基于分布滞后非线性模型的蟹塘水质受投喂量影响的关系分析

Analysis of the relationship between water quality of crab pond and feeding amount of feedstuff based on distributed lag non-linear model

为明晰投喂量与蟹塘水质变化之间的关系,基于2020年宜兴市中华绒螯蟹养殖试验池塘的水质、气象和投喂数据,采用分布滞后非线性模型分析饲料投喂量对溶解氧质量浓度、pH值等6个水质指标的影响。结果表明:水质变化与饲料投喂量之间存在长期滞后效应。相对于投喂量的中位数,在高投喂量下,溶解氧质量浓度在75%的观测点呈现显著减少的趋势,滞后期内最大负效应达-1.781 mg/L(95%置信区间:-2.916~-0.647 mg/L)。氨氮质量浓度、电导率、pH值在部分滞后期显著减小,浊度显著上升。在低投喂量下,氨氮质量浓度和浊度在部分滞后期显著增加,其余指标显著减少。但高、低两种投喂量情景下叶绿素质量浓度变化的滞后效应均不显著。另外,同一深度不同位置及同一位置不同深度的溶解氧质量浓度受投喂量影响的滞后效应模式有所不同。研究结果可为生产环境下投喂量对水质变化的影响分析和水质调节策略制定提供支撑。

To understand the relationship between feeding amount of feedstuff and water quality variation in crab pond, impacts of feeding amount of feedstuff on six water quality indicators including mass concentration of dissolved oxygen, pH value, mass concentration of ammonia nitrogen, mass concentration of chlorophyll, turbidity and conductivity were analyzed by using distributed lag non-linear model, based on data including water quality, weather and feeding from the experimental pond for Eriocheir sinensis breeding in Yixing City in 2020. The results showed that, there was a long-term lag effect between water quality change and feeding amount of feedstuff. Compared with the median feeding amount, under the condition of high feeding amount, mass concentration of dissolved oxygen showed significant decrease trend in 75% of all the observation points and the maximum negative effect during the lag period reached-1.781 mg/L(95% confidence interval:-2.916~-0.647 mg/L). Mass concentration of ammonia nitrogen, conductivity and pH value decreased significantly, while turbidity increased significantly during part of the lag periods. Under the condition of low feeding amount, concentration of ammonia nitrogen and turbidity increased significantly, while other indices decreased significantly during part of the lag periods. However, the lag effect of high or low feeding amount on mass concentration change of chlorophyll was not significant. In addition, the lag effect modes for the mass concentration of dissolved oxygen at the same depth of different positions and at the same position of different depths affected by feeding amount were different. This results can support analysis of the impact of feeding on water quality changes in the production environment and making strategies for water quality adjustment.