Agroforestry on alkali soils: Effect on some management practices on initial growth,biomass accumulation and chemical composition of selected tree species

This field study started in July 1982 on a typical alkali soil (Aquic Natrustalf, ESP 99.7) examined the growth responses to some management practices in a unified system planned to establish agroforestry. The planting of 3 salt tolerant tree species with two methods: on flat natural surface (FSPB) without rainwater conservation and on ridges (0.6 m high, 1.5 m at top and 2.5 m at base) having parallel trenches of the same section to store 300 mm of monsoon rainwater; constituted the main plot treatments. The tree planting with and without forage grassDiplachne fusca linn. in the inter-row space and planting in shallow (15 × 60 cm) and deep (15 × 180 cm to cross hard pan) augerholes filled with amendment treated soil (2 kg gypsum, 8 kg FYM, 50 g N, 10 g zinc sulphate and original soil) formed the sub and sub-plot treatments replicated 4 times in a split-split plot design.The mean plant height ofEucalyptus tereticornis smith;Acacia nilotica L; andParkinsonia aculeata L. in 2 years period was 273 and 328, 240 and 240 and 211 and 199 cm respectively with and without rainwater conservation. The corresponding height of the 3 tree species was 314 and 287, 250 and 231 and 207 and 203 cm with and without grass in the inter-row space. Similarly the plant height was 247 and 354, 182 and 298, 172 and 238 in shallow and deep augerholes respectively. The tree height and basal diameter differences with and without rainwater conservation and grass growth remained non-significant but deep augerhole planting was markedly superior to the shallow augerhole planting. The 2 year biomass accumulation also followed the same trend. The grass competed with trees for moisture during hot dry summer months and increased plant mortality particularly in the shallow augerholes and more so on ridges. The plant roots, essentially, remained confined to the amended soil of the augerholes in FSPB but proliferated in the loose soil of ridges or grass and submergence ameliorated surface soil of trenches.Acacia nilotica accumulated low sodium and had the lowest Na:Ca and Na:K ratio. It was found more promising than eucalyptus and parkinsonia as it experienced low mortality and had better chemical constitution to tolerate adverse alkali soil environment. The rainwater conservation system needed further evaluation before drawing final conclusions.     

三分式径流增肥整地对黄土丘陵区土壤理化性状和蓄水能力的影响

依托中日合作第二期黄河中游流域防护林建设项目,以昕水河流域的典型地区吉县、大宁、蒲县、隰县4个县为试验点,运用三分式径流增肥整地技术对该地区土壤理化性质、蓄水能力展开了试验研究,结果表明:土壤孔隙状况得到明显改善,10 cm~60 cm土层总孔隙度和毛管孔隙度平均提高了6.4%~7.8%和8.8%~11.2%,特别是0 cm~30 cm土层,与对照相比,孔隙状况得到极大改善;4种三分式径流增肥整地方式0 cm~40 cm土层的有机质、全氮、全磷、全钾及水解氮、有效磷、速效钾均有较大提高,与对照相比分别提高了57.1%,21.21%,17.0%,3.2%,38.1%,51.1%和22.5%;水平沟整地秋季、春季土壤含水率分别比对照高1.1%和1.3%,相对提高了5.7%和13.7%.鱼鳞坑整地秋季、春季土壤含水率分别比对照高1.1%和2.4%,相对提高了5.5%和26.4%.在最干旱的6月份,水平沟整地和鱼鳞坑整地平均土壤含水率分别提高了2.5%和2.4%,相对提高了35.7%和37.5%.     

基于三分式径流增肥整地方式下不同营林模式对土壤孔隙状况和养分变化的影响

笔者基于三分式径流增肥整地的方式,分析了山西省黄土丘陵区相同林龄(8 a)4种不同营林模式下林地土壤孔隙和养分的状况,研究结果表明,林地土壤孔隙状况总体表现为水平沟整地优于鱼鳞坑整地;土壤养分改善状况总体表现为水平沟整地优于鱼鳞坑整地;总体来看,营林模式一[水平沟(A/B)整地+针阔块状混交+壮苗+抚育]造林效果最佳。     

