農藝作物有機栽培法之探討

An Organic Farming Approach on the Food Crop Production

高德錚(Te-Chen Kao)

《臺中區農業改良場特刊》 16號 (1989/06) Pp. 117-132

https://doi.org/10.29563/ZHWHGX.198906.0002

摘要

農藝作物之經營大多屬於粗放性大面積的栽培方式，傳統低效率地人工或牛馬等獸工操作，在現代科技文明發達的沖激下，已因產量低落，生產成本過高，而被大型高效率的農機技術或化學性栽培法所取代，唯大量的施用化學性氮素、農藥及密集的單一作物栽培方式，已嚴重地導致自然生態之劣化。因之，站在農藝生產的立場上，如何導入使農地再生的有機農法，是吾人值得深思的課題。由有機農法中最少投入而獲致最大淨益的理念而言，以本省最大宗之栽種作物水稻為例，由於生產過程中，人工費、肥料及農藥費逐年日增，慣行的移植方式已被證實比直播方式之單期淨利減少7,267元／公頃，亦比再生方式減收22,727元／公頃之淨益。若以水稻（一期）－大豆（夏作）－玉米（秋作）之輪作法為例，則大豆之根瘤固氮作用其對後作玉米之增產效果，足以比擬直接施用20公斤／公頃以上之化學性氮素，而且大豆種植期間，消耗之土壤磷素經後作玉米之補償後，又回歸土壤中。換言之，有機農法中強調之輪作栽培方式，確實有利於土壤肥力之平衡且有利於淨所得之提昇。間作栽培方式，是有機農法中常用來減少主作物因應病蟲害、雜草、動物或風、雨、雪等為害損失之手段之一。在沿海地區，夏作西瓜之後作以田菁供為植巷綠肥則除具有擋風牆而減少東北季風對落花生之為害之效用外，且因兼具誘餌作用可引誘小黃薊馬之著生於田菁上導致主作物落花生之鮮莢產量，增產達14.3%及淨收益多18,920元／公頃。總之，在農藝作物栽培立場上，論及有機農法，並非復古地回復到傳統之栽培方式；而是從生態平衡之前提下來長程規劃農地之利用，藉由輪作、混作及間作制度之精密控制下，允許作物、土壤、昆蟲、微生物…等等之自然消長。如此作物生產量或許並不如現代化學性農法，但其優良的產品品質而獲致之高利潤將可補償其產量之損失。

並列摘要

As the traditional way of low-efficiency farming by hand labor and animal power is not suitable for the extensive farming system for the agronomic crops, it has already been replaced by the modern high efficiency farming system with big farm machinery and ample application of agricultural chemicals many years ago. However it has caused the serious concern of our people in these years that the long-lasting monoculture and application of large amount of chemical fertilizers and pesticides has already made a very unfavorable affection to the ecological balance of the farm environments. This is the impetus for us to find a low input and low pollution way of farming or organic farming. From the viewpoint of low input and high profit, it has been found in our experience in rice culture that shifting from transplanting method to direct seeding way of rice cultivation may save 7,267 NT$/ha, and the ratoon method may save 22,727 NT$/ha in cost. Under the cropping system of rice (1st crop)-soybean (summer crop)-corn (fall crop), the soybean may supply about 20kg/ha of nitrogen from nitrogen fixation by ”Rhizobia” for the corn, and the consumed phosphorus by soybean may return to the soil during the growing period of the succeeding crop, corn. In other words, the highly emphasized rotational cropping system in the organic agriculture is really very helpful to the maintenance of soil fertility and raising of profits; and intercropping is used as a measure to reduce the losses of the main crop from the attack of pests, weeds, animals, and the unfavorable environmental factors such as wind, rain, and frosts etc. In the coastal area, growing ”Sesbania as” the succeeding crop of summer water melon and using it as the alley crop for peanut may protect the peanut from the damage of northeast monsoon and play as an attractant for samll yellow thrip to make about 14.3% increase in fresh pod yield of peanut, and 18,920 NT$/ha gain in net profit. In conclusion, organic farming is not a simple retrocession from modern farming to the traditional old way of farming. Rather it is a well-arranged land utilization system under the consideration of ecological balance, which allows the natural competition of crops, soils, insects and microorganism by strick control of rotational cropping, mixed cropping, and intercropping ect. The crop yield in the organic farming system may not be competitive to the chemical farming system, nevertheless, its higher price in the market may compensate for its slight losses in yield.