本文選題：栽培模式　切入點：土壤水分　出處：《西北農(nóng)林科技大學(xué)》2017年碩士論文

【摘要】：黃土高原雨養(yǎng)農(nóng)業(yè)區(qū)水分缺乏是制約農(nóng)業(yè)生產(chǎn)的關(guān)鍵因子。本研究通過在黃土高原長武塬(35?12'N,107?40'E)進行土壤水熱野外連續(xù)觀測小區(qū)試驗,同時結(jié)合Hydrus-1D與Hydrus-2D模擬的方法,對比玉米傳統(tǒng)栽培與壟作覆膜栽培模式下土壤水分和溫度變化特征與差異,分析影響因素,闡明傳統(tǒng)栽培模式玉米生產(chǎn)受水分脅迫的機制以及覆膜栽培下水熱耦合運移過程特征,以期為解決該地區(qū)限制作物生產(chǎn)的土壤水分脅迫問題提供基礎(chǔ)理論依據(jù)。研究結(jié)果表明:(1)壟作覆膜-壟和溝在30~60 cm土層土壤含水量分別顯著高于平作不覆膜約49%和55%,而平作不覆膜在深層(100~160 cm)土壤土體儲水量明顯高于壟作覆膜約26%。壟溝覆膜-壟土壤表層10 cm處溫度較壟溝覆膜-溝與平作不覆膜分別高2.01℃和1.91℃。兩種栽培模式下,降雨事件對于土壤水分動態(tài)變化影響差異顯著。平作不覆膜在玉米生長季初期由于干旱引起強烈的土壤蒸發(fā)以及作物耗水導(dǎo)致犁底層“自覆蓋”現(xiàn)象產(chǎn)生,而壟作覆膜由于改善了土壤水分和溫度條件,促使深層水分得到利用,從而避免“自覆蓋”現(xiàn)象對玉米生長的不利影響,因而對于維持作物生長具有重要的意義。(2)Hydrus-1D可以很好的模擬玉米傳統(tǒng)栽培模式下土壤水分變化趨勢,校準期(2013年玉米生長期)和驗證期(2014年玉米生長期)擬合程度分別為70.6%和77.0%。模擬與實測數(shù)據(jù)表明,土體儲水量(SWS)在表層0~10 cm變化明顯,受降雨入滲(P/In)、土壤蒸發(fā)(ES)和作物蒸騰(Tp)影響,根系吸水(RT)對60~100 cm土層SWS的影響最明顯,深層土壤(100~160 cm)SWS相對穩(wěn)定。而犁底層不同容重條件對土壤水分入滲的模擬表明,犁底層容重的越大,水分入滲滯后效應(yīng)越明顯,土體儲水量越小。在玉米生長初期降雨稀少,犁底層由于蒸發(fā)作用以及根系吸水極易形成干層(出現(xiàn)“自覆蓋”現(xiàn)象),因此玉米生長初期的干旱時期與犁底層分別是黃土高原玉米生長受水分脅迫的敏感時期與敏感土層。但種植時土體前期含水量也是犁底層是否形成干層的重要影響因素。(3)通過設(shè)置不同的邊界條件,Hydrus-2D可較好的模擬覆膜栽培下土壤水熱耦合運移過程特征。無降雨情況下,壟下表層土壤水分橫向補充溝內(nèi);膜下溫度比溝內(nèi)表層溫度高,并向溝內(nèi)傳輸;當降雨量小時,土壤基本處于非飽和態(tài),重力勢作用較小,土壤水分僅由溝內(nèi)表層入滲;強降雨事件下,土壤水分下滲明顯,且60 cm土層以上溝內(nèi)降雨橫向補充壟下土壤。雨后由于蒸發(fā)作用,溝內(nèi)水分向上遷移,同時,膜下淺層土壤水具有向溝內(nèi)側(cè)向遷移的驅(qū)動力。
[Abstract]:Water deficiency in rain-fed agricultural areas of the Loess Plateau is a key factor restricting agricultural production. 12? The field continuous observation plot experiment of soil water and heat was carried out, and the variation characteristics and differences of soil water and temperature under traditional maize cultivation and ridge mulching cultivation were compared with Hydrus-1D and Hydrus-2D simulation, and the influencing factors were analyzed. The mechanism of maize production under water stress and the characteristics of water-heat coupled transport in film mulching cultivation were expounded. The results showed that the soil water content of ridge mulching, ridge mulching and furrow mulching was significantly higher than that of non-mulching soil layer (about 49%), respectively. And 55m, and the water storage of soil mass was significantly higher than that of ridge mulching film mulching about 26cm. The temperature of the top layer of furrow film mulching and ridge mulching was 2.01 鈩，

本文編號：1653827