杨树速生丰产林的节水灌溉试验

水分是植物生长的主要限制因子之一,在沙地进行速生丰产林建设,水分又显得更为重要[1,2]。沙地由于构成土壤的颗粒较大,导致土壤结构疏松,水分的下渗速度较快,在进行灌溉时耗水量比一般黄土地和粘土地要大[3～5],通过改变灌水方式可有效地节约用水量,因此笔者进行了节水灌溉方面的试验。1　试验地概况试验地在中卫县赛金塘治沙林场位于距县城15km的北干渠两侧,地处黄灌区与北部沙漠交界的地区,海拔1211 4～1221 6m,地势由西北向东南倾斜,西高东低,北高南低,气候属典型的大陆性气候,同时也具有沙漠气候的特点。日照充足积温较高,光能丰富,干…     

杨树人工林旱作保水措施的土壤水文效应

在堆积沙地杨树人工林内进行不同旱作保水技术研究,系统测定土壤水分含量、土壤蓄水性能、林木蓄积量,并进行统计分析。研究结果表明：白（白膜）＋草（麦草）＋保（保水剂）、黑（黑膜）＋草＋保、黑＋保、白＋保、草＋保、黑＋草的处理能有效地起到蓄水保水作用,促进杨树人工林生长,从而增加了杨树林木蓄积量。     

海南岛热带山地雨林皆伐后不同更新方式对土壤物理性质的影响及恢复研究

通过样地调查和取样测定,运用方差分析、差异显著检验和聚类分析方法,以海南热带山地雨林原始林(0501,植被类型代码)为对照,对热带山地雨林皆伐后的天然更新林(0502)、皆伐炼山后人工促进天然更新林(0503)和皆伐炼山后种植人工林(0504)等3种次生林的土壤物理差异和恢复程度进行了研究,结果表明:(1)热带山地雨林采伐更新造成土壤密度的增加和表层毛管孔隙度的差异,进而引起总孔隙度的变化,影响040 cm土层的最小持水量及2040 cm土层的毛管持水量;皆伐天然更新措施(0502样地)的土壤质地较好,表层土粒淋洗下移较少,整个剖面土壤毛管孔隙度较高,土体发育良好,具有很强的持水保水能力;皆伐炼山措施(0503和0504样地)使表层土壤易于向下淋溶和淀积,底层毛管孔隙度降低,增加了中层土壤密度并形成明显的淀积层,影响土壤的通气透水性能,容易造成雨季地表径流和旱季底层水分难向上传输;人工造林更新措施(0504样地)造成土壤表层土粒淋洗严重,各层毛管孔隙度降低和中、底土层非毛管孔隙度的减少,中、底土层明显的板结,影响林地的通气透水性能,各种持水保水能力大大降低,容易产生地表径流和存在土壤表层砂化危险.(2)皆伐天然更新林具有与原始林相似的土壤物理性质.人工促进天然更新林土壤属黏壤土至黏土质地,表层毛管孔隙度较大,底层毛管孔隙度最小及持水量递减率明显.人工更新林土壤为砂质黏壤土至黏土,表层土粒淋溶下移和砂化现象明显,中、底土层具有明显淀积层,持水保水能力最低.(3)皆伐迹地天然更新林(0502)和人工促进天然更新林(0503)土壤物理恢复程度较接近原始林,人工更新林(0504)土壤恢复程度明显不及天然更新林,次生林的土壤总孔隙度和持水量恢复较好,土壤颗粒比例较难恢复,表层土壤密度和中层土壤粉黏比的恢复度较差,中层土壤的毛管与非毛管孔隙度之比的恢复度较表层和底层高,皆伐炼山对深层土壤的恢复影响较大.     

