苹果斑点落叶病的发生规律及防治

苹果斑点落叶病是苹果早期落叶病的一种，由苹果轮斑病的一个强毒菌株系所致，近几年在本地普遍发生，许多果园2005年病叶率达90％以上，平均每个叶片有病斑9个，多者达数十个，造成大量前期落叶，当年果实个小品质差，并影响到树势和来年产量。我们于2004年至2005年对苹果斑点落叶病进行了侵染循环和发生规律的研究，分析了其流行的因素并进行了有效防治，现将主要结果报告如下：     

草地火灾的调查方法

草地作为牧民群众赖以生存的生产、生活资料，直接关系着畜牧业生产的稳定和牧民的安居生活，而且对水土保持、调节气候、改良土壤、防风固沙、防治污染、维护生态平衡等方面都具有重大的影响。草地火是影响草地发生与发展的一个重要因素。管理和利用好草地火，能产生很多有益的生态作用。然而，青海省地处高寒牧区，海拔高，气候寒冷，牧草生长缓慢，畜牧业生产中草畜矛盾十分严重。加上冬春枯草期长，多风干旱，草地火险高，每年因草地火灾造成经济损失数万元。所以，就目前生产管理条件下，草地火具有强烈的破坏性，是与旱灾、雪灾、水灾…     

枯草菌可净化鱼池(水库)底污泥

日本佐贺县外律渔场的养鱼池和水库养殖了25年末清淤，底部的残饵、鱼粪等有机物污泥厚达1．0一2．sin，使水环境严重恶化，经常发生赤潮和鱼病。枯草菌是一种微生物，对库底污泥和污水吸收分解能力很强，能增强池底细菌活性及繁殖力、促进有机质分解，收到净化水质的效果。该场在库底引入散播枯草菌后两个月，污泥平均厚度减少了10～20cm，污泥被分解为土粒状，从而证明了枯草菌对清除池底污泥切实可行。枯草菌可净化鱼池(水库)底污泥@张平远$四川省江油市水电局!江油,621700     

浅析落叶松毛虫的生物学特性与防治

落叶松毛虫是针叶树主要的食叶性害虫之一。其危害具有周期性，生殖能力强，具有迁移能力，其发生与地形、地势、林分组成等条件有关。防治应从落叶松毛虫的生物学特性出发，利用物理防治、营林措施、生物防治、化学防治等措施进行。     

枯草芽孢杆菌在发酵饲料中的应用研究进展

枯草芽孢杆菌是一种益生菌，在粗饲料中添加枯草芽孢杆菌进行发酵处理得到的饲料为发酵饲料。本文对枯草芽孢杆菌发酵饲料，几种发酵饲料原料和发酵饲料工艺，以及固态发酵、液体发酵和枯草芽孢杆菌发酵饲料在不同领域内的应用进行综述，并对枯草芽孢杆菌发酵饲料的应用前景进行展望。 [关键词] 枯草芽孢杆菌|发酵饲料|研究进展     

青海省部分地区家畜棘豆中毒调查

笔者通过对青海省部分地区家畜棘豆中毒调查，发现其对家畜的危害甚为严重。老疫区家畜中毒主要发生在枯草季节，造成的损失是以影响繁殖为主，而新疫区家畜中毒全年均可发生，造成的损失是以引起家畜死亡为主。     

宁夏西海固地区“牛猝死症”调查与分析

近年来，一种发病急，死亡快，致死率极高、多侵害青壮年牛的疾病在宁夏西海固地区频频发生，因其病复杂，暂称之为“牛猝死症”。该病主要发生在２￣５月的枯草季节，特别是春耕使役中的牛多发。     

聚乙烯吡咯烷酮处理可延长水蜜桃贮藏期

河北农业大学植物保护学院的科技人员在1998、1999年两个生长季，对不同品种苹果树上斑点落叶病的发生和流行情况进行了系统调查，并结合气象数据进行分析。结果表明，降雨能在不同品种的苹果树上同时引发发病高峰。在对中等感病品种白龙上的斑点落叶病发生情况进行逐日系统调查的基础上．     

