外文翻译---挖掘机开垦森林土壤与修正方案

附录Reclamation of forest soils with excavator tillage and organic amendments Abstract In early 1994, a research project was initiated to evaluate the success of several techniques aimed at restoring productivity to degraded soils on landings near Vama Vama Creek, 44 km east of Prince George in Central British Columbia. Soils were developed from morainal parent materials, the usual surface soil texture was silt loam. Two organic amendments were used in this study, including freshly prepared wood chips and old sawdust. An excavator equipped with a site preparation rake was used to till the soils to a depth of 0.50 m. Organic amendments were subsequently added to the plots, and either left as a mulch or incorporated into the surface 0.20 m of the soil. Nitrogen was applied to all plots at a rate of 225 kg N ha-1, which represents about one-third of the 500700 kg ha-1 that was estimated to be required to compensate for N immobilization during decomposition of the woody residues. Survival was good for all treatments, but after 3 years, trees were growing best in areas that were treated with tillage alone. Trees growing on areas where old sawdust was used as an amendment had more volume than trees growing in areas where wood chips had been used. Control plots with no treatment had intermediate growth. Soil temperature and chemical properties were evaluated for their effect on growth.#2000 Elsevier Science B.V. All rights reserved.Keywords: Forest soil rehabilitation; British Columbia; Soil disturbance; Soil conservation; Soil productivity; Landing and road rehabilitation 1. Introduction Soils on forest landings in central British Columbia are frequently characterized by compaction and nutrient depletion (Carr, 1988a). Degraded soils on landings and other areas where soils have been disturbed by forest operations often support only meager growth of planted conifers (Arnott et al., 1988). In many cases, soil conditions are so degraded that planting is not attempted on landings. Restoring soil productivity on degraded soils requires that growth-limiting conditions be alleviated (Bulmer, 1998). Tillage is frequently employed to decompact soils and improve soil productivity(Andrus and Froehlich, 1983). On coarse-textured soils, tillage alone may provide significant benefits for growth of conifers such as lodgepole pine, although the long-term consequences of soil nutrient depletion may be of concern. On fine-textured soils,tillage results have been inconsistent (Carr, 1988b;McNabb, 1994), partly because there is a narrow rangeof moisture content where effective tillage can be carried out, but also because stable aggregates are required to prevent puddling and poor physical conditions from reappearing shortly after tillage. Stable soil aggregates form when soil mineral grains establish an intimate association with soil organic matter(Tisdall and Oades, 1982). Several approaches could be employed to re-establish stable soil structure after tillage of fine-textured soils. A cover crop of deep rooted grasses and legumes could be established to provide organic matter and enhance biological activity in the root zone,thereby encouraging the development of stable soil aggregates. Another approach that has been proposed involves the incorporation of organic amendments into the surface soil layer to bring organic and mineral soil materials in contact with each other, and possibly encourage the formation of stable aggregates. This project was developed in order to gain more information about