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崇明大白菜的栽培历史悠久,全县每年栽培面积约3～5万亩,近十几年来,亩产量起伏很大。据统计,1971年全县平均单产为69担,1975年只有30担。趋势是1973年以前单产较高,1974年后单产相对较低,其原因是多方面的,我们初步认为主要与栽培技术有关,现就几个问题分述如下。(一)培育壮苗1.适当的播种期是培育壮苗的关键。崇明大白菜的播种期一般在立秋前后,定植在9月上,中旬,苗龄约30天。如遇到不利天气,定植还要推迟,苗龄往往超过35天。苗龄过长,秧苗过高(7～8寸),对定植不利。上海地区立秋前后天气高温干旱或多暴
Chongming cabbage cultivation has a long history, the county annual cultivation area of about 3 to 5 acres, nearly a decade, a great ups and downs per acre yield. According to statistics, in 1971, the average yield of the whole county was 69 tents, only 30 in 1975. The trend is that the high yield before 1973 and the relatively low yield after 1974 are due to many reasons. We initially believed that the major issues related to cultivation techniques are as follows. (A) nurturing strong seedlings 1. The appropriate sowing seed is the key to nurturing. Chongming cabbage sowing generally before and after the beginning of autumn, colonization in September, mid, seedling age of about 30 days. In case of unfavorable weather, colonization should also be postponed, seedling age is often more than 35 days. Seedling age is too long, too high seedlings (7 ~ 8 inches), unfavorable colonization. Before and after the setting of autumn and winter in Shanghai, the weather is hot and humid or stormy