我国粮食主产区稻田土壤肥力及基础地力的时空演变特征

【作者】 李建军；

【导师】 段建军； 徐明岗； 张会民；

【作者基本信息】 贵州大学 ， 土壤学， 2015， 硕士

【摘要】 稻田土壤肥力和基础地力对水稻产量以及肥料用量和利用率起着决定性的影响。因此,研究并明确稻田土壤肥力和基础地力的演变动态是科学合理指导水稻土壤管理、施肥的前提和基础,对保障水稻产量稳定性和持续增长具有非常重要的意义。由于过去的研究未能从大的时间与空间角度出发去探究其时空演变特征,尤其不同区域之间的变异情况,并未形定量化的对比分析;并且对水稻的大部分研究都集中在早、晚稻和单季稻上,对中稻的研究较少。所以,本研究依托农业部全国水稻土监测数据资料,运用中值分析的方法来探究近25年(1988-2012年)稻田土壤养分的动态演变特征,并将各肥力指标和权重因子采用数值归一化处理,然后结合土壤综合肥力指数模型和基础地力指数模型分析对比全国不同区域之间稻田土壤肥力与基础地力的时空演变规律;同时在全国范围内探讨了农田基础地力提升的“水涨船高”效应,主要研究结论概括如下:(1)经过验证得出,运用FI值、PI值和BPI值来研究表征土壤综合肥力、土壤生产力和基础地力是合理的。(2)从1988-2012年间,在农民习惯性施肥条件下,我国粮食主产区(长江中下游区、东北区、西南区、华南区)稻田土壤有机质(SOM)、全氮(TN)、碱解氮(AN)、有效磷(AP)和速效钾(AK)的含量基本均呈现上升趋势;但土壤pH值呈下降趋势(东北区经查阅长期试验数据可知其pH亦略呈下降趋势),尤其长江中下游区、西南区和华南区稻田已表现出一定的酸化趋势。(3)在农民习惯性耕作与管理条件下,长江中下游、西南、华南以及东北四区稻田土壤综合肥力指数(FI值)均随时间呈极显著上升趋势(p<0.01),表明近25年来我国粮食主产区稻田土壤肥力总体得到了改善。并且随着时间的增加,土壤综合肥力可以达到“饱和”,即相对的平衡状态(FI值的最大阈值)。(4)从整体变化趋势来看,长江中下游区稻田土壤综合肥力的演变状态在时间序列上要早于西南区、华南区和东北区。因此,较之于长江中下游区,西南、华南和东北三区的土壤综合肥力的提升空间更大;也即在通过科学合理施肥来提高土壤综合肥力这条途径上,其余三区比长江中下游区的效果将更明显。(5)通过对长江中下游区不同年代土壤肥力差异性演变的主成分分析可得出,从农田养分平衡管理的角度来看,土壤速效钾和有效磷仍然是该区稻田持续生产和农业持续发展的重要影响因素,在以后的施肥管理过程中对钾与磷素的投入和补充仍需加强,而氮肥施用量需要合理控制。(6)施肥量的增减和施肥种类的不断变化而导致的农田养分平衡尤其农田氮、磷、钾养分平衡的波动是导致稻田土壤综合肥力变异的主要因素。(7)农民习惯性施肥管理水平下,我国粮食主产区稻田土壤基础地力近25年来总体呈现上升趋势。并且长江中下游区的基础地力水平明显高于其他三区,西南区基础地力水平最低,东北区与华南区无明显差异,即长江中下游区>东北区≥华南区>西南区。(8)从1988年到2012年间,我国粮食主产区稻田土壤生产力随时间不断提升,并且各区稻田基础生产力BPI值与土壤生产力PI值均呈显著正相关关系(p<0.01);从而说明稻田基础地力的提升,可以实现稻田土壤生产力的提高,即农田基础地力提升的“水涨船高”效应。(9)综合四大区土壤肥力(FI值)与基础地力(BPI值)的动态演变趋势可以看出,我国粮食主产区稻田土壤肥力和基础地力均存在巨大的提升空间,是实现稻田生产力提升的重要途径。更多还原

