椪柑园套种魔芋的效果初探

为充分利用土地资源,提高单位面积生产效率,推动魔芋新型产业发展,探讨了椪柑园套种魔芋生产栽培技术。结果表明,椪柑园套种魔芋,魔芋抗病能力明显增强,软腐病发病率较对照低57.1%,球茎膨胀倍数提高14.0%,产量提高15.53%。     

苹果园地表覆盖方式对土壤含水量及果实品质的影响

研究了地面生草、地膜覆盖、地面覆草和清耕处理4种地表覆盖方式,对苹果园土壤含水量及苹果果实品质的影响。结果表明:河北省果园的最适覆盖方式为地面覆草。普通推广的生草法模式不适合河北省干旱少雨的生长环境,并且在缺水季节会在一定程度上造成土壤更加缺水和干旱。     

多效唑对橘园杂草控制效用研究

采用不同浓度的多效唑控制橘园的主要杂草,以探索对橘园杂草高度与密度有效控制的途径。结果表明:在试验剂量900～1800g/hm2范围内,多效唑对禾本科杂草的生长抑制作用随处理剂量的加大而增强,以1350g/hm2剂量的多效唑处理效果最为理想。3种剂量的多效唑处理均对禾本科杂草的分蘖具有强烈的促进作用,使田间杂草密度大大增加;对2种阔叶杂草——一年蓬和觅菜的生长表现出强烈的抑制作用,但未达到理想的控制高度。     

Peach orchard protection strategies and aphid communities: Towards an integrated agroecosystem approach

Aphid populations, including a widespread pest, Myzus persicae, are known to be affected by cultural practices, plant growth and natural regulation, but their control in orchards most frequently relies on regular treatments aiming to avoid direct damage and virus transmission. This study aimed first at characterising farmers’ management strategies towards aphids and, secondly evaluating them in terms of efficiency and impact on aphid natural enemies. Protection methods were first identified through semi-open interviews and peach orchard pesticide records from 19 organic and conventional fruit farms in south-eastern France. It appeared that in addition to the regular use of direct control, farmers also used cultural and/or alternative methods and various decision-making indicators to optimise their orchard crop protection. Comprehensive variables based on the technical guidelines of the IOBC (International Organisation for Biological and Integrated Control) for crop protection made it possible to differentiate four strategies: intensive, optimised, input-substitution and integrated. Visual monitoring of aphid infestations and of beneficial populations was performed at the plot level. Brachycaudus schwartzi and Myzus varians were the most frequently encountered aphid species but the structures of the communities were affected by protection strategies: the more integrated the strategy, the more diverse and abundant the aphids. The two most effective strategies were dominated by chemical treatments, whereas the other two, less detrimental to aphid antagonists, were mostly carried out by organic farmers. Variations in aphid communities were related to: (i) the use of toxic products, correlated with low-infestations and low-abundance and diversity of antagonists; (ii) alternative and cultural methods (such as mowed ground cover and manual pruning of infested branches, respectively) that promoted high populations of both guilds. Unexpectedly, the structures of these communities were not related to the number of treatments, management of tree vigour or of the surrounding environment. The four strategies identified can be further interpreted as steps towards a redesign of orchard protection where integrated organic farming would be the most advanced stage. However, the paradox between effective protection strategy and biodiversity conservation still remains, casting doubts on the agroecological concept of sustainability.     

龙眼传粉昆虫种类及其传粉活动与温度的关系

以随机网捕方式采集传粉昆虫进行鉴定,选择不同天气类型观察蜂类和蝇类等传粉昆虫在龙眼花穗上的活动情况,并通过架设防虫网研究龙眼传粉的主导因子。结果表明,龙眼主要传粉媒介为昆虫,传粉昆虫有3目9科17种,其中以蜂类和蝇类个体数量最多,分别占总数的73.3%和20.6%。蜂和蝇类昆虫在龙眼花穗上的活动主要受温度影响,蜂类访花的适宜温度在25～30℃之间;蝇类在20.0℃开始访花并随温度升高访花次数增多,超过30.5℃访花次数减少。不同天气类型对蜂和蝇类昆虫访花活动也有影响,在晴天条件下蜂和蝇类昆虫访花次数较多,并且在花穗上的活动时间较长。     

