Chemical mulching technology and application of soil structure improver

With the economic and social development of   , the shortage of water resources has become a constraint to China's agricultural and economic and social development. The technology of water saving and water conservation in dryland agriculture is particularly important.

   chemical mulching technology is one of many water-saving technologies. It uses asphalt emulsion, epoxy hexane and high-carbon alcohol preparation, synthetic fatty acid residue preparation and other soil surface moisture preservation agents to make emulsion, spray to the soil surface to form a mulch film, which can hinder the evaporation of soil water, but does not affect the infiltration of precipitation into the soil, so as to achieve the purpose of water conservation, water saving and effective water supply. At present, two kinds of chemical preparations from La1ofima Company of Belgium are mainly used in dryland agriculture in the world: one is asphalt preparation Homofina, referred to as HA. The appearance of the preparation is brown-black latex, the basic component is asphalt, it is a hydrophilic emulsion, it can be diluted with water without precipitation, and the water can be kept in the soil. When the water evaporates, the dry asphalt can be redispersed in the presence of water. It has reversible change and is suitable for arid areas. The other is polyacrylamide preparation (Poyacryiamde), referred to as PAM. The appearance of the preparation is milky white colloidal liquid, the basic component is polyacrylamide, it can also be diluted with water without stratification, with many active groups, strong biological stability, not easy to be degraded by microorganisms in the soil, and non-toxic. Although drought-resistant and water-saving chemical mulching technology has been studied for several decades, it has not been widely used in production, and there are still many problems to be further solved.

The application of    soil improver in water-saving agriculture can improve soil, save water and protect fertilizer. According to the principle of the formation of aggregate structure, soil structure improver can improve soil structure by improving soil internal structure and material composition. Humic acid, cellulose, lignin, polysaccharide carboxylic acid and other substances were extracted from plant residues, peat and lignite as raw materials, which were used as cementing agents for agglomerated soil particles, or high molecular polymers synthesized by simulating the molecular structure and properties of natural aggregate cementing agents. The former type of preparation is natural soil structure improver, and the latter is called synthetic soil structure modifier. There are many kinds of synthetic soil modifiers, such as BIT emulsion, PAM and so on.

   soil improver is mainly applied by spraying and mixing. Drainage is to remove the powder directly into the topsoil, because the soil improver is difficult to dissolve into the soil solution, so the soil improvement effect of this application method is small. Under the same circumstances, if the improver is dissolved in water and sprayed, the physical properties of the soil will be significantly improved.

The dosage of    soil improver should follow the principle of appropriate amount. If the dosage is too large, not only the cost is high, the investment is large, but sometimes the phenomenon of concretization occurs, and too little dosage does not work. The study shows that there are significant differences in the application effects of the same soil improver in different types and properties of soil, and the application effects of different application methods and different amounts of soil improver are also different, even the same soil improver. The application effect is also different when applied in different soil layers of the same soil. Therefore, in specific application, the reasonable dosage should be determined according to the results of the preliminary test.