Melioration Of Saline-Alkali Soil With Sulfur In Northern Yinchuan Plain, Ningxia

Through the pot-culture and field experiment,we discuss the effects of sulfur to the alkali-saline soil in Pingluo,Ningxia hui autonomous region in soil physical and chemical properties and microflora.The results indicated:(1) Using the sulfur to the alkali-saline soil could decrease the soil pH.The effect was not significant because of the low soil alkalinity and abundant soil water in pot -culture experiment.In field experiment,the effect showed positive correlation with amount of sulfur in 0-20cm horizon,But in the 20-40cm horizon,there was not any tendency.(2) Sulfur oxidation lead to the change of soil EC.The content of soil SO₄^2-,Ca²⁺,Mg²⁺ and Na⁺ were increasing,and the content of soil CO₃^2- and HCO₃ were reduced by improved solubility of insoluble calcium and magnesium salt.At the same time,the content of soil Cl^-and K⁺ had little change.(3) The changes of salt ions resulted in the increasing of soil EC.In the pot -culture experiment and wheat field experiment(0-20cm),with the growing of sulfur amount the effect was more significant.The treatment S2 showed the best effect in maize field experiment(0-20cm).In 20-40cm horizon,soil EC had a complicated change because of other factors.(4) The use of sulfur reduced the content of soil exchangeable Na⁺,and showed a trend of positive correlation.(5) The CEC is determined by the amount of clay and the kind of clay mineral,the treatments did not change them,so the CEC had no significant difference;with the use of sulfur,soil ESP was decreasing and showed the regulation of positive correlation with amount of sulfur.(6) Soil available nutrients were affected.Because of a better soil fertility treatment,the soil available K had little change,but the available N and available P of sulfur treatment was less than CK2 in pot -culture experiment.In field experiment,available P and available K were increased;available N showed an increasing trend in wheat experiment.(7) The treatments improved the soil physical character,which could be obviously seen from the change of bulk density,soil porosity,soil field capacity and soil capillary height.In maize field experiment,the change of bulk density and soil porosity had close relativity with amount of sulfur.There wasn't any law between soil field capacity and soil capillary height and amount of sulfur.(8) Effect of soil microflora under sulfur treatments indicated that soil microbial diversity under sulfur treatment was same to control,total number of soil microbial of CK2 was more than sulfur treatment in august.With the passage of time,soil microbial diversity had a remarkable growth;the sulfur treatment had a better effect than CK2.In brief,using of sulfur already have improved the soil physical and chemical property and guided soil to a better status.