整地施肥对I-69杨人工林生长效应的研究

在淮北平原宿县,通过大穴整地、施肥改良砂姜黑土、营造Ⅰ-69杨的五年试验证明,大穴整地当年效应明显(径、高增长19.8%、91.8%);头二年肥效不显;第三年起N肥、有机肥、N×有机肥交互作用效应极显著(材积增加77%),施P+K肥效应较差,N+K肥和N+P肥经济效益较高,投入/产出为1/6.22和1/3.78;材积增加60%和58%。整地加施肥综合效益明显,有效施肥占综合效益85.1%～88.8%。     

Soil macrofauna and litter nutrients in three tropical tree plantations on a disturbed site in Puerto Rico

Tree plantations are increasingly common in tropical landscapes due to their multiple uses. Plantations vary in structure and composition, and these variations may alter soil fauna communities. Recent studies have demonstrated the important role of soil fauna in the regulation of plant litter decomposition in the tropics. However, little is known about how plantation species affect soil fauna populations, which may in turn affect the biogeochemistry of the plantation system. We measured soil macroinvertebrate abundance and biomass in 9-year-old N₂-fixing Leucaena leucocephala, Casuarina equisetifolia, and non-N₂-fixing Eucalyptus robusta plantations on a degraded site in Puerto Rico. Nutrient concentrations and standing stocks of forest floor litter were also determined to examine the relationship between litter chemistry and soil macroinvertebrates. Leucaena plantations had significantly higher abundances and biomass of millipede species than Casuarina and Eucalyptus. Earthworm biomass did not differ among plantation treatments. Nitrogen, P, and K concentrations were generally higher in Leucaena litter, which resulted in higher standing stocks of these nutrients in fragmented, moderately decomposed litter (Oe horizon). Millipede biomass was highly correlated to N concentration and C/N ratio in the Oi litter horizon. These results suggest that plantation species differ in their influence on soil fauna, and the biomass and abundance of soil fauna can be regulated through careful selection of plantation species in degraded tropical lands.     

White spruce regeneration following a major spruce beetle outbreak in forests on the Kenai Peninsula, Alaska

Between 1987 and 2000, a spruce beetle (Dendroctonus rufipennis) outbreak infested 1.19 million ha of spruce (Picea spp.) forests in Alaska, killing most of the large diameter trees. We evaluated whether these forests would recover to their pre-outbreak density, and determined the site conditions on which spruce germinated and survived following the spruce beetle outbreak in forests of the Anchor River watershed, Kenai Peninsula, Alaska. White spruce (Picea glauca) and Lutz's spruce (Picea × lutzii), a hybrid between white and Sitka spruce (Picea sitchensis), dominate the study area. We measured the pre- and post-outbreak density of spruce in 108 3 m × 80 m plots across the study area by recording all live trees and all dead trees >1.5 m tall in each plot. To determine the fine scale site conditions on which spruce germinated and survived, we measured ground surface and substrate characteristics within 20 cm circular plots around a subset of post-outbreak spruce seedlings. The density of post-outbreak spruce (855/ha) was adequate to restock the stands to their pre-outbreak densities (643/ha) for trees >1.5 m tall. We could not accurately estimate recovery for pre-outbreak spruce seedlings because dead seedlings may have decayed in the 5–18 years since the beetle outbreak occurred. At the fine scale, spruce that germinated post-outbreak grew on a wide variety of substrates including downed log, stump, mesic organic mat, peat, hummocks and mineral soil. They exhibited a strong preference for downed logs (53%) and stumps (4%), and most (91%) of the downed logs and stumps that spruce rooted on were heavily decayed. This preference for heavily decayed logs and stumps was especially evident given that their combined mean cover was only 2% in the 3 m × 80 m plots. Within the 3 m × 80 m plots, spruce seedling survival was negatively correlated with bluejoint (Calamagrostis canadensis) litter cover.     

整地与栽植深度对林木生长量影响的研究

通过整地与栽植深度对林木生物量影响的分析研究,结果表明:大工程穴状整地(穴径100 cm、深60、80、100 cm)较一般小穴整地(穴径30 cm、深30 cm)之5年生林木径生长量分别提高7%、9.7%和11.3%;高生长量分别提高3.4%、7%和9.6%;林木根量可增加78.2%;栽植深度以40~50 cm为宜,这有助于降低生产成本。     

Agroforestry on alkali soil: effect of planting methods and amendments on initial growth,biomass accumulation and chemical composition of mesquite (Prosopis juliflora (SW) DC) with inter-space planted with and without Karnal grass (Diplachne fusca Linn. P. Beauv.)

