Abstract
The influence of planting density, on the mulberry yield, had been studied for 5 years period since 1982. For this purpose, a hilly land (15$^{\circ}$) was selected and 5 planting density level (926, 1,667, 2,780 and 3,444 tree/10a) were used. Following results were obtained. 1. Vinyl mulching promoted 2 days earlier of green tip sprouting stage and 3 days earlier of shallow-bill stage, compared with the non-mulching. 2. It was shown that increase of the length of the branch with vinyl mulching and decrease of the mulching effect with the higher density of plants from, 2,780 tree/10a. 3. When the planting density was higher, length and width of leaf was decreased sharply, and chlorosis of the lower part of the branch was occured heavily. 4. With the higher planting density, number of branches per tree and average length of the branch was decreased. Number of shorter branch-normal branch ratio were increased. However, number of branches and total length of branch per area were shown opposite. 5. Yield of mulberry was increased for the peroid of 3 years after planting with the all the levels of planting density after that, yield increase was dully in 926 tree plot, and more dully in 1,677 trees plot, while decrease of the yield were showen with density of 2,780 and 3,444 trees plots. 6. The highest average yield for the 5 years were obtained from 2,780 trees plot, 46.6% higher than in 926 trees plot, followed 40% higher in 3,444 trees plot, and 29.9% higher in 1,667 trees plot. 7. Soil pH, organic matter, Ca and Mg decreased with cultivation, especially P2O5, pH, Ca and Mg in the density of more than 926 trees plot.
1. 식재당년 비닐 피복은 무피복에 비해 탈포기는 2일, 연구기는 3일 앞당겼다. 2. 피복은 최장 가지 길이를 16.9-25.3cm 더 증가시켰으나, 2,780주 이상 밀식한 경우는 피복의 효과가 떨어졌다. 3. 밀식할수록 엽장과 폭이 작아지고, 가지 기부의 황변된 잎의 수는 증가하였다. 4. 밀식은 주당 가지수와 조장은 감소시켰으며, 정상지에 대한 왜소지의 비율은 증가시켰다. 그러나 10a당 가지수와 총조장은 증가하였다. 5. 식재밀도별 경년적 뽕잎 수량의 변이는 식재후 2년차까지는 계속 증가하였으나, 그 후부터 1,677주구는 926주구에 비해 증가 폭이 둔화되었고, 이보다 밀식한 구에서는 떨어지는 경향이었다. 6. 식재후 5년간 평균 뽕잎 수량은 2,780주구에서 가장 많아서 926주구 대비 46.6% 증수를 보였으며, 3,444주구가 다음으로 40%를, 1,667주구에서 29.9% 증수를 보였다. 7. 식재후 토양의 화학성은 pH, 유기물, Ca, Mg 등이 떨어졌으며, 926주 이상 심을 때는 인산, pH, O.M, Ca, Mg등의 함량이 저하되었다.