九種果園覆蓋作物在臺灣山區之生長與覆蓋效果

Comparison of Nine Grasses of Cover Crop in Orchard in Mountainous Area of Taiwan

收集九種會為政府推廣、學校或民間引入的果園覆蓋作物種植於南投縣仁愛鄉梅峰，海拔2,100m的國立臺灣大學農學院附設山地農場，比較其生長與覆蓋效果，期求選出適用於臺灣高山坡地果園山邊溝系統的覆蓋作物。經1979年到1985年調查的結果顯示：大理草（Paspalum dilatatum Pior et.）在臺灣高山地區生長勢弱，不易形成地表覆蓋。戀風草（Eragrostis curuula Nees）與百喜草（Paspalum notatum Fluegge）冬季枯草期長，有火災危險；且春季恢復生長慢，純化栽培費工。克育草（Pennisetum clandestinum Hochst ex Chiov,）夏季生長旺盛，走莖蔓延快速，控制生長不易，皆不宜為臺灣高山坡地果園的覆蓋作物。鴨茅草（Dactylis glomerata L.）、多花黑麥草（Lolium multiflorum Lam.）、多年生黑麥草（Lolium perenne L.）與大扁雀麥（Bromus catharticus Vahl.）在臺灣高山可周年生長，以30cm行距分株定植，一年內均可形成60%覆蓋。鴨茅草生長最旺盛，割草量最豐富，在施肥的情況下（200kg氮肥／公頃），春季夏季均有50至80公噸／公頃的割草量；割草敷蓋於果樹冠下可持續150天以上不必補充。多花黑麥草與大扁雀麥春季生長較旺盛，夏季開花結子，草較直立需常刈割。多年生黑麥草單株生長分藥最多，但割草後織地度最底，亦為春季生長旺盛草種，惟草株較低，佈置果園中可以周年不割草。白花三葉草（Trifolium repens L.）為豆科植物；覆蓋形成最快，夏季45cm行距分株種植70天內可以達到60%覆蓋；織地嚴密，亦可四季常青，惟生長勢受幹旱壓抑較為明顯。綜合上述觀察，以坡地果園覆蓋迅速、穩定、管理省工與避免與果樹競爭的需要而言，似以黑麥草（多花的或多年生的）或大扁雀麥等禾本科草種與豆科的白花三葉草混植較適於臺灣高山坡地果園。

The aim of this experiment was to find out some suitable kinds of cover crop permanently used in orchard-hillside-ditch-system in mountainous area of Taiwan. Eight non-legume grasses, namely resecue grass (Bromus catharticus), orchard grass (Dactylis glomerata), weeping grass (Eragrostis curvula), Italian rye grass (Lolium multiflorum), perenoial rye grass (Lolium perenne), Kikuyu grass (Pennisetum clandestinum), dallies grass (Paspalum dilatatum) and bahia grass (Paspalum notatum) as well as a legume of white clover (Trifolium repens) were used in the experiment at Meifeng, the High-Land Farm of National Taiwan University from 1979 through 1985. The significant findings are described as below. T. repens and P. clandestinum belonging to stolon type grasses, had fast and excellent ground cover effects could reach 60% coverage within 70 days after planting even in 45cm spacing. B. catharlicus, D. glomerata, L. multiflorum, L. perenne sod E. cures/a, belonging to non-stolon grasses, established ground cover relatively slow, but got higher hay-yield than that of stolen grasses. Besides L. perenne, all the non-stolon grasses grew more taller and needed mowing frequently. D. glomerata, E. curvula, P. clandestinum and P. notatum grew more vigorously in summer, while B. catharticus, L. multiflorum, L. perenne and T. repens grew better in spring than in summer. E. curvula and P. notatum had a lung wilting period which was subject to fire hazard in orchard during winter and difficult in weed control in spring; while others, still remaining green in winter and regrowing early in spring, were shown easier in management as cover crops in slope orchard. Regarding the decomposition of hay by mulching, T. repens decomposed fastly, decreasing to half of its air-dry weight in 28 days, followed by L. multiflorum and L. perenne in 70 days; while D. glomerata and B. catharticus were the longest, of which could persist more than 150 days. According lathe preliminary observation of this experiment, using grass clover cover crop, namely Consisting of legume of T. repens and non legume of B. cutharticus L. multiflorum or L. perenne would be more suitable to be a permanent and easy managing one on slope orchard in mountainous area of Taiwan.