Study On The Water And Fertilizer Retention Properties Of Super Absorbent Polymer And Its Effect On Crops

At present, with the increasingly serious water shortage situation, to develop water saving agriculture and promote water-saving irrigation techniques is one effective measure to solve the problem of agricultural water resources shortage in China. Super absorbent polymers (SAP) technology, a high-tech chemical water-saving technologies, is developing rapidly in recent years. The main objective of the present study was to investigate the interactive mechanisms of three kinds of SAP (Polyacrylamide, PAM; Attapulgite/ Polypropylic acid,WT; Polyacrylate sodium, HM), nitrogen fertilizer solution, soil and crop with four experiments, such as measurement of the water absorb rate, soil water and nutrient retention properties, soil cumulative evaporation and soil aggregates distribution, the growth, physiology, water and nitrogen use efficiency of maize plant with SAP and fertilzer application in soil. The main conclusion of the research as the follow.(1) The experimental SAP has a strong absorption capacity. The absorption rate of SAP showed a descending trend with the increase of salt and fertilizer concentrations, but a little absorption water rate was found with SAP in urea solution. The effect of ionic type on water absorption rate of SAP was presented as Na⁺2+2+3+ , the WT showed a strong anti-ion characteristic. The absorption ability of three SAP in nitrogen fertilizers was PAM3^--N and NH₄⁺-N in soil centrifugal filtrate significantly, as with the increased dosage of SAP, the accumulated amount of NO₃^--N and NH₄⁺-N presented a downward trend. In respect of the effect of the mixed application of SAP and nitrogen fertilizer on the accumulated amount of NO₃^--N and NH₄⁺-N in soil centrifugal filtrate, the capacity of the three SAP is : HM3^--N and NH₄⁺-N in soil aggregate also increased with the increase application of SAP.(5) The interaction between SAP and nitrogen fertilizer had effect on the physiological properties of maize in seeding stage, nutrient absorption and water utilization efficiency. To be specific, in respect of the effect on the aboveground dry biomass, leaf chlorophyll content and root activity in maize, the amount of nitrogen fertilizer plays the most important role, followed by the dosage of SAP, and then the variety of SAP. In respect of the effect on nitrogen absorption, the dosage of SAP plays the most important role, followed by the amount of nitrogen fertilizer, and then the variety of SAP. In respect of the effect on water use efficiency (WUE) of maize in seedling stage, the dosage of SAP ranks the first, followed by the variety of SAP, and nitrogen fertilizer affects the least.