基于遥感指数的草原火后植被恢复研究     

宫大鹏  闫淳  郭赞权 《西北林学院学报》2021,36(6):204-210

草原火是草原生态系统重要的干扰因子，严重影响着系统的结构与功能。基于遥感数据，以2015年“4·16”特大草原火灾为例，利用ENVI和ArcGIS等软件，分别对NDVI和GPP指数及火烧严重度下的植被恢复过程进行定量分析。结果表明，基于NDVI和GPP指数的火后植被恢复过程表现相似，不同年份植被恢复情况存在一定差异。火灾发生当年（2015年）火烧迹地植被恢复状况高于未发生火灾区域，而在火后第1年（2016年）却又稍低于未发生火灾区域，直到火后第2年（2017年），火烧迹地植被基本恢复到火前状态。同时，不同火烧严重度下的植被恢复过程在存在明显差异。草原火灾发生后当年（2015年），中强度火烧下植被恢复最好，其次是轻度，重度表现最差。草原火烧严重度对植被恢复的影响，主要表现在火后第1个植被生长季。在之后的年份里，由于草原更新能力强大，不同火烧严重度对草原植被的影响不明显。本研究可丰富草原火灾及火烧迹地植被恢复等相关研究成果，同时为草原火灾管理和草原生态系统的可持续发展提供科学依据。  相似文献   

Effects of natural pyrethrum and synthetic pyrethroids on the tiger mosquito,Aedes albopictus (skuse) and non-target flower-visiting insects in urban green areas of Padua,Italy     

Daria Corcos  Luca Mazzon  Pierfilippo Cerretti  Maurizio Mei  Edoardo Giussani  Andrea Drago 《国际虫害防治杂志》2020,66(3):215-221

Abstract

The tiger mosquito is a key vector of several human diseases and is considered a public health concern worldwide. The implementation of strategies aimed at maximizing mosquito control without affecting non-target insect groups is of major importance. In a field trial, we tested the efficiency of a natural pyrethrum-based vs. a synthetic pyrethroid-based insecticide in reducing tiger mosquito population and how they affect the diversity of non-target flower-visiting insects in green urban areas. Only the pyrethroid insecticide was effective in reducing mosquito abundance, although its effects disappeared nine days after application. The two adulticides did not significantly affect the diversity of flower-visiting insects, probably because of their large body size and the difference in flying and foraging activity. To effectively control mosquito populations while preventing intoxication of non-target flower-visiting insects, adulticide applications should be applied early in the morning and only on bushes and trees. Results from our small-scale applications cannot be extrapolate when larger areas are treated.  相似文献   

An evaluation of the Olsen test as a measure of plant-available phosphorus in grassland soils derived from basalt parent material     

A.A.W. Bell  J.S. Bailey  R.V. Smith 《Soil Use and Management》2005,21(3):322-329

Abstract. Anecdotal and circumstantial evidence have suggested that the Olsen test underestimates plant-available phosphorus (P) in basaltic soils in Northern Ireland. Therefore, the ability of this test to predict plant-available P in basaltic (and non-basaltic) soils was investigated by regressing Olsen-P data against herbage P indices calculated from plant tissue test data using the diagnosis and recommendation integrated system. The average Olsen-P concentration for a range of fields situated on basaltic soils was considerably lower than the average Olsen-P concentration for a range of fields situated on non-basaltic soils, and yet mean sward P status, as given by the herbage P indices, was similar for both groups of fields. Herbage P indices were also much better correlated with Olsen-P measurements in non-basaltic soils than in basaltic soils. Furthermore, at low Olsen-P values (≶9mgPL⁻¹) some swards on basaltic soils were genuinely deficient in P, while others were sufficient or even in surplus for this nutrient. The results confirm that Olsen-P is inadequate as a predictor of plant-available P in basaltic soils. It is concluded that an alternative soil test is needed to provide a reliable assessment of plant-available P in basaltic soils, to prevent overuse of fertilizer and manure P and to minimize the amounts of P entering local watercourses.  相似文献   

Evaluation of two N cycle models for the prediction of N mineralization from grassland soils in the UK     

