【摘要】：季節(jié)性干旱是黏質紅壤地區(qū)農業(yè)生產的主要限制因素之一。對于黏質紅壤,隨著含水量降低,土壤穿透阻力隨之增加,影響作物根系生長和分布,改變吸收水分和養(yǎng)分的能力,從而也影響作物的根葉水勢等水分關系。干旱脅迫和阻力脅迫對作物的影響錯綜復雜,但關于干旱過程中土壤穿透阻力對作物影響的研究較少,二者的共同作用尚不清楚。本文研究黏質紅壤不同干旱程度下,穿透阻力對玉米作物水分關系的影響,為防治紅壤地區(qū)季節(jié)性干旱提供理論依據(jù)。本文的田間試驗在位于湖北咸寧的紅壤試驗站內進行,于2014-2015年的6-10月進行兩季玉米小區(qū)試驗。試驗設置了4個耕作處理(深耕D、常規(guī)耕作C、免耕N和壓實P),以得到不同的穿透阻力;從玉米8葉期開始,每個耕作處理分別設置3個干旱水平,即不干旱(每星期灌水12 mm,共灌水72 mm)、輕度干旱(共灌水24 mm)和嚴重干旱(不灌水)。田間小區(qū)土壤為第四紀紅色黏土發(fā)育的紅壤,種植的玉米品種為鄭單958。在玉米12葉期、16葉期、抽穗期分別測定土壤穿透阻力、土壤含水量、根葉水勢、氣孔導度與凈光合速率等,每個處理重復三次,玉米收獲后考種,得到以下研究結果:1)土壤含水量和穿透阻力在土壤剖面分布上具有一定的規(guī)律性。土壤含水量隨深度增加而顯著增加,而土壤穿透阻力呈先增加后降低的趨勢,在20 cm處達到峰值,嚴重干旱處理下壓實的阻力最大達到2.797 MPa。不干旱條件下,各耕作處理間含水量和穿透阻力的差異較小,隨著干旱程度的增加,耕作處理間的差異變大。穿透阻力隨含水量的升高而降低,兩者呈非線性負相關(P0.05),但當土壤含水量處在較高水平(0.24 g/g),土壤穿透阻力到達一個臨界點(0.5~0.6MPa)而趨于平穩(wěn),說明不干旱的紅壤也具有較高的穿透阻力,這與黏質紅壤特性有關。2)玉米根葉水勢以及凈光合速率等與土壤含水量和基質勢呈顯著正相關,而與穿透阻力呈顯著負相關。耕作處理間的土壤含水量與根葉水勢和凈光合速率等的關系有明顯的差異,從大到小的順序為DCNP,與土壤穿透阻力大小順序相反,隨著干旱程度增加,耕作處理間的差異變大。干旱和耕作對作物根葉水勢和凈光合速率等的影響達到極顯著(P0.01),同時干旱和耕作對根葉水勢等表現(xiàn)出顯著的交互作用(P0.05)�；貧w分析表明,在不干旱處理下,土壤穿透阻力的回歸系數(shù)大于含水量的系數(shù),說明此時穿透阻力對根葉水勢等的影響大于含水量。而隨著干旱程度的增加,穿透阻力增加,由方差分析結果可知,干旱和阻力共同影響作物水分關系,此時干旱對玉米根葉水勢等水分關系的影響更大。3)紅壤干旱和穿透阻力影響玉米根系的分布。在輕度干旱下,玉米根系的分布范圍有所增加;而在嚴重干旱時,根系的垂直和水平分布范圍均減小。在土層深度20-40 cm范圍內,深耕比常規(guī)耕作、免耕和壓實分別高-0.23%、15.13%和160%。在10-15cm范圍內,深耕比常規(guī)耕作、免耕和壓實分別高30.40%、44.13%和53.45%。說明耕作(穿透阻力)可以調控根系水平和垂直分布。4)土壤干旱和穿透阻力對玉米產量的影響都達到了極顯著,兩者的交互作用達到了顯著水平,說明穿透阻力促進作物干旱致災,而耕作能有效調控干旱和作物產量的關系。土壤含水量和基質勢與玉米產量呈顯著正相關,而土壤穿透阻力與玉米的產量呈負相關。不同干旱水平下作物產量總體順序均為DCNP,隨著干旱程度的增加,耕作處理間的差異變大�；貧w分析表明,在不干旱處理下阻力的系數(shù)大于含水量的系數(shù),說明此時穿透阻力對作物產量的影響大于含水量;而隨著干旱程度增加,土壤含水量降低,穿透阻力急劇增加,由方差分析可知,干旱和阻力共同影響玉米產量,此時干旱對玉米產量的影響更大。黏質紅壤在不干旱條件下,玉米作物表現(xiàn)阻力脅迫;隨著干旱程度增加,水分脅迫的影響大于阻力脅迫,是紅壤季節(jié)性干旱致災的重要原因。耕作措施可同時顯著改變黏質穿透阻力和水分狀況,其中免耕對作物水分關系有明顯的副作用,而深耕能夠明顯降低土壤穿透阻力,調控作物水分關系效果明顯。
[Abstract]:Seasonal drought is one of the main restrictive factors for agricultural production in clay red soil. With the decrease of water content, the penetration resistance of soil increases with the decrease of water content, the growth and distribution of crop roots, the ability to absorb water and nutrients, and the water relationship of the root and leaf water potential of the crops. Drought stress and resistance stress are also affected. The impact on crops is complex, but the study of soil penetration resistance in the course of drought is less. The effect of the two is not clear. This paper studies the influence of penetration resistance on the water relationship of corn crop under different degree of drought in clay red soil. This paper provides a theoretical basis for the prevention and control of seasonal drought in red soil. Field trials were carried out in the red soil test station in Xianning, Hubei, in the two quarter of 6-10 months of 2014-2015 years. 4 tillage treatments (deep ploughing D, conventional tillage, no tillage N and compacted P) were set up to obtain different penetration resistance. From the beginning of the 8 leaf period of corn, 3 drought levels were set in each tillage treatment, that is, Drought (12 mm per week irrigation, 72 mm in total water), mild drought (total irrigation 24 mm) and severe drought (no irrigation). The soil in the field is red soil developed in the Quaternary red clay. The cultivated maize varieties are Zhengdan 958. at 12 leaf stage and 16 leaf stage, and the soil water content, root leaf water potential and stomatal conductance of soil water content, root leaf water potential, and leaf water potential respectively. With net photosynthetic rate, each treatment was repeated three times, after maize harvest test, the following results were obtained: 1) soil moisture content and penetration resistance have certain regularity in soil profile distribution. Soil water content increased significantly with depth, and soil penetration resistance increased first and then decreased, reaching a peak at 20 cm. Under the condition of severe drought, the maximum resistance to compaction reached 2.797 MPa.. The difference of water content and penetration resistance between different tillage treatments was smaller. With the increase of the degree of drought, the difference