設(shè)施園藝ppt課件(編輯修改稿)
2025-05-26 03:46 本頁(yè)面
【文章內(nèi)容簡(jiǎn)介】 除雜草。? 節(jié)省勞力。? 節(jié)水抗旱。Date 21四、地膜的種類及特點(diǎn)* 22n Straw mulch was widely used by vegetable growers for decades. Over the past 40 years, straw has been largely replaced by plastic mulch.n There is renewed interest in straw mulch particularly for anic production. The high carbon to nitrogen ratio of most types of straw means that it breaks down slowly in the soil. Straw prevents soil paction, slows evaporation of water from the soil surface, and keeps plants and fruit clean. 1Date 23 無(wú)色地膜n 高壓膜 （ LDPE）q 透光好、柔軟性好、易與土壤粘著q 適于北方地區(qū)n 高密度 膜（ HDPE）q 強(qiáng)度高、光滑、柔軟性差、保溫保水性同高壓膜、q 不易粘著土壤、透明性和耐候性差q 不適于沙質(zhì)土壤地覆蓋n 線型膜（ LLDPE）兼具前兩者優(yōu)點(diǎn)Date 24優(yōu)點(diǎn)優(yōu)點(diǎn) 膜透光性好，土壤增溫效果明顯，早春可使耕膜透光性好，土壤增溫效果明顯，早春可使耕層土壤增溫層土壤增溫 2～～ 4℃℃ ，高溫時(shí)期膜下地表溫度可達(dá)，高溫時(shí)期膜下地表溫度可達(dá) 60℃℃ 以上以上，適用于東北、西北、華北等低溫、寒冷的干旱與半干旱地，適用于東北、西北、華北等低溫、寒冷的干旱與半干旱地區(qū)應(yīng)用。區(qū)應(yīng)用。缺點(diǎn)缺點(diǎn) 透明地膜因?yàn)橥腹庑院茫采w下面易生雜草，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。所以在鋪膜前最好噴灑除草劑。Date 25 有色地膜q 黑色地膜q 白色地膜q 銀灰色地膜 根據(jù)不同染料對(duì)太陽(yáng)光譜有不同的反射與吸收規(guī)律，以及對(duì)作物、害蟲有不同影響的原理，人們?cè)诘啬ぴ现屑尤敫鞣N顏色的染料，制成有色地膜。 Date 26n This experiment at the University of Florida pares effects of different colored mulches on tomato development. n Yellow mulch is believed to attract certain insects away from the crop. Brown wavelengthselective mulches heat the soil slightly, but less than clear, while maintaining weed control. n Silver mulches provide cool to ambient soil temperatures, deter aphids and whiteflies until the plant canopy forms, reflects light which may increase photosynthesis, and controls weeds.n Red mulch provides ambient to cool soil temperature. Some research shows that red mulches improve plant
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