土壤與作物營養診斷技術應用於氣候變遷下低投入型耕作制度發展

Abstract

本研究主要利用本所農場68 號田區設立的長期不同耕作制度與肥力監測試驗田，旨在應用土壤與作物營養診斷技術於低投入型耕作制度發展，以因應氣候變遷下耕作制度調適。試驗田土壤屬砂頁岩粘板岩非石灰性混合沖積土，研究顯示：1.長期旱作嚴重影響土壤酸化，水田種植水稻為防止或減緩土壤酸化與維持土壤肥力平衡穩定之自然方法。2.作物殘株處理方式不論是移除、掩埋或焚燒，三者間對土壤有機質含量的影響，差異並不顯著；相反的，三種殘株處理方式均造成土壤中有機質含量呈逐年遞增趨勢。3.完成不同耕作制度下，水土環境親和指標之建立，及其量化影響；如土壤有機質分解與pH 變化與溫度有關，可作為氣候變遷下溫度變化之影響指標監測；土壤有效性鉀可作為防範旱作水患之臨界濃度為80 mg/kg。4.灌溉水與土壤中之有效性氮 (銨態氮與硝酸態氮) 含量嚴重影響水稻之N 管理，包括N 肥用量、倒伏、穗肥需要與無N區產量百分率等；其相關臨界濃度分別為6 與30 ppm。5.強酸性土壤施苦土石灰可有效調節改善土壤營養元素之有效態含量，顯著提高水稻、玉米、大豆與小麥產量。6.土壤質地、土壤有效水份供應 (土層深度) 及土壤pH 嚴重影響缺水環境下旱作 (小麥、玉米、大豆) 之生育，可為發展旱作適栽區規劃之考量因子。 A long-term experiment was conducted from 1987 to 2014 in a field of noncalcareous sandstone and slate alluvial soil at the experimental farm of Taiwan Agriculture Research Institute, Wufeng, Taichung, Taiwan, to evaluate the effects of cropping systems on soil fertility and farming adjustment with climate changes. In this study, there were four cropping systems including Rice-Rice monoculture; Rice-Corn rotation; Corn-Rice rotation; and Corn-Corn monoculture. Research shows: 1. The prolonged upland cropping seriously affected soil acidification, paddy rice cultivation was the best natural method to prevent or mitigate soil acidification and the maintenance of soil fertility balance and stability. 2. Crop redisues treatment whether removal, incorporation or burning, among the three effects on soil organic matter content, the difference is not significant; on the contrary, three types of stubble soil organic matter content has an increasing trend. 3. Completed establishment of soil and water environment compatible pointer, and quantify impact under different cropping systems, such as soil organic matter decomposition and changes in pH and temperature, can be used as monitoring the effects of temperature changes in the climate change pointer; effectiveness of potassium in soils as a precaution upland flooding critical concentration of 80 mg/kg. 4. Available nitrogen (ammonium nitrogen and nitrate nitrogen) of irrigation water and soil in severely affected n management in rice, including n-fertilizer dosage, lodging, fertilizer needs and percentage yield; its threshold concentration was 6 and 30 ppm. 5. Applying magnesium oxide- lime can improved or regulated the strongly acidic soil on the nutrient content of effective state, and significantly improve the production of rice, corn, soybeans and wheat.6. Soil texture , soil available water supply (soil depth), soil pH with serious impact on water environment in dryland (wheat, corn, soybeans) to produce, are consideration factors for the development of suitable planting in dryland areas.