Study On The Mechanism And Application Of Improvement Of Bentonite In Sandy Soil

Cultivation experiments with sand filter pipe.glass house culture tests and model experiments of nutrient leaching have been carried out to study the effect of different dosage of bentonite on the water and nutrient conservation, the content of organic matter,the composition of humus,the content of oxy-functional group,the characteristics of infrared absorption spectrum, the soil organo-mineral complex of sandy soil.The results showed that the reasonable dosage of bentonite could improve the physical and chemical property of sandy soil. If the percentage of the dosage of bentonite added to sandy soil is up to 20%, the moisture of the treated sand soil would raise 20%, the enzyme activity of hydrogenperoxidase would doubled than before. On the basis of this case, if organic materials have been added to the treatments, the water content of sand soil would raise by 16%, and the content of organic matter would improve by 20%, the enzyme activity of hydrogenperoxidase would increase 1.1 times of that of before, what's more, Use of bentonite was beneficial to improvement of the total of humic acid and fumic acid. It can decrease the decomposition rate of organic substance, improve humification coefficient, increase the enzyme activity of hydrogenperoxidase and improve the complex of organic-inorganic matter, so it can raise the quantity and quality of organic matter and improve the sand soil fertility.Compared with using maize straw,using bentonite will be a little higher in the degree of complexing.By using the organic materials such as maize straw in sandy soil, the combined form of humus of the sandy soil exist mainly in the form of loose and compact combined form of humus.And it is 41.01% and 38.31% respectively by the percentage of the whole carbon. Firm combined form of humus only accounts for 20.67% by the percentage of the whole carbon. On the basis of this case, if bentonite have been added to the treatments, the close combined form of humus of sandy soil would increase to 44.67% by the percentage of the whole carbon, the loose combined form of humus of sandy soil would drop to 30.92%,and the firm combined form of humus would account for 24.21%.It indicates that bentonite play an important role in the promoting the loose combined form of humus to resolve and accelerating the close combined form of humus to synthesis,and help to increase the inside stability of soil system.The bentonite not only has raised the content of soil organic and the total amount of humus, but also has improved the quality of humus,and it mainly lies in the accumulationof HA in the form of close and steady combined form of humus,what's more,it has improved the HA/FA too.Within the range of 0 to 5% of the bentonite's consumption,It can obviously strengthen the soil's conservation of nitrogen, reduce the leaching loss of nitrogen, promote the sprouting rate,growth and the output of crops.In a word, the best economic amount of application of bentonite is 5% by the percentage of the soil weight in the sandy soil.