發(fā)布時間：2019-05-20 02:09

【摘要】：本文主要針對內(nèi)蒙古河套灌區(qū)農(nóng)膜殘留存在的嚴(yán)峻現(xiàn)實問題,開展不同降解速率的生物可降解地膜覆蓋下的降解特性及其對農(nóng)田水土環(huán)境變化的影響研究。通過2年田間試驗,主要研究了可降解地膜降解進程及地膜覆蓋下土壤水-熱-鹽-氮變化特征,并探索了不同降解速率地膜對作物的生長、產(chǎn)量和水分利用效率的影響,為該地區(qū)篩選適合當(dāng)?shù)刈魑锷L的可降解地膜,以及農(nóng)田節(jié)水節(jié)肥、高產(chǎn)增收提供理論和技術(shù)依據(jù),研究結(jié)果對于緩解塑料地膜的"白色污染"以及提高水肥高效利用具有重要意義,特別為推廣生物地膜應(yīng)用奠定基礎(chǔ)。主要結(jié)論如下:1.降解膜的表觀特征和力學(xué)特性在作物生育期不同于普通塑料地膜。收獲期,普通地膜降解率和破損率分別為3%左右,而不同降解膜的降解率達(dá)到14%～30%,破損率達(dá)30%～60%,與普通塑料地膜存在顯著差異(P0.05)。對于地膜表面電鏡掃描照片,降解地膜與普通地膜在鋪設(shè)前質(zhì)地較均勻,顆粒之間相容性好。鋪設(shè)100d后,普通地膜表面結(jié)構(gòu)疏松,顆粒之間出現(xiàn)縫隙,降解緩慢;降解膜表面明顯出現(xiàn)大量大小不一的孔洞和凹凸不平,機械性能下降。2.覆蓋地膜顯著增加土壤上層(0～40cm)地溫和含水率,隨著降解膜破損率增大,降解膜處理下的地溫和含水率與普通地膜處理差異逐漸增大,在作物生育后期顯著低于普通地膜。隨著土壤深度增加,地溫呈現(xiàn)降低趨勢。高肥處理下,灌水量由W1(600m3/hm2)增加至 W3(1200m3/hm2),0～40cm 土層含水率由 17.23%下降至 14.78%,地溫由23.41℃下降到22.30℃,含水率與灌水量呈正比關(guān)系,溫度與灌水量呈反比關(guān)系。3.作物生長前期,可降解地膜和普通塑料地膜均未發(fā)生降解,不同處理之間土壤電導(dǎo)率值無顯著差異。在作物成熟期,降解地膜處于崩解期,大多碎裂成塊,覆蓋面積減少,水分蒸發(fā)嚴(yán)重,不同處理間差異明顯。全生育期0～40cm 土層普通地膜處理和降解膜處理土壤EC顯著低于未覆膜區(qū)域,可見地膜覆蓋處理能有效減小0～40cm土壤電導(dǎo)率,而對60～100cm處土壤鹽分影響小。增加灌水量能夠有效控制鹽分表聚現(xiàn)象。4.不同地膜覆蓋對0～40cm 土層硝態(tài)氮含量影響顯著,對40～100cm 土層的硝態(tài)氮的影響較小。隨著覆膜時間的推進,硝態(tài)氮含量逐漸下降,在收獲期普通塑料地膜處理0～40cm 土層硝態(tài)氮含量明顯高于降解膜處理下硝態(tài)氮含量。增加灌水量,使得下層土壤中硝態(tài)氮含量明顯增加,淋洗嚴(yán)重。5.覆蓋普通地膜的水分利用效率分別比覆蓋慢速(OM3)、中速(OM2)、快速(OM1)降解膜處理提高了 6.05%、9.16%、18.64%,差異顯著(P0.05)。在同一施肥條件下,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。為避免造成水資源的不必要浪費,使灌水能夠最大程度的被利用,應(yīng)選擇合理灌水,在干旱地區(qū)具有很大意義。
[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，

本文編號：2481263