马桑薪炭林埋条造林

在川中丘陵紫红色砂页岩裸露石骨子地上,马桑直播造林的保存率仅17.25％。本项研究,采用整地客土,每穴用2～4根马桑母条,在早秋或冬末春初进行理条造林,造林保存率86～95％,2～3年郁闭成林,平均薪材产量11000～22000kg/ha。     

白花草木樨改造紫色石骨坡初报

紫色石骨坡既是造林绿化的难关,又是急待开发的国土资源。解放以来,群众对紫色石骨坡采取挖大窝、打撩壕或爆破等方式,栽植了柏木、刺槐、马桑、芭茅、柑桔和黄桃,虽取得了一定成绩,但花工量大、成效不佳,或因财力不足,很难推广。白花草木樨(Melilotus albus Desr)属豆科两年生草本,茎直立,高1～4米,全草有香气,适生于湿润和半干燥气候,为家畜重要饲料,可作绿肥、护地作物和燃料,根有很强的穿透力,能改善石骨母质的适生条件。1988年底,我市从外地引入白花草木樨种子,1989年开始对无土石骨荒坡进行直播试验。     

长江上游地区林业生态建设与治理模式(续)

<正> 6.3 红色石骨子“馒头山”水土保持桤柏混交治理模式 四川盆地,以发育在紫色砂页岩上的紫色土分布面积最广,素有“红色盆地”之称。盆地中部又以丘陵地貌为主,丘陵山头被称为红色石骨子“馒头山”。紫色砂页岩易风化,极易引起水土流失,纯林病虫害较多,易形成低产低效林分,森林生态系统不稳定,经济效益较低。多年来的生产和科研表明,桤柏混交     

2.潼南县水电站渠道和厂房附近山头造林防护的效果

在渠提外坡采用宽行窄株直播刺槐,紫穗槐;在沙卵石渠堤行间种芭茅;在土壤较肥的地段混栽柑桔和经济林木;在山头上带栽柏树、刺槐、紫穗槐、大芭茅。从1980年至1983年底,渠堤上的树木一般已高速4米以上,基本无垮塌现象。1983年测定渠道的泥沙量,原为5万立方米,现为1万立方米。芭茅积土厚度为0.3—0.5米,同时收种芭茅20万斤。     

落叶松苗期施氮的试验

现代苗圃实行的是位置固定、永久经营。每年育苗仅从土壤中被苗木吸收的可给态养分,氮素约在30～100kg/ha、磷素约在5～30kg/ha、钾素约在10～80kg/ha。尽管温带地区每年通过降水带给土地上的氮素约5kg/ha和部分土中固氮微生物的固氮量,但苗床上的养分仍然是入不敷出。所以对苗床     

河滩种植芭茅防护效益的调查

涪江在我县境内长88公里,两岸宜植树种草的河滩面积两万余亩。1981年特大洪灾后,现已种植树草9084宙,年产二芭茅(甜根子草Saccharum spontanem L)1051万斤,1984,1985两年我们对二芭茅的防护效益进行了调查观测。     

对南充地区薪炭林发展现状的看法

<正> 南充地区位于川中盆地东北部,嘉陵江中下游,地形北高南低;土壤绝大部分是由紫色页岩发育成的中性或微碱性紫色石骨子土,胶体品质差,潜在养分少,保水保肥能力弱,水土流失严重。十二个县、市幅员2,537.02万亩,其中林业用地496.212万亩,占总面积的19.5%。     

望谟红球油茶性状评价与发展

望漠红球是望谟油茶中的一个优良霜降类型,主要分布于贵州望谟县境内的城关、乐旺二区,面积约3000ha。该品种具有速生、早实、早期丰产、抗病性强的特性。试验表明:造林后次年开花率达12.4％,第3年开花率达90％,5年生开始大量结实,产果量达1032.75kg/ha,产油量60.95kg/ha。嫁接是望谟红球繁殖的主要途径之一,以撕皮嵌接、皮节枝接、芽苗砧接效果较好。并对其发展提出了建议。     

美路易斯安那州北部火炬松林中薪炭材生物量干重和养分含量

本研究是在路易斯安那州北部3个正常采伐后的火炬松成熟林中;设样测定林分下层硬阔叶树和火炬松剩余物生物量干重、养分含量。估计采伐后林分中约有52t/ha 的下层硬阔、22t/ha 的松采伐剩余物存在。这些生物量中氮、磷、钾、钙和镁的含量分别为208kg/ha、16kg/ha、114kg/ha、215kg/ha 和40kg/ha,这些养分随着薪炭材的收获而发生了潜在转移,但并没有明显地减少土壤中相应的养分含量。     