果树经营管护技术问题的研究

1适宜果树生产的土壤 　　果树对土壤的适应性比较广，无论是山地、沙滩、粘土、砂土，只要逐步加以改良，再选择适宜砧木嫁接的苗木，都可正常生长。栽植果树尤以砂壤土最为适宜。根系从土壤中吸收水分和养分，土层深浅与果树根系的生长关系十分密切。土层深，根系可利用深土水分，根系分布广、发育好，地上生长部分健壮；肥料流失少，增强果树抗低温、干旱、高温和病虫害能力。 　　最好的土壤结构是土粒胶结成团，具有不被水泡散的性质，能保水透水，有利于根系生长和摄取养分，耕作时阻力少，增施有机肥可促使团粒结构的形成。有机质是…     

日本推出沙漠耕地技术

日本狮子公司与东京大学教授松本聪,最近共同发明了沙漠耕地化技术。该技术是把一种特殊的水溶液撒在沙漠上,使土壤在一定深度内形成一个固定层。该固定层可以阻挡地下水渗出的盐分,使土沙可以栽种农作物和植物。他们将聚丙烯酸用水稀释,成为聚丙     

不同覆盖方式对刺槐直播造林出苗率的影响

为了使山东石质山地直播造林有较高的出苗率和成活率,我们研究了不同覆盖方式对刺槐直播造林的影响,结果表明:地膜覆盖有效地增加了土壤各层温度;提高了0～30cm土壤的水分含量,给刺槐生长造就了良好的水分环境;提高了出苗率和苗高,确保了干旱土地上幼苗发芽出土,且苗全苗壮。覆草的各层地温比露地的低,但温度相对稳定,变幅小;提高了0～20cm土壤的水分含量;覆草的出苗率虽然较露地的低,但苗高比露地的高,可以晚些去草,以提高出苗率。     

信息窗

日本发明沙漠绿化新技术.日本东京大学土壤研究室发明了利用聚丙稀酸水溶液进行沙漠绿化的新技术.聚丙稀酸溶液渗入土壤后,与土壤中的盐分发生化学反应,形成一层防止盐分上升和水分下降的不透水层,起到防止水分流失和盐分烧死植物的作用.与过去在土壤中铺放薄膜再栽培植物的做法相比,这种方法不仅成本低,而且有利于植物生长.     

太行山区生物多样性修复关键技术浅析——以鹤壁市淇滨区南山为例

针对太行山区气候干旱、土壤瘠薄和生态环境脆弱的特点,通过造林绿化、固土保水和丰富物种等3项措施,探索太行山区生物多样性修复的关键技术。实践表明,营造混交林、合理确定造林密度、乔灌草立体种植是太行山区植被恢复的基本措施,生草刈割覆盖、节水滴灌、微型秸秆速渗贮水穴等是太行山区固土保水的实用技术,禁用农药、增施菌肥、立体种养是丰富太行山区生物多样性的必要手段。     

果园覆草节水效果研究

通过在张掖市林果业研究所苹果梨园内进行的果园覆草节水效果的研究,结果表明:果园覆草具有明显的保水作用。0～60cm土层的土壤含水量显著高于清耕对照;不同深度土层以0～20cm土层含水量最高,为10.4%,说明覆草能抑制表面蒸发;覆草能促进苹果梨树体生长,明显提高果实品质,使大果率增加25%,平均单果重增加12.1%。     

生草栽培对核桃园土壤养分和水分的影响

为探讨生草栽培对于安康市核桃园土壤养分和水分的影响,解决土壤养分不足、除草成本过高等实际问题,本文以安康市典型的核桃园连续行间种植3 a长柔毛野豌豆为研究对象,以行间自然生草为对照,探讨0～20 cm的土壤养分和水分变化特征,反映人工生草栽培对土壤养分、水分的影响。结果表明,人工生草较自然生草可以显著提升土壤有机质、碱解氮、速效磷、速效钾含量,其中土壤有机质、速效钾、速效磷、碱解氮含量分别提高54.52%、37.64%、64.77%和40.29%。此外,通过对核桃园不同时期的土壤养分水分测定分析发现,人工生草栽培较自然生草可以相对稳定保证土壤含水量,土壤碱解氮、速效磷、速效钾含量在5-9月均高于自然生草。综合而言,行间人工种植长柔毛野豌豆可以有效增加土壤养分含量、水分含量,调节土壤pH值,提高土壤综合肥力,在核桃园生产管理中有很好的推广价值。     

