Research On The Mechanism And Technology Of Modified Rice Soda Saline Alkali Soil In Western Jilin Province

Saline alkali soil in the western part of Jilin province is a type of inland soda saline alkali soil, which is the most difficult type to ameliorate and utilize that covers an area of about 1.7 square kilometers, and has a great potential for the cultivated land resource. More than the last half century, soil researchers always focus on the study of ameliorating and utilizing soda saline alkali soil. Practice shows that rice growing is an important way to ameliorate. But as a result of soda saline soil salt composition is given priority to with Na+, CO32-, HCO3-, and it’s a complex area of solonchak, solonetz, and salinization meadow soil, which has obvious micro-regional distribution. Soluble salt content in surface soil is 0.20%~0.64%, p H 8.0~10.8, ESP 36.5%~48.5%, soil colloid is highly fragmented and has very low soil fertility. Conventional rice growing mode not only cost a lot of fresh water resources, but also can float seedling and submerge plants after seedling transplanting, the early rice yield is very low precipitously. Through the soil profile morphological and physical and chemical properties, found that regular rice need 5 years of continuous cropping can preliminary form “desalination surface” soil.Therefore, in order to speed up forming the “desalination surface” of new paddy soil, to promote the surface soil “curing”, and to further improve the soil fertility to adapt to the growth and development and realize the goal of stable high yield of rice, this study start from the mechanism of soda saline soil amelioration. Reveal use aluminum ion modifier application as the core of soda saline soil using the improved mechanism, and present the method of quickly create “desalination surface” and technology of soil organic matter rapid ascension. At the same time, put forward the technology of efficient utilization of water resources from the field management way. Based on pot experiment, field investigation and indoor analysis of test results, obtain the following conclusions:(1)In the paddy field of different year of assart, choose the paddy arable layer soil which rice yield is stable as the standard formation of “desalination surface”. Through the description of its top layer soil profile morphological characteristics and the test analysis of physical and chemical indicators, determines the new paddy saline-alkali soluble salt content < 0.30%, p H < 9.5, ESP < 35%, as a “desalination surface” evaluation indexes and quantitative standard.(2)The profile feature of soda saline soil "desalination surface" arable layer, such as thickness, color, root volume and structural can be used as the "desalination surface" field IV observation of qualitative evaluation index. Major expressions are: arable layer reach 15~20cm, color dim obviously, root volume increased significantly, the soil granular structure, loose texture, calcareous reaction weakly.(3)Along with the increasing year of rice growing, the arable layer of soil soluble salt content showed a trend of gradual decline, content of K+、Na+、CO32-、HCO3- reduced significantly, surface convergence phenomenon of salt basically be suppressed. Soda saline soil by soda type gradually transition to a soda- sulfate type and sulfate type.(4)The soda saline soil after adding aluminum ion modifier, aluminum ion hydrolysis to produce a large number of H+, neutralize OH- in water, reduce the soil p H value. Aggregation state of aluminum ions that formed by hydrolysis, promote the soil colloid reunite, at the same time the exchange adsorption on soil colloids of Na+、K+、Ca2+、Mg2+, in the solution with water, have played an important role to the improvement of exchange dealkalization. Test shows that the aluminum ion modifier addition amount of 0.4%(more than arable layer soil heavy), after drainage were 2 times, p H value can be reduced to 8.2 or so, meet the requirements of “desalination surface” data.(5)Under the condition of use of aluminum ion modifier, aluminum ion can produce Polymeric hydroxy aluminum ion in hydrolysis reaction, form the organo-mineral colloidal complex with soil mineral colloid and humus molecules, compare with clay mineral in soil(dominated by montmorilonite) the maximum amount of adsorption on soil organic increased 2.73~4.06 times. Promote the organo-mineral colloidal in soil(G0) transform to G1 and G2.(6)From the perspective of soil preparation way of water resource utilization, Put forward the best way to field management of high efficient utilization of water resources in saline-alkali soil grow rice. Optimized the field management model only, water production efficiency in new saline-alkali water field is 1.34 times of common management. The management of straw return to field and enriching organic fertilizer within 3 years can increase organic matter content to more than 30 percent, Accelerate rapid formation of “Slaking arable layer” on heavy saline sodic soil.Conclusions above point that under the use of aluminum ion modifier, planting rice in Saline sodic soil can “dealkalization and demineralization by ion exchange process”, “seepage on saline-alkali land for leaching”, accelerate formation of “desalination surface” and accumulation of organic matter and improve soil fertility. Break traditional point of “Planting rice in Saline sodic soil will improve the underground water level, Aggravate secondary on surface layer”. Established by soluble salt content, ESP and p H saline-alkali land as the core indicators of paddy field "desalination surface" qualitative and quantitative evaluation index system and standard, saline-alkali land for paddy field "desalination surface" create provides scientific basis. Put forward the rapid ascension of soil organic matter and the technology of efficient utilization of water resources model. For soda saline soil in western jilin province rice improvement, improve food production, to ensure national food security and improve the ecological environment to provide the important theory and technical support, has great social, ecological and economic benefits.