枯草芽孢杆菌在畜禽养殖应用中的研究进展

枯草芽孢杆菌是畜禽养殖中常用的益生菌之一，在土壤及植物体表广泛存在，可形成芽孢，抗性好，并且在芽孢状态下具有良好的稳定性。枯草芽孢杆菌具有提高动物生长性能、稳定肠道菌群、提高免疫力及改善肉品质等作用。文章综述了枯草芽孢杆菌的生理特性、作用机制及其在常见动物生产中的应用研究进展，以期为饲用枯草芽孢杆菌的进一步开发和利用提供参考。     

东北羊草草原枯草层对植物群落的作用

通过对东北典型羊草群落枯草层的调查和观测，结果表明，枯草层对羊草早春的返青有一定影响。适宜的枯草层促使羊草提前返青，生长加快，而过厚和缺少时则使返青延迟。群落的物种数随着枯草层厚度的增加而增加，枯草层800g／m2达到峰值后有所下降，枯草层厚度的处理梯度越接近，样地间的物种相似性系数也越接近，反之相似性系数差异越大，群落的各种数量特征，如密度、高度、盖度、频度和地上生物量随着枯草层厚度的增加而增加，达到峰值后则逐步减少。羊草地上生物量占地上生物总量的比例随着枯草层的增厚而呈递减趋势。     

Ranking of grass species according to visible wilting order and rate of recovery in the central orange free state

Abstract

A number of grasses were ranked according to the order in which they wilted with diminishing moisture availability, and according to their ability to recover after water replenishment. Digitaria eriantha and Digitaria argyrograpta were the most sensitive to moisture stress, whereas Sporobolus fimbriatus and Panicum stapfianum were last to show signs of wilting. The latter two grass species were the first to recover from wilting during optimum soil water conditions. The leaf water potential and soil water content at which each grass species wilted were recorded.     

Changes in the bacterial community and composition of fermentation products during ensiling of wilted Italian ryegrass and wilted guinea grass silages

To gain further insights into temperate and tropical grass ensiling, fermentation products and bacterial communities were examined at both the initial and late stages of ensiling of wilted Italian ryegrass and wilted guinea grass silages. 2,3‐Butanediol and ethanol fermentation were observed in wilted Italian ryegrass silage. Enterobacteria such as Rahnella sp. and Enterobacter sp. may have been involved in fermentation; however, alcohol production was intensified after the silage enterobacterial community overwhelmed the pre‐ensiled enterobacterial community. Pediococcus spp. appeared in silage stored for 4 months, when a significant increase in lactic acid content was seen compared with that at 2 months. Prolonged storage enhanced acetic acid fermentation in wilted guinea grass silage. The disappearance of Enterococcus sulfureus and appearance of Lactobacillus plantarum may have been associated with the increased acetic acid content. Although many species of enterobacteria were found in common between the pre‐ensiled crop and silages of Italian ryegrass and guinea grass, marked differences were seen in the type of fermentation from the initial stages. These results indicate that the bacterial community of pre‐ensiled crops may be immediately replaced by one that is adapted to ensiling environments, although metabolic changes may continue over the course of ensiling.     

Consumption and ruminating behavior in sheep. 3. Experiments on infertile female sheep of different breeds with reference to feed type and feeding duration

Ewes of the breeds merino fattening sheep, Stavropol merino and fertility hybrid were studied as to their consumption and ruminating behaviour after receiving a pelleted straw-concentrate mixture, maize silage and wilted silaged grass. During the feeding periods of 2 X 45 min or 2 X 180 min/d unlimited rations were available to the animals. With 86 min/d the sheep used the short feeding period nearly completely for feed intake. In the longer feeding period the sheep consumed 18% more feed in 161 min/d, ate more slowly, however, and ruminated somewhat less. In comparison with the straw-concentrate mixture, the silage rations were ruminated for shorter periods and less effectively, the number of ruminating movements per day and cycle was reduced, the breaks between bites became longer. The wilted grass silage stimulated ruminating even less than chopped maize silage. There were significant differences between the breeds in the ruminating frequency, which affected the number of ruminating movements per day and cycle.     

