草莓苗圃草害综合防治技术

草莓苗圃杂草危害严重,应从苗期入手,根据杂草发生的不同特点,运用农业措施和化学方法综合防治,保证草莓苗健壮生长。     

非洲破布木子代测试

非洲破布木是埃塞俄比亚的本土商业木材树种,在自然种群中,存在着巨大的品种变异。由于当地苗圃优良种质资源匮乏,筛选优良母树建立种子园非常必要。该研究从其不同的自然种群中,采集了大量的供试种子样品,对其种子外部特征和在苗圃中发芽率和种苗生长表现,进行了观察;方差分析显示,在所有的研究属性中,不同种源显示出较大的属性差异性,同时初步筛选出适合种子园所需的优树。     

酒泉市林业苗圃杂草危害规律及除草剂防治应用研究

2017年4月,在酒泉市林业苗圃基地针对不同种类苗木,从杂草的种类调查入手,分析杂草的危害及群落构成,通过药剂筛选试验,筛选出适合本地区不同防治时期和防治对象的化学药剂。结果表明,在萌芽前对一两年苗圃中的杂草可选用甲戊·乙草胺进行防除,对多年生苗圃,乙氧氟草醚防除效果最佳。在生长季防除禾本科杂草高效氟吡甲禾灵防效最高,2甲·氯氟吡对阔叶杂草的防除效果最高,在生产上可将2种不同防除对象的药剂混合使用。     

扑草净除草试验初报

1987～1988年我们对东至县杉木苗圃杂草发生动态进行观察、调查及化学防除试验,取得明显效果,现将结果报道如下。一、杉木苗圃杂草发生动态东至县位于长江中游,是皖赣边境的山     

割地草在森林苗圃的应用研究

通过对割地草选择性原理、森林苗圃杂草发生规律、用药最佳期的选择等研究，提出了割地草在森林苗圃的应用技术     

除草剂在林业苗圃中的应用技术

苗圃杂草一直是林业苗圃工作中的一大难题.苗圃杂草来源多而杂,且根系发达,茎叶茂密,生长迅速,有强大的生命力,消耗了苗圃地大量的水分和养分,造成苗圃地阴湿,通风不良,透光少,影响苗木正常生长和光合作用,降低苗木长势,促使苗木病虫害的增加,从而提高了生产成本.     

南昌城市绿地夏季杂草发生特点及防除对策

采用普查与定点取样相结合的方法,对南昌城市绿地夏季杂草的发生规律与危害特点进行调查与分析。结果表明:南昌城市绿地夏季有杂草123种,隶属于37科,其中,以阔叶杂草为主,占79.67%;禾本科杂草其次,占16.26%;莎草科杂草较少,仅占4.07%;杂草种群结构复杂。并对不同除草方法进行比较分析,提出相应的防除建议。     

割地草在森林苗圃的应用研究

通过对割地草选择性原理，森林苗圃杂草发生规律，用药最佳期的选择等研究，提出了割地草在森林苗圃的应用技术。     

南昌城市绿地冬季杂草发生特点及防除利用

采用普查与定点调查相结合的方式,对南昌城市绿地冬季杂草的种类与发生特点进行调查分析。结果表明:南昌城市绿地冬季有杂草26科67种,大多为株体低矮的种类或株体高大种类的幼苗,种群结构较为简单,以1种或2种杂草群落为主。同时,从生态学与景观营造角度对不同绿地及不同时期的杂草进行害与益比较分析,提出了相应的防除与利用对策。     

固原市苗圃杂草及危害程度调查及防治初报

指出了随着近年来固原市苗木产业的迅速发展,苗圈杂草发生情况日趋严重,主要论述了固原市苗圃杂草发生程度,并分析了杂草发生的原因、萌发高峰期和主要防治方法。经调查表明:固原市苗圃主要杂草有刺儿菜、灰绿藜、苦荬菜、黄花蒿、冰草、狗尾草6种,次要杂草有苦苣菜、稗草、白草、菊叶香藜、莎草、反枝苋等18种。防治的主要化学除草剂有秋刺、惠儿、针管用、冰草净和草甘膦。     

Weed seedbank characteristics of arable fields under different fallow management systems in the humid tropical zone of southeastern Nigeria

The composition and pattern of weed flora in arable fields are determined by their seedbank structure; but the influence of fallow management practices on weed seedbank structure is presently unknown. The objective of this study was to investigate weed seedbank characteristics and weed population dynamics in arable fields in natural and planted-fallow systems. The study plots were at Mbaise, a densely populated area of southeastern Nigeria, where farmers regenerate their exhausted soils by maintaining planted fallows of Dactyladenia barteri (Hook. F. ex Oliv.) Prance & F. White, and at Umuahia, a less-densely populated area in the same region, where farmers depend on natural bush fallow for soil regeneration. The effect of three years of fallow on the weed flora of arable fields in the two fallow management systems differed remarkably. The first flush of weeds on fields that were cultivated after three years of planted D. barteri fallow (Mbaise) consisted of 80% broadleaf weeds, 7% grass weeds and 13% sedges. On the other hand, the first flush of weeds on the natural bush fallow fields (Umuahia) of the same fallow duration as the D. barteri fallow system consisted of 17% broadleaf weeds, 70% grasses and 13% sedges. Three years of planted fallow caused 36% decrease in weed seedbank at Mbaise relative to the cropped field while the same duration of natural bush fallow caused a 31% increase in weed seedbank at Umuahia. These results show that the planted D. barteri fallow system has a higher potential to reduce weed pressure in smallholder agriculture than the natural bush fallow system and may explain in part why farmers in this humid forest zone have adopted the practice. This revised version was published online in June 2006 with corrections to the Cover Date.     

