Abstract:

The influence of 28 years fertilization into soil on crops outputs of root crops (sweet potato) was studied in three typical parent material soils in South Hunan under long-term location test. The results showed that: Among the three typical parent material soils, the yield of sweet potato planted in purple soil was the best (the highest annual output), and NPK treatment was the best in purple soil (the highest annual output). With planting sweet potatoes in the three types of parent material soils, CK treatment was the worst. The root yield (underground) of sweet potato planted in purple soils was in sequence of NPK > OM > CK, while the root yield (underground) of sweet potato planted in quatenary red soil or granitization red soil was in sequence of OM > NPK > CK. Among the NPK treatment in quaternary red soil and granitization red soil, 80% of that had no output, only the region near the edge of district cement stalk could find sweet potato grow. Among the root yield (underground) of sweet potatoes planted in three parent material soils (6 treatments in each parent material), the treatment of upground crop straw returning to field was better than the treatment of removing the upground crop straw away.