吉林省农田耕层土壤pH的时空变化特征

本研究通过分析2005~2013年测土配方施肥项目在吉林省采集的大量土壤样品,明确了不同地区农田耕层土壤pH的空间变异特征,并与第二次土壤普查数据对比探讨了土壤pH的变化趋势。结果表明,目前吉林省农田耕层土壤pH分布在3.8~9.1之间,平均值为6.5。不同类型农田土壤pH的高低顺序为:黑钙土风沙土草甸土黑土白浆土≈暗棕壤水稻土。空间上,吉林省农田耕层土壤呈现自西向东逐渐降低的分布特征,以西部白城市的通榆县最高而东部延边朝鲜族自治州的汪清县最低。时间上,与第二次土壤普相比,吉林省各种土类的pH存在共性的土壤酸化趋势。不同土类间pH的降幅存在较大差异,代表性的黑土下降约0.5个单位,酸化程度较大的草甸土和水稻分别下降了1.4和1.6个单位,而酸化程度较小的白浆土下降了0.1个单位。吉林省农业生产中应控制化肥用量,调整肥料品种,合理增施有机肥,大力推广秸秆还田,从而缓解土壤酸化趋势,改善土壤肥力。

Temporal and Spatial Variability of Soil pH in Cropland of Jilin Province

The soil testing and recommended fertilization (STRF) program have been conducted in Jilin Province since 2005,and a large amount of soil samples were taken to measure basic physical and chemical properties for guiding reasonable fertihzation.Data of soil pH in the STRF program during 2005 ～ 2013 were collected and analyzed in this study,aiming to evaluate the spatial variability of soil pH across the different regions in Jilin Province,and to discuss the changing trend of soil pH by comparing with the data obtained during the second national soil survey.The results showed that soil pH in the present Jilin Province ranged between 3.8 and 9.1 with a mean of 6.5.The order,from high to low,of pH among different soil types was chernozem ＞ aeolian sandy soil ＞ meadow soil ＞ black soil ＞ albic soil ≈ dark brown soil ＞ paddy soil.In view of the province as a whole,the spatial distribution of soil pH was characterized by being high in the west and low in the east.The highest soil pH was observed in Tongyu County,Baicheng City that located at the west region and the lowest value was observed in Wangqing County,Yanbian Korean Autonomous Prefecture that located at the east region.Compared with the findings in second soil survey,soil pH showed coincident acidification trends across all soil types of Jilin province.However,obvious differences were observed in the pH decline among soil types.Of which,as the typical soil in Jilin Province,black soil showed 0.5 unit decline in pH from 6.9 to 6.4.Much greater pH declines were observed in meadow soil (1.4 unit decline) and paddy soil (1.6 unit decline),while only a litter pH decline was observed in albic soil (0.1 unit decline).Therefore,to mitigate acidification and improve soil fertility,appropriate chemical fertilizer rate and resource should be adopted in crop production of Jilin Province,in combination with applying organic fertilizer and returning crop straw to the field.