连作对谷子土壤酶活性及养分的影响

为探明谷子连作对土壤环境的影响,分析不同连作年限对谷子土壤养分和酶活性的影响,本研究在4a不施肥定位试验的基础上,设置连作2 a(T1)、连作3 a(T2)、连作4 a(T3)和轮作(CK)4个处理,分别测定了土壤养分、土壤脲酶、碱性磷酸酶、蔗糖酶和过氧化氢酶活性及其变化。试验结果表明,与轮作(CK)相比,连作2 a(T1)、连作3 a(T2)和连作4 a(T3)分别减产6.9%、12.7%和35.6%,随着连作年限增加,减产幅度加大;连作土壤氮、磷含量降低,其中速效氮含量降低最为显著(P0.05),速效钾含量变化不显著(P0.05),土壤p H升高。连作条件下,土壤脲酶、碱性磷酸酶、蔗糖酶和过氧化氢酶活性均呈现逐年降低的趋势,且随着连作年限增加,降低越显著,连作4 a(T3)显著低于其它处理(P0.05)。

Effects of foxtail millet continuous cropping on soil enzyme activities and nutrients

In order to explore the effects of foxtail millet continuous cropping on soil environment, a 4-year located field experiment based on different continuous cropping years (T1:2 years, T2:3 years and T3:4 years) of foxtail millet without fertilization was conducted in the north semi-arid region. Foxtail millet rotated with legume crops was set as the control (CK). The soil nutrient, the enzyme activities of urease, alkaline phosphatase (ALP), sucrase and catalase were determined in the experiment. The results showed that compared with CK, the yields of T1, T2 and T3 were decreased by 6.9%, 12.7% and 35.6%, respectively. With the increase of the foxtail millet continuous cropping years, the yield of foxtail millet became decreased and soil pH went increased. Compared with CK, the contents of N and P were decreased, in particular the content of available N (P<0.05). The changes of available K were not significantly (P>0.05). The enzyme activities of urease, alkaline phosphatase (ALP), sucrase and catalase became decreased year after year under the continuous cropping, and the activity of each enzyme in T3 was significantly lower than that in other treatments (P<0.05).