【作者】 王姗娜；

【导师】 徐明岗； 黄庆海；

【作者基本信息】 中国农业科学院 ， 土壤学， 2012， 博士

【摘要】 红壤性水稻土是我国南方中部地区，尤其是江西省主要的农业土壤之一。近年来，由于土地过度利用，为了追求高产，不合理地大量施用化学肥料，引起一系列生产及环境生态问题。因此，阐明红壤性水稻土土壤肥力的动态变化及养分资源的作物吸收利用特点是该区域农业科学中的一个重要问题，对于生态环境保护和农业可持续发展，均具有重要的理论意义和实践价值。本论文以位于江西省进贤县的红壤性水稻土长期定位试验（1981-2007）为基础，分析了不施肥（CK）、单施肥（N、P、K）、化肥配施（NP、NK、PK、NPK）、倍量施肥（2NPK）和有机-无机肥配施（NPKM）下红壤性水稻土的肥力演变及生产力可持续性，主要结果和结论如下：1、长期施用有机肥可提高红壤性水稻土耕层的有机质含量。施肥以来，红壤性水稻土有机质含量在化肥有机肥配施处理下显著增加，2002年土壤有机质含量与1981年试验前比较增幅达到32％，耕层土壤有机质多年平均含量为20.55g/kg。长期施用化肥，红壤性水稻土耕层有机质含量保持稳定，多年平均含量维持在16-18g/kg范围内。2、长期施用有机肥可显著提高土壤全氮与有效氮的含量，土壤氮含量在化肥有机肥配施处理下有显著增高，其中全氮含量增长12%，有效氮含量增长25%。而在其他处理下土壤氮素增加不显著。施氮对土壤全氮含量的影响不显著，对土壤有效氮含量的影响显著。长期施用含磷肥料可不同程度上提高耕层土壤全磷和有效磷含量，其中有机肥和过量施磷对土壤磷素的提升作用最为显著。NPKM和2NPK两处理，土壤全磷含量与试验初相比分别提高了83.9%和79.6%；土壤有效磷含量与试验初相比分别提高了672.3%和409.9%。施磷对土壤全磷含量的影响显著，对土壤有效磷含量的影响不显著。长期施用施钾与不施钾肥对土壤全钾含量的影响不显著，说明施用钾肥与否在至少在本试验时间内对耕层土壤全钾无明显影响。含钾配合的各处理土壤有效钾含量明显高于不施钾肥的各处理，说明长期施用含钾配合的肥料对耕层土壤速效钾含量具有累积作用。3、不同施肥下的化肥氮回收率差异显著，26年的平均氮肥回收率N处理为9.4%-11.6%、NP为13.0%-18.5%、NPK为19.8%-26.1%，NPKM为29.9%-40.1%。磷肥、钾肥和有机肥可显著提高水稻氮肥回收率，且对早稻的贡献大于晚稻；NPK和NPKM的早稻氮肥回收率比晚稻平均高6.3和10.2个百分点。N和NK处理的氮肥回收率随年度显著降低，平均每年下降约0.6个百分点，而NPK、NPKM的氮肥回收率基本保持稳定。不同施磷处理对早、晚稻磷肥回收率影响较大。早稻年均磷肥回收率在NPK处理下最高，为33.02%；晚稻年均磷肥回收率在高量NPK处理下最高，为20.22%。相同处理下，晚稻的磷肥回收率低于早稻。早稻和晚稻在不同施钾处理下差异较大。不同施肥下的化肥钾回收率差异显著。有机肥对钾肥回收率的作用不显著，磷肥可显著提高水稻钾肥回收率，且在晚稻上效果明显。4、在早、晚稻连作体系中，土壤基础肥力对水稻产量的地力贡献分别为65%和69%，氮磷钾肥料对早稻和晚稻的增产贡献分别为35%和31%；在26年定位试验中，红壤性水稻土对早稻的地力贡献率多年呈下降趋势，红壤性水稻土对晚稻的地力贡献率多年总体呈上升趋势，早稻对肥料的依赖性高于晚稻。氮磷钾化肥配施及化肥有机肥配施处理下早稻籽粒产量显著高于其他处理，且多年间保持稳定。早稻籽粒产量在N、K和NK处理下分别以每年73.2kg ha-1、61.7和90.6kg ha-1的速率下降。晚稻籽粒产量在施用有机肥处理下显著高于其他不平衡施肥处理下，且在N和NK处理下以每年29.8kg ha-1和44.3kg ha-1的速率显著下降。对于早稻，平衡施肥及有机肥配施处理下产量可持续指数最高；对于晚稻，不同处理间产量可持续指数差异较小，且施用钾肥后对晚稻产量可持续没有影响。综上所述，不平衡施肥既不利于高产，也不利于作物吸收及养分积累，培肥效果差；平衡施用化肥，能够维持作物较高的产量，土壤养分含量与试验初差异不大；化肥配施有机肥，土壤肥力水平、作物对养分的吸收利用及籽粒产量均最高，说明无论是从提高养分利用率还是高产稳产方面，化肥有机肥配施都是红壤水稻土上可持续的施肥模式。另外，本研究结果阐明了早稻对肥料的依赖性高于晚稻，且对磷肥需求高于钾肥，为生产中因作物施肥，提高粮食产量和保持红壤性水稻土地区农业可持续发展提供了理论依据。更多还原