Role of weeds in the management of nitrogen in a young Pinus radiata plantation

Pinus radiata trees were grown on a podzolized sandy soil at a second rotation site under the following treatments: total weed control, total weed control plus ammonium nitrate, strip weed control and no weed control. During the first two summers after planting the differences in needle water potential between trees under no, strip or total weed control were very small. Despite similar rates of net N-mineralization in strip and total weed control treatments, which averaged 64 kg ha^–1 yr^–1 in the 0–15 cm soil depth, weeds in the strip weed control treatment reduced soil mineral-N concentrations by 50–80%, leaching of N by the end of the first growing season by 45%, foliar-N concentrations by 4–14% and stem biomass at 20 months after planting by 46%. Although N-uptake by above-ground vegetation (trees plus weeds) was 49% higher in the strip weed control treatment, the amount of N apportioned to trees during the first 20 months after planting was reduced from 15.5 to 9.0 kg ha^–1. These effects of weeds were even more pronounced in the no weed control treatment. Since weeds had little effect on the needle water potential of trees and the annual rates of N-mineralization, but adversely affected N-uptake by trees, results indicate that weeds directly competed with trees for N, and thereby aggravated N-deficiency in trees. Application of ammonium nitrate after complete weed control increased foliar-N concentrations, and N-uptake and growth of trees, but also induced severe stem deformation.     

Alley cropping and mulching withErythrina poeppigiana (Walp.) O. F. Cook andGliricidia sepium (Jacq.) Walp.: effects on maize/weed competition

The potential of allye cropping systems to sustain a high productivity with low external inputs and the reduction of maize/weed competition through weed suppression in different alley cropping and sole-cropped mulched systems was studied in Costa Rica at CATIE. Data were recorded eight years after establishment of the experiment. Plant residues ofErythrina poeppigiana trees (10 t/ha dry matter) planted at 6 by 3 m reduced weed biomass by 52%, whileGliricidia sepium trees (12 t/ha dry matter) planted at 6 by 0.5 m reduced weed biomass by 28%, in comparison to controls.Erythrina had a considerable impact on grass weeds, whileGliricidia reduced the incidence of some dicot weeds. Weed competition significantly reduced maize yield in all systems. Nevertheless weed suppression contributed to the higher maize grain yield underErythrina andGliricidia alley cropping of 3.8 t per hectare as opposed to the unmulched control yield of 2.0 t per hectare.     

马尼拉草坪应用高效盖草能和草甘膦杂草防除试验

用10．8％的高效盖草能10ml加水13kg喷雾170m^2能有效杀灭4叶期以内的禾本科杂草，用10％含量的草甘膦50ml加水13kg喷雾170m^2能有效杀灭4叶期以内的单子叶和双子叶植物杂草，总体除草效果均在90％以上，对草坪安全。     

Weed management through short-term improved fallows in tropical agroecosystems

Weeds in tropical agricultural systems can cause serious economic damage, and their control often requires the commitment of substantial resources in the way of labor, capital, or pesticides. Tropical shifting cultivation systems employ a fallow period to help overcome weed infestations in addition to improving soil productivity and reducing other pest populations. Short-term, intensive fallow systems that employ herbaceous and woody species to facilitate rapid restoration of soil productivity have evolved as an alternative to long-term fallows. Short-term fallows can impact weeds at all growth stages and play a role in the integrated management of weeds and crops. Fallow management that promotes vegetative soil cover may reduce weed recruitment due to attenuation of soil temperature and/or shift in light quality at the soil surface. Residues or litterfall from fallow species may alter the chemical and microbial ecology of the soil to favor losses from the weed seed bank due to germination, loss of seed vigor, or seed decay. In addition, fallow vegetation can influence weed seed predation. Enhancement of soil productivity should increase the vigor of crop growth and enable crops to better compete with weeds. The burning of fallow species residues may result in weed seed death due to extreme temperatures or may induce seed germination by the release of mechanical dormancy or chemical germination cues. Certain weeds may serve as improved fallow species due to their high nutrient scavenging efficiency in low-fertility environments and their ease of establishment. Short-term improved fallows can be an important component of integrated weed management, particularly by promoting the prevention and tolerance of weeds in crops.This revised version was published online in November 2005 with corrections to the Cover Date.     

