基于遥感指数的草原火后植被恢复研究

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。     

大豆高产理想株型的构成

根据大豆理想株型的概念，分析了大豆的主要生理性状和形态性状与产量的关系，并提出了大豆高产理想株型的合理构成，以期为大豆育种的田间选择和株型育种提供理论依据和实践指导。     

高原鼠兔对草地植被的危害及防治阈值研究

对高原鼠兔在不同时期的危害特征进行了研究，针对该鼠在补偿危害期和非补偿危害期的危害量提出了一种估算方法，得出其群体全年平均危害量β（干重）为4．94kg／只。同时根据春季灭鼠率（k）、秋季种群数量变化的预测值（λ）以及群体平均危害量（β）等参数估算可挽回损失值y。当可挽回损失值与成本参数（c）相等时，春季防治的经济阈值（x）为19．09只／hm^2或63．6个洞口／hm^2。     

草地类型梯度分析

紫泥泉地区位于天山北坡低山带，具有代表性的冬春秋放牧场。本文应用数量分类（ＴＷＩＮＳＰＡＮ）、排序（ＤＣＡ）和回归分析方法研究了草地类型的分类及其分布的梯度规律。研究结果表明：该地区的草地类型按传统分类划分出１８个型，ＴＷＩＮＳＰＡＮ分类结合ＤＣＡ排序归纳出８个型，其中６个型为地带性草地类型，２个型为非地带性草池类型；地带性草地类型沿水热梯度分布，非地带性草地类型沿质地梯度分布。     

江西省主要人工混交林类型的优化与筛选

以杉木或湿地松为主要树种,用南酸枣、檫树、樟树、乐昌含笑、福建柏、鹅掌楸、蓝果树等作伴生树种,开展了13个类型的混交林试验研究,在定性分析筛选的基础上,初选出9个比较优良的混交类型,再依据Ii=P1h/H+P2d/D+P3v/V计算出混交类型的优选指标,用I标准=I单均+aδn计算出类型的优化标准为6.12.据此对参试的混交类型进行优选,选出的最佳混交类型为杉木+南酸枣、杉木+檫树、杉木+樟树和湿地松+鹅掌楸4个混交类型,供林业生产上推广应用.     

Quantitative site classification in the key county in the conversion of farmland to forests project

According to the requirements of the conversion of farmland to forests project (CFFP), we investigated the vegetation factors and environmental factors from more than 6,105 sub-compartments in Liangcheng County, Inner Mongolia by using the Matlab, analytic hierarchy process (AHP), and the hierarchical cluster method (HCM). The site conditions were classified quantitatively. The results show that CFFP at this site comprises five site-type groups and 19 site types. A quantitative site classification system method has been established in this paper. __________ Translated from Journal of Beijing Forestry University, 2005, 27(6) [译自: 北京林业大学学报, 2005, 27(6)]     

Residue management for reducing evaporation in relation to soil type and evaporativity1

Abstract. Usual residue-management options are to remove the residue, use it as mulch with or without undercutting or to incorporate it into the soil. While the role of surface mulch in evaporation has been widely studied, the information on the effect on evaporation of mulch with undercutting or residue incorporated into soil, particularly in relation to soil type and evaporativity (E_o) is lacking. We studied the effect of wheat straw used in various ways on the course of evaporation loss from soil columns with three soils at Ludhiana, India and one soil at Bushland, Texas, USA, under two E_o's Energy-limited evaporation rates under mulch (E_om) followed the soil-specific relation E_om/E_o= a e^(bRes+cEo), where Res is residue rate t/ha and a, b and c are constants; E_o, is expressed in mm/d. In an effort to model the total evaporation (CE) during the energy-limited stage ‘U’ was obtained from appropriate CE versus time curves and (CE-U) was regressed over (t - ti)^0.5 to obtain the slope ‘α’ (Ritchie 1972) for the soil-limited evaporation stage. The observed ‘U’ was independent of mulch rate and E_o but was strongly affected by soil type, Values of ‘α’ decreased with increase in mulch rate and decrease in E_o and coarseness of soil. The otherwise short lived benefit of evaporation reduction with mulch per se, which peaked after a few days was maintained when residue was mixed with soil at the stage when evaporation reduction reached a maximum; this benefit continued for several weeks. Cumulative evaporation values computed from ‘U’ and ‘α’ agreed closely with the observed values under straw mulch for loamy sand and clay loam soils and for ‘undercut’ and ‘residue mixed’ treatments on all soils regardless of E_o, and for all situations under small E_o. However, for sandy loam and silt loam soils under E_o of 10 mm/d, the modified square root of the time function of Jalota et al. (1988) gave a better fit.     

高寒草甸退化草地—“黑土滩”植物量测定

依据高寒草甸草地秃斑地的多少和距居民点的远近划分为轻度退化草地(极少量秃斑地)、中度退化草地(少量秃斑地)、重度退化草地(大量秃斑地)和极度退化草地(全部秃斑地)四个退化草地等级。对各等级退化草地进行了植物量测定。结果表明:草地植物量(地上和地下)及土壤含水量,随着草地退化程度的加剧明显下降(P<0.01),毒杂草量则明显上升(P<0.01)。其中极度退化草地较轻度退化草地植被中嵩草属牧草优势度减少38,可食鲜草量减少219.2g/m~2,而毒杂草则增加99.6g/m~2,植物活根量(干物质)减少2390.6g/m~2,土壤含水量(0—10cm)减少10.02％,并对高寒草甸退化草地(黑土滩)的成因及治理途径提出了看法和意见。     

新建县沙生植被的保护与开发利用

以农业生产为支柱产业的新建县地处鄱阳湖流域，区域内沙生植被较脆弱。随着经济与人口的快速增长及农、林、旅游业的大发展，如何保护县域内沙生植被、更好的开发和利用这种资源十分重要。在分析新建县沙生植被现状及影响其生长的主要因素的基础上，就该地区内沙生植被的保护和开发利用提出建议。