秸秆成型块保水载肥腐解试验

The Test on Water Retention and Decomposing Properties of Straw Blocks

为探究玉米秸秆碎料压缩为成型块后作为干旱沙土地区保水载肥基质的可行性,模拟辽西北部地区土壤情况及环境条件,研究秸秆成型块保水性和腐解特性。保水性试验将松弛密度为540kg·m^(-3)的秸秆成型块分别置于有沙土和无沙土的两个玻璃盒中,以释水情况评价其保水性;采用尼龙网袋法,将540kg·m^(-3)的秸秆成型块埋藏在盛有沙土的有机玻璃盒内,加300g水,通过网络环境监控云平台实时监控成型块腐解的环境条件,以研究成型块的腐解特性。研究结果表明:成型块在沙土中释水较自然释水量少且缓慢,随时间变化分别符合对数模型与线性模型,拟合方程的回归系数均大于0.9,成型块在沙土中保水性显著增强;成型块腐解率呈现出前期(0~60d)腐解量快速增加,中期(60~100d)缓慢,中后期(100~130d)增加,后期(130~200d)再次放缓的状态;成型块的腐解速率整体呈现出前期腐解加快,中期、中后期以及后期腐解速率依次减小的趋势;通过多元线性回归方法分析得出腐解期温度、相对湿度和腐解时间是秸秆腐解特征的主要影响因子,其主次为腐解期温度>腐解时间>相对湿度。所建立的回归模型(R2>0.99)揭示了秸秆成型块腐解规律,为秸秆成型块作为植物营养靶向载体提供理论依据。

In order to explore the straw blocks compressed by corn stalk scraps as a carrier for water retention and fertilizer supply in arid sandy soil areas,soil and environmental conditions in the Northwestern Liaoning were simulated to study the water retention and decomposition law of straw block in sandy soil.In the water retention test,the straw blocks with a relaxed density of 540kg·m^(-3) were placed in two plexiglass boxes with and without sandy soil,and the water retention of the blocks was evaluated by the water release of the blocks under two simulated environment conditions.Using the nylon mesh bag method,a straw block with a relaxed density of 540kg·m^(-3) was buried in a plexiglass box filled with sandy soil,300g of water was poured in it and was covered the glass box with plastic wrap.And then the soil temperature and humidity moisture sensors were inserted to test the decomposing characteristics.Through the network environment monitoring cloud platform,the decomposing environment of the straw blocks was monitored,and the temperature and humidity were recorded during the decomposing period.The results showed that the relationship between the amount of water released from the billet and the natural water release in sandy soil varied with time,which accords with the logarithmic model and the linear model,and the regression coefficients of the fitting equations were all more than 0.9.The decomposing rate of the shaped block showed a rapid increase in the early stage(0-60d),slowed down in the middle stage(60-100d),increased in the middle and late stage(100-130d),and slowed down again in the later stage(130-200d).The decomposing speed overall showed a trend that the decomposing speed in the early stage was accelerated,and in the middle and late stages decreased in turn.Moreover,the correlation between decomposition conditions and decomposition characteristics was analyzed by multiple linear regression method.The results showed that the main influencing factors of straw decomposition were temperature during decomposition period,relative humidity and decomposition time,and the order of importance was temperature during decomposition period,decomposition time and relative humidity,respectively.The correlation coefficients of the regression models established by decomposition test are 0.99,which verifies the validity of the relationship.The regression equation established in this paper reveals the decomposition law of straw block,which provides a theoretical basis for straw block as a targeted carrier of plant nutrition.