关键词: 玉米主产区, 土壤养分, 空间变异, 影响因素, 地理信息系统, 中国

Abstract:

【Objective】 The objective of this study was to analyze the current status, regional spatial variation and its influencing factors of soil fertility in the major regions of maize production in China, so as to provide the guidance for soil nutrient management and fertilization strategy. 【Method】 Large-scale soil sample collection and farmer surveys were carried out throughout the major regions of maize production during the harvest season of maize in 2017. By using geostatistics and geographical information systems (GIS) methods, the regional variability and distribution patterns of soil fertilities were determined and mapped. According to relevant grading standards, the current status of soil fertilities in major regions of maize production was evaluated. Correlation analysis and variance analysis were used to assess the effects of major factors (soil texture, climate and fertilization) on soil fertility status.【Result】 The median values of soil pH, organic matter, total nitrogen (N), Olsen phosphorus (Olsen-P), and NH₄OAc extractable potassium (available K) in the major regions of maize production were 6.9, 21.0 g·kg^-1, 1.5 g·kg^-1, 22.4 mg·kg^-1, and 164.5 mg·kg^-1, respectively, and their coefficient of variation were 12.7%, 48.5%, 50.0%, 83.6% and 52.0%, respectively, which all belonged to moderate variation. The concentrations of soil organic matter, total N, Olsen-P, and available K were mainly varied at middle to extremely high level, which occupied 93.5% area of the whole production regions. Significant regional variation was observed for soil fertilities. The concentrations of soil organic matter, total N and Olsen-P were the highest in the Northeast region (with median of 32.0 g·kg^-1, 2.2 g·kg^-1, 32.3 mg·kg^-1, respectively) and the lowest in the Northwest region (with median of 17.2 g·kg^-1, 1.2 g·kg^-1, 16.2 mg·kg^-1, respectively). The concentration of soil available K was the lowest in the Southwest region but showed no significant difference in the other regions. On the national scale, soil pH had strong spatial dependence (nugget to sill ratio <25%) and its spatial variation was likely caused by natural factors (soil texture and precipitation). Soil Olsen-P had weak spatial dependence (nugget to sill ratio >75%) and its spatial variation was probably affected by anthropic activities (fertilization). Soil organic matter, total N and available K had moderate spatial dependence (nugget to sill ratio 25%-75%), which likely was due to the combined effect of natural factors and anthropic activities. 【Conclusion】 Due to high soil fertility, the fertilization rate should be reduced to save fertilizer cost in the maize production of Northeast region. For North China Plain with moderate soil fertility, the amount of nitrogen and phosphorus fertilizer should be strictly controlled to improve fertilizer use efficiency and to reduce environmental pollution. For Northwest region with inadequate soil fertility, the fertilizer input should be appropriately increased to further improve maize yield. The soil fertility in the Southwest region varies greatly. Appropriate fertilization management should be adopted in each subregion to improve soil nutrient preserving capability and maize yield.

Key words: major regions of maize production, soil fertilities, spatial variability, influencing factors, GIS, China