3.3 Total N, available P and available K in soils
Contents of soil total N, available P and available K in the two
counties increased, and the increase was higher in Meixian County (Fig.
4). Total N in soils of Wugong and Meixian counties increased from 0.8 g
kg-1 and 0.9 g kg-1 in 1980 to 0.95
g kg-1 and 1.21 g kg-1 in 2017,
respectively. Available P in Wugong County increased 3.1 times from 9.6
mg kg-1 in 1980 to 30 mg kg-1 in
2017, whereas in Meixian County, available P increased from 4.9 mg
kg-1 in 1980 to 111 mg kg-1 in 2017.
Available K in Wugong County increased slowly from 1980 to 2017, from
112 mg kg-1 to 159 mg kg-1. For
Meixian County, the available K increased rapidly, from 107 mg
kg-1 to 509 mg kg-1.