【Abstract】 Paddy soil fertility and basic soil productivity had a decisive effect on rice yield and fertilizer dosage and utilization. Therefore, it has very important significance to safeguard the stability of rice production and sustained growth that researching and clarifying the dynamic evolution of paddy soil fertility and basis, which is the premise and foundation of guiding paddy soil management and manuring scientifically and reasonably. In the past, studies failed to proceed from the big perspective of time and space to explore the spatial and temporal evolution characteristics, especially, there wasn’t any quantitative comparative analysis of variation between different regions; and most rice research has focused on the early and late rice and single cropping of rice while few studies focused on middle rice. Therefore, relying on the USDA National paddy soil monitoring data, this study uses the value analysis method to explore the past 25 years(1988-2012 years) dynamic evolution characteristics of paddy soil nutrients, and various fertility indicators and weighting factor using numerical normalization, then combining integrated soil fertility index model and foundation soil fertility index model to analyze the temporal evolution of soil fertility and basic soil fertility between different regions of the country: and discussed the "gone" effect of basic farmland soil fertility improvement across the country at the same time. And the main conclusions are summarized as follows:(1) Through proven, it is reasonable to use the F value, P value and BPI values to characterize integrated soil fertility, soil productivity and soil fertility.(2) From 1988 to 2012, basically it showed an upward trend under the conditions of the farmers habitual fertilization that the content of paddy soil organic matter(SOM), total nitrogen(TN), nitrogen(AN), available phosphorus(AP) and potassium(AK) in our major grain producing areas(the Yangtze River region, the Northeast, Southwest Region, Southern Region), but soil p H decreased(Northeast After checking the long-term trial data showed that the p H is also slightly downward trend), and has shown some acidification trend especially in the Yangtze River, Southwest and South paddy fields.(3) Under customary peasant farming and management conditions, the Yangtze River, Southwest, South and Northeast Fourth District paddy integrated soil fertility index(FI value) over time for both the upward trend was significant(p <0.01), which shows that there have improved overall paddy soil fertility in major grain producing areas nearly 25 years. And increase over time, integrated soil fertility can be reached "saturation", which is equal to the relative equilibrium(FI value of the maximum threshold).(4) From the overall change of view, in the Yangtze River area, the evolution state of integrated paddy soil fertility was earlier than in the Southwest Region, Southern Region and the Northeast region in time series. Thus, compared to the Yangtze River area, areas showed more integrated soil fertility for improvement in southwest, south and northeast; the remaining three districts will be more pronounced than the effect of the Yangtze River region when through scientific and rational fertilization to improve integrated soil fertility.(5) Through differences of the Yangtze River region’s soil fertility in the evolution of the different principal component, analysis can be drawn that, soil potassium and phosphorus are still important factors of ongoing paddy production and sustainable development of agriculture in the area from a perspective of nutrient Balance, potassium and phosphorus inputs and supplements need to be strengthened in the future management of the process of fertilization, but the amount of nitrogen fertilizer required reasonable control.(6) Changes in fertilizer nutrient balance and changing the type of fertilizer, especially nitrogen, phosphorus and potassium balance fluctuations are the main factors leading integrated paddy soil fertility variation.(7) There has shown an overall upward trend of major grain producing areas in paddy basic soil productivity for nearly 25 years under customary farmer fertilizer management. And the basic soil productivity level of the Yangtze River area was significantly higher than the other three areas, Southwest was the lowest level fertility basis, there was no significant difference between Northeast and South China, namely the Yangtze River area> Northeast ≥ Southern Region> Southwest.(8) The soil productivity of paddy in major grain producing areas improved over time from 1988 to 2012, and basic soil productivity(BPI values) and soil productivity(PI value) showed a significant positive correlation(p <0.01). Thus explained that soil productivity could be improved with the enhancing of basic soil productivity, which is equal to the "Corresponding Rise" effect.(9) Integrated Soil Fertility four(FI value) and basic fertility(BPI value) of the dynamic evolution of the trend can be seen that soil fertility and basic soil productivity of China’s major grain producing areas all have a huge room for improvement, which is an important way to enhance the productivity of paddy.更多还原