海东地区荒山荒坡三种治理措施的效果对比研究

对治理荒山荒坡常用的封育、补播、重新建植三种方法进行了对比、调查和分析。结果表明,采用补播措施治理荒山荒坡是较为有效的途径,也是合理开发利用荒山荒坡、尽快恢复植被、控制水土流失和改善生态环境经济实用而又可行的方法。     

不同浓度CO2对牛卵母细胞体外成熟和受精的影响

对牛卵巢卵泡内卵母细胞在不同浓度的CO2培养箱内体外成熟、体外受精后的卵裂率及胚胎体外发育进行了研究。结果显示,含5%小牛血清(CS)的TCM-199内的卵母细胞在2%CO2条件下培养20h后,达到第二次减数分裂期(MⅡ期)的卵子数明显高于在5%CO2条件下培养的卵母细胞数(P<0.05)。两种浓度的CO2条件下培养的牛卵母细胞体外受精后的卵裂率无明显差异,2%CO2浓度下培养的卵母细胞的囊胚发育率高于5%CO2浓度下培养的卵母细胞。     

牦牛放牧率对小嵩草高寒草甸不同植物类群地上生物量生产率的影响

2年的牦牛放牧试验表明:除不同植物本身的生理特性外,降水和地温是影响小嵩草高寒草甸两季草场不同植物类群地上生物量绝对生长率的关键因素。小嵩草高寒草甸两季草场地上总生物量的绝对生长率1999年在7月份最大;1998年,冷季草场各放牧处理的绝对生长率在8月份达到最大,暖季草场的对照组和轻牧组在7月份最大,中牧组和重牧组在8月份最大。不同植物类群地上生物量生长率的变化不尽相同。1998年,冷季草场禾草和莎草地上生物量的绝对生长率8月份达到最大,暖季草场禾草和莎草地上生物量的绝对生长率7月份达到最大,且9月份出现了营养的再次积累;1999年,冷季草场禾草地上生物量的绝对生长率在6月份和8月份出现了两个峰值,暖季草场禾草地生物量的绝对生长率在7月份达到最大。对杂草类而言,1998年冷季草场的绝对生长率6月份最大,暖季草场重牧组的绝对生长率8月份达到最大,其他各处理7月份达到最大;1999年重牧组杂草的绝对生长率在6月份达到最大,其他各处理杂草在8月份达到最大。     

不同播期和不同肥力条件下向日葵干物质形成和物质分配对杂交种产量的影响

不同的播期明显影响向日葵籽实产量及病害发生的程度。通过调整播期，可防止或减轻叶部斑病和菌核病的发生，在向日葵生产上起着很大作用。向日葵不同品种干物质积累规律符合Logistic生长曲线，可用方程y=k/(1 ae^-bx）模拟。向日葵植株的器官平衡依次为：除空壳外，茎秆（28.5%)、籽实（24.5%)、叶片（22.5%)、葵盘（17.3%)、叶柄（4.9%)。土壤肥力对向日葵的器官平衡有较大影响。经济系数不高是向日葵的一个特点。栽培条件不同，经济系数差异较大。在一般情况下，春播条件下经济系数较高，夏播条件下经济系数较低。     

奎屯地区气象要素对玉米播种及苗期的影响

奎屯地区农七师位于天山北麓,准噶尔盆地的西南缘,总面积5986km2,其中作物种植面积120万亩,随着农七师产业结构的调整,2003年实施了“万头澳牛引进工程”,养牛业的发展使农七师畜牧业对玉米的需求量增加,尤其是澳牛养殖业对青贮玉米需求量更大,因此,研究分析气象要素对玉米播种及苗期的影响是重要工作之一。     

杨干象对杨树生长的影响和防治指标的研究

1995～2000年，对杨干象对杨树生长的影响和防治指标进行了研究。结果认为，不同虫口密度对杨树生长的影响明显，通过建立虫口密度与杨树生长(树高、胸径、材积)损失率回归预测模型表明，随着虫口密度的增加，胸径、材积生长明显下降，其关系呈直线、对数回归关系；高生长总的趋势是下降的，呈多项式回归关系；杨干象防治指标确定为：5年生以下杨树为2头／株，6～8年生杨树为3头／株，9年生以上杨树为4头／株。     

Effect of Nitrogen Rate and Stubble Height on Dry Matter Yield,Crude Protein Content and Crude Protein Yield of a Sorghum–Sudangrass Hybrid[Sorghum bicolor (L.) Moench × Sorghum sudanense (Piper) Stapf.] in the Three‐Cutting System

In this study, the effects of nitrogen (N) rate (60, 120, 180 and 240 kg N ha^?1 applied in three equal dressings at seeding and after the first and second cuttings) and stubble height (7, 14 and 21 cm) on the dry matter (DM) yield, crude protein (CP) content, and CP yield of a sorghum–sudangrass hybrid [Sorghum bicolor (L.) Moench × Sorghum sudanense (Piper) Stapf., cv. Pioneer 988] in the three‐cut system was investigated. The N rate had no significant effect in the first and third cuttings, but in the second cutting DM yields increased significantly with increase in N rate. The highest yield of 9.1 t ha^?1 was obtained with 80 kg N ha^?1 for the average of 2 years at the second cutting, but no significant difference was found among the 40, 60 and 80 kg N ha^?1 rates. CP content and yield were not significantly affected by N rate at the first and third cuttings, but CP content and yield were significantly affected by application of N at the second cutting. Stubble height had a significant effect on CP content at the third cutting. However, it had no significant effect on CP content at the first and second cuttings. Stubble height had a significant effect on the CP yield at the first cutting, but no significant effect on CP yield at the second and third cuttings.     

水稻机械化喷直播技术的应用现状及对策

分析了水稻机械化喷直播技术的特点和技术要求，介绍了水稻机械化喷直播技术的应用现状及其技术推广的制约因素．提出了推广水稻机械化喷直播技术的对策．     

A grower-friendly method to transfer predacious mites to commercial orchards

The establishment of predacious mites in commercial orchards may be accelerated by the transfer of pruned wood in winter and summer from donor orchards to release orchards. Following winter pruning, 3-year-old and older wood is collected and transported as soon as possible in bundles to a release orchard for distribution. If the release orchard is composed of dwarf trees, then one or two bundles of 5 kg each are placed vertically at the base of the trunk of every tree in the block (0.5 to 1 ha); if the trees are of standard size, then four or five bundles used. Following summer pruning, annual shoots and suckers are distributed immediately in a release orchard composed of dwarf trees by placing 12–15 branches on the foliage of fruit-bearing branches; if the release orchard is composed of standard trees, then 50 branches are used. The pruned wood should have 20–25 leaves and not less than one predator per leaf. The release orchard should have a light infestation (two or three mites per leaf) of pest tetranychids. These phytophagous mites would serve as food and help establish the predators. The release orchard grower should develop a pest management program based on the same groups of pesticides used in the donor orchard. http://www.phytoparasitica.org posting Aug. 31, 2005.