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为了探寻冻融循环次数和冻结温度对典型地带性土壤(黑土、潮土、黄土)养分形态和酶活性的作用机制,应用室内冰柜模拟不同冻结温度(-20℃强冻和-10℃弱冻),以及不同的冻融循环次数(1次和2次)。结果表明,经过冻融循环3种土壤NO3--N含量增加,增加量趋势为黄土>潮土>黑土,与冻结前相比黄土和潮土NO3--N含量分别达到5%显著水平;冻融循环3种土壤NH4+-N含量减少,减少量趋势为黑土>黄土、潮土;黑土速效磷含量显著增加(P<0.05);冻融循环增强了过氧化氢酶活性,却降低了脲酶活性;冻结温度对耕作土壤速效养分和酶活性影响不显著。建议耕作潮土和黄土应考虑冻融循环后养分总量,从而适当调整氮肥投入。
In order to explore the mechanism of action of freeze-thaw cycles and freezing temperature on nutrient status and enzyme activity of typical zonal soils (black soil, alluvial soil and loess), indoor freezers were used to simulate different freezing temperatures (-20 ℃ and -10 ℃ weak freezing ), And different freeze-thaw cycles (1 and 2). The results showed that the contents of NO3 - N in the three soils after freezing and thawing cycles increased, and the increasing tendency was loess> tidal loam> black soil, and the content of NO3 - N in the loess and the tidal loam reached a significant level of 5% respectively. The content of NH4 + -N in the three soils in the thaw cycle decreased and the decreasing trend was black soil> loess and flood soil; the content of available phosphorus in black soil was significantly increased (P <0.05); the freeze-thaw cycle enhanced the catalase activity but decreased the urease activity The effect of freezing temperature on soil available nutrients and enzyme activity was not significant. It is suggested that tillage soil and loess should consider the total amount of nutrients after the freeze-thaw cycles, so as to adjust the input of nitrogenous fertilizer properly.