微咸水-腐植酸肥耦合滴灌系统灌水器堵塞机理及调控方法

For the essential problems of the shortage of agricultural water resources and soil salinization in the northwest arid area, one of the effective solutions may be the combined application of saline water and humic acid fertilizer. However the flocculent precipitate under the coupling effect may cause more severe clogging of emitter, which has become the key barrier to the large-scale promotion of this technology. We design different experiment to regulate the emitters clogging of the drip irrigation system in coupling saline water and humic acid fertilizer, considering humic acid fertilizer types, concentration and saline water quality conditions. The application of three-dimensional white light interferometer, ICP-AES, XRD to analyze the distribution characteristics of the clogging material, the dynamic change process of chemical composition and quantitatively characterized the correlation of clogging parameters of the emitters with the composition of the clogging material, identifying the main influencing factors of flocculation and its quantitative relationship, and establish a kinetic model of humic acid complex formation, fragmentation and recovery under different factors, and then to reveal the inducing mechanism and effect of humic acid flocculation on emitters clogging. Finally we propose a method of controlling clogging by chelating agent with humic acid fertilizer by application of new chelating agents such as IDHA、GLDA and MGDA, and it provides theoretical basis and technical support for further solution of the problem of emitters clogging.

针对西北旱区农业用水资源紧缺与土壤盐渍化突出的问题，应用微咸水与腐植酸肥料联合施用将成为有效的解决途径之一，但耦合作用下腐植酸肥料对滴灌系统灌水器堵塞的影响机理尚不清晰。因此，本项目以微咸水-腐植酸肥耦合滴灌系统灌水器堵塞规律入手，充分考虑腐植酸肥料类型、浓度以及微咸水水质条件，利用三维白光干涉形貌仪、X射线衍射仪等先进技术与方法，研究堵塞物质的分布特征与化学组分动态变化过程，定量表征灌水器堵塞参数与堵塞物质组分含量之间的相关关系；辨识影响灌水器絮凝沉淀堵塞物形成的主要影响因素及其定量关系，建立不同因素影响下腐植酸絮凝沉淀形成-破碎-再恢复的动力学模型，揭示腐植酸絮凝过程对灌水器堵塞的诱发机制与效应；探索利用IDHA、GLDA、MGDA等新型可降解螯合剂复配腐植酸肥料进行改性，提出适宜微咸水滴灌系统高效利用腐植酸肥料的螯合剂复配控堵方法。为进一步系统解决灌水堵塞问题提供理论依据和技术支持。

滴灌条件下微咸水与腐植酸肥料联合施用可作为解决农业用水资源短缺和抑制土壤酸化的有效途径，但微咸水-腐植酸肥耦合滴灌系统灌水器堵塞机理尚不清晰。本项目以此为题，借助滴灌堵塞原位测试平台，运用三维白光干涉形貌仪、X射线衍射仪等先进技术与方法，系统的研究了不同类型腐植酸肥料施用条件下灌水器堵塞发生规律与堵塞物质分布，探究并定量表征了微咸水水质因子的影响效应，并利用新型螯合肥与腐植酸肥配施，探索适宜微咸水滴灌系统高效利用腐植酸肥料的螯合肥联合施用控堵方法。经过三年的研究，获得的主要成果有：（1）与常规肥料(CK)相比，腐植酸肥处理富含大量的活性基团，会与水中阳离子形成稳定的可溶性络合物，间接影响了堵塞物质中沉淀和颗粒污垢的产生，且随着HA施用量的增加，滴灌系统的防堵塞效果更好。（2）微咸水中钙镁离子浓度的提高会显著增加灌水器的堵塞风险，离子浓度越高，堵塞越严重，且高钙微咸水导致了更为严重的堵塞，相同浓度条件下，高镁微咸水下Dra和CU较高钙微咸水分别高9.16%-32.17%和8.31%-51.13%，其主要是因为镁离子的加入改变了碳酸盐的晶型，减缓了污垢的形成速度，从而使得碳酸盐的含量显著降低19.74%-40.21%，减少了灌水器堵塞的风险。（3）螯合肥与腐植酸肥配施条件下，两种新型螯合肥EDTA-Zn和IDHA-Zn的增施能够进一步缓解灌水器的堵塞，且增施IDHA-Zn的控堵效果优于EDTA-Zn肥，初步确定了适宜的螯合肥配施有效施用浓度。研究成果已发表SCI论文3篇、1篇SCI论文在审。研究成果可为进一步系统解决灌水堵塞问题提供理论依据和技术支持。