近30a江西省农田土壤pH时空变化及其与酸雨和施肥量间关系

论文以1979—1986年(以下简称1980S)江西省第二次土壤普查时期和2005—2012年(以下简称2010S)江西省测土配方施肥阶段这两个时期的pH数据成果为基础,运用ArcGIS对比分析30 a间江西省农田土壤pH的时空变化。结果表明:江西省农田土壤pH总体呈酸化趋势,2010S江西省农田土壤pH平均值为5.24,较30 a前的5.77下降了0.53;全省酸化趋向西南,其中酸化最突出的地区为赣州市,其次是鄱阳湖周边,特别是南昌市、鹰潭市,pH降幅较大;赣北局部地区农田土壤pH有所上升。定量分析氮施用量与酸雨对农田土壤酸化的影响,结果显示:氮施用量、酸雨强度的差异和农田土壤酸化程度在空间上存在一定的相关性,长期过量施用氮肥是江西省农田土壤酸化的主要原因,地区土壤pH酸化程度同氮肥施用量呈显著正相关,且在30 a间,施肥量每增加50 kg/hm~2,农田土壤pH下降0.26个单位;地区土壤pH酸化程度同酸雨pH值呈显著负相关,且随着酸雨pH值越低,农田土壤酸化速率越快。

Spatio-temporal Variation of pH in Cropland of Jiangxi Province in the Past 30 Years and Its Relationship with Acid Rain and Fertilizer Application

Soil acidification has become the most common problem of the world's farmland. Cropland soil acidification causes serious damage to Chinese food security and agricultural sustainable development. This study, which was based on the two periods of pH data during the second soil survey in 1980S (1979-1986) and during the soil testing and formulated fertilization in 2010S (2005-2012), analyzed the spatio-temporal variation of pH in cropland soil of Jiangxi Province in the past 30 years and its relations with nitrogen fertilizer application and acid rain. The results showed that the pH value of cropland in Jiangxi Province presented a trend of acidification. The average pH value of cropland soil in Jiangxi Province was 5.24 in 2010S, decrease 0.53 compared with that in 1980S. Acidification is more serious in southwest of the province. The most prominent area of acidification is Ganzhou City, followed by Nanchang City and Yingtan City, where the average pH value fell more than 0.8 units. According to linear regression, the acidification of cropland soil is closely related to the nitrogen application rate and acid rain. The long-term excessive application of nitrogen fertilizer is the main reason of soil acidification in Jiangxi Province. Cropland soil acidification was positively correlated with nitrogen application rate. Soil pH of cropland declined 0.26 unit with nitrogen application rate increasing 50 kg/hm² in the past 30 years. Cropland soil acidification has negative correlation with the pH value of acid rain. The lower the pH value of acid rain, the faster the acidification of cropland.