A soil temperature control system for ecological research in greenhouses

We designed and tested a soil temperature control system for plant ecophysiological experiments in greenhouses and growth chambers. The system consists of a plywood box, polyethylene liner, insulation, seedling containers, a water pump, and a flow-through heater or chiller. One hundred and twelve seedling containers (11cm diameter, 13.5 cm high) are mounted in the plywood box. There is a hole at the bottom center of each container to allow the free drainage of irrigation water and fertilizer solution. The space between containers is filled with water that is circulated through the chiller/heater. The water is also circulated within the plywood box by a water pump to increase the uniformity of temperature. The system was tested for three soil temperatures (5, 20, and 30°C) over a period of four months. The containers were filled with a peat-moss vermiculite mixture and planted with tree seedlings. The test showed that the soil temperature was almost equal to the water temperature for all three soil temperatures (regression slop = 0.99, intercept = 0.12,r ² = 1.00). The average soil temperatures were within (0.41°C of the set values. The soil temperature of the 112 containers within the same box followed a normal distribution with a small standard deviation (0.34°C for the 30°C treatment). There was a temperature gradient from the top to the bottom of the container (< 1°C). The direction of the temperature gradient was determined by the direction of temperature difference between the soil and the ambient air. When the soil temperature was lower than air temperature, the soil temperature decreased from the top to the bottom of the container, and vise versa. The soil temperature was higher during the day than at night (difference < 1.5°C). Funding for this research was provided by Lakehead University, CFI, ORDCF, and NSERC research grants to Dang, and an NSERC PGS A to Cheng.     

The influence of trees on soil fertility on two contrasting semi-arid soil types at Matopos,Zimbabwe

An investigation into the influence of indigenous trees on soil fertility was conducted in an area of semi-arid tropical savanna in Zimbabwe on two contrasting soil types: dystrophic savanna soils (sandy soils) and eutrophic savanna soils (fine-textured soils). The study adds further support to the growing literature showing that trees have a positive influence on soil fertility. The study suggests that tree clearance, as advocated in these agropastoral systems, may not necessarily result in long-term benefits. It is argued that the primary mechanism by which soil fertility is improved is through increased litter and soil organic matter compartments under trees. The influence of trees on cation levels is greater on sandy soils than fine-textured soils because the exchange capacity of fine-textured soils is determined largely by soil texture whereas organic matter is the prime determinant of exchange capacity in sandy soils. The present study demonstrates that fertility improvement under trees is not at the expense of fertility decline in the surface soils of the zone around the tree. Leaf quality, as reflected simply in leaf C:N ratio, influences decomposition rates but the activities of termites probably confound any simple relationship. Litter quality of tree species is probably important in determining levels of soil organic matter under canopies, with higher levels under species with lower leaf quality.     

Rosellinia necatrix attack according to soil features in the Mediterranean environment

A study was carried out on Rosellinia necatrix attack on young woody plants, as possibly affected by selected soil features under three water regimes. Six different soil systems representing five agro‐environments and one forest in the Puglia Region (southern Italy – Mediterranean climate) were compared. R. necatrix attack on sweet cherry trees was simulated using artificial inoculum and saplings of Prunus mahaleb, the most widely used rootstock of sweet and sour cherries, monitored during the spring period. Soil features significantly influenced disease score, which did not differ from one water regime to another, even though disease level in the different soils was affected by water content. Rosellinia mahaleb saplings grown in forest soil showed the highest disease score, which differed significantly from that observed in all the agricultural soils tested in this study. Amongst these, disease score was lower in sandy soils than in soils that were richer in loamy fraction.     

A new model to analyze water retention characteristics of forest soils based on soil pore radius distribution

The soil water retention model proposed by Kosugi was modified to have a relatively simple functional form. The resulting water retention model (the lognormal distribution model) contains two parameters which have physical significance on the water retention curve and are related directly to the statistics of the soil pore radius distribution functiong(r). The observed retention data sets of 282 undisturbed forest soils taken from Mashimo were analyzed using the lognormal distribution model, and it was shown that the model performs fairly well for every data set. The estimated parameters of the model indicated that the water retention characteristics of the undisturbed forest soils are related to the soil structure more closely than to the soil texture. Many crumb-structure forest soils have greater median ofg(r) than the crumb and granular-structure soils. Disturbed loamy soils have smaller median ofg(r) than many of the undisturbed forest soils and disturbed sandy soils have smallerg(r) width than the forest soils. The brown forest soils taken from A-horizon generally have the greater median ofg(r) than the brown forest soils taken from B-horizon. Some of the brown forest soils have the greater width ofg(r) than the black soils. The median ofg(r) of brown forest soil taken from A-horizon generally becomes greater as the soil moisture condition becomes wet.     