晾晒、添加物及不同温度对象草青贮发酵品质和微生物的影响

华南地区气候潮湿多雨,象草收获时水分含量高,单独青贮发酵品质较差。通过晾晒（水分含量由83.19%降至75.11%）、添加10%玉米粉或2%蔗糖,探究象草在不同温度（20、30和40 ℃）下青贮的发酵特性和微生物组成。研究结果表明：温度对象草各处理的青贮饲料的发酵品质有显著影响。晾晒后原材料的水溶性碳水化合物含量显著降低,青贮后发酵品质变差,尤其在30 ℃,pH达到5.85,乳酸含量只有1.56% DM,乙酸含量为2.10% DM,NH₃-N含量高达25.09% TN。对照和添加物处理的青贮饲料均随青贮温度升高,乙酸含量增加。晾晒后在20和30 ℃时青贮,产气量显著高于40 ℃或未晾晒处理。此外,象草青贮前的细菌多样性较丰富,青贮后主要是肠杆菌属和乳球菌属,尤其是20 ℃青贮的相对丰度较高,且晾晒处理在20和30 ℃青贮肠球菌属的相对丰度高于40 ℃。因此,在华南地区,象草原料中添加玉米粉或蔗糖可以降低环境温度对象草青贮发酵品质的不良影响,阴湿条件下晾晒未发挥积极效果。     

A pragmatic approach to improving small ruminant diets in the Indonesian humid tropics

Research conducted since 1980 on the nutrition and feeding of Kacang goats and Javanese Thintail sheep for meat production in Indonesia is reviewed. Feeding practices in three villages were monitored, along with animal production criteria, to better understand the limitations imposed by feed resource availability. Village and experiment station data showed that native or cultivated tropical grasses fed alone did not support growth of young goats and that lambs fed napier grass alone grew at no more than 20 to 25 g/d. Supplementing these grasses with tree legume foliage or wilted cassava leaves at modest levels improved ADG to about 50 g for lambs and 20 g for kids. Faster gains were obtained with higher intakes of tree legume foliage, or with combinations of higher-energy supplements such as rice bran, cassava meal and molasses. A response to mineral supplementation also was shown. Reproductive performance of North Sumatran ewes grazing a native pasture under rubber trees also was improved with supplementation. These experiments show that economically effective options exist for improving small ruminant diets in the humid tropics.     

Absence of a Grass/Fire Cycle in a Semiarid Grassland: Response to Prescribed Fire and Grazing

Many nonnative invasive grasses alter fire regimes to their own benefit and the detriment of native organisms. In southern Arizona the nonnative Lehmann lovegrass (Eragrostis lehmanniana Nees) dominates many semiarid grasslands where native grasses were abundant. Managers are wary of using prescribed fire in this fire-prone community partly due to the perceived effects of a grass/fire cycle. However, examples of the grass/fire cycle originate in ecosystems where native plants are less fire-tolerant than grasses and the invasive plant does not mimic the physiognomy of the native community. We investigate the effects of prescribed fire and livestock grazing on a semiarid grassland community dominated by a nonnative invasive grass. Lehmann lovegrass does not appear to alter the fire regime of semiarid grasslands to the detriment of native plants. Prescribed fire reduced the abundance of Lehmann lovegrass for 1 to 2 yr while increasing abundance of native grasses, herbaceous dicotyledons and fall richness, and diversity. Effects of livestock grazing were less transformative than the effects of fire in this long-grazed area, but grazing negatively affected native plants as did the combination of prescribed fire and livestock grazing. Although Lehmann lovegrass produces more fuel than native plants, fire frequency in semiarid grasslands appears to be limited by the paucity of above-average precipitation, which constrains high fuel loads. In addition, many native grasses tolerate high temperatures produced by Lehmann lovegrass fires. Consistent with previous research, fire does not promote the spread of Lehmann lovegrass, and more importantly human alteration of the fire regime is greater than the nominal effects of Lehmann lovegrass introduction on the fire regime.     

Soil Resources Influence Vegetation and Response to Fire and Fire-Surrogate Treatments in Sagebrush-Steppe Ecosystems

