九三农场不同开垦年限农田黑土养分分析

Analysis on nutrient content in black soil with different reclamation ages in Jiusan farm

研究了九三农场不同开垦年限黑土有机质、全氮、全磷、碱解氮,速效磷和速效钾的含量变化。结果表明,开垦年限对土壤平均养分含量有一定的影响。有机质,全氮和速效磷含量变化趋势一致,均随开垦年限的增长而不断降低。有机质平均值从112.0 g.kg-1(荒地)下降到26.9 g.kg-1(开垦后40年),下降了75.90%;表层全氮含量由7.41 g.kg-1下降到2.23 g.kg-1,下降了69.90%。速效磷含量下降了90.59%。有机质和全氮含量均在开垦初期下降速率较大;全磷含量呈现出先下降后增高的趋势,土壤平均全磷含量以第5年为分界点,但在各个粒级上分界点有所变化;碱解氮含量随开垦年限显著增加;速效钾在第2年下降了42.72%,之后趋平。

The variation of black organic matter,total nitrogen,total phosphorus,alkali-hydrolyzable nitrogen,available phosphorus and potassium under different reclamation ages were studied.The results showed that reclamation ages had a certain influence on soil content of the average nutrient.Organic matter,total nitrogen and available phosphorus content had the same trend,and reduced with the increase of reclamation ages.Average organic matter content reduced by 75.90% from 112.0 g.kg-1（the original land） to 26.9 g.kg-1（40 years later）,total nitrogen reduced by 69.90% from 7.41 g.kg-1 to 2.23 g.kg-1;and available phosphorus reduced by 90.59%.Organic matter and total nitrogen had greater declining rate in the initial reclamation stage,total phosphorus decreased in the initial and then increased,the division-point of average total phosphorus content was in the fifth year,but it was different in soil partical;nitrogen increased prominently with the increase of reclamation ages.Available potassium reduced in the second year and then leveled off.