不同措施对提高沙地造林成活率的研究

采用固体水、保水剂和覆膜措施，对提高造林成活率进行了比较试验。结果表明，与对照相比，这些措施明显提高了土壤含水量，从而不同程度提高了沙区造林成活率。其中覆膜措施效果最佳，其次为保水剂，最后是固体水措施。     

A new apparatus for measuring the gas diffusion coefficient in soil using a large sample and controlling soil water suction

A new apparatus that determines the gas diffusion coefficient in soil after establishing steady state gas conditions was developed. The CO₂ concentration is kept constant above and below the soil sample to establish the steady state conditions. The sample column is 60 cm long with an inner diameter of 20 cm. The gas diffusion coefficients of sandy soil were measured at 10 cm intervals using this apparatus while controlling the soil water content. The ratios of gas diffusion coefficients in soil and air,D _s/D₀, with different soil water conditions were determined. A part of this paper was presented at the 110th Annual Meeting of the Japanese Forestry Society (1999).     

古尔班通古特沙漠南缘不同密度人工梭梭林改善小气候效应研究

通过对古尔班通古特沙漠南缘不同密度人工梭梭林的林内风速、气温、相对湿度、土壤含水量等指标的观测,就不同密度人工梭梭林改善小气候效应进行了研究,结果表明：人工梭梭林保留密度为1111株？hm^-2与833株？hm^-2时,改善小气候效应与高密度梭梭林相当;保留密度为500株？hm^-2时,改善小气候效应略有降低,但显著提高了土壤含水量,有利于抑制梭梭林的衰败退化;保留密度为278株？hm^-2时,改善小气候效应严重降低,土壤含水量提高不显著。     

不同改良利用模式对辽西北风沙土理化性质的影响

为了研究不同改良措施对辽西北风沙土理化性质的影响,选择了4种不同的改良利用模式作为研究对象,以流动风沙土作为对照,对不同模式下土壤的物理化学性质进行了测定分析。结果表明:风沙土经过各种措施改良后土壤的物理化学性质得到了很好的改善,风沙土三相比例更加趋于协调。不同利用模式对风沙土土壤养分的改善效果是阔叶树模式好于苜蓿改土模式,苜蓿改土模式好于灌木林模式,灌木林模式好于针叶树模式。各模式土壤的胡敏酸与富里酸的比值与流沙比较呈降低趋势,且HA/FA<1。     

沙地柏土壤特性与生物量的关系

对毛乌素沙地固定沙地不同地形（沙丘的顶部、迎风面、底部）中的沙地柏生物量进行比较,分析了土壤养分状况、土壤粒径与生物量关系。结果表明：迎风面的氮、有机质含量比较高,能够促进生物量的提高;天然沙地柏（土层深度〈50 cm）土壤颗粒组成均是以50-100μm的颗粒为主,生物量与土壤颗粒之间可相互影响。     

浑善达克沙地3种典型灌丛固沙能力的比较研究

[目的]研究荒漠草原区出现灌丛化现象后,灌丛沙堆在退化生态系统中发挥的保育功能和防风固沙作用。[方法]该研究以浑善达克沙地3种典型荒漠草原灌丛长柄扁桃(Amygdalus pedunculata)、小叶锦鸡儿(Caragana microphylla)和狭叶锦鸡儿(Caragana stenophylla)为研究对象,通过测定分析3种灌丛形态参数、沙堆形态参数和灌丛下土壤颗粒分形维数,探讨其沙堆形态发育和土壤颗粒组成特征,以及与植物灌丛形态特性和固沙能力的关系。[结果]表明:3种典型灌丛沙堆均为圆锥状,其沙堆高度随沙堆半径的增加呈对数曲线增加,即在沙堆形态较小时,随着沙堆半径的增大,沙堆高度增加较快,而随着沙堆底面积不断增大,沙堆高度变化就会趋于稳定且增加速度降低,整个沙堆在水平方向的延伸速度大于垂直方向;沙堆形态参数之间以及与灌丛形态参数间表现出显著相关性,随着灌丛地上生物量的增加,沙堆高度、半径、底面积和体积均呈显著增加(P<0.05),3种灌丛沙堆体积和固沙率差异性显著(P<0.05),表现为:小叶锦鸡儿>狭叶锦鸡儿>长柄扁桃;灌丛使降尘等细粒物质拦截或聚...