桤木薪炭林群落学特征及生物量的研究

本文对桤木人工薪炭林群落学特征做了分析,桤木薪炭林是人工造林配置的树种,故群落简单。对估测桤木人工薪炭林乔木层生物量建立了多个数学模型,选用W_(树干)=147.1914D~(2.0616)、W_(枝条)=37.5577D~(2.3962)、W_(叶)=31.0578(D~2H)~(0.7776)和W_(地上部分)=258.6222D~(2.0622)幂函数方程,分别获得各器官的生物量,树干重8895.720kg/ha,枝条重3657.651kg/ha,叶重3345.324kg/ha,乔木层地上部分总重量15898.696kg/ha。对林下灌木和草本植物采用收割法测定,灌木地上部分生物量为2265kg/ha,草本植物地上部分生物量为459kg/ha。所以桤木人工薪炭林的地上部分生物量为18622.696kg/ha。     

Growth and yield responses of cotton (<Emphasis Type="Italic">Gossypium hirsutum</Emphasis>) to inorganic and organic fertilizers in southern Malawi

Fertilizer trees, the nitrogen-fixing legumes, such as gliricidia (Gliricidia sepium) and tephrosia (Tephrosia spp.) have been used to improve soil fertility for higher crop yields in nitrogen deficient soils. Many studies have focused on how these fertilizer trees improve maize yield, but there has been a dearth of information on the effect of fertilizer tree species on cotton growth and yield. A study was undertaken for two cropping seasons (2012/13 and 2013/14) with the objective of assessing IRM 81 cotton growth and yield responses to tephrosia and/or gliricidia biomass with or without inorganic fertilizer application. Boll opening significantly varied (P < 0.0001) with treatments and early boll opening was observed in plots where only inorganic fertilizer was applied. Higher lint yield (mean of 1397 kg/ha) was obtained in the second cropping season than in the first cropping season (480 kg/ha) and the application of gliricidia biomass with fertilizer gave the highest lint yield (2121 kg/ha). The lowest lint and seed yields were obtained from plots where tephrosia biomass only was applied. It is concluded that the use of gliricidia biomass with inorganic fertilizer improved cotton yields. The high amount of gliricidia biomass (due to prolific coppicing) applied contributed to higher cotton lint yields with reduced rates of inorganic fertilizer application, making gliricidia-cotton intercropping a cost-effective option to smallholder farmers.     

Acacia cyanophylla for forage and fuelwood in North Africa

Forage and wood yield of Acacia cyanophylla, also known as Acacia saligna, was studied in a 300–400 mm precipitation zone in Tunisia. Yields were measured during and after drought. This short (2–8 m) evergreen leguminous tree is used as a forage drought reserve in frost free regions where mean annual precipitation exceeds 250 mm. The standing crop of leafy forage builds up year after year for at least four years or until the tree is cut. It rapidly regrows after cutting from coppice shoots. The leaves provide high protein forage for sheep and goats during the long dry summer season typical of the Mediterranean climate as well as emergency forage during drought. The tree is used to stabilize moving sand dunes, and as a windbreak to protect cropland. It also provides fuelwood and increasaes soil nitrogen by fixation. The need for supplemental irrigation during establishment is a major constraint. Research in the 350 mm precipitation zone of Tunisia found 3.2 year old trees to yield over 1400 kg of forage standing crop per hectare after a severe drought. Trees harvested at 2.5 years of age in May, during the worst drought in over 30 years, yielded a standing forage crop of 724 kg per hectare. Forage regrowth 8 months after cutting and 4 months after rains returned was 700 kg/ha. The forage standing crop for trees harvested only once during the 3.2 year period was double the amount of forage regrowth from trees harvested the previous year, but mean annual forage yield similar. This demonstrates that it is possible for forage to be conserved as a living forage reserve for later use during drought. Total wood yield was only 1621 kg/ha for trees cut twice compared to 3683 kg/ha for trees cut only once. Annual cutting will substantially reduce the amount of forage available during drought and reduce the production of fuelwood. It may also reduce the vigor, productivity and life of the tree. Acacia cyanophylla alley cropped on cereal farmland can protect the soil from erosion, protect the associated crop from wind damage, fix nitrogen, provide fuelwood and provide a reserve of high quality forage for use during drought. This work was supported by the Government of Tunisia and the U.S.A.I.D. Tunisia Range Development and Management Project (664-0312.8).     