methods for restoring productivity to compact and nutrient-poor soils. We evaluated the effect of several combinations of tillage and the addition of organic amendments on soil properties and the establishment and early growth of lodgepole Pine.2. Materials and methods2.1. Study sitesThe study was carried out on three forest landings 44 km east of Prince George, in the SBSwk1 biogeoclimatic subzone. Soils were developed from morainal parent materials. The usual surface soil texture was silt loam, but in at least one location, a clay-rich B horizon was encountered. Coarse fragment content varied between 15 and 40%. The landings were located on level or gently sloping areas. Prior to treatment, there was little vegetation growth on the Landings.2.2. Experimental design Nine treatments were applied to 5 m6 m plots, as described in Table 1. Two control plots were established on each landing. The two organic amendments used were wood chips produced as part of treatments to reduce re hazard on the adjacent cutblock, and well-rotted sawdust from an old sawmill site. These materials are typical of soil amendments that may be available at remote rehabilitation sites. The chips had typical particle size of 0.1 m 0.05 m 0.005 m,while the sawdust particles had all dimensions smaller than 0.003 m. 2.3. Treatments Treatments were carried out in the summer of 1994 using an excavator equipped with a five-tooth site preparation rake. Soils were tilled to a depth of 0.50 m, and organic amendments were subsequently shoveled onto the plots to obtain an even distribution of the material. Amendments were either left as a mulch or subsequently incorporated into the surface 0.20 m of the soil. Pine seedlings (PSB 313) were planted at 1 m spacing on all plots. A legume seed mix was applied in the summer of 1995, but very poor establishment of the legume cover crop occurred due to dry weather.Grass and legume cover has been maintained at a low level throughout the experiment. All plots, including controls, were fertilized in the summer of 1995, using a combination of urea (45-0-0) and a complete NPK fertilizer (18-18-18). Nitrogen was applied at a rate of 225 kg N ha-1, which represents about one-third of the 500700 kg N ha-1 that was estimated to be required to compensate for N immobilization during decomposition of the woody residues. The plots received 50 kg ha-1 of K2O and P2O5.2.4. Soil analysis and tree productivity measurements Composite soil samples were collected in October,1994 from the recently treated plots. Samples were air dried, passed through a 0.002 m sieve, and analyzed at the Pacific Forestry Centre. Soil temperature and moisture were evaluated approximately every two weeks during the summer of 1995 by obtaining three readings with a hand-held thermometer that was inserted 0.15 m below the mineral soil surface. Tree survival and early growth was monitored after one,two, and three growing seasons. Tree height and caliper was determined, along with an assessment of the tree condition. Tree volume was determined as the volume of a cylinder with base diameter equal to the caliper, and height equal to the seedling height. 