贵州省桐梓县耕地表层土壤养分元素有效性研究

通过研究贵州省桐梓县耕地表层土壤养分元素有效性及其影响因素,为耕地资源规划、发展现代农业提供科学依据。根据桐梓县耕地质量地球化学调查评价所获得的表层土壤有效态样品,对其养分元素(指标)测试分析,探讨耕地表层土壤养分元素及其有效态的含量、分布特征、等级状况及影响因素。结果表明,研究区耕地表层土壤养分元素全量整体较丰富,硼、钼、锌全量以丰富等级为主,分别占总样本数56.34%、65.49%、77.96%;氮全量以较丰富为主,占比41.16%;而磷全量以较缺乏为主,占比32.23%。有效量整体较缺乏,速效磷、有效钼以缺乏为主,分别占比46.05%、30.14%;有效硼、速效钾以较缺乏为主,占比分别为64.66%、50.94%;而有效锌较丰富,占比50.83%。研究区耕地表层土壤养分元素全量是其有效量的主控因素,养分元素有效性受表生地球化学及土壤理化性质的影响;不同的地质单元、土壤类型、土地利用类型中土壤养分元素有效性差异性显著;增加阳离子交换量可以促进土壤养分元素有效量的转化,提高土壤中有机质含量能增加养分元素有效性。

Influences of Post-fires on Subsequent Population of Japanese Pine Sawyer Beetles, Monochamus alternatus Hope (Coleoptera: Cerambycidae) in Masson Pine Forests

[Objective]Both fire and insect outbreaks are considered as important natural disturbance factors in many forest ecosystems,yet few studies have addressed the effects of fires on subsequent insect outbreaks.[Method]In this paper,tree mortality,larval density and vertical distribution were measured through field investigation and sampling method to evaluate the short-term response of Japanese pine sawyer beetle,Monochamus alternatus Hope to Masson pine,Pinus massoniana Lamb.in the second year after the fire in Jiangxi Province,China.[Results]compared with unburned Masson pine forest,burned Masson pine forest suffered from higher tree mortality and more pine trees were attacked by M.alternatus.Burned Masson pine tended to harbor much higher larval density further up along the trunk than unburned pine trees,and most individuals distributed in the middle section and middle-lower section of the trunk.[Significance]The results confirmed that Masson pine forest after being damaged by non-lethal fires were more susceptible to attacks by Japanese pine sawyer beetles,displaying higher population density and higher vertical distribution position.The study will provide an important guideline for the managers of Masson pine forests suffering from fires and pest invaded areas.

中国绵蚧科一新记录属及一新记录种(半翅目:蚧次目)

柑橘唇绵蚧Labioproctus poleii在我国新发现于云南省普洱市,为中国新记录种,唇绵蚧属Labioproctus也为中国新记录属。本文对柑橘唇绵蚧的形态特征、寄主植物、地理分布、生物学等进行介绍,并提供了中国绵蚧科昆虫分属检索表。

云南一新记录粉蚧——杜鹃臀纹粉蚧

杜鹃臀纹粉蚧Planococcus japonicus Cox,1989是一种可危害杜鹃花的蚧害,已在印度、日本、马来西亚、菲律宾和美国有记录。近些年,该蚧在我国云南的朴属Celtis sp.和桂花Osmanthus fragrans上被发现。本文对其鉴别特征、寄主植物、地理分布、经济重要性等进行介绍,以期为其鉴定提供参考。

马尾松毛虫灾对松林中松褐天牛种群的影响

在自然生态系统中,植物通常遭受多种昆虫的危害,从而构成昆虫的种间关系。本文通过设立标准地,对遭受马尾松毛虫不同程度危害后的马尾松林中松褐天牛种群的变化规律开展调查。结果表明,随着马尾松遭受马尾松毛虫危害的加重,松树死亡率从9.57%上升至22.86%且存在显著差异;含有松褐天牛的松树有虫株率在90.60%~95.83%之间但不存在差异;松褐天牛幼虫的平均虫口密度从20.58头·株^(-1)上升至41.11头·株^(-1),且存在极显著差异;松褐天牛幼虫有70%左右集中分布在中下部和中部且在不同部位间的分布存在极显著差异,但同一部位的幼虫占比在不同受虫灾程度的树体中并不存在差异。这些结果表明马尾松毛虫对马尾松的危害为松褐天牛的危害创造了条件,从而加重了松褐天牛对马尾松的危害。

虚拟现实技术在工业设计中的应用策略

在当今工业领域的不断发展中,越来越多的先进技术也开始被应用到工业设计中。其中,虚拟现实技术就是目前工业设计领域中所应用到的一种先进科学技术。该技术的应用对于工业设计质量的提升与工业领域的发展都有着十分积极的促进作用。因此,为实现虚拟现实技术在工业设计领域中的良好应用,发挥出该技术的充分优势,本文对其具体的应用策略进行分析,以此来为其应用提供指导与帮助。