Water-holding Capability And Effects On Soil Microorganism Of Two Super Absorbent Polymers Made From Chinese Fir And Bamboo Sawdust In Forestry

Soil and Water Conservation was the subject of eco-environmental construction and was veryimportant for the development of Agriculture and Forestry. Therefore, the application of SuperAbsorbent Polymer as a new approach to save water agriculture, had extremely important meanings inresisting drought and saving water of Chinese Agricultural.This objective of paper is to evaluate the application potential and environmental risks of twosuper absorbent polymers (SAPs) respectively made from Chinese fir (CF-SAP) and bamboo sawdust(BB-SAP) by contrast with commercial SAP:Potassium Polyacrylate (PP-SAP) by means ofmeasurement of water absorption capacity of different types of SAPs and their effects on soilphysiochemical and biological properties. The results were as following:1.Three SAPs in pure water all had strong water absorbing ability, which the water absorbency ofPP-SAP was the largest, while CF-SAP was the smallest;when mixed with soil, CF-SAP and BB-SAPhad stronger water retaining capacity than PP-SAP while soil made little influence on them, andCF-SAP was stronger than BB-SAP.2.To some extent，the soil water-preserving rate was positively correlated with dosage of SAPs:the more SAPs，the larger soil water-preserving rate; when0.5%,0.25%of CF-SAP and BB-SAPwere applied into soil, soil field capacity were respective73.81%and58.8%for CF-SAP,67.8%and49.3%for PP-SAP,58.4%and46.5%for BB-SAP,which were significantly higher than that for CK35.8%(with no any SAP).3.When0.5%,0.25%of CF-SAP and BB-SAP were applied into soil, soil field capacity wererespective73.81%and58.8%for CF-SAP,67.8%and49.3%for PP-SAP,58.4%and46.5%forBB-SAP,which were significantly higher than that for CK35.8%(with no any SAP). The resultsrevealed from dynamics of soil (mixed with0.25%of SAP) water content during70days observationthat the maximum moisture content with respective43.21%，40.57%and38.58%for CF-SAP, BB-SAP, PP-SAP were higher (P<0.05) than CK(35.59%), while PP-SAP and CK were at similar level inmost of time. The advantage of CF-SAP and BB-SAP in water absorption was decreasing with thetime and almost disappeared in70days.4. Soil pH was improved by three SAPs and while soil available N, P and K were observed nochange except available K in PP-SAP treatment. There were no adverse effects on soil bacteria and fungi being detected, on the contrast, CF-SAP and BB-SAP SAP had a positive effect on bacteriainstead. CF-SAP and BB-SAP exhibited better influence on both water retention and soil microbialactivity, and had a good potential to be applied in forest in southern China. The recommendedCF-SAP or BB-SAP dose is0.5%based on dry soil weight.