3. Results and discussion3.1. Soil properties Soil temperature results are presented in Fig. 1.Even though no analysis was done on the data, and replication was limited, general conclusions appear to be justified. Daytime soil temperatures tended to be lower for mulch treatments compared to soils without added amendments. Plots where organic amendmentshad been tilled into the surface had intermediate soil Temperatures. The sawdust had a much lower C : N ratio than the wood chips (Fig. 2), reflecting higher N concentrations for woody materials that have experienced several years of decomposition. P, Ca, Mg and Fe concentrations also appeared to be slightly higher in the sawdust material (data not shown). Concentrations of other elements did not appear to vary consistently between the sawdust and wood chip amendments. C : N ratios of surface mineral soils ranged from16.5 to 72.9. Incorporated sawdust increased the C : N ratio of the ne fraction of mineral soils compared to plots without added amendments. Incorporated wood chips also resulted in a slight increase in mineral soil C : N, even though the wood chips were generally much larger than 0.002 m. Carbon concentrations of surface mineral soils were affected by several factors,including the presence of buried wood and other organic materials in the untreated landings, and the effect of the organic amendments on soil C concentrations.Untreated soils at one of the landings had high C concentrations in surface mineral soils, probably resulting from the presence of buried wood and forest floor material. A 0.05 m layer of wood chips is equivalent to an addition rate of 500 m3 ha-1. The chips had dry bulk density of 152 kg m-3, so the addition rate is equivalent to 76 000 kg ha-1 of organic matter, or approximately 44 000 kg ha-1 of carbon. Incorporation of wood chips at a rate of 44 000 kg ha-1 of C into the surface 0.20 m of a hypothetical mineral soil with a bulk density of 1200 kg m-3, would increase the C concentration by 1.8%. Only a portion of this C would end up in the ne fraction of soil in the first few years after treatment, but all of it is expected to become part of the soil carbon cycle, and portions will eventually contribute to the ne soil organic matter content. In contrast, sawdust incorporation would be expected to result in similar changes to total C concentration, but the C would appear in the fine soil fraction sooner,because the initial particle size is much smaller for sawdust than for wood chips. As expected, Fig. 2 shows that the plots where sawdust was incorporated into the surface had higher organic matter levels in the surface mineral soils than other treatments. Concentrations of other nutrients in surface mineral soils were variable, and did not show obvious trends arising from the treatments.3.2. Tree survival and early growth Seedlings on plots with tillage alone produced the most volume over the 3 year period (Fig. 3). Trees growing in plots where sawdust was used as an amendment tended to have more volume after 3 years than trees growing where wood chips were used as the amendment. Heavy applications of wood chips left as a surface mulch resulted in the lowest volume growth after 3 years. Survival rates were over 90% for all treatments (Fig. 4). The silty soils were prone to frost heave, and high mortality rates and seedling damage due to frost heave were observed on control and tilled only plots on a wet area of one landing where seepagewater was present, while lower rates were observed for adjacent plots that had received organic amendments. Although data on soil moisture content are not presented here, several effects of the treatments on soil moisture status and availability to tree roots could be considered as causing the observed growth response. Lower soil moisture contents may result from better drainage from areas with raised surfaces, resulting in warmer soil temperatures and