Agroforestry systems in the rural landscape – a case study in Garhwal Himalaya, India

A mid altitude (700–1200 m amsl.) village in Garhwal Himalaya was analysed in terms of energy and economic efficiency of different land use-land cover types constituting the landscape. Simultaneous agroforestry, sequential agroforestry, home garden and community forests accounted for 27.47%, 27.47%, 1.1% and 43.96% of the total geographical area of the village. Simultaneous agroforestry is the traditional land use involving substantial input of manure derived from forest litter and animal excreta and was practised on terraced slopes in private ownership. Tree cover in this system was represented by nine species with total average density of 390 trees ha⁻¹, Grewia optiva and Boehmeria rugulosa being the most dominant. Sequential agroforestry system involving slash-burn practice and cultivation on unterraced slopes without tillage and manuring was an illicit land use on community lands where forestry land use is desirable as per the government policy. Per ha annual energy input in simultaneous agroforestry system was 305267 MJ compared to 279 MJ in sequential agroforestry and 27047 MJ in home garden. In monetary terms, highest per ha annual output was obtained from simultaneous agroforestry (Rs 25370, Rs 35 = US$1) followed by home garden (Rs 18200) and sequential agroforestry (Rs 9426). Local food, fodder and fuelwood production was in excess of the local consumption. While most of the surplus food was stored, surplus fodder and fuelwood were sold for cash. Production in simultaneous agroforestry system in private lands was sustained with substantial biomass and nutrient inputs from the community and government forests. Land use-land cover changes in the region are driven by the interaction of ecological, policy and human factors. It is concluded that present policy of treating forests and agriculture as closed and independent ecological or production systems needs to be replaced by an integrated land use policy. This revised version was published online in August 2006 with corrections to the Cover Date.     

Fuelwood Resources and Forest Regeneration on Fallow Land in Uganda

Abstract

East African forests have been largely converted to agriculture. The remaining forests hold many endangered species but are threatened by the heavy local demand for fuelwood. Here we evaluate fallow land in western Uganda as an alternate fuel source to diverse forests. We quantify the regeneration process on fallows, calculate tree bio-mass increases, and measure grass and woody herb biomass over 44 months. The biomass values we measured were typical or slightly below the average from 11 studies elsewhere in the tropics. Variation in biomass between our neighboring study sites exceeded that between sites on different continents, indicating the sensitivity of vegetation regeneration to local land use. Tree regeneration was extremely slow (0.46 g/m²/year); however, the woody herbs and grasses on a 4 year old fallow of ～0.5 ha can provide much of a family's domestic fuel. Fallow land is generally abundant in western Uganda and can partially alleviate pressure on forests for domestic fuels. Fallows cannot however provide the trees demanded by charcoal, brick, and gin manufacturers. In the future, conserving forests while meeting fuelwood demands will require improving local land tenure security, enhancing the productivity of cultivated and abandoned land, promoting more efficient stoves, stills and kilns, and curtailing illicit, inefficient charcoal manufacture.     

Potential of improved fallows to increase household and regional fuelwood supply: evidence from western Kenya

Fuelwood is the main energy source for households in rural Africa, but its supply is rapidly declining especially in the densely populated areas. Short duration planted tree fallows, an agroforestry technology widely promoted in sub-Sahara Africa for soil fertility improvement may offer some remedy. Our objective was to determine the fuelwood production potential of 6, 12 and 18 months (the common fallow rotation periods) old Crotalaria grahamiana, Crotalaria paulina, Tephrosia vogelli and Tephrosia candida fallows under farmer-managed conditions in western Kenya. Based on plot-level yields, we estimated the extent to which these tree fallows would meet household and sub-national fuelwood needs if farmers planted at least 0.25 hectares, the proportion of land that is typically left under natural fallows by farmers in the region. Fuelwood yield was affected significantly (P < 0.05) by the interaction between species and fallow duration. Among the 6-month-old fallows, T. candida produced the highest fuelwood (8.9 t ha⁻¹), compared with the rest that produced between 5.6 and 6.2 t ha⁻¹. Twelve months old T. candida and C. paulina also produced significantly higher fuelwood yield (average, 9.6 t ha⁻¹) than T. vogelli and C. grahamiana of the same age. Between the fallow durations, the 18-month fallows produced the most fuelwood among the species evaluated, averaging 14.7 t ha⁻¹. This was 2–3 times higher than the average yields of 6 and 12-month-old fallows whose yields were not significantly different. The actual fuelwood harvested from the plots that were planted to improved fallows (which ranged from 0.01 to 0.08 ha) would last a typical household between 11.8 and 124.8 days depending on the species and fallow duration. This would increase to 268.5 (0.7 years) and 1173.7 days (0.7–3.2 years) if farmers were to increase area planted to 0.25 ha. Farmers typically planted the fallows at high stand densities (over 100,000 plants ha⁻¹ on average) in order to maximize their benefits of improving soil fertility and providing fuelwood at the same time. This potential could be increased if more land (which fortunately exists) was planted to the fallows within the farms in the region. The research and development needs for this to happen at the desired scale are highlighted in the paper.     