Current paradigm suggests that spatial and temporal competition for resources limit an exotic invader, cheatgrass (Bromus tectorum L.), which once established, alters fire regimes and can result in annual grass dominance in sagebrush steppe. Prescribed fire and fire surrogate treatments (mowing, tebuthiuron, and imazapic) are used to reduce woody fuels and increase resistance to exotic annuals, but may alter resource availability and inadvertently favor invasive species. We used four study sites within the Sagebrush Steppe Treatment Evaluation Project (SageSTEP) to evaluate 1) how vegetation and soil resources were affected by treatment, and 2) how soil resources influenced native herbaceous perennial and exotic annual grass cover before and following treatment. Treatments increased resin exchangeable NH₄⁺, NO₃^-, H₂PO₄^-, and K⁺, with the largest increases caused by prescribed fire and prolonged by application of imazapic. Burning with imazapic application also increased the number of wet growing degree days. Tebuthiuron and imazapic reduced exotic annual grass cover, but imazapic also reduced herbaceous perennial cover when used with prescribed fire. Native perennial herbaceous species cover was higher where mean annual precipitation and soil water resources were relatively high. Exotic annual grass cover was higher where resin exchangeable H₂PO₄^- was high and gaps between perennial plants were large. Prescribed fire, mowing, and tebuthiuron were successful at increasing perennial herbaceous cover, but the results were often ephemeral and inconsistent among sites. Locations with sandy soil, low mean annual precipitation, or low soil water holding capacity were more likely to experience increased exotic annual grass cover after treatment, and treatments that result in slow release of resources are needed on these sites. This is one of few studies that correlate abiotic variables to native and exotic species cover across a broad geographic setting, and that demonstrates how soil resources potentially influence the outcome of management treatments.     

Spring Clipping,Fire, and Simulated Increased Atmospheric Nitrogen Deposition Effects on Tallgrass Prairie Vegetation

Defoliation aimed at introduced cool-season grasses, which uses similar resources of native grasses, could substantially reduce their competitiveness and improve the quality of the northern tallgrass prairie. The objective was to evaluate the use of early season clipping and fire in conjunction with simulated increased levels of atmospheric nitrogen deposition on foliar canopy cover of tallgrass prairie vegetation. This study was conducted from 2009 to 2012 at two locations in eastern South Dakota. Small plots arranged in a split-plot treatment design were randomized in four complete blocks on a warm-season grass interseeded and a native prairie site in east-central South Dakota. The whole plot consisted of seven treatments: annual clip, biennial clip, triennial clip, annual fire, biennial fire, triennial fire, and undefoliated control. The clip plots consisted of weekly clipping in May to simulate heavy grazing. Fire was applied in late April or early May. The subplot consisted of nitrogen applied at 0 or 15 kg N · ha^?1 in early June. All treatments were initially applied in 2009. Biennial and triennial treatments were reapplied in 2011 and 2012, respectively. Canopy cover of species/major plant functional groups was estimated in late August/early September. Annual clipping was just as effective as annual fire in increasing native warm-season grass and decreasing introduced cool-season grass cover. Annual defoliation resulted in greater native warm-season grass cover, less introduced cool-season grass cover, and less native cool-season grass cover than biennial or triennial defoliation applications. Low levels of nitrogen did not affect native warm-season grass or introduced cool-season cover for any of the defoliation treatments, but it increased introduced cool-season grass cover in the undefoliated control at the native prairie site. This study supports the hypothesis that appropriately applied management results in consistent desired outcomes regardless of increased simulated atmospheric nitrogen depositions.     

Resistance to Invasion and Resilience to Fire in Desert Shrublands of North America

Settlement by Anglo-Americans in the desert shrublands of North America resulted in the introduction and subsequent invasion of multiple nonnative grass species. These invasions have altered presettlement fire regimes, resulted in conversion of native perennial shrublands to nonnative annual grasslands, and placed many native desert species at risk. Effective management of these ecosystems requires an understanding of their ecological resistance to invasion and resilience to fire. Resistance and resilience differ among the cold and hot desert shrublands of the Great Basin, Mojave, Sonoran, and Chihuahuan deserts in North America. These differences are largely determined by spatial and temporal patterns of productivity but also are affected by ecological memory, severity and frequency of disturbance, and feedbacks among invasive species and disturbance regimes. Strategies for preventing or managing invasive plant/fire regimes cycles in desert shrublands include: 1) conducting periodic resource assessments to evaluate the probability of establishment of an altered fire regime; 2) developing an understanding of ecological thresholds associate within invasion resistance and fire resilience that characterize transitions from desirable to undesirable fire regimes; and 3) prioritizing management activities based on resistance of areas to invasion and resilience to fire.     

Effect of fire intensity on the grass and bush components of the Eastern Cape thornveld

Abstract

Fire intensity is an important component of the fire regime and its effect on the grass sward and bush were investigated in the Eastern Cape thornveld. Research indicated that fire intensity had no effect on the recovery of grass after a burn. Conversely it had a marked effect on the topkill of bush to a height of 2 m. The results provide valuable guidelines for the use of fire in controlling bush encroachment.