increased aeration of the root zone. During dry periods,increased soil organic matter contents of soils treated with sawdust or chip incorporation may improve soil moisture retention and provide moisture for plants.Surface mulches can also enhance moisture retention,although mulches also insulate the surface and may result in lower temperatures. Several factors, including the extent of summer drought during a particular year would determine the beneficial or detrimental effects of variations in soil moisture storage or altered thermal properties on seedling growth. In general,only minor summer moisture deficits are experienced in the SBSwk1.4. Conclusion After 3 years, trees were growing best in areas that were treated by tillage alone, and trees growing on areas where old sawdust was used as a soil amendment had more volume than trees growing in areas where wood chips were used as a soil amendment. Control plots with no treatment had intermediate growth. Soil temperature appears to have a large influence on tree growth rates on these plots. Survival after 3 years was high, indicating that commonly available techniques for landing rehabilitation can restore soil conditions to a state suitable for establishment and early growth of conifer seedlings. Some of the variation in early growth results may relate to differences in initial conditions on the landings.The results also likely reflect the condition of the planting stock shortly after leaving the nursery, along with conditions at the time of planting. These effects have diminished after 3 years and significant treatment effects were observed. Treatment effects are expected to become even more dramatic in subsequent years as the establishment effects diminish further. The old sawdust had chemical (low C : N) and physical (smaller particle size, expected higher water holding capacity) that may be implicated in the improved growth, but the data available to date and analyses that have been carried out so far do not allow further interpretation of the cause for the improved growth of trees on the plots treated with sawdust.Acknowledgements Funding for establishment of this project in 1994and 1995 was provided by a grant from Canadas Green Plan to the Canadian Forest Service. Since1996, continued measurements have been made possible by the BC Ministry of Forests. Support for this project was also provided by Carrier Lumber. Field assistance during plot installation and for subsequent measurements was provided by Matthew Plotnikoff and Colin Peters. ReferencesAndrus, C.W., Froehlich, H.A., 1983. An evaluation of fourimplements used to till compacted forest soils in the Pacificnorthwest. Res. Bull. 45. For. Res. Lab., Oregon StateUniversity, Corvallis, OR.Arnott, J.T., Carr, W.W., Waines, A.C., 1988. Establishing forestcover on winter landings in the central interior of BritishColumbia. For. Chron. 64, 121126.Bulmer, C.E., 1998. Soil rehabilitation in British Columbia: aproblem analysis. Land Manage. Handbook 44. BC Min. For.,Victoria, B.C.Carr, W.W., 1988a. Nutritional and soil compaction aspects ofestablishing forest cover on winter landings in the Fort St.James area. FRDA Report 047. BC Min. For. and Can. Fore.Serv., Victoria, BC.Carr, W.W., 1988b. The rehabilitation of degraded forest soil inBritish Columbia: an overview. In: Lousier, J.D., Still, G.W.(Eds.), Degradation of forested land: forest soils at risk. Proc.10th BC Soil Sci. Workshop, February, 1986. Land Manage.Rep. No. 56. BC Min. For., Victoria, BC, pp.197204.McNabb, D.H., 1994. Tillage of compacted haul roads and landingsin the boreal forests of Alberta. Canada. For. Ecol. Manage. 