TITLE:
Contents and Changes of Potassium in Plough Layers of Xuancheng, South Anhui Province
AUTHORS:
Ka Lin, Decheng Li, Xiaodong Song, Chaolong Zu, Chaoqiang Jiang, Jia Shen, Chengxin Ma, Qin Gao, Qifa Zhu, Xuejun Ji, Guo Zhang, Lin Xue
KEYWORDS:
Rapidly Available Potassium (RA-K), Slowly Available Potassium (SA-K), Topsoil, Tobacco-Rice Rotation, Xuancheng City
JOURNAL NAME:
Agricultural Sciences,
Vol.8 No.5,
May
22,
2017
ABSTRACT: Xuancheng City is the dominant tobacco-planting area of Anhui province
due to the high quality of the tobacco leaves. However, the potassium content
in the tobacco leaves shows a gradual decreasing trend in recent years, which
may be attributed partly to the possible low potassium content in topsoil of
tobacco-planting farmland. Therefore, the content data in the year of 2005-2007
of rapidly available potassium (RA-K) of 7730 topsoil samples mainly under double
rice rotation or wheat/rice-rice rotation at that time and the content data of
slowly available potassium (SA-K) and RA-K of 124 typical topsoil samples in
the year of 2015 under tobacco-rice rotation were used and compared in order to
disclose the status of topsoil potassium and to provide a guidance for reasonable
potassium fertilization in Xuancheng. The results showed that in 2005-2007 RA-K
content ranged from 1 mg·kg-1 to 844 mg·kg-1 with an average of 68
mg·kg-1, and 82.7% of topsoil samples were insufficient in RA-K (-1). Comparatively in
2015 SA-K content ranged from 230 mg·kg-1 to 1340 mg·kg-1 with an average of
595 mg·kg-1, and 13.7% of soil samples were insufficient in SA-K (-1); RA-K content ranged
from 46 mg·kg-1 to 352 mg·kg-1 with an average of
134 mg·kg-1, and 25.8% of soil samples were insufficient in RA-K (-1). The above data show
that RA-K content has increased gradually in farmland topsoil mainly due to
fertilization since 1980s, particularly to farmland under tobacco-rice
rotation, but insufficient RA-K in topsoil is still widely and serious for
farmland under double rice rotation or wheat/rice-rice rotation. Under
tobacco-rice rotation, RA-K insufficiency usually occurred in the farmlands
which plant tobacco less than 3 years, indicating more potassium fertilizer
should be applied.