Effects Of Super Absorbent Polymers On Growth And High-Efficient Use Of Water And Fertilizer Of Pepper

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. Superabsorbent polymers applying have become a means of chemical saving water in agriculture in recent years. Effect of superabsorbent polymers (SPA) on the growth and chlorophyll content of leaves, the photosynthesis, enzymes activities, as well as osmolities were conducted with pepper variety’Chaoyue No.5’in flowering stage under10days and20days medium water stress and the subsequent recovery process. We also study the effects of combination superabsorbent polymers (SPA) with nitrogen on growth and photosynthesis of pepper during flowering period using SAP absorbing carbamide. The main conclusions of the research are the followings.(1) Adding2%o of SAP significantly decreased stomatal limitation (Ls), water efficiency (WUE), significantly increased the plant height, stem diameter, dry fresh weight, chlorophyll content, and photosynthetic rate (Pn), intercellular CO2(Ci), stomatal conduct (Gs), transpiration rate (Tr) under the water stress. Under moderate water stress SAP can significant mitigate this damage in a short period of time, while the effect of SAP is limited with the time. When resume the normal water supply, the plants’growth, chlorophyll content and photosynthetic parameters were significantly higher with SAP compared with those not added SAP, while the recovery effect under short time stress was significantly better than the long time stress. It indicates that SPA treatment could increase photosynthetic parameters, improve the growth and relieve the water stress of damage on pepper by increasing the content of chlorophyll, and with the shorter time of water stress, the better effect of the SAP.(2) Adding2%o SAP significantly increased the plants growth, decreased SOD, APX, CAT, POD, soluble sugar and protein, MDA and electrolyte leakage. SAPs can significantly alleviate the damage in a short period of water stress, while with the time of water stress prolonged, SAPs had limited mitigation effect. After rewatering, plants with SAPs growth was significantly higher compared with the plants without SAPs, and osmolities, accordingly, MDA and electrolyte leakage were significantly decreased, and the recovery was significantly better under short time water stress. This indicates that SAPs could increase the plants growth through decrease enzymes activities, the content of osmolities, MDA and electrolyte leakage.(3) The results showed that combination SAP with nitrogen significantly increased the height, stem diameter, fresh weight, dry weight, nitrogen accumulation and chlorophyll content of leaves, as well as the Pn, Ci, Gs and Tr, but decreased the Ls and WUE under the same nitrogen condition.(4) The growth, chlorophyll content, Pn, Gs, and Tr of pepper with SAP combining0.75nitrogen treatment is significantly higher than the1nitrogen treatment. It indicates that using SAP absorbed carbamide can increase the fertilizer use efficiency, and decrease the lost of fertilizer.