Growth responses of mesquite (Prosopis juliflora (SW) DC.) during establishment stage to planting methods and amendments were studied in a highly alkali soil (Aquic Natrustalf, ESP 94), at the experimental farm of the Central Soil Salinity Research Institute, Karnal in July, 1984. Six combinations of planting methods and amendments with and without Karnal grass (Diplachne fusca Linn. P Beauv) in the inter-row space were compared in a four times replicated field experiment in randomised block design. The mean plant height (MPH), diameter at stump height (DSH), diameter at breast height (DBH), lopped biomass 16 months past planting and total biomass attained in 2 years period were significantly less when inter-row space was planted with Karnal grass. The MPH (cm), DSH and DBH (mm) attained in 2 years period were 319, 43.4 and 15.1 in with grass as compared to 405, 53.4 and 20.3 in without grass treatments. Similarly, the total biomass attained in 2 years was about 3 times more where inter-row space was not planted with grass. Growth was better when mesquite was planted by auger hole and pit methods than in trench plantation, when the original soil was treated with gypsum at 3 kg plant^–1 and then refilled. However, using trenches of dimensions 30 × 30 cm and filled with a mixture of original soil, 3 kg gypsum and 8 kg farm yard manure plant^–1 appeared to be promising method for establishing mesquite plantations on highly deteriorated alkali soils. The effect of amendments on growth decreased in the order gypsum + FYM, gypsum + rice husk, gypsum, control. In two years period, 37 percent mesquite died in the trenches in which the original soil was left unchanged. Effect of treatments on nutrient concentrations and total accumulations in different segments of mesquite is discussed. Karnal grass gave 25.3 t ha^–1 green forage yield in 8 cuts without amendment in a growth period of 26 months proving its great potential as a folder crop for the adverse sites. The inorganic chemical composition of the shoots, including trace elements Fe, Mn, Zn and Cu, is such as to make this species a highly promising plant for the exploitation of alkali soils. Growing Karnal grass with mesquite for a period of about 2 years reduced soil pH and EC significantly and improved organic carbon and available N contents. The grass improved water infiltration rates and moisture storage in the lower layers of the profile.     

北京开花竹林土壤主要养分分析

采用对比分析法,研究了北京市早园竹开花竹林和正常竹林土壤主要养分含量的差异。结果表明:开花竹林土壤中氮肥和磷肥含量明显低于正常竹林,钾肥含量没有明显差异;随着土壤深度增加,土壤中氮、磷、钾肥含量明显降低,尤其是竹鞭和竹根集中分布的10~30 cm深的土层,土壤养分严重亏缺。因此,在竹林经营中,应以"补氮提磷"为土壤养分管理目标,同时将10~30 cm深的土层作为竹林施肥的"目标土层",积极探索有效的竹林施肥和土壤改良技术。     

Site preparation of abandoned fields and early establishment of planted small-sized seedlings of silver birch

Field experiments at two sites in Sweden investigated the possibility of establishing silver birch (Betula pendula Roth) on abandoned fields by planting small (5–10 cm tall) seedlings. The effects of five modes of soil preparation (no preparation, rotary cultivation, deep ploughing, soil inversion, and removal of topsoil) with or without preliminary herbicide weed control on seedling performance were studied for three growing seasons following plantation. Both a split-plot design and a randomized block design were used to evaluate the experiments. Where there was no site preparation, seedling survival was close to nil. The highest seedling survival rates on the site with sandy soil were obtained on sites prepared by removing topsoil, or by transposing it by deep ploughing. On the site with silty soil, the best survival was observed on sites created by soil inversion or rotary cultivation. The tallest seedlings were found on sites with topsoil retained within the soil profile. Herbicide application with glyphosate promoted seedling survival and seedling height in combination with no soil preparation, but was of little effect when followed by mechanical soil preparation.     

