤不同土层的速效磷(OP)、全磷(TP)的影响,耕作与施肥对磷酸酶活性的影响,耕作与施肥对有机磷(OP)和无机磷(IOP)及其组分的影响,施肥与耕作对土壤磷的吸附-解析特性与土壤固磷能力的影响。主要结论有：1)渗漏水溶解磷(RP)/渗漏水总磷(TP)在61.13%～92.74%范围,说明稻田肥料磷主要以可溶态磷下渗；施肥显著提高稻田田面水的磷素浓度,施肥后NTC和CTC田面水TP浓度分别达到9.79±0.65 mg/L和8.25±0.29 mg/L,一周后显著下降,施肥后一周内是控制田面水磷素径流损失的关键时期；在施磷肥后,田面水溶解磷(DP)的浓度达到稳定后仍保持在0.04mg/L-0.1 mg/L,渗漏水RP浓度在0.047 mg/L～0.117mg/L,超过了水体富营养化的临界值,表明这部分磷对环境的影响是不可忽视的；处理NTC田面水各形态磷素浓度均显著高于CTC处理。2)施肥显著增加了稻田土壤0～5 cm土层的AP和TP含量,在土壤中呈现上高下低的分布,且这种随土层加深而含量降低的趋势免耕较翻耕明显。在施肥条件下TP有逐年增加的趋势；免耕没有影响0～5 cm土层的TP和AP；但免耕施肥TP显著高于翻耕施肥处理；而翻耕施肥AP显著高于免耕施肥；施肥与耕作不影响5～20 cm土层的AP与TP。3)免耕有利于提高磷酸酶活性,施磷肥有抑制磷酸酶活性的趋势。土壤磷酸酶活性在土层中的分布与AP分布相似,但是通过相关分析在表土层与AP没有相关性,而在深土层与AP呈现出显著正相关。4)施肥在表层土上降低了土壤磷固定能力。施肥降低了土壤的磷缓冲能力与对磷的吸附,增加了解析能力,但吸附与解析并不是简单的相反过程。在不施磷肥的条件下,免耕比翻耕促进土壤磷缓冲能力的增加；在翻耕条件下施肥降低了土壤磷缓冲能力,但在免耕的条件下,施肥增加了土壤磷缓冲能力。5)施肥与耕作不影响TOP含量。OP含量高低顺序为：MLOP>HROP>MROP>LOP;施肥抑制OP各组分转化动态向LOP方向进行。免耕促进了LOP的转化。MLOP是较活跃的一个组分,向LOP与MROP和HROP的转化都比较活跃。IOP含量高低顺序为：Fe-P, O-P>Al-P>Ca-P;水稻收获后的TIOP含量较水稻种植前的TIOP含量降低。Al-P与Fe-P的有效性较高,翻耕促进Al-P与Fe-P的转化。免耕土壤磷的有效性高于翻耕。更多还原

【Abstract】 Rice was one of the major Grain crops in Hubei province China. The no-tillage is an important agricultural practices to implement low-carbon economy. No-tillage had implemented promotion over large areas, but the study of paddy tillage is not perfect. This study aimed to explore P transformation in no-tillage (NT) paddy fields in the region and contribute to further optimization of no-tillage technology. Test point was located at Hubei Province Wuxue City was rape-rice rotation system in 2008 and 2009. The four treatments in this study were no-tillage+no fertilizer (NT0), conventional tillage+no fertilizer (CT0), no-tillage+compound fertilizer (NTC) and conventional tillage+ compound fertilizer (CTC) in rice (Oryza sativa L.) cultivation. This study was conducted to Mainly studied floodwater and percolation water P dynamics, leakage losses and effects of tillage and fertilizer on available phosphorus (AP), total P (TP), phosphatase activities, organic P (OP) and inorganic P (IOP) and their fractions, soil P adsorption-desorption and solid ability to fixed P et al. The results indicate:1) Reactive phosphorus (RP)/total phosphorus (TP) in Percolating water was 61.13%-92.74%, was mainly P state in percolation water; Application of P fertilizer significantly enhanced concentration of TP, dissolved P (DP) and particulate phosphorus (PP) concentrations in floodwater, in witch concentration of TP respectively came up to 9.79±0.65 mg/L和8.25±0.29 mg/L in NTC and CTC. It was the key time in one week after P application to control P losser; P fertilizer applied, floodwater DP concentrations remained 0.04 mg/L-0.1 mg/L, leakage of water RP concentration remained 0.047 mg/L-0.117 mg/L, contributed to eutrophication, indicated that this part of the environmental impact of phosphorus can not be ignored; P concentrations in floodwater is higher in NTC than CTC.2) P application significantly increased AP, TP in 0-5cm layer soil, their content decreased with layer deepened, and this tendency was more significant in NT than CT. TP content increased year by year in CT. NT did not afect AP and TP in 0-5cm layer soil, but TP is significantly higher in NT than that in CT, while AP is significantly higher in CT than that in NT. Fertilizer and tillage did not affect AP and TP in 5-20cm layer soil.3) P application restrained Soil phosphatase activity, NT promoted soil phosphatase activity. Distribution of Soil phosphatase activity in the soil was similar to AP, but phosphatase activity was not relevant to AP in surface soil, while relavant toAP in deep soil by correlation analysis.4) P fixed capacity of the soil is relatively stable, was not subject to fertilization and tillage. P application reduced the P buffering capacity and adsorption, while increased the desorption capacity, but adsorption is not a simple contrast with desorption. Buffering ability in NTO higher than that in CTO, in CTO was higher than that in CTC, in NTC was higher than that in NTO.5) Fertilizer and tillage did not affect the TOP content. The content of OP fractions and ratio of each fractions to TOP were as follows:Moderately labile organic P (MLOP)> moderately stable organic P (MROP)>highly stable organic P (HROP)> labile organic P (LOP). Fertilizer restrained the transformation of LOP. Tillage promoted the transformation of LOP. The content of IOP fractions and ratio of each forms to TIOP were as follows:Fe-P, O-P> Al-P> Ca-P; Fe-P and O-P was major existing form of IOP. CT promoted the transformation of Al-P and Fe-P. correlation analysis showed, Al-P, Fe-P, Ca-P, O-P and MLOP existed better correlation to AP in NT than that in CT.更多还原