A. Bhogal  A. Bhogal  M.A. Shepherd  D.J. Hatch  L. Brown  S.C. Jarvis 《Soil Use and Management》2001,17(3):163-172

Abstract. The ability of two nitrogen cycle models, of contrasting complexity, to predict N mineralization from a range of grassland soils in the UK, was evaluated. These were NCYCLE, a simple mass balance model of the N cycle in UK grasslands, and CENTURY, a more complex model simulating long-term C, N, P & S dynamics in grassland ecosystems. The models were tested using field measurements of net N mineralization from a range of grassland soils (differing in soil type, history & management practice), obtained over a 2 year period using a soil core incubation technique. This method was considered to measure the total net release of mineral N from the soil organic matter over a specified time, including N which may have been recycled several times. NCYCLE consistently under-estimated mineralization rates at all sites. By contrast, there was some correlation between CENTURY predictions of net N mineralization and field measurements. This may have reflected the different abilities of the two models to simulate N recycling. Neither model, however, was able to predict adequately the effect of cultivation and reseeding on net N mineralization.  相似文献   

扁穗牛鞭草人工草地中空心莲子草杂草防除效果研究   总被引：3，自引：0，他引：3  

徐胜  张新全  李建龙 《中国草地学报》2003,25(2):34-37

利用水花生净除莠剂可有效地防除扁穗牛鞭草人工草地中的杂草空心莲子草,平均株防效达26.7%～99.8%,并且在较高防效下药剂对扁穗牛鞭草较为安全。在空心莲子草杂草生长盛期,14%的水花生净乳油以浓度为675ml/hm2～900ml/hm2、各处理对水600ml的防除效果最佳,可达到100%。综合考虑,以525ml/hm2～675ml/hm2的浓度为宜。  相似文献   

天山北坡中山带野生牧草种质资源评价     

郑子英 《草业科学》1995,12(4):2-4

通过对新疆３８野生种牧草种植试验，证明许多野生牧草不但在产量、质量上高于栽培牧草，在抗逆性能方面也为许多载培牧草所莫及，对建设新疆中山带的优质人工草地具有重要意义。  相似文献   

西藏山南地区草地资源及其合理利用   总被引：5，自引：2，他引：3  

王建林  邓小军 《草业科学》1994,11(2):28-30

由于对西藏山南地区草原状况缺乏全面认识，未能合理利用，出现了草原退化等一系列问题。为了合理开发利用草地资源，通过调查提出：调整畜群结构，推行草场有偿承包责任制，开展季节性畜牧业，建立草地农业生态系统等建议。  相似文献   

不同稳定剂对胭脂萝卜红色素稳定性的影响     

芮春梅  李成琼  司军  宋洪元  任雪松  李利军 《勤云标准版测试》2006,(12)

天然胭脂萝卜红色素属于花青素类化合物,性质不稳定。笔者以新鲜胭脂萝卜(Raphnussativuscv.)肉质根为原料,提取胭脂萝卜红色素,选择常用的5种稳定剂对其稳定性进行研究,从而确定出最佳的稳定剂及其用量。研究结果发现0.03%维生素C、0.03%谷氨酸、0.03%柠檬酸能明显地延缓其颜色变化,0.03%维生素C 0.03%柠檬酸的组合对该色素的稳定效果最佳;进一步研究确定维生素C和柠檬酸的最佳用量分别为0.04%和0.08%。  相似文献   

甘孜州退化草地生态系统综合治理对策研究   总被引：5，自引：0，他引：5  

张骑 《四川草原》2003,(1):32-34

介绍了甘孜州草地生态系统现状,在分析草地退化原因和危害的基础上,提出了综合治理退化草地生态系统的措施。  相似文献   

河北省天然草地禾本科植物的生活型、生态型及区系分析     

任永霞  郭郁频  吕进英  王海  姜风琴 《草业科学》2001,18(1):1-3

对河北省天然草地禾本科植物的生活型、生态型及区系特征进行了分析，结果表明，多年生草本为优势生活型，占78．4％；生态型以中生植物为主，占77．2％，旱生植物占16．0％，湿生植物仅占6．8％；植物区系成分多样，温带分布属最多达42属，占总属数的57．5％，其次为热带分布属，有24属，占32．9％。  相似文献