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通过东北黑土农田的广泛采样、化验分析,目前黑土农田有机质含量平均为33.9 g kg-1,全氮1.91 g kg-1,速效磷24.85 mg kg-1,速效钾159.95 mg kg-1。1979年~2002年期间黑土农田土壤有机质下降了3.76 g kg-1~4.14 g kg-1,平均每年下降0.16 g kg-1~0.18 g kg-1;而土壤速效磷含量大幅度上升,已是原来1979年的2倍以上,23年里土壤速效磷上升了12.66 mg kg-1~14.66 mg kg-1,平均每年上升0.55 mg kg-1~0.64 mg kg-1。认为土壤速效磷是过去的20多年里人为生产活动改变最大的肥力因子,其他土壤养分指标的空间分布有较明显的地带性,存在显著的空间变异,尤其是土壤有机质、全氮、碱解氮与地理纬度高程度相关,受气候等自然因素影响较大。
Through extensive sampling and laboratory analysis of black soil farmland in Northeast China, the average organic matter content of black soil farmland is 33.9 g kg -1, total nitrogen 1.91 g kg -1, available phosphorus 24.85 mg kg -1, and available potassium 159.95 mg kg -1. Soil organic matter in black soil farmland decreased by 3.76 g kg-1 ~ 4.14 g kg-1 in 2002, with an average annual decrease of 0.16 g kg-1 ~ 0.18 g kg-1. The content of available phosphorus in soil increased significantly, More than twice as much as that in the previous year, and available phosphorus in soil increased by 12.66 mg kg-1 ~ 14.66 mg kg-1 in 23 years with an average annual increase of 0.55 mg kg-1 ~ 0.64 mg kg-1. Soil available phosphorus is the most fertile factor that man-made production has changed in the past 20 years. The spatial distribution of other soil nutrient indicators has obvious zonality and significant spatial variability, especially soil organic matter, total nitrogen and available nitrogen It is related to the high degree of geographical latitude and is greatly influenced by natural factors such as climate.