摘要
【目的】研究中国农田土壤pH时空变化特征及其主要的驱动因素,为土壤酸化阻控、土壤质量提升和土地可持续利用提供理论基础。【方法】基于农业农村部布置在全国主要农田区域的耕地质量监测点数据(950个),分析旱地、水旱轮作、水田等不同土地利用类型下土壤pH时空变化特征,并利用提升回归树模型探究影响土壤pH变化的主要驱动因素。【结果】就全国而言,土壤pH及其变异系数表现为旱地(6.74±1.19和17.63%)>水旱轮作(6.54±0.93和14.26%)>水田(5.80±0.81和13.95%),其中华南地区农田土壤pH表现为水田(5.74±0.79)大于水旱轮作(5.47±0.56)和旱地(5.45±0.91)。从监测初期(Ⅰ阶段,1988—2000)到监测中期(Ⅱ阶段,2001—2010),旱地和水田土壤pH整体上随时间呈降低趋势,下降速率分别为0.065和0.054/年(P<0.01),而水旱轮作土壤pH无显著变化;从Ⅱ到Ⅲ阶段(2001—2018),旱地和水旱轮作土壤pH整体上随时间呈上升趋势,上升速率分别为0.022和0.016/年(P<0.05),而水田土壤pH无显著变化。东北、华北、西南、长江中下游地区的旱地土壤pH随时间均呈线性下降趋势(P<0.05),而华南地区从Ⅱ到Ⅲ阶段呈线性上升趋势(P<0.01);西南、长江中游和华南地区水田土壤pH从Ⅰ到Ⅲ阶段呈线性下降趋势(P<0.01),而东北、西南和长江下游地区pH从Ⅱ到Ⅲ阶段呈上升趋势(P<0.01);西南地区水旱轮作土壤pH从Ⅰ到Ⅲ阶段呈线性下降趋势(P<0.01),而华北、长江下游和华南地区pH从Ⅱ到Ⅲ阶段呈上升趋势(P<0.05)。通过Pearson和提升回归树分析发现,年均降雨量是造成土壤pH空间尺度上差异的最主要因素,其次是土壤质地、容重和有机质含量。此外,在旱地土壤上长期的氮肥投入和在水田和水旱轮作土壤上钾肥的投入对pH变化的影响较大。【结论】整体而言,我国旱地和水田土壤pH从监测初期到中期呈快速下降趋势,而旱地和水旱轮作土壤pH从监测中期到2018年呈缓慢增加趋势。东北地区的旱地土壤pH呈持续下降趋势,需要引起重视。氮肥在旱地和钾肥在水田上的施用导致土壤pH的降低,今后应优化水肥运筹,通过改善土壤容重和有机质进而有效调控土壤pH。
【Objectives】Exploration of the temporal and spatial changes of soil pH in Chinese farmland and the main driving factors are of great significance in alleviating acidification,soil quality improvement and sustainable land use.【Methods】Based on the national long-term farmland fertilization monitoring data from the Ministry of Agricultural and Rural Affairs(950 experiments),we analyzed the temporal and spatial variations of soil pH in upland field,paddy field and paddy-upland rotation field.The main factors affecting the change of soil pH were analyzed using boosted regression tree model.【Results】The soil pH value and coefficient of variation in China followed the sequence of upland(6.74±1.19 and 17.63%)>upland-paddy rotation field(6.54±0.93 and 14.26%)>paddy field(5.80±0.81 and 13.95%).While the paddy soil pH(5.74±0.79)was higher than that of upland-paddy field and upland field in South China.From the initial stage of monitoring(Ⅰ,1988-2000)to the middle stage(Ⅱ,2001-2010),the pH of upland and paddy soils showed a decreasing trend,and the decreasing rates were 0.065 and 0.054 units per year,respectively(P<0.05).From stage Ⅱ to Ⅲ(2001-2018),pH of upland and upland-paddy soil increased with time,and the rising rates were 0.022 and 0.016 units per year,respectively(P<0.05),but there was no significant change in paddy soils.The soil pH of uplands in Northeast,North China,Southwest,Middle and Lower Reaches of Yangtze River decreased linearly with time(P<0.05),while opposite trend was found in South China from stage Ⅱ to Ⅲ(P<0.01).The pH of paddy soils in Southwest,Middle Reaches of Yangtze River and South China decreased linearly from stage Ⅰ to Ⅲ(P<0.01),but increased linearly from stage Ⅱ to Ⅲ(P<0.01)in Northeast,Southwest and Lower Reaches of Yangtze River.The pH of upland-paddy soil in Southwest China decreased linearly from stage Ⅰ to Ⅲ(P<0.01),while opposite result was observed in North China,Lower Reaches of Yangtze River and South China from stage Ⅱ to Ⅲ(P<0.05).Pearson’s correlation and boosted regression tree model revealed that mean annual precipitation was the most important factor driving regional soil pH change,followed by soil texture,bulk density and organic matter content.Moreover,the long-term inputs of nitrogen fertilizer in upland and the input of potassium fertilizer in paddy and upland-paddy fields also played key roles in soil pH change.【Conclusions】Overall,soil pH shows a trend of decreasing from the initial stage to the middle stage in upland and paddy soil,then slow increasing from the middle stage to 2018 in upland and upland-paddy soils,except that the pH in upland soil of Northeast China shows durative decrease.The application of nitrogen fertilizer in upland and potash in paddy field has caused soil pH decrease,so reasonable nutrient management,and the soil bulk density and organic matter amelioration should be considered to alleviate the decrease of soil pH in Chinese farmlands.
作者
韩天富
柳开楼
黄晶
马常宝
郑磊
王慧颖
曲潇林
任意
于子坤
张会民
HAN Tian-fu;LIU Kai-lou;HUANG Jing;MA Chang-bao;ZHENG Lei;WANG Hui-ying;QU Xiao-lin;REN Yi;YU Zi-kun;ZHANG Hui-min(Institute of Agricultural Resources and Regional Planning,Chinese Academy of Agricultural Sciences/National Engineering Laboratory for Improving Quality of Arable Land,Beijing 100081,China;College of Resources and Environmental Sciences,China Agricultural University,Beijing 100193,China;Jiangxi Institute of Red Soil/National Engineering and Technology Research Center for Red Soil Improvement,Jinxian,Jiangxi 331717,China;National Field Observation and Research Station of Farmland Ecosystem in Qiyang,Hunan 426182,China;Center of Arable Land Quality Monitoring and Protection,Ministry of Agricultural and Rural Affairs,Beijing 100125,China)
出处
《植物营养与肥料学报》
CAS
CSCD
北大核心
2020年第12期2137-2149,共13页
Journal of Plant Nutrition and Fertilizers
基金
国家重点研发计划“粮食丰产增效科技创新”重点专项(2016YFD0300901)
国家自然科学基金项目(41671301)
中央级公益性科研院所基本科研业务费专项(161032019035)。
关键词
土壤PH
土地利用类型
时空演变
驱动因素
提升回归树模型
soil pH
land use type
spatio-temporal evolution
driving factors
boosted regression tree model
