农作物秸秆基新型保墒缓释肥料的制备及其性能研究

Droughts and low fertilizer use efficiency are the important factors that limit the agricultural production in the western region. The preliminary experiments show that the water retention slow-release fertilizer, which integrates slow-release fertilizer technology and superabsorbent resin, could efficiently improve the fertilizer use efficiency and water resource. This project focuses on the development of environmentally friendly, biodegradable, low-cost multifunctional slow-release fertilizer, based on biomass resources of crops straw matrix, urea and ammonium zinc phosphate and ammonium polyphosphate as fertilizer raw materials, chitosan，cellulose, and konjac glucomannan as raw materials. Crops straw-based water retention slow-release fertilizers will prepared by coating method and adsorption.So, the water retention slow-release fertilizer has function of water absorption , water conversation, drought resistance and moisture conservation, it also enabled the nutrients release slowly.The nutrients content of sample, the release properties of nutrients in the soil, the degradation of the coating materials, the influence of the products on water-retention capacity of soil, as well as the function of improvingthe soil conditioning were investigated in details.The introduction of crops straw is not only environmentally-friendly, but also can effectively reducing the cost of slow release fertilizer. Therefore, in consideration of the economic and ecological environment, the development of novel crops straw-based slow release fertilizer has important practical significance for the development of sustainableand efficient agriculture.

干旱缺水和肥料利用率低是制约西部地区农业生产的重要因素。前期实验表明，缓释肥料技术与高吸水性树脂复合一体化的保墒缓释肥料是提高肥料利用率、节水增效的重要技术。本项目着眼于开发环境友好、可降解、成本低廉的多功能缓释肥料，以生物质资源农作物秸秆为基材，尿素和磷酸锌铵、聚磷酸铵等为肥料原料，壳聚糖、纤维素以及魔芋葡甘露聚糖等为原材料，采用包膜法和吸附法制备既具有吸水保水、抗旱保墒功能，又能使肥料缓慢释放的农作物秸秆基保墒缓释肥料。对样品的养分含量、在土壤中的养分缓释效果、包膜材料的降解性、肥料对土壤保水能力的影响，以及改良土壤结构的功能等方面进行系统研究。其中农作物秸秆的加入，不仅环境友好，而且可有效降低缓控释肥料成本。因此，无论从高效利用天然再生资源，还是从提高肥料利用效率，达到材料与生态环境的和谐等角度考虑，研发农作物秸秆基新型缓释肥料，对于发展可持续高效农业具有重要而现实的意义。

农作物秸秆是自然界中数量极大的可再生资源，它富含纤维素成分，可以在许多领域发挥重要作用。将成本低廉的农作物秸秆引入高吸水树脂的制备中，然后与肥料复合，制备具有吸水保水功能的新型缓控释肥料，不仅环境友好，而且可有效降低缓控释肥料成本，对于发展可持续高效农业具有重要而现实的意义。本课题以农作物秸秆为基材，经过预处理，与阴离子型、非离子型和阳离子型单体共聚，合成了一系列高吸水树脂，通过吸附法和包膜法使秸秆基高吸水树脂与肥料养分复合，制备了三种农作物秸秆基新型保墒缓释肥料：(1) 制得预处理小麦秸秆-g-聚（丙烯酸-co-2-丙烯酰胺基-2-甲基丙烷磺酸）高吸水树脂，对 NH4+的吸附动力学进行了研究，结果表明，该树脂对 NH4+的吸附40 min 可达到平衡，最佳吸附量为 7.15 mmol L-1。通过对 NH4+ 吸附所制得的肥料有较好的缓释性能，可以提高土壤的持水量，调节土壤的酸碱度。但是所制得的肥料含量较低，氮含量为 11.2%。(2) 通过接枝聚合和半互穿网络技术，制备了预处理小麦秸秆-g-聚（丙烯酸 -co-丙烯酰胺）/聚二甲基二烯丙基氯化铵半互穿网络两性高吸水树脂。分别对NH4+和 PO43-的吸附动力学进行了研究，结果表明，该树脂对 NH4+ 和 PO43-的吸附均较快，对 NH4+和 PO43-的吸附是自发进行的。通过吸附法制得的肥料氮（N）含量为 10.0%，磷（P2O5）含量为 15.9%，且所负载的氮和磷在土壤中有较好的缓释性能。（3）以尿素和磷酸氢钙包埋于坡缕石中为肥料内核，以小麦秸秆/海藻酸钠共混物为内层包膜材料，以聚（丙烯酸-co-N-羟甲基丙烯酰胺）/小麦秸秆复合高吸水树脂为外层包膜材料，制备了一种双层包膜的保水性氮磷缓释肥料，肥料样品中氮（N）和磷（P2O5）的含量分别为20.6%和9.9%，具有较好的缓释性能。