间作苜蓿草枣园地表优势昆虫种类及优势度动态分析

了解间作牧草枣园地表昆虫种类及其动态变化,有助于有效地控制枣树害虫。2009年7—10月,研究了间作苜蓿草枣园地表昆虫群落物种组成及优势度动态变化。结果表明,7—10月份枣园地表昆虫群落总计9目42科,优势种是长蝽科和果蝇科。地表昆虫群落结构随着季节气温变化而不断变化,优势天敌昆虫有步甲、草蛉、缘蝽和食蚜蝇,优势天敌害虫有叶蝉、蝽和长蝽。枣草间作不仅可增加枣林植被的多样性,扩大捕食性天敌昆虫的生态容量,而且有助于实现枣树生产可持续发展和有害生物生态调控。     

梨园土壤研究进展

我国是世界第一产梨大国,但不同产区的梨品质差异较大.文章从梨园土壤营养、土壤对梨产量和品质的影响、梨园土壤管理等3个方面综述了梨园土壤研究进展,重点介绍了梨园土壤pH值、有机质及钙含量与梨品质的关系,指出土壤覆盖和施肥是改善梨园土壤理化性状、提高梨产量和品质的重要措施.今后应加强对梨园土壤的系统研究,建立梨园生态平衡施肥技术体系,为促进我国梨产业可持续发展提供技术支撑.     

陕西苹果园土壤砷和重金属污染评价

应用地积累指数和生态危害指数,对陕西苹果主产区果园土壤砷(As)和重金属污染进行了评价。结果表明:从应用黄土母质土壤背景值计算的平均地积累指数结果来看,果园土壤中Hg达到轻-中度污染,Cd,Cr,Pb,Cu,As 5种元素都没有造成污染。从6种元素的地积累指数分级频率来看,Hg和As的污染频率最大,达到46.8%;其次是Cd和Cu,分别是27.4%和4.8%;Pb和Cr均没有造成污染。从6种元素的潜在生态危害系数来看,果园土壤中Hg的生态风险危害最大,其次为Cd,其余4种元素都为轻微危害程度,生态危害系数均小于20;从果园土壤As和重金属的生态危害指数来看,有27.42%的果园达轻微危害,56.45%达中等危害,16.13%达强危害程度。     

红火蚁入侵对荔枝园土壤性理化质的影响

对红火蚁Solenopsis invicta Buren荔枝园发生区土壤理化性质进行了研究,结果表明:3类红火蚁不同发生区之间、红火蚁蚁巢4个不同方位之间以及距红火蚁蚁巢中心不同距离之间的土壤各项理化性质均有显著的差异(p<0.01)。从对照区、轻度发生区到重度发生区土壤粘粒变得越来越细,酸性逐渐升高。土壤有机质、碱解N、有效P的含量在轻、重度发生区较对照区分别下降了29.0%与39.9%、42.1%与53.6%、43.3%与52.6%,但速效K的含量在轻、重度发生区较对照区则分别升高了8.5%与34.0%。此外,在红火蚁发生区,蚁巢上的土壤理化性质与蚁巢以外的土壤理化性质明显不同(p<0.01)。蚁巢上的土壤明显比蚁巢以外的土壤酸性强。土壤有机质、碱解N、有效P的含量在蚁巢上明显最小,但土壤速效K的含量在蚁巢上明显最高。蚁巢不同方位上土壤的理化性质相对差异较小,红火蚁在荔枝园的分布存在一定的空间随机性。     

多效唑与草甘磷对果园杂草的影响研究

采用草甘磷与多效唑综合运用来控制梨园的主要杂草,以探索对果园杂草的种类、高度与密度进行有效控制的途径。结果表明：试验的处理中（草甘磷、多效唑、草甘磷＋多效唑）,以草甘磷＋多效唑的处理对禾本科杂草的生长抑制与促进分蘖效果最为理想,使田间杂草密度大大增加,达到了类似于人工生草的效果。该处理对阔叶杂草的生长也表现出强烈的抑制作用,达到理想的控制效果。