1980s—2010s东北农田土壤养分时空变化特征

Spatial and temporal variations of soil nutrients of cropland in Northeast China from the 1980s to the 2010s

近年来,东北地区农田土壤“变薄、变瘦、变硬”等退化问题日趋严峻,严重影响了东北农业的可持续发展。本研究基于1980年代(1980s)《中国土种志》和2010年代(2010s)《中国土系志》土壤样点的土壤剖面属性数据,通过大样本统计分析,揭示了30年来东北不同地区、不同土壤类型的土壤养分状况变化规律。结果表明:1)1980s—2010s,东北地区各土壤养分指标变化程度不同,土壤pH总体下降0.03,土壤有机质(SOM)含量下降最突出,下降了8.99 g·kg^(-1),降幅为23.6%,土壤全氮(TN)、全磷(TP)和全钾(TK)含量呈现出不同程度的上升趋势,增幅分别为17.1%、46.8%和4.9%。2)各省市土壤养分指标变化表现出较大差异,辽宁土壤酸化最明显,pH降低了0.32,SOM含量下降最明显,降低31.0%,土壤TN、TP、TK含量上升最显著,增幅分别为73.8%、248.1%和44.0%。3)不同土壤类型土壤养分变化差异较大,棕壤和栗钙土pH下降最多,几乎所有类型土壤的SOM含量均为下降趋势,其中棕壤、暗棕壤和黑钙土分别下降了35.4%、33.8%和26.0%,而TN、TP、TK含量上升最多的为棕壤,增幅分别为89.1%、232.8%和48.5%。综上,有机质含量下降和土壤酸化是1980s—2010s东北土壤退化的核心问题,探索合理的耕作方式,制定针对性的保护策略,是保证东北地区农业可持续发展的迫切需求。

In recent years,the degradation of cropland soils in Northeast China,such as“thinned,barren,and hardened”,has become increasingly serious,with consequences on sustainable development of agriculture.Based on the data from Soil Types of China(1980s)and Soil Series of China(2010s),we examined the change patterns of soil nutrient conditions across different regions and soil types in Northeast China over the past 30 years through the statistical analysis of large samples.The results showed that:1)from the 1980s to the 2010s,soil nutrient indicators in Northeast China changed to different degrees.Soil pH decreased by 0.03.Soil organic matter(SOM)content decreasd most prominently,by 8.99 g·kg^(-1)or 23.6%.Soil total N(TN),total P(TP)and total K(TK)contents showed increasing trends,with increases of 17.1%,46.8%,and 4.9%,respectively.2)Changes in soil nutrient indicators differed across different provinces and cities.Soil acidification in Liaoning was the most obvious,with pH decreasing by 0.32.SOM content in Liaoning decreased most significantly,by 31.0%.Soil TN,TP,and TK contents in Liaoning increased most significantly by 73.8%,248.1% and 44.0%,respectively.3)The changes of soil nutrients varied greatly among soil types,with brown soil and kastanozems showing the greatest decrease in pH.The SOM content of all soil types showed a decreasing trend,with 35.4%,33.8% and 26.0% reduction in brown soil,dark brown forest soil and chernozem respectively.The greatest increase in TN,TP and TK contents were observed in brown soil by 89.1%,232.8%,and 48.5%,respectively.In summary,declining organic matter content and soil acidification were the core problems of soil degradation in Northeast China from the 1980s to the 2010s.Reasonable tillage methods and targeted conservation strategies are critically needed to ensure the sustai-nable development of agriculture in Northeast China.