不同覆盖措施无公害清除五味子园杂草的试验

通过对凤城市郊区北五味子园杂草种群分布情况的调查和实施不同覆盖措施清除杂草试验，结果表明：凤城市郊区五味子园杂草具有鲜明的季节特性和杂草分布不均匀特性，杂草滋生数量较大，对五味子植株生产影响较大；杂草主要通过草籽和串根繁殖；不同覆盖措施间控制杂草的效果差异极显著，以覆双层黑地膜取得的效果最好，杂草比对照减少99．80％。采取双层黑地膜覆盖技术是有效控制五味子园杂草滋生蔓延的最佳措施，能够达到彻底控制杂草的目的。     

Vegetation response to intensity of herbaceous weed control in a newly planted loblolly pine plantation

Growth of loblolly pine (Pinus taeda L.) seedlings through three growing seasons after planting increased with intensity of herbaceous weed control using herbicides. Weed control had no effect on pine survival. Two years of complete herbaceous weed control (CHC, control throughout the first two growing seasons after planting) and operational herbaceous weed control (OHC, sulfometuron at 0.42 kg ai/ha at the beginning of the first growing season), resulted in lower biomass of weeds plus trees than with no herbaceous weed control (NHC) during the first growing season. Differences in total biomass during the first year were due to differences in biomass of herbaceous weeds. Total biomass on CHC and OHC plots was at least as great as NHC the second year, and greater by the third year, as pines assumed dominance as a result of increased growth from reduction of herbaceous weeds. The operational herbicide treatment had no significant impact on overall herbaceous weed biomass and cover, and little effect on species composition compared to no herbaceous weed control two and three growing seasons after treatment. The CHC treatment significantly reduced herbaceous weed biomass, cover and composition through three growing seasons.     

不同抚育措施对毛竹叶螨种群密度及危害影响的研究

对毛竹叶螨发生的竹林进行劈草和锄草抚育,通过1a观察发现,锄草的竹林中的毛竹叶螨的种群密度和危害高于劈草的竹林。建议竹林抚育要因地制宜,对杂灌不繁茂、土壤较疏松的竹林不劈草。对杂灌繁茂的竹林于8～9月份劈草,尽量不锄草。释放捕食螨防治毛竹叶螨结果表明,捕食螨防治效果留草竹林大于劈草竹林、大于锄草竹林,所以毛竹叶螨的防治要与竹林抚育管理相结合,竹林在释放捕食螨防治毛竹叶螨的当年林下要留草,禁止全垦全劈。     

Advances in modelling and decision support systems for vegetation management in young forest plantations

The two most common forest vegetation management objectivesare to (1) minimize resource competition, and (2) to developmethods for managing specific weed species. This paper reviewsrelevant models and decision support systems for assisting inachieving these objectives. The aim of reducing resource competitionis to increase crop-tree growth and survival. Several modellingapproaches have been applied to this problem and these generallyestimate crop survival and growth benefits following some formof generalized weed control. Linkages with models of older treecrops are needed for comparing vegetation management strategiesin the context of complete silvicultural regimes. More refinedindividual tree models use competition indices to estimate thequantity of weed vegetation within the growing space aroundeach tree. The indices reflect resource use by the weeds andare sensitive to changes in weed growth over time and to theapplication of specific vegetation management treatments. Hybridand process-based models have the potential to provide moregeneralized models of inter-specific competition, but theirusefulness for forest practitioners has yet to be proven. Someforest vegetation management problems require a more detailedunderstanding of the biology and ecology of a specific species.In this case, different modelling approaches that consider overallweed population dynamics, distribution or spread may be appropriate.     

Foliar delta(13)C and delta(18)O reveal differential physiological responses of canopy foliage to pre-planting weed control in a young spotted gum (Corymbia citriodora subsp. Variegata) plantation

Weed control may improve the growth of forest plantations by influencing soil water and nutrient availability, but our knowledge of leaf-level physiological responses to weed control at different within-canopy positions is limited for tropical and subtropical plantations. Foliar carbon (delta(13)C) and oxygen (delta(18)O) isotope compositions, gas exchange, and nitrogen (N(mass)) and phosphorus (P(mass)) concentrations at four canopy positions were assessed in a young spotted gum (Corymbia citriodora subsp. Variegata (F. Muell.) A.R. Bean & M.W. McDonald) plantation subjected to either weed control or no weed control treatment, to test if leaves at different positions within the tree canopy had the same physiological responses to the weed control treatment. Weed control increased foliar delta(13)C but lowered delta(18)O in the upper-outer and upper-inner canopy, indicating that weed control resulted in a higher foliar photosynthetic capacity at upper-canopy positions, a conclusion confirmed by gas exchange measurements. The increased photosynthetic capacity resulting from weed control can be explained by an increase in foliar N(mass). In the lower-outer canopy, weed control reduced foliar delta(13)C while lowering delta(18)O even more than in the upper-canopy, suggesting strong enhancement of the partial pressure of CO(2) in the leaf intercellular spaces and of foliar stomatal conductance in lower-canopy foliage. This conclusion was supported by gas exchange measurements. Foliar photosynthesis in the lower-inner canopy showed no significant response to weed control. The finding that leaves at different canopy positions differ in their physiological responses to weed control highlights the need to consider the canopy position effect when examining competition for soil nutrient and water resources between weeds and trees.