黄金刚竹竹鞭生长特征及地上部分生长指标相关性研究

测定分析了黄金刚竹竹鞭生长特征及地上部分各生长指标间的相关性。结果表明:黄金刚竹竹鞭以2~3年生竹鞭为主,所占比例超过竹鞭总量的50%;竹鞭分布于0~30 cm的土层,以10~20 cm土层分布最多;在地上部分各生长指标中,秆高和胸径与地径、胸径处节间长、地径处节间长、地上部分总质量及根质量间均呈显著性相关关系;以胸径作为自变量建立的黄金刚竹生长模型,可以可靠地估计其他生长量指标。     

Fertilization,weed control,and pine litter influence loblolly pine stem productivity and root development

Following site preparation, three cultural treatments and three open-pollinated loblolly pine (Pinus taeda L.) families were studied on a gently sloping Beauregard silt loam in central Louisiana. The treatments were: (1) fertilization (either broadcast application of 177 kg N and 151 kg P/ha or none); (2) herbicide application (either broadcast application of herbicides during the first through third growing seasons, and felling of a few, scattered volunteer hardwood trees greater than 2.5 cm dbh during the third growing season or none); and (3) litter application (either broadcast application of 37 Mg/ha (oven-dried weight) of pine straw over the plots to form a 10 to 15 cm layer or none). The subplot treatment was planting stock, where in November 1988, 28-week-old container-grown loblolly pine seedlings from three open-pollinated families were randomly assigned to planting locations. Through five growing seasons, fertilization and weed control with herbicides resulted in the greatest loblolly pine productivity, but the use of herbicides severely reduced other vegetation. Applying litter, which was less effective than herbicides as a weed control treatment, increased the presence of blackberry (Rubus spp.) when herbicides were not applied. Applying litter resulted in a decrease and fertilization resulted in an increase in the number and length of live lateral roots. Soil temperature was reduced by litter application. Treatment responses were not influenced by loblolly pine family.     

黄土丘陵沟壑区抗旱造林综合措施试验

在黄土丘陵沟壑区半阴坡立地上,采用正交设计进行抗旱造林综合措施分析。结果表明,采取整地,保水剂浸根和穴施菌根菌综合措施营造油松,刺槐和侧柏,虽然增加了造林成本,但造林成活率和苗木生根数量都明显高于对照。经济有效的综合措施为：造林树种为刺槐,鱼鳞坑整地上保水剂浸根,穴施菌根菌。     

梯田地埂灌木树种栽培技术研究

对西吉县梯田地埂灌木树种(以杞柳和柠条为主)的栽培技术进行了研究。结果表明：(1)造林整地时，梯形槽和鱼鳞坑整地均可，整地深度以40cm左右为宜，整地时间以雨季预整地最佳；(2)造林方法要根据具体树种而定。柠条最好选择植苗造林，春秋皆宜，杞柳适宜秋季造林，总体上秋造的苗木成活率和存活率明显好于春造。另外，在柠条播种造林时，坡向最好在阴坡；(3)杞柳造林时的种植深度以种条覆土2cm最佳，适宜的几种种植深度模式为：阳坡种条覆土2cm、阴坡种条齐地面、阴坡种条覆土2cm；(4)造林整地、种植深度对苗木生长量的影响较大，造林方法、造林坡向、种植深度对造林成活率和保存率的影响相对显著。     

湘南丘陵地桉树纸浆林栽培模式研究

桉树已成为湖南湘南地区栽培的主要纸浆林树种。通过对桉树肥料、整地、密度等分析，得出湘南地区桉树集约经营的主要栽培模式：使用较耐寒的桉树品种(赤桉、邓恩桉、柳桉)的优良无性系或种源，15-20cm的容器苗，整地方式为人工带垦、中穴或机耕，每穴施放430g磷肥作为底肥，其间追施尿素65g、氯化钾肥25g，或追加氯化钾50g，或追加尿素130g，造林密度为1667-2505株/hm^2，轮伐期6-8年，栽植后要连续抚育3年，每年1-2次，主要是松土、扩穴、培蔸、施肥、控制杂草、防治病虫害。     

整地对桉树人工林生态效益的影响

为了探讨整地方式对桉树林分生长和林地生态效益的影响,在3种整地方式下的尾巨桉林地分别设置样地和样方进行调查分析,结果表明：机械带垦和炼山全垦的尾巨桉林分生长均较人工穴垦快,炼山全垦的尾巨桉林下植被生物多样性最差,机械带垦的林地土壤有机碳含量最大,炼山全垦林地表层(0~40 cm)土壤含水量最高,人工穴垦林地深层(40~80 cm)土壤含水量最高。     

First-year survival and height-growth of red ceiba following various site preparation techniques on vertic soils in northern Colombia

