塿土中有机质的累积和分解

用田间定位试验和砂泸管模拟试验,研究不同有机物料、灌水条件和有机肥用量对土壤有机质累积和分解系数的影响。结果表明:不同有机物料,第一年矿化率毛苕秸秆、玉米秸秆>厩肥,第二年趋于一致,达到相对稳定。当年累积系数,根茬>厩肥>玉米秸秆,受施用量的影响较小。稳定有机质分解系数,旱地>水浇地。土壤有机质消长,不施肥有下降趋势,施化肥能维持土壤原有机质水平。在化肥基础上增施有机肥,土壤有机质提高程度与施有机肥量呈极显著正相关。

ACCUMULATION AND DECOMPOSITION OF ORGANIC MATTER IN LOUTU SOIL

The fixed-position experiments in the fields and simulant experiments with sand penetrating tubes were conducted to study the effects of different organic materials,the amount of fertilizer and irrigation conditions upon the accumulation and decomposition coefficient of soil organic matter.The results showed that the mineralization rate of different organic materials in the first year was different, i.e.those of winter vetch and corn stalks were higher than that of barnyard manure,and in the second year,their mineralization rate tended to be in uni- formity,relatively reaching the stability.In the current year,the accumulation coefficients were less affected by the amount fertilizer applied,i.e.that of root residues was greater than that of barnyard manure,and that of barnyard manure was higher than that of corn stalks.The decomposition coefficient of stable organic matter in dryland was higher than that in irrigated land.without fertilizer added,soil organic matter contents tended to decrease,but with chemical fertilizer applied,soil organic matter contents maintained the original level.Thus, based on chemical fertilizer with increasing application of organic fertilizer, the level of organic matter increase was significantly correlated with the amount of organic fertilizer applied.