海南省中北部丘陵地区优良速生薪材树种的选择

海南省中北部贫瘠丘陵地区20个薪材树种，经4年选择试验，结果表明，马占相思、赤桉、细叶、大叶相思和斑皮桉适应性强，生长快，产量高，燃烧性能性，发热量大，用途广，经济效益高，年年均干生物量为17．5－23．9t/ha，纯利润为1199－2064元／ha，是最适合于当地生长和发展的优良速生薪材料种。     

笋用红竹林施肥效应研究

2001-2006年,采用随机区组排列,对红竹笋用试验林设置施用有机肥、化肥、有机肥和化肥混施及对照(不施肥)4个处理。结合精确施肥和试验区内长期定位观测,研究了不同施肥处理对笋用红竹林笋产量、土壤物理性质等的影响。在此基础上,根据整个竹林的投入、产出计算了竹林的经济效益;用环境能耗评价法研究了竹林小区水文生态效益。结果表明:施肥初期,不同处理对红竹笋产量影响不明显,处理2 a后施肥效应开始显现,表现为有机无机混施>单施无机肥>单施有机肥>对照(不施肥)。不同模式下的经济效益评价结果表明,通过荒山改人工经营红竹林,5 a就可以收回成本。与种植红竹试验林之前的荒山土壤相比,施肥明显改善了土壤物理性质,表现为容重降低,毛管孔隙度增大,使土壤涵养水源的作用明显增强,不同施肥模式下蓄水量从大到小为:混施>有机>无机>对照。生态效益的评价也表明,相比荒山而言,四种施肥模式涵养水源的生态效益分别可达:855.60、662.40、1 035.00和565.8元.hm-2。     

不同滴灌处理下沙棘林内土壤盐分变化研究

为了研究滴灌措施下干旱地区防护林内土壤盐分的变化情况,选择建平地区常见的荒山绿化树种——沙棘作为研究对象,开展了滴灌与不滴灌、不同滴灌年限处理下的土壤盐分含量研究,结果表明,滴灌处理可以明显降低浅层土壤中的盐分含量,不灌溉林地处理下土壤盐分变化情况与流动沙丘的对照处理趋于一致,但是后者盐分空间分布的异质性程度更强;滴灌后1~3年,随着年限的增加,同土层中盐分含量逐渐降低,根系生物量干重逐渐增加,且根系分布情况上移,主要集中在0~60 cm的土层中。由此可知,滴灌对浅层土的洗盐效果较好,但是滴灌时间长了根系有向浅层土层集中的趋势,建议每年大水漫灌1次,以有利于根系的下扎。     

Large cardamom (Amomum subulatum Roxb.) plantation — An age old agroforestry system in Eastern Himalayas

Large cardamom (Amomum subulatum Roxb.) is a shade loving plant grown in the Indian hill states of Sikkim and Dargeeling district of West Bengal. About 30 important tree species are used to provide shade to the cardamom plants. Alnus nepalensis, a deciduous, nitrogen fixing and fast growing tree, is the species most commonly underplanted with cardamom. In addition to providing shade, it is also used for fuelwood. The old trees are cut and young plants coming up are allowed to grow in cyclic order. The quick decomposing leaf litter of A. nepalensis also fertilises the cardamom plants. The nitrogen added to the soil in this way has been found to be as high as 249 kg/ha. Large cardamom thrives well in a moist soil, which is maintained by water diverted from seasonal springs on the upper slopes. The system is well suited to conserving soil, water and tree cover of the characteristically steep slopes of the region. Moreover, the management inputs required for growing cardamom are low but the crop gives a higher financial return than rice or maize. The shade trees used in the system are also a major source of fuel, fodder and timber, especially as access to state owned forests is restricted by legislation. However, increasing incidence of viral chirkey and foorkey disease, panicle rot and capsule borer are reducing the cardamom productivity. It has been observed that integrating dairying and apiculture will further augment profitability from large cardamom agroforestry system.