黑龙江省黑土农田养分时空演变分析

通过黑龙江省黑土农田的广泛采样、化验分析,结果表明目前黑土农田有机质含量平均为39.44g/kg,全氮含量为2.22g/kg,速效磷26.66 mg/kg,速效钾160.12 mg/kg。1979~2002年期间黑土农田土壤有机质下降了3.76 g/kg,平均每年下降0.16 g/kg;土壤速效磷含量大幅度上升,已是1979年的2倍以上,23年里土壤速效磷上升了14.66 mg/kg,平均每年上升0.64 mg/kg。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。除土壤速效磷之外,其他土壤养分指标的空间分布有较明显的地域性,存在显著的空间变异,尤其是土壤碱解氮与地理纬度高程度相关。图7,表4,参3。

Analysis for spatial variability of soil fertility on black soil in Heilongjiang province

Through large scale collection of soil samples in black soil of Heilongjiang province,the result of assays indicates that the organic content,total N,available P and available K are 39.44 g/kg,2.22g/kg,26.66 mg/kg,and 160.12 mg/kg in average respectively.From 1979 to 2002,the organic matter has reduced 3.76g/kg,which means decreasing 0.16g/kg every year.To the contrary,available K has increased greatly,which now is more than double of that in 1979.Available P has increased 14.66mg/kg during the 23 years,0.64mg/kg increasing annually.It is available P that has been changed the most greatly by human production activities during the past 20 years.Except for available P,other soil factors distribute evidently regionally in the space and have distinct spatial variation,what must be underlined,available N and geographic latitude correlate extraordinarily.