【Abstract】 Red paddy soil is one of the leading agricultural soils in southern part of China, especially inJiangxi Province. In recent years, excessive land utilization and unreasonable application ofchemical fertilizers to achieve high yield have caused a series of production and environmentalecological issues. Therefore, to clarify the dynamic changes of red paddy soil and characteristicsof absorption and utilization of nutrient resources by crops is an important issue in the agriculturalscience in this area, and has important theoretical meaning and practical value for both theprotection of ecological environment and sustainable development of agriculture. With thelong-term positioned experiment (1991-2007) of red paddy soil in Jinxian County, JiangxiProvince as a platform, this paper analyzes the fertility evolution and sustainability of productivityof red paddy soil under no fertilization, unbalanced fertilization (N, P, K, NP, NK, PK), balancedfertilization (NPK and2NPK) and mixed application of chemical fertilizers and organic fertilizers(NPKM). Main results and conclusions are as follows:1. Long-term application of organic fertilizers could improve the content of organic substancein the plough-layer red paddy soil. Since the application of fertilizers, the content of organicsubstance increased significantly under the treatment of mixed application of chemical fertilizersand organic fertilizers. The content of organic substance in soil grew32%in2002as comparedwith the level before experiment in1981. The several-year average content of organic substance inthe plough-layer soil was20.55g/kg. With long-term application of chemical fertilizers, thecontent of organic substance in the plough-layer red paddy soil kept stable, with the several-yearaverage content maintaining within16-18g/kg.2. Long-term application of N could improve the content of N in the soil. The content of N inthe soil increased significantly under the treatment of mixed application of chemical fertilizers andorganic fertilizers, and did not increased significantly under other treatments. Long-termapplication of P-contained fertilizer may increase the content of total P and available P inplough-layer soil to different extents. For26years since the application of fertilizers, the contentof total P in the soil grew significantly under the treatments of NPKM and high-volume NPK, atthe greatest growth rate; also grew significantly under the NP and N treatments, at smaller growthrates; and remained flat under the treatments of PK and NPK. As compared with the beginning ofthe experiment, the several-year average content of available P in the soil grew at the greatest rateof672.3%under the treatment of mixed application of chemical and organic fertilizers; grew at409.9%under the treatment of2NPK; and declined by17.47%and21.25%under the N and CKtreatments respectively. The content of available K under the treatment of K application wassignificantly greater than that under the treatment of no K application, indicating that thelong-term application of K-containing mixed fertilizers could significantly improve the content ofavailable K in the plough-layer soil. In terms of the years of changing trend, the content of available K under all treatments changed sharply in different years. But in terms of the treatments,the content of available K was greatest under the treatment of mixed application of chemical andorganic fertilizers.3．The rate of N utilization by chemical fertilizers was significantly different under differentfertilizations. The26-year average N utilization rate was9.4%-11.6%under the N treatment,13.0%-18.5%under the NP treatment,19.8%-26.1%under the NPK treatment, and29.9%-40.1%under the NPKM treatment. P, K and organic fertilizers could improve the N recovery rate in ricesignificantly, and contributed more to early rice than to late rice; the N recovery rate in early riceunder the NPK and NPKM treatments was6.3and10.2percentages points greater than in late ricerespectively. The N recovery rate under the N and NK treatments declined significantly on yearlybasis, with an annual average decline of about0.6percentage points. And the N recovery rateunder the NPK and NPKM treatments remained stable basically. Different P treatments hadgreater effect on the P utilization rate in early and late rice. The greatest annual average Putilization rate in early rice occurred under the NPK treatment, as33.02%；The greatest annualaverage P utilization rate in late rice occurred under the NPK treatment, as20.22%. Under thesame treatment, the P utilization rate in late rice was less than that in early rice. There was a sharpdifference between early rice and late rice under different treatments of K application. The greatestK utilization rate in early rice occurred under the high-volume NPK treatment, as60.18%. Thegreatest K utilization rate in early rice occurred under the ordinary-volume NPK treatment, as57.40%.4．In the continuous farming of early and late rice, the fertility contribution of basic soilfertility to the rice yield was65%and69%respectively. The contribution of NPK to the yieldincrease of early and late rice was35%and31%respectively；In the15-year positionedexperiment, the rate of contribution of red paddy soil to the soil fertility of early rice appeareddeclining in several years. The rate of contribution of red paddy soil to the soil fertility of earlyrice appeared rising in several years. Early rice relied more on fertilizers than late rice. The grainyield of early rice was significantly greater under the NPK treatment and the treatment of mixedapplication of chemical and organic fertilizers than other treatments, and remained stable inseveral years. The grain yield of early rice declined by73.2kg ha-1,61.7and90.6kg ha-1per annumunder the N, K and NK treatments respectively. The grain yield of late rice was significantlygreater under the treatment of organic fertilizer application than under other unbalanced treatmentsand declined significantly by29.8kg ha-1and44.3kg ha-1per annum under the N and NKtreatments respectively. As for early rice, the sustainability index of yield was the greatest underthe treatments of balanced fertilization and mixed application of organic fertilizes; as for late rice,the sustainability index of yield was less different between treatments, and the application of Khad no effect on the sustainability of yield of late rice.In a word, unbalanced fertilization is neither helpful for high yield, nor helpful for cropabsorption and nutrient accumulation, with poor effect of fertility fostering; balanced application of chemical fertilizers could maintain higher yield of crops, and the content of nutrients in the soilwas not significantly different from that at the beginning of experiment, indicating that, both interms of nutrient utilization increase and high yield maintaining, mixed application of chemicaland organic fertilizers is a model of sustainable fertilization for red paddy soil. In addition, resultsof this study clarify that early rice relies more on fertilizers than late rice, and needs more P than K,providing theoretical basis for fertilization depending upon crops in the production in order toincrease the grain yield and maintain the sustainable development of agriculture in the red paddysoil area.更多还原