Potato Growth and Soil Enzyme Activities as Affected by Rotation or Continuous Cropping Cultivation

  Objective  Effects of rotation or continuous cropping potatoes on the plant growth and soil chemical and biochemical properties were studied.

  Method  A 5-year fix-point experiment was conducted to compare the effects of a potato-maize rotation cultivation, the commonly practiced continuous annual planting of potatoes in spring, and an intensified continuous spring and autumn cropping in a same year on the morphological indices of the potato plants as well as the enzyme activities and total effective and available nutrients in the soil.

  Result  Both common and the intensified continuous cropping caused reductions on the plant height, stem girth, and leaf area but an increase on the root length in comparison with control. On the other hand, the rotation cultivation of potatoes and maize raised those first 3 indicators in increasing differentiations from the other cropping practices along with growth of the plants. Meanwhile, the enzyme activities in the soil were higher than the continuous cropping fields, especially the intensified continuous cropping one. In addition, the available nutrients were also significantly affected by the cultivation practices. For instance, at time of crop maturation, the total nitrogen, total potassium, and total phosphorus in the soil, where the cultivation was conducted by rotating potato and maize crops, were 4.98%, 6.79%, and 16.38%, respectively, higher than those in the soil under the common continuous cropping, and 13.02%, 15.21%, and 16.12%, respectively, higher than those under the intensified continuous cropping.

  Conclusion   Rotation cultivation of potatoes and maize significantly promoted the potato plant growth and development, enhanced the soil enzyme activity, and accelerated the transformation of available nutrients in soil to materially reduce the stress on the plants incurred by long-term continuous cropping.