In the case of growers in northern florida , for example , plastic mulch allows them to produce a crop in between crops harvested in southern florida and those harvested in the neighboring states of georgia and south carolina , thus marketing in a higher - priced window 例如对佛罗里达北部的种植者来说，应用塑料薄膜覆盖可使作物的收获期介于佛罗里达南部和相邻的佐治亚及南卡罗莱纳州的作物收获期之间，所以其产品在市场上较高的价格优势。
In recent years , such problems as the extension and application of on - film irrigation , reclamation of salinized soils , and prevention of secondary salinization have made it important to study coupled movement of soil water , salt and heat transfer under plastic mulch in arid and semi - arid areas 近年来覆膜灌溉的推广应用、盐碱地开发和改良以及土壤次生盐碱化防治等问题使得研究西北干旱-半干旱地区覆膜条件下土壤水、盐、热耦合迁移规律成为重要课题。
6 . the order of the effect to wheat productivity in different combination of tillage and application rate is : mulching + high application rate > mulching + middle application rate > plastic mulching + high application rate > furrow and ridge tillage + high application rate > plastic mulching + middle application rate > furrow and ridge tillage + middle application rate , etc . mulching is easy and with better benefit , so should popularize 耕作措施与施肥量的不同组合对黄?土坡耕地小麦产量的影响作用中，按增产效益排序的前几个较优组合为：覆盖+高肥覆盖+中肥覆膜+高肥沟垄+高肥覆膜+中肥沟垄+中肥。覆盖耕作与肥料的组合简单易行且效益较好，所以应加以推广。
The results are as follows : ( 1 ) based on soil temperature data measured at different time in the field , soil temperature characteristics under plastic mulch were analyzed at four locations : the middle , the edge , in - between the plastic film and uncovered spot ; the characteristics of soil temperature profile from 0 to 25cm depth and the correlation of soil temperatures in different soil layers were studied at different time with and without plastic mulch ; on the basis of analyzing temporal and spatial variations of soil temperature in a corn field , the relations between soil temperature and air temperature were established , and a new method that only uses air temperature to predict soil temperature profile at different time is proposed . the predicted results showed good accuracy 成果如下： ( 1 )根据大田实测地温资料，分析了覆膜条件下膜中、膜边、膜间和揭膜四种处理在早、中、晚三个不同时刻的地温特征；分析研究了各观测时刻覆膜与不覆膜条件下0 25cm剖面地温的特点及各层地温间的相关关系；在重点对玉米田地温时空变化特征分析的基础上，首次将覆膜与不覆膜不同时刻观测的剖面地温与气温建立了联系，提出了仅根据气温资料来预测一日内不同时刻剖面地温的新方法，预测结果表明其精度较高。
The technique of water conservation in gneiss area of tai - hang mountain : on the facet of water conservation measure , four sorts of water conservation measures can all improve the soil water content . the result of straw mulch is best , using water holding agent in soil and plastic mulch are better , stone mulch is worse . four sorts of water conservation measures all improve the physical character of surface layer soil 太行山片麻岩区保水技术：在保水措施方面：四种保水措施均能提高土壤含水量，秸秆覆盖的效果最好，土施保水剂和地膜覆盖的效果其次，石块覆盖的效果较差；四种保水措施使表层土壤的物理性状均有一定改善，使土壤容重降低、孔隙度和土壤饱和含水量增加。
In the next few years china will concentrate on spreading the following agricultural techniques : improved new varieties , paddy rice nurturing in dry nursery and thin planting by throwing rice seedlings , plastic mulching , precise and semi - precise mechanical seeding , integrated pest management , scientific fertilization , water - saving irrigation , and dry land farming 今后几年，将重点推广以下重要农业技术：优良新品种、水稻旱育稀植及抛秧、地膜覆盖、精量半精量机械化播种、病虫害综合防治、科学用肥、节水灌溉和旱作农业等重大适用技术。
The technical routes in this paper are to 1 ) combine theoretical analyses with laboratory and field studies with emphasis on the field studies , 2 ) combine field and laboratory tests with emphasis on the laboratory tests studies , and 3 ) combine theoretical studies with applications with emphasis on theoretical studies . the whole study focused on the characteristics of coupled movement of soil water , salt and heat transfer under plastic mulch 本论文结合国家自然科学基金和霍英东教育基金课题，采取理论分析与室内外试验相结合、以试验研究为主；大田与室内试验相结合、以室内试验为主；应用与机理研究相结合、以机理为主的技术路线，研究覆膜条件下土壤水、盐、热耦合迁移特点。
