增進台灣農地旱作生產力Ⅱ.土壤内部排水、壓實問題的診斷和改良

Abstract

Since 80s, the farming industry of Taiwan has entered a transition period. Government carried out Acts like Farmland-transplanting, Farmland release, Joining the WTO, plus the farm commodities' market has transited into highquality oriented, the correspond strategy is to improve the soil productivity, which also improve our farming industry competency. A good soil condition can improve soil productivity efficiently. but problems like poor drainage, compacted soil are common in Taiwan's farmlands, which are limiting factors that constrains soil productivity. Texture profile is the basis of how to differentiate soil series in Taiwan. Whilst each different texture combinations is a feature of farmland, it's also the major factor that cause soil drainage problem. A Drainage Grading System that depends on how deep the texture "Grey mottling" will appear is highly accurate and easy to distinguish. A field examination of farmland area of 7,300 thousand ha. comes out with 80% of the farmland have drainage problem and further more, 30% of it are graded as "worst". Rice-planting is the majority usage of the farmlands in Taiwan, over 800,000 ha. were used to grow rice at it's peak. Thus, the cross-sections of soil in Taiwan are commonly contains a layer which called plowpan. And this plowpan is a problem that will constrain plant root expanding when Farmland-transplanting, which means grow another type of plant on the same farmland. As for another issue, the depths compacted, is usually come with drainage problem. After Deep soil-chiseling to establish better plant root environment, Quality increased in the case of planting color Calla Lily. For growing the cabbage, 30% decreased of Black-rot and Soft-rot disease. Deep soil-chiseling can benefit to groundwater recharge, decrease crop damage, flood damage, and soothe drainage problem. Soil Diagnosis and improve can ameliorate farmland producing condition, growing high economic value crop, increase crop producing efficiency, raise farmer's income, establish upland productivity improvement system. Hope this can be a decision-making reference when it comes to promote farming industry competency and farmland planning.

自八○年代起，台灣的農業進入轉型期，政府陸續推動稻田轉作，農地釋出，積極加入WTO等政策，加上農產品的消費趨向高品質。從農地利用的因應策略為增進土壤生產力，以提昇農業競爭力。 健康的土壤根系環境可有效增進土壤生產力。土壤內部排水不良、土壤壓實問題在台灣耕地土壤普遍發生，是限制土壤生產力的重要因子。 質地剖面是台灣耕地土壤區分土系的依據。各種不同的質地層理組合更是耕地土壤的特性之一，也是造成土壤內部排水不良的主要原因，根據灰斑開始出現的深度而制定的排水分級，明確而容易辨識。田間校核耕地面積約73萬公頃，結果顯示約80%存在排水問題。更有約30%屬排水極差。 種植水稻是台灣最主要的農地利用，最多種植面積達80萬公頃，因此土壤剖面普遍存在犁底層；在轉種旱作後，犁底層成為限制根系伸展的重要因子；深層壓實則普遍和排水不良同時發生。 深層翻土的土壤改良工程技術，可有效解決土壤內部排水不良和壓實問題，增進土壤生產力。深層翻土改良根系環境後，種植彩色海芋花梗較長，品質提高；種植甘藍，可減少30％的黑腐病和軟腐病發病率。實作過程並作效益分析和建議篩選改良後種植的作物以提升農業競爭力。 深層翻土亦可減少農作物水害損害，洪水災害，及減輕農田排水系統的負擔。 土壤問題診斷和改良可強化農地生產條件，種植高產值作物，增加農作物生產效益，提高農民收入。建立的旱作生產力增進系統，希望可作為提昇農業競爭力和農地規劃利用的決策參考。