Gao Shikai, Zhang Xiaoyuan, Wang Songlin, Fu Yuliang, Li Weiheng, Dong Yuanzhi, Li Yanbin, Dai Zhiguang
School of Water Conservancy, North China University of Water Resources and Hydropower, Zhengzhou 450045, China.
College of Agricultural Engineering, Henan University of Science and Technology, Luoyang 471003, China.
Polymers (Basel). 2024 Oct 14;16(20):2890. doi: 10.3390/polym16202890.
To investigate the mechanism and influence of applying gamma-polyglutamic acid (γ-PGA) on soil water infiltration, laboratory experiments and numerical simulations were conducted using Hydrus-1D. These studies assessed the impact of various application rates of γ-PGA on soil water characteristic parameters. Orthogonal simulation experiments on soil bulk density, γ-PGA application rates, and burial depths were performed utilizing predefined soil water characteristic values (twelve groups: nine groups of numerical simulation experiments and three groups of laboratory verification tests), and the soil infiltration characteristics were analyzed. Concurrently, an empirical model was developed to elucidate the relationships between the empirical model parameters and influencing factors, as well as to examine the sensitivity of these factors to changes in soil infiltration rate. The relationship between cumulative infiltration and the distance of wetting front movement, based on the water balance equation, was refined. The results indicated that γ-PGA significantly affected soil water characteristic parameters, where the saturated water content and the reciprocal of soil intake suction increased with rising γ-PGA applications ( < 0.01), while the saturated hydraulic conductivity and the parameter n decreased ( < 0.01), with no notable changes in the retained water content ( > 0.05). The trend in cumulative infiltration influenced by various factors could be modeled by a capacitive charging model function, which yielded a superior fit. A negative correlation existed between the sensitivity index and all the influencing factors ( < 0.05), with the order of influence being soil bulk density, γ-PGA application rate, and γ-PGA burial depth, respectively. Utilizing the modified water balance equation, the ratio of cumulative infiltration to wetting front migration distance corresponded more closely with a power function. These findings provide a theoretical foundation for further studies on the effects of γ-PGA on crop growth characteristics in fields and the optimization of γ-PGA technical element combinations.
为了研究施用γ-聚谷氨酸（γ-PGA）对土壤水分入渗的机制及影响，采用Hydrus-1D进行了室内实验和数值模拟。这些研究评估了不同γ-PGA施用量对土壤水分特征参数的影响。利用预先定义的土壤水分特征值（十二组：九组数值模拟实验和三组室内验证试验），对土壤容重、γ-PGA施用量和埋藏深度进行了正交模拟实验，并分析了土壤入渗特征。同时，建立了一个经验模型，以阐明经验模型参数与影响因素之间的关系，并检验这些因素对土壤入渗率变化的敏感性。基于水平衡方程，细化了累积入渗与湿润锋移动距离之间的关系。结果表明，γ-PGA对土壤水分特征参数有显著影响，其中饱和含水量和土壤进气吸力的倒数随γ-PGA施用量的增加而增加（<0.01），而饱和导水率和参数n则降低（<0.01），而持水量无显著变化（>0.05）。各因素影响下的累积入渗趋势可用电容充电模型函数进行模拟，拟合效果较好。敏感性指数与所有影响因素之间存在负相关（<0.05），影响顺序依次为土壤容重、γ-PGA施用量和γ-PGA埋藏深度。利用修正后的水平衡方程，累积入渗与湿润锋迁移距离的比值更符合幂函数关系。这些研究结果为进一步研究γ-PGA对田间作物生长特性的影响及γ-PGA技术要素组合优化提供了理论依据。
