寒区旱区间歇性干旱对接种根瘤菌苜蓿草地土壤养分动态的影响

通过盆栽法模拟田间土壤的干湿交替变化过程和强度,研究了寒区旱区间歇性干旱条件对接种根瘤菌(Rhizobia)苜蓿(Medicago sativa L.)草地土壤养分的影响。结果表明:1年龄苜蓿接种根瘤菌能显著提高土壤全N、有机质、速效N、速效K和速效P含量,而对土壤pH和全P含量影响不大,间歇性干旱处理能显著降低土壤全N、有机质、全P、速效N、速效P和速效K含量,且土壤养分下降量总体上为有机质>全P>全N>速效K>速效N>速效P;通过相关和回归分析,土壤全P和有机质含量的下降量与干湿交替间隔周期呈显著直线正相关(P<0.05),土壤速效K和速效P含量的下降量与干湿交替间隔周期呈显著直线负相关(P<0.05);当干湿交替间隔周期相同时,土壤全N、全P、速效N和有机质含量的下降量,50%田间持水量的处理大于80%田间持水量的处理,而土壤速效K和速效P含量的下降量,50%田间持水量的处理小于80%田间持水量的处理。

Effect of Intermittent Drought on Soil Nutrients of Alfalfa Grassland Inoculated with Rhizobium in a Cold and Drought Region

A pot experiment was carried out to study the effect of intermittent drought on soil nutrients of Alfalfa grassland inoculated with rizobia in a cold and drought region,and the drying-wetting course and intensity of soil in farm was simulated.The results showed that a-year-alfalfa inoculated with rizobia could increased the content of total N,organic matter,available N,available K and available P,significantly,but there was no significant effect on total P and pH value.Dying-wetting cycle could decreased the content of total N,organic matter,total P,available N,available P and available K significantly.There is positive linear interrelationships between drying-wetting cycle and the decreased quantity of total P and organic matter(P<0.05),but negative linear interrelationships between drying-wetting cycle and the decreased quantity of available K and available P(P<0.05).The decreased quantity of total N,total P,organic matter and available N under drying-wetting with 50% moisture field capacity was more than that in the treatment with 80% moisture field capacity.However,the decreased quantity of available K and available P was contrary,while the cycle of drying-wetting was same.According to the result we could estimate soil nutrient change.