Abstract:

To investigate and analyze the soil fertility status of paddy fields in Yingde, so as to provide reference for scientific fertilization management of rice production. In the main rice planting areas of Yingde, the soil samples for test were collected from surface of paddy rice field for 4 consecutive years, the soil pH, organic matter, total nitrogen, available nitrogen, available phosphorus and available potassium were detected, and the current status and variation characteristics of soil fertility in paddy fields of Yingde were analyzed. The results showed that the changes of soil pH, total nitrogen, available nitrogen and available potassium in Yingde paddy field were not significant during the 4 years, but the available phosphorus increased significantly. The paddy soil in Yingde City was generally acidic. The average pH values of the east, middle, northwest and southwest of Yingde City were pH 5.29, 5.94, 6.01 and 6.41, respectively. Soil was acidic in the east of Yingde City, and weakly acidic in other areas. In terms of soil organic matter, grade 3 soil accounted for 28.3%-39.4%, grade 4 soil accounted for 35.6%-41.7%, which was at a middle level. And organic matter in middle and northwest regions of Yingde City were significantly higher than those in east and southwest regions in this respect. The proportion of total nitrogen and available nitrogen in grade 1-3 soil was 70.0%-81.1% and 79.4%-87.2%, respectively, indicating that nitrogen was abundant in soil. Total nitrogen in the middle and northwest regions were significantly higher than those in east and southwest regions. Available phosphorus in grade 1-3 soil accounted for 73.9%-86.1%, which was at a rich level. The proportion of available phosphorus in eastern region was significantly higher than those in the southwest and northwest regions. Available potassium of grade1-3 soil accounted for 30.6%-37.8%, thus available potassium was generally lacking. In addition, the correlation between soil fertility indicators was significant. It is suggested to improve soil fertility by adding organic fertilizer and returning straw and green manure to the paddy field in Yingde, and appropriately reduce phosphate fertilizer and increase potassium fertilizer to balance soil nutrients. In addition, attention should be paid to the application of acid soil conditioner in east area of Yingde.

Key words: Yingde City, pH, organic matter, soil nutrients, fertility