Study On The Synthesis And Application Of The Starch Super Absorbent Resin With Phosphorus

Drought resistance and saving water is an inevitable choice for China's agricultural development, because water shortage is the major problem in agricultural production in our country. In addition, the total phosphorus content in soil is not high in both north and south of China, effective phosphorus is easily fixed in the soil, and crops are difficult to use it. Increasing soil moisture content, reducing soil moisture evaporation and improving the utilization of phosphorus in the soil are extremely important.In this paper, six kinds of the starch super absorbent resin(SSAR) are synthesised with using corn starch as matrix, acrylic acid and acrylamide as monomer, adding the phosphorus to the reaction system with a solution polymerization, These SSARs are different in the phosphorus content and phosphorus compounds (WP0,WP1,WP2,WP3 and WPâ… ,WPâ…¡). The characteristics of the SSAR were identified. The rape as tested crops for the pot-experiment setted up four treatments, named CK(without the starch SAR, but have the phosphorus with the equivalent P2O5 content of WP2),WP0,WP2 and WPâ…¡, four phosphorus levels, were 0.00,0.500,1.00,2.00g/kg soil respectively, repeated three times for each level. The length and width of the leaf and stem diameter and other morphological index of rape were observed during the growth process of rape. The characters of the soil and the biomass of rape were determined after the harvest. The major findings are as follows:1. The starch SAR has high water absorption rate. The water absorbency in distilled water is up to 208.17g/g(WP0). The water absorbency of SSAR without phosphorus in distilled water is higher than these with phosphorus, the water absorbency of SSAR with phosphorus is between 145.13g/g-205.74g/g.2. The SSAR has fast water absorption rate and good regeneration performance. Experiments show that the water absorbency in distilled water of SSAR with phosphate can reach 70.39g/g during the first 2 minutes. The rate of absorption is fast at the first 16 minutes, then levels off and reaches water saturation. The regeneration of SSAR with the phosphate by cycle of wetting and dry is still well after 6 times, water absorbency is still 175.84g/g. In addition, the moisture retention and inhibiting soil water evaporation of the SSAR with phosphate are superior to the control treatment, indicating that the SSAR has a higher water retention.3. The concentration and type of base ions in solution affect the absorption rate of the SSAR significantly. Water absorbency is up only to 34.35g/g in 0.9% NaCl solution; The sequence of influence power of reducing the water absorbency is Mg2+> Na+> K+ at the same concentration and the same anion because the SSAR has stronger water absorption, but the cation has greater impact on water absorbent rate to the SSAR.4. The SSAR with the phosphorus has good phosphorus release. The phosphorus contents both the total and the available phosphorus is higher in the solution or in the soil with the SSAR with phosphorus than without phosphorus. This means that phosphate and the SSAR compositing system is feasible, and the SSAR with the phosphorus does have contain phosphorus effect.5. The SSAR with phosphorus can improve soil physical properties and improve the performance of soil drought. The SSAR with phosphorus can increase the germination rate of rape, during the drought season the soil with SSAR can maintain a higher moisture longer, reduce water evaporation, finally extending the growth times for rape. At the same time, the SSAR with the phosphorus can reduce soil bulk density and improve soil structure.6. The P-fertilizer efficiency of SSAR is affected by soil temperature and water condition. With the same phosphorus content in theory, WP2,WPâ…¡,CK, CK treatment is better than the SSAR in rapeseed plants and biomass yield on physiological indicators in seedling period. By incubation experiment with different temperatures the phosphorus releases faster at a higher temperature than at a lower temperature. This meams that the SSAR with the phosphorus has the function of P-release, and phosphorus releasing rate is affected by both the temperature and moisture.