between the tillage treatments became larger. The penetration resistance decreased with the increase of water content, and the difference was nonlinear negative correlation (P0.05), but when the soil water content was in the soil, The higher level (0.24 g/g), soil penetration resistance reached a critical point (0.5~0.6MPa) and tended to be stable, indicating that the unarid red soil also had higher penetration resistance, which was related to the characteristics of the clay red soil. The root leaf water potential and net photosynthetic rate of maize were significantly positively correlated with soil water content and matrix potential, but significantly negative to penetration resistance. The relationship between soil water content and root leaf water potential and net photosynthetic rate was significantly different. The order from large to small was DCNP, which was opposite to the order of soil penetration resistance. The effect of drought and tillage on the root leaf water potential and net photosynthetic rate of crops increased with the increase of soil penetration resistance. The regression analysis showed that the regression coefficient of soil penetration resistance was greater than the coefficient of water content in the non drought treatment, indicating that the penetration resistance had greater influence on the root and leaf water potential than the water content, but with the increase of drought, the regression analysis showed that the influence of penetration resistance on the water potential of root and leaf was greater than water content. Through the analysis of variance, the results of variance analysis showed that drought and resistance had a common influence on the relationship between crop water and water. At this time, the effect of drought on the water relationship of maize root and leaf water potential was more.3). The drought and penetration resistance of red soil affected the distribution of maize root system. In the range of 20-40 cm soil depth, deep tillage is higher than conventional tillage, no tillage and compaction by -0.23%, 15.13% and 160%. in the 10-15cm range. Deep tillage is 30.40% higher than conventional tillage, no tillage and compaction are higher, 44.13% and 53.45%., respectively, to indicate that tillage (penetration resistance) can regulate root level and vertical distribution of.4). The effect of soil drought and penetration resistance on the yield of maize reached a very significant level. The interaction of the two has reached a significant level, which indicates that the penetration resistance promotes the drought caused by the crop, and the cultivation can effectively regulate the relationship between drought and crop yield. The yield of maize was negatively correlated. The overall order of crop yield under different drought levels was DCNP. With the increase of drought, the difference between the tillage treatment was larger. The regression analysis showed that the coefficient of resistance was greater than the water content, which indicated that the penetration resistance had greater influence on the crop yield than the water content. With the increase of drought, the water content of soil decreased and the penetration resistance increased sharply. By the analysis of variance analysis, drought and resistance had a common effect on maize yield. At this time, the effect of drought on maize yield was greater. Under the condition of non drought, the corn crop showed resistance stress; with the increase of drought, the effect of water stress was greater than that of resistance stress. It is an important cause of the seasonal drought in red soil. The tillage measures can also significantly change the penetration resistance and water condition of the clay. The no tillage has obvious side effects on the water relationship of crops, while deep tillage can obviously reduce the penetration resistance of the soil, and the effect of regulating the water relationship of the crops is obvious.
【學位授予單位】：華中農業(yè)大學
【學位級別】：碩士
【學位授予年份】：2016
【分類號】：S513;S423

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本文編號：2160490