玉米-苹果轮作体系对苹果根际土壤酶活性和pH值的影响

Effects of corn-apple rotation on enzyme activity and pH value in rhizosphere soil of apple trees

研究玉米-苹果轮作体系下,玉米种植年限(1 a和2 a)对苹果花期、幼果期、膨大期、成熟期根际土壤酶活性和pH值的影响,以期阐明玉米-苹果轮作体系缓解苹果连作障碍的作用机理。结果表明,在苹果各生育期内,根际土壤中脲酶、土壤磷酸酶和土壤转化酶活性以及pH值趋势均为苹果非连作>玉米(2 a)-苹果轮作>玉米(1 a)-苹果轮作>苹果连作(未轮作玉米)。与苹果连作(未轮作玉米)相比:玉米(2 a)-苹果轮作和玉米(1 a)-苹果轮作后的根际土壤脲酶活性在成熟期增长幅度最大,分别达105.95%和78.30%;土壤磷酸酶活性在幼果期分别显著增高26.45%和23.06%,在膨大期分别显著增高37.07%和29.19%,在成熟期分别显著增高45.59%和18.77%;转化酶活性在膨大期增长幅度最大,分别达53.11%和47.29%。pH值在成熟期提高最大,玉米(2 a)-苹果轮作和玉米(1 a)-苹果轮作与苹果连作(未轮作玉米)相比,pH值由6.86分别提高到7.57与7.25。综上,苹果连作可使根际土壤酶活性和pH值显著降低;玉米-苹果轮作对苹果连作障碍有明显改善作用;轮作2 a玉米较轮作1 a玉米更能缓解连作障碍。

In order to clarify the functional mechanism for alleviating the apple continuous cropping obstacles under corn-apple rotation system,the impact of corn plantation years( 1 a or 2 a) on rhizosphere soil enzyme activities and pH value of continuous cropping apple orchards were studied. Rhizosphere soil of apple orchard in flowering stage,fruitlet stage,expanding stage and maturity stage was collected,respectively. It was shown that rhizosphere soil urease activity,phosphatase activity,invertase activity and soil pH value all showed a trend of non-continuous cropping of apple > corn( 2 a)-apple rotation > corn( 1 a)-apple rotation > continuous cropping of apple in all tested apple growth stages. Compared with apple continuous cropping,rhizosphere soil urease activity in the treatment of corn( 2 a)-apple rotation and corn( 1 a)-apple rotation increased the most in the maturity stage,which were 105. 95% and 78. 30% ,respectively. The activity of soil phosphatase in the treatment of corn( 2 a)-apple rotation and corn( 1 a)-apple rotation was significantly increased by 26. 45% and 23. 06% ,respectively,in fruitlet stage,and by 37. 07% and 29. 19% ,respectively,in expanding stage,and by 45. 59% and 18. 77% ,respectively,in maturity stage. The activity of soil invertase increased the most in expanding stage,reaching 53. 11% and 47. 29% ,respectively. Meanwhile,compared with apple continuous cropping,of which pH value was 6. 86,the rhizosphere soil pH in corn( 2 a)-apple rotation and corn( 1 a)-apple rotation was increased to 7. 57 and 7. 25,respectively. In summary,apple continuous cropping reduced soil enzyme activities and pH value,yet corn-apple rotation could remarkably increase soil enzyme activities and pH value. Corn( 2 a)-apple rotation had better alleviation effect than that of corn( 1 a)-apple rotation on obstacles of apple continuous cropping.