Field experiments with different rotations were conducted in the soil where potato had been grown for two years .Soil enzyme activities and the number of microorganisms were tested and calculated during 4 growing periods .The results showed that compared with the control (bare) ,there was an increasing trend in soil catalase activity by the wheat- peas - potatoes crop rotation .Soil invertase activity was increased by the peas - potatoes - peas crop rotation and the largest increase was 47 .95% at the potato maturing stage .Soil polyphenol oxidase activity by crop rotations was lower than that by continuous cropping .Soil urease activity was changed obviously under different crop rotations .The urease activity by the peas - potatoes - peas crop rotation was 14 .73% higher than that by wheat - potatoes - wheat rotation during the potato tuber expansion period .The results of root zone soil microorganisms quantities during potato tuber ex-pansion period showed that with the increase of continuous cropping years ,the number of bacteria and total microorgan-isms went declined and fungi quantities were increased by 54 .66% .The number of bacteria and actinomyces were the highest by the wheat - peas - potatoes crop rotation reaching values of 6 .40 × 106 CFU·g - 1 and 2 .22 × 106 CFU·g - 1 , respectively .%在连续种植2年马铃薯的土壤上进行不同轮作方式田间试验，探讨轮作方式对马铃薯土壤酶活性及土壤微生物数量的影响。试验结果表明：与对照（裸地）相比，小麦－豌豆－马铃薯轮作时土壤过氧化氢酶活性有增加的趋势；豌豆－马铃薯－豌豆轮作条件下，土壤的蔗糖酶活性提高，且在马铃薯成熟期提高幅度最大，为47．95％。轮作条件下土壤多酚氧化酶活性低于连作；轮作方式不同，土壤脲酶活性变化明显，在马铃薯块茎膨大期，豌豆－马铃薯－豌豆轮作方式的土壤脲酶活性比小麦－马铃薯－小麦高14．73％。马铃薯块茎膨大期根区土壤微生物数量测定结果显示：随着连作年限的增加，细菌数量及微生物总量降低，真菌数量升高了54．66％；小麦－豌豆－马铃薯轮作后，土壤中的细菌、放线菌数量最高，分别为6．40×106 CFU·g －1和2．22×106 CFU·g －1。
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