不同可降解地膜的降解特性及其覆盖下的水—热—盐—氮变化特征研究
发布时间：2019-05-20 02:09
【摘要】：本文主要针对内蒙古河套灌区农膜残留存在的严峻现实问题,开展不同降解速率的生物可降解地膜覆盖下的降解特性及其对农田水土环境变化的影响研究。通过2年田间试验,主要研究了可降解地膜降解进程及地膜覆盖下土壤水-热-盐-氮变化特征,并探索了不同降解速率地膜对作物的生长、产量和水分利用效率的影响,为该地区筛选适合当地作物生长的可降解地膜,以及农田节水节肥、高产增收提供理论和技术依据,研究结果对于缓解塑料地膜的"白色污染"以及提高水肥高效利用具有重要意义,特别为推广生物地膜应用奠定基础。主要结论如下:1.降解膜的表观特征和力学特性在作物生育期不同于普通塑料地膜。收获期,普通地膜降解率和破损率分别为3%左右,而不同降解膜的降解率达到14%～30%,破损率达30%～60%,与普通塑料地膜存在显著差异(P0.05)。对于地膜表面电镜扫描照片,降解地膜与普通地膜在铺设前质地较均匀,颗粒之间相容性好。铺设100d后,普通地膜表面结构疏松,颗粒之间出现缝隙,降解缓慢;降解膜表面明显出现大量大小不一的孔洞和凹凸不平,机械性能下降。2.覆盖地膜显著增加土壤上层(0～40cm)地温和含水率,随着降解膜破损率增大,降解膜处理下的地温和含水率与普通地膜处理差异逐渐增大,在作物生育后期显著低于普通地膜。随着土壤深度增加,地温呈现降低趋势。高肥处理下,灌水量由W1(600m3/hm2)增加至 W3(1200m3/hm2),0～40cm 土层含水率由 17.23%下降至 14.78%,地温由23.41℃下降到22.30℃,含水率与灌水量呈正比关系,温度与灌水量呈反比关系。3.作物生长前期,可降解地膜和普通塑料地膜均未发生降解,不同处理之间土壤电导率值无显著差异。在作物成熟期,降解地膜处于崩解期,大多碎裂成块,覆盖面积减少,水分蒸发严重,不同处理间差异明显。全生育期0～40cm 土层普通地膜处理和降解膜处理土壤EC显著低于未覆膜区域,可见地膜覆盖处理能有效减小0～40cm土壤电导率,而对60～100cm处土壤盐分影响小。增加灌水量能够有效控制盐分表聚现象。4.不同地膜覆盖对0～40cm 土层硝态氮含量影响显著,对40～100cm 土层的硝态氮的影响较小。随着覆膜时间的推进,硝态氮含量逐渐下降,在收获期普通塑料地膜处理0～40cm 土层硝态氮含量明显高于降解膜处理下硝态氮含量。增加灌水量,使得下层土壤中硝态氮含量明显增加,淋洗严重。5.覆盖普通地膜的水分利用效率分别比覆盖慢速(OM3)、中速(OM2)、快速(OM1)降解膜处理提高了 6.05%、9.16%、18.64%,差异显著(P0.05)。在同一施肥条件下,灌水量由低水(600m3/hm2)增加至高水(1200m3/hm2),水分利用效率由22.56%下降至20.51%,灌水量的增加使得水分利用效率降低。为避免造成水资源的不必要浪费,使灌水能够最大程度的被利用,应选择合理灌水,在干旱地区具有很大意义。
[Abstract]:In order to solve the serious practical problems of agricultural film residue in Hetao irrigation district of Inner Mongolia, the degradation characteristics of biodegradable plastic film mulching with different degradation rates and its influence on soil and water environment change in agricultural fields were studied in this paper. Through 2 years field experiment, the degradation process of degradable plastic film and the change characteristics of soil water, heat, salt and nitrogen under plastic film mulching were studied, and the effects of plastic film with different degradation rates on crop growth, yield and water use efficiency were explored. It provides theoretical and technical basis for screening degradable plastic film suitable for local crop growth, saving farmland water and saving fertilizer, and increasing high yield and income. The results are of great significance for alleviating the "white pollution" of plastic film and improving the efficient utilization of water and fertilizer, especially for popularizing the application of biofilm. The main conclusions are as follows: 1. The apparent and mechanical properties of the degradation film are different from those of the ordinary plastic film during the crop growth period. During the harvest period, the degradation rate and damage rate of ordinary plastic film were about 3%, while the degradation rate of different degradation film was 14% 鈮，
本文编号：2481263
[Abstract]:In order to solve the serious practical problems of agricultural film residue in Hetao irrigation district of Inner Mongolia, the degradation characteristics of biodegradable plastic film mulching with different degradation rates and its influence on soil and water environment change in agricultural fields were studied in this paper. Through 2 years field experiment, the degradation process of degradable plastic film and the change characteristics of soil water, heat, salt and nitrogen under plastic film mulching were studied, and the effects of plastic film with different degradation rates on crop growth, yield and water use efficiency were explored. It provides theoretical and technical basis for screening degradable plastic film suitable for local crop growth, saving farmland water and saving fertilizer, and increasing high yield and income. The results are of great significance for alleviating the "white pollution" of plastic film and improving the efficient utilization of water and fertilizer, especially for popularizing the application of biofilm. The main conclusions are as follows: 1. The apparent and mechanical properties of the degradation film are different from those of the ordinary plastic film during the crop growth period. During the harvest period, the degradation rate and damage rate of ordinary plastic film were about 3%, while the degradation rate of different degradation film was 14% 鈮，
本文编号：2481263
本文链接：https://www.wllwen.com/shoufeilunwen/zaizhiyanjiusheng/2481263.html
