旱作种植条件下基础地力贡献率演变特征及影响因素分析

【目的】耕地基础地力是其生产潜能的重要指标。探究耕地基础地力区域差异、演变特征及其驱动因素,可为耕地地力提升与可持续利用提供科学依据。【方法】基于国家级长期定位监测点试验平台,按照种植区域、监测年限、土壤类型和土壤理化性状分别进行分组,分析小麦和玉米季基础地力贡献率特征,并采用随机森林模型和非参数检验等统计学方法,探究小麦/玉米季基础地力贡献率的时空演变特征及影响因素。【结果】总体上,小麦季和玉米季的基础地力贡献率为48.9%和53.4%（中位值）。东北地区玉米季（60.8%）和西北地区小麦季（57.0%）的基础地力贡献率最高;而西南地区小麦季和玉米季的基础地力贡献率均最低（分别为35.8%和21.3%）。近30年我国基础地力贡献率总体呈现上升趋势,2010s比1980s增长了约15个百分点。在全国尺度上,土壤类型、土壤pH是影响基础地力贡献率的主要因素。对于不同区域小麦而言,有机质是影响华北地区基础地力贡献率的第一要素,长江中下游地区与西南地区的则为有效磷;而在玉米季,影响东北地区与西南地区是有机质,华北地区和长江中下游地区基础地力贡献率的主要因素则分别为速效钾和pH。【结论】我国耕地基础地力贡献率整体上呈增长趋势,区域间差异明显。就全国尺度,土壤类型和土壤pH是小麦与玉米季基础地力贡献率变异的主要因素。土壤类型、pH、有效磷和有机质含量是影响区域尺度上耕地基础地力主要因素。

Evolution Characteristics and Influencing Factors on Inherent Soil Productivity Across Dryland

【Objective】Inherent soil productivity of cropland is an important index of its productivity potential. The main objective of this study was to explore the evolution patterns and to identify the main influencing factors on the contribution of inherent soil productivity (CISP), which could provide the guidance for sustainable utilization of cultivated land to improve of CISP. 【Method】Based on the national long-term field monitoring network in China, the monitoring dataset were grouped according to regional distributions, monitoring years, soil types, and soil physical and chemical properties to explore the spatial-temporal evolution patterns and importance factors on the CISP for wheat/maize season.【Result】The median values of CISP for wheat and maize were 48.9% and 53.4% across main producing regions. The CISP for maize in Northeast and Northwest China were 60.8% and 57.0%. In southwest China, the CISP for the wheat and maize were both the lowest, with the median values of 35.8% and 21.3%. During the past 30 years, the CISP of China’s cropland showed an increasing trend. The CISP in the 2010s significantly were increased by 15 percentage points compared with the value in the 1980s. The results of random forest model showed that soil type and soil pH were the main factors influencing the CISP at national scale. As for wheat on regional scale, soil organic matter (SOM) was the most important factor in the North China, and available phosphorus (AP) was the most important factor in the Southwest China and the middle and lower reaches of Yangtze River. However, as for maize, regardless of soil type and area, available potassium (AK) and soil pH were mainly important influencing factors in the North China and the lower reaches of Yangtze River. Soil organic matter (SOM) was the most important factor in the Northeast and Southwest China. 【Conclusion】The CISP in China is increasing on the whole with obvious differences among regions. On the national scale, soil type and pH were main factors casing variation of CISP. The soil type, SOM, AP and pH were mainly important factors casing variation of CISP on regional scale.