德宏州油茶芽砧嫁接技术

以尚未木质化的芽苗为砧木,半木质化的树枝为接穗,在芒市城郊的德宏州林业局中心苗圃进行油茶芽砧嫁接试验．文章重点介绍了砧木培育、接穗采集、嫁接、栽植等芽砧嫁接技术以及嫁接后的管理技术．观察结果表明,用保鲜膜包扎不伤砧木,保湿性好,嫁接口愈合快,成活率高,降低了嫁接和育苗成本．     

马来西亚的红麻研究及开发进展

红麻作为多用途可持续利用的再生资源引人关注。本文详细介绍了马来西亚将红麻的用途定位于饲料、纤维强化合成材料、制浆造纸原料而开展的红麻品种筛选、种植、病害虫防治、贮存、加工利用及其生产经济学方面的研究进展和下一步工作计划，以期为我国的红麻研究及开发利用提供一些参考。     

春小麦膜上灌最佳覆膜宽度和单宽流量试验研究

研究了河西内陆灌区膜上灌在不同覆膜宽度和单宽流量条件下对春小麦全生育期耗水量、产量构成要素以及产量和水分利用效率的影响,得出该区春小麦膜上灌采用覆膜宽度和单宽流量分别为125 cm和1.3 L/(s.m)时节水增产效应明显.     

Inter‐row Mulch Increase the Water Use Efficiency of Furrow‐Irrigated Maize in an Arid Environment

The effect inter‐row polyethylene mulch on the water use efficiency and crop productivity of furrow‐ and drip‐irrigated maize (Zea mays L.) was evaluated in a field study. In contrast to the traditional ‘on ridge’ mulching, the inter‐row polyethylene mulch was placed in such a way that it could be easily removed for reuse since the row of plants itself was not covered but the furrows were completely covered. Irrigation needs were computed by multiplying the cumulative Class A Pan evaporation between irrigations by a crop coefficient that changed through the growing season. Our results indicate that inter‐row mulching induced earliness under both irrigation treatments. Seventy five percent of canopy density was attained in the mulched treatments contrasting with 45–61 % in the non‐mulched treatments at 34 days after sowing. Throughout the growing period, shoot biomass was significantly higher for the mulched treatments that had as well higher root biomasses. The overall estimated evaporative losses from the non‐mulched treatments were between 37 % and 39 % of the total water applied. The whole gross canopy water use efficiency in the furrow and drip mulched treatments was 64 % and 45 % higher than in the respective non‐mulched treatments. These results indicate that inter‐row polyethylene mulch is an efficient technique by which soil evaporation is reduced and plant productivity increased.     

木塑复合材料的表面润湿性研究

热塑性聚合物之间的熔融共混改性和木材纤维与热塑性聚合物之间的复合,加入偶联剂均可提高复合材料的润湿性,对材料的相容有利;在偶联剂加入量相同的情况下,增加木材纤维的用量可以加速材料的润湿速度,有利于提高材料的润湿性;在热塑性聚合物用量一定的前提下,改变加入的增强材料的形状,对材料润湿性有影响,木材纤维可以提高复合材料的润湿性.     

四翅滨藜微型塑料棚嫩枝扦插育苗技术研究

四翅滨藜微型塑料棚嫩枝扦插育苗技术研究结果表明:微型塑料棚进行四翅滨藜嫩枝扦插育苗,成活率可达73.5%,比露天嫩枝扦插育苗的成活率高16.2个百分点。虽然比全光照自动喷雾育苗的成活率稍差,但从综合效益分析,其成本低、方法简单易行,可以在乡村苗圃进行规模化生产。     

抗菌塑料的微生物检测方法

随着人们生活质量的提高,高科技含量的材料不断被开发出来,抗菌塑料就是重要的一种。由于向塑料的原材料中添加了抗菌剂,使它具有抑菌和杀菌效果,而抗菌塑料的抗细菌、抗霉菌的效果需要微生物学的方法加以检测,根据塑料的几何形状和接触菌体的效果应该采用覆膜法:在待检测的材料上,均匀涂上一定量的细菌接种培养液,培养后用活菌平板计数法综合统计抗细菌率,根据抗细菌率确定材料属于抗菌还是强抗菌材料。     

川中丘陵区覆膜再生稻田N2O排放规律研究

为明确覆膜再生稻田N_2O排放规律,采用静态箱-气相色谱法原位观测了川中丘陵区覆膜条件下再生稻田的N_2O排放通量。试验设置覆膜单季中稻(SR)和覆膜中稻-再生稻(SR-RR)两个处理。结果表明:SR-RR处理中稻季有两个明显的N_2O排放峰,第一个排放峰出现时间较SR处理提前13 d,再生季出现N_2O排放最高峰,峰值为1 630.7μgN·m~(-2)·h~(-1)。全观测期内SR-RR处理N_2O排放量为5.63 kgN·hm~(-2),其中再生季N_2O排放量为2.35 kgN·hm~(-2),约占两季总排放的42%。SR-RR处理两季的N_2O排放总量比SR处理的单季排放量高246%(P0.05)。SR-RR处理两季稻谷总产量为10.4 t·hm~(-2),其中再生季产量为1.89 t·hm~(-2),约占两季稻谷总产量的18%,SR-RR处理两季稻谷总产量比SR处理高出22%(P0.05)。SR-RR处理单位产量的N_2O排放量为0.54kgN·t~(-1),较SR处理增加184%(P0.05)。研究结果为进一步研究覆膜再生稻田N_2O排放规律及寻求有效的减排措施提供数据支撑和科学依据。     

残膜污染治理回收技术研究

我国的地膜覆盖栽培技术从20世纪70年代未开始示范推广,目前,已广泛应用于蔬菜、棉花、小麦、玉米、马铃薯及甜菜等多种作物。由于塑料残膜难以降解,若不得以及时有效回收,就会对农田和生态环境造成严重影响,带来“白色污染”。从农膜生产、投入使用到清理回收和再生利用等多个环节,进行全方位地残膜污染治理回收技术研究,并提出加快发展残膜治理回收技术的建议。     

Comparison of water absorption and mechanical properties of wood–plastic composites made from polypropylene and polylactic acid

Abstract

This study focuses on the water absorption and mechanical properties of composites made from softwood sawdust and plastics, such as virgin and recycled polypropylene and polylactic acid (PLA). The composites were processed by extrusion, and their properties were investigated by a water immersion test, mechanical tests and a cyclic test for moisture resistance. Scanning electron microscopy was used to study the morphology of the fracture surfaces of the composites. The composites made with recycled polypropylene had the lowest water absorption and thickness swelling of the studied composites. The PLA composites made with heat-treated sawdust showed the highest flexural strength. Of the polypropylene based composites, virgin polypropylene resulted in composites with higher flexural strength. The Charpy impact strength of the composites was found to have an inverse trend compared to flexural strength. Cyclic treatment of the studied composites resulted in 20–60% loss of flexural strength, depending on type of composite.