A degradable agricultural mulch film as disclosed herein includes a plurality of layers for the controlled release of plant nutrients. The first layer is formed from a water-soluble synthetic resin, a releasable form of nitrogen and a releasable form of a plant nutrient in addition to nitrogen. A second layer includes a water-soluble synthetic resin having an average molecular weight which is greater than the average molecular weight of the water-soluble synthetic resin in the first layer and a releasable form of nitrogen admixed therein. The second layer also includes a thin film of water-resistant polymer to retard the degradation rate of the second layer and to slow the release of nitrogen in the second layer. And in the preferred embodiment of the invention a second film of water-resistant polymer which is relatively thin with respect to the first film separates the first and second layers.
本文公开的一种可降解农用地膜包括多层,用于控制植物养分的释放。第一层由
水溶性合成
树脂、可释放形式的氮和除氮以外的可释放形式的植物养分组成。第二层包括一种
水溶性合成
树脂,其平均分子量大于第一层中
水溶性合成
树脂的平均分子量,并在其中掺入一种可释放形式的氮。第二层还包括一层防
水聚合物薄膜,以延缓第二层的降解速度并减缓第二层中氮的释放。在本发明的优选实施方案中,相对于第一层薄膜较薄的第二层防
水聚合物薄膜将第一层和第二层隔开。