If growth of red ceiba, Bombacopsis Quinata (Jacq.) Dugand, is to be increased in plantations established on Vertisols, site preparation techniques must be identified to overcome the soil management difficulties of these soils. This research was conducted to identify specific site preparation techniques appropriate for Vertisols that increase survival and height growth of red ceiba. The effects of subsoiling within the row (prior to planting) to depths of 40 and 60 cm, subsoiling between the rows, and additions of organic mill waste on red ceiba survival and height growth, soil water content, bulk density, and penetrometer resistance were investigated. The soil was a very fine, montmorillonitic, isohyper-thermic Entic Chromustert. No difference in survival due to subsoiling was found, but the additions of mill waste significantly decreased survival after 1 year (94.7%) compared to the control subplot (98.7%). Height was increased by subsoiling to the 40-cm depth (92.3 cm) and to the 60-cm depth (97.4 cm) over no subsoiling (80.7 cm). Trees on the subplots receiving mill waste were significantly lower in height (83 cm) compared to the control subplots (93.1 cm) and the subsoiling between the planting rows subplots (94.2 cm). Survival was most highly correlated with bulk density at the 50-cm depth within the planting row (r=–0.44) and height with soil water content at the 30-cm depth within the planting row (r=–0.56). Subsoiling affected height more than survival. Subsoiling to 40 cm is the most cost-effective treatment. Mill waste addition did not improve height or survival, possibly due to harmful decomposition by-products.     

花椒干旱造林研究

通过正交试验表明,在天水浅山半干旱地区,采取鱼鳞坑工程整地和定植区薄膜覆盖蓄水保墒,苗木根系保湿醮根处理,花椒造林成活率可达到98%,第2年新梢平均最长生长量在45 cm以上,分别比一般造林提高30.7%和21.6%;并且提前2～3年挂果受益,第5年平均单株花椒产量在2kg以上。     

Comparison of two coniferous plantations in central Japan with respect to forest productivity, growth phenology and soil nitrogen dynamics

Japanese cypress (Chamaecyparis obtusa Endl.) and Japanese cedar (Cryptomeria japonica D. Don) are common species for plantation forestry in Japan. Cypress is conventionally planted on sites of low fertility whereas for cedar high fertility sites are used. Objectives of this study were to compare the productivities of cypress and cedar plantations grown on adjacent sites where common properties of soils, such as pH values and C and N contents, were similar, and to relate the N cycling at their site with productivities. The stem diameter of trees, aboveground litter production and fine root biomass were measured as indices of forest productivity. Parameters of N cycling included pools of total N and mineral N (ammonium + nitrate), annual N leaching, and potentially mineralizable N. The radial stem increment of the two tree species was similar. However, cedar site had higher total basal area and annual basal increment than cypress site reflecting higher tree density on the cedar site. Aboveground litter, fine root biomass, soil organic matter, and N turnover were higher on the cedar site than on the cypress site. However, litter production and fine root biomass per unit basal area was greater at the cypress site. Phenological pattern of stem growth and periodical litter production were similar for both species during the study period (1992–2000), but showed distinct annual variations caused by the fluctuation in the ambient temperature and precipitation. Mineral N content and the N mineralization potential were greater on the cedar site, indicating greater N availability and higher total tree productivity at the cedar site than those at the cypress site. When provided with more space in the canopy to expand more needles and in the soil to develop more fine roots to exploit sufficient resources, the individual cypress trees have the potential to grow faster. On fertile site and at lower tree density, thicker logs of cypress might be yielded.     

Reduction of frost heaving of Norway spruce and Scots pine seedlings by planting in mounds or in humus

This study was carried out in northern Sweden to determine the effects of frost heaving on the establishment of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) seedlings in relation to planting methods. For this purpose, one year old containerised seedlings were planted on two sites and on two dates: during the spring (early planting) and during the fall (late planting). In each case, two planting depths (normal and deep planting) and four planting sites (in mineral soil in the depressions, in the scalp/trench area, on the top of the mound and in the untreated humus layer) were used. On each site, 50 seedlings were planted for each treatment. Frost heaving was observed and measured during two years. The amount of heaving was highest in the hole and almost insignificant on the top of the mound and in the humus layer. Planting depth influenced the degree of heaving only for Scots pine planted in the hole and was not related to the planting time.