地膜覆蓋ppt課件(完整版)
【正文】 primary advantages of black plastic mulch is that it shades the soil so most weeds cannot grow and pete with the crop. 2022/2/9 31 黑色膜 在聚乙烯樹(shù)脂中加入 2～ 3%的碳黑制成。厚度為 ～ mm。這種地膜經(jīng)過(guò)一定時(shí)間（ 60、 80天）后，能自行老化降解破碎成小塊，進(jìn)一步降解成粉末摻混于土壤中，不造成污染，對(duì)土壤結(jié)構(gòu)無(wú)不良影響。 。 （ 2）生物降解膜：依靠微生物的活動(dòng)來(lái)分解。 國(guó)內(nèi)廠家生產(chǎn)的殺草膜采用的除草劑主要有： ① 撲草凈 主要用于水稻 、 花生 、 玉米及果樹(shù) ， 但對(duì)黃瓜甜椒 、 豆類 、 西紅柿等有藥害 ， 忌用 。 缺點(diǎn) 對(duì)土壤的增溫效果不如透明膜 ， 一般可使土溫升高 1～ 3℃ 。 缺點(diǎn) 透明地膜因?yàn)橥腹庑院?， 覆蓋下面易生雜草 ， 所以在鋪膜前最好噴灑除草劑 。 2. 促進(jìn)作物早熟。 2022/2/9 13 二、地膜覆蓋的方式 —— 覆蓋操作 2022/2/9 14 ? Plastic is laid using the apparatus shown in this picture. The plastic is laid tighly over a preshaped bed. Drip irrigation tubing on the reel above the plastic is laid under the center of the plastic. The tank at the front of the tractor contains methyl bromide that is injected into the soil as a fumigant before the plastic is laid. the crop can be planted only after the fumigant dissipates. It takes approximately 3 weeks for the methyl bromide to dissipate 2022/2/9 15 This is properly installed plastic mulch. It is tightly spread across the bed and slightly peaked in the middle to drain rain water. The sides are securely anchored with soil so the plastic will not blow in the wind. Holes are cut, punched, or burned in the plastic to allow planting. 2022/2/9 16 This punch wheel makes holes in plastic mulch in advance of planting. The wheels can be adjusted to vary the row spacing and distance between plants. 2022/2/9 17 ? It is important to create the proper size hole in the plastic. If holes are excessively large, than many of the beneficial effects of the plastic are lost, while if the holes are too s
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