DONG He-Zhong, XIN Cheng-Song, LI Wei-Jiang, TANG Wei, ZHANG Dong-Mei, LUO Zhen
Cotton Science. 2009, 21(4): 290-295.
Soil samples (0~20 cm) from 318 saline cotton fields randomly selected in the Yellow River Delta were used to study the [JP2]characteristics of salinity,contents of organic matter and major nutrients.The results showed that,of the total 318 saline fields tested,the lightly salty (LS) fields (salt content <2.5g·kg-1),moderately salty (MS) fields (2.5~4.49 g·kg-1) and severely salty（SS）fields (>4.50 g·kg-1) accounted for 44.3%,40.6% and 15.1%,respectively. The levels of N,P,K in MS fields were moderate,but K level in LS fields was low. The contents of organic matter,N and P were deficient,but K content was abundant in SS fields where cotton had been planted shorter than 5 years.In contrast,the contents of organic matter,N and P were moderate,but K content was relatively low in SS fields where cotton had been planted longer than 5 years.Regression analysis showed a significant linear correlation between soil salt content (y) and soil solution conductivity (x) at 25°С (y=3.4058x+ 0.1427,n=27,R2=0.9964**). Normal emergence and stand establishment rates were obtained when soil salinity was lower than 2 g·kg-1. Rates of emergence and stand establishment were reduced to 60%~78% and 45%~55%, respectively,when salinity was 2~3g·kg-1.The emergence and stand establishment rates were only about 40% and < 30%,respectively,in saline fields with salinity higher than 4 g·kg-1.Reasonable agronomic measures for stand establishment and chemical fertilization should be taken according to the characteristics of salinity and fertility,to improve cotton productivity in saline fields.