66,179194.Tisdall, J.M., Oades, J.M., 1982. Organic matter and water stableaggregates in soils. J. Soil Sci. 33, 141163. 13 / 13文档可自由编辑打印挖掘机开垦森林土壤与修正方案 BC省的森林,卡拉玛卡研究站,水库路3401,弗农,加拿大不列颠哥伦比亚省c7 V1B 2 审核1999年10月6日。摘要： 在1994年初发起的一个研究项目评估成功的几种技术，旨在恢复瓦马瓦马溪以东44公里附近中环不列颠哥伦比亚省乔治王子上岸退化土壤生产力。土壤从材料开发，通常表面土壤质地为粉质壤土。两个有机修订这项研究中，包括新制的木屑和旧木屑。一台挖掘机配备整地耙来耕地土壤深度0.50米。随后添加有机添加物的地块，要么离开覆盖或纳入0.20米的土壤表面。氮225公斤每公顷的速度被应用到这次研究，据估计500700公斤公顷的约三分之一，被要求固定应用为在木质残留物的分解。挽救措施是处理好了，但3年后，树木的长势最好的领域分别用单独耕作。老锯末作为一项修正案量比在木片的地方已被用于生长的树木有更多的树木生长。没有治理的对照地块中间有增长。土壤温度和化学性质进行了其对经济增长的影响评估。2000 爱思唯尔科学BV保留所有权利1.介绍：众多的特点，在不列颠哥伦比亚省中部的森林着陆土壤板结，养分耗竭（卡尔，1988a）。退化的土壤上和其他地区的土壤已经不妥善的森林经营活动往往只支持种植针叶树（Arnott等人，1988）轻微增长。在许多情况下，土壤条件退化，种植不试图上岸。土壤生产力恢复退化的土壤上生长限制条件得到缓解（布尔默，1998）。经常采用松软土壤耕作，提高土壤的生产力（安德鲁斯和弗勒利希，1983）。在粗质地的土壤，耕作可提供黑松等针叶树的增长，虽然土壤养分长期枯竭的后果可能会是关注的问题。在NE质感土壤，耕作结果不一致（卡尔，1988B;麦克纳布，1994年），部分原因是一个狭窄的范围内可以进行有效的耕作，水分含量，而且还因为稳性团聚体需要防止耕作后不久再次出现树体状况不佳。稳定的土壤团聚形成土壤矿物颗粒时，建立土壤有机质（蒂斯和奥德的，1982年）。有几种方法可以重新建立稳定的土壤后免耕土壤结构。根深蒂固的牧草和豆科植物可以建立覆盖作物根区域中提供有机质和提高生物活性，从而鼓励发展稳定的土壤团聚体。已经提出的另一种涉及到土壤表层带来土壤有机和无机材料相互接触方法，并有可能鼓励掺入有机物稳性团聚体的形成。 这个项目是为了获得更多的信息的方法恢复紧凑、贫营养的土壤生产力。我们对土壤理化性质评估性耕作，并建立和早期生长的黑松添加有机添加物的几种组合的效果。2. 材料与方法2.1研究网站这项研究进行了三个森林着陆乔治王子市以东44公里，在生物地球化学气候分区。土壤开发的材料。通常的表面土壤质地为粉砂壤土，但至少有一个位置，遇到富含粘土的B层。粗碎屑含量介于15和40。着陆位于水平或平缓地区。处理之前，很少有植有生长。2.2实验设计9个5米x6米处理应用，如表1中所述。两个控制地上建立每次着陆。两个有机添加物使用木屑作为处理的一部分减少相邻的切口块重再次危害，以及旧锯木厂腐烂的木屑。这些材料是典型的土壤改良剂，可能是远程康复站点。该模片有典型的颗粒尺寸为0.1mx 0.05米x 0.005米，而木屑颗粒有所有尺寸小于0.003米。2.3治理在1994年的夏天进行治理使用的挖掘机配备一个VE齿整地耙。土壤耕种的深度0.50米，有机修正随后铲到地块，以获得均匀分布的材料。修订要么离开覆盖或随后并入0.20米的土壤表面。所有种植松苗（PSB313）的地块树苗在1米的间距。豆科植物种子组合被应用在1995年的夏天，但是非常贫瘠的土地由豆科植物建立作物覆盖，由于天气干燥，在整个实验草和豆科植物一直维持在一个较低的水平。在1995年的夏天，所有的细节，包括控制，受精使用尿素（45-0-0）和一个完整的氮磷钾复合肥（18-18-18）的组合。适用于氮气225公斤每公顷，据估计约占500700 KGN公顷比例的三分之一，以固定在分解的木质残留物作为补偿。该地块收到50公斤K2O和P2O5每公顷。2.4土壤分析和树生产力测量1994年10月采集复合土样，从最近处理的情况。样品在空气中干燥后，通过0.002筛，并在起搏C林业中心分析了。土壤温度和湿度在1995年夏天进行了大约每两个星期与手持式温度计评估，插入0.15米以下的矿质土壤表面获得三读通过。一个，两个，三个生长季节后，林木成活率和早期生长监测。树高和卡尺，随着评估确定树的条件。立木蓄积量被确定为一个圆柱体的体积与基地的树苗直径等尺寸，高度等于苗高。3. 结果与探讨3.1土壤性质土壤温度的结果示于图中。虽然没有分析1.上的数据，和复制是有限的，一般的结论是正当的。白天土壤温度与不加修正的土壤覆盖相比往往会有较低的治理效果。有机修正耕种的地块中间土壤温度。已经历了数年的分解，证明锯末比木片的C：N比率低得多（图2），木质材料表现出了较高的氮浓度。锯末材料中磷，钙，镁，铁含量也显得略高（数据未示出）。其他元素的浓度并没有出现变化木屑和木片之间一致。土壤表面矿质C：N比率从16.5到72.9不等。与不加修订地块相比加入锯末增加的C：N比。加入木片也导致矿质土壤C：N略有增加，即使木片一般远大于0.002米的。表面矿质土壤的碳含量受多种因素影响，包括对土壤碳浓度的有机添加物的效果的存在下埋木材和其它有机材料在未经处理的降解。降解在一个未经处理的土壤矿质土壤表面，高C浓度可能阴沉木和森林地板材料的存在造成。木片是0.05米层相当于加入速率500立方米每公顷的。该芯片有干容重152公斤每立方米，所以除率相当于76 000公斤每公顷有机物，或约44万公斤的碳每公顷。加入木屑44 000公斤的每公顷，入面0.20米的一个假设的矿质土壤体积密度为1200公斤每立方米的速度，治理几年后的土壤中将增加C的浓度为1.8 NE分数，只有一小部分，这个C会耗尽，但它有望成为土壤碳循环的一部分，和部分最终将有助于NE土有机质含量。相比之下，锯末的掺入会预计将导致总碳浓度变化相似，但土分数早晚将出现，因为最初的粒径比木屑锯末小得多。正如预期的那样，图2锯末表面被纳入该地块具有较高的矿质土壤表面的有机物质水平高于其他处理。其他营养物质浓度在表面矿质土壤中是可变的，并没有表现出明显的治理的趋势所产生。3.2树的生存和早期生长单独耕作地块上幼苗产生量超过3年期（图3）。树木生长在木屑被用来作为一个修正的重复中往往比生长的树木在3年后的木片被用作修正有更大的体积。离开表面覆盖的木片应用在3年后的最低量增长。所有的治理生存率分别为90以上（图4）。粉砂质土壤很容易冻胀，在潮湿的地区渗水高死亡率和幼苗霜冻造成的损害上观察控制和仅耕种的地块，而观察相邻地块有机修订已经收到较低的利率。 图一 对土壤水分含量的数据，这里就不介绍了，几个方面的影响可以被视为导致对土壤水分的状态和可用性树根响应生长的处理。土壤水分含量较低，可能从地区有凸起的表面导致在温暖的土壤温度和增加根区的曝气更好的排水系统。在干旱期间，增加土壤有机质含量与锯末或芯片掺入土壤处理可提高土壤水分储留，并为植物提供水分。表面覆盖物也可以提高保湿性，虽然绝缘覆盖物表面，可能会导致较低的温度下。有几个因素，包括夏季干旱的程度，在某年内将确定土壤水分存储或改变幼苗生长的热性能变化的益处或不利影响。在一般情况下，只有轻微的夏季水分在SBSwk1。 图二 图四4. 结论三年后，树木的长势最好的治理领域，单独耕作，树木生长的地方老锯末被用作土壤改良剂有更多的剂量比在木屑被用作土壤改良剂的地方树木生长。没有治理的对照地块中间有增长。土壤温度出现在这些地块上对树木生长率有很大的影响。三年后存活率高，早期生长的针叶树苗适合的状态，表明常用的技术着陆康复可以恢复土壤条件。在早期生长的结果中的变化中的某些的可能涉及到同上的地方.在初始条件有区别的搜寻结果，也很可能在离开的儿童起居室中，沿与上面的时间条件种植下后，短期内反映的种植条件。这些影响已经减少3年后不能观察疗效。预计在随后的几年中变得更为显著地治理效果，效果更进一步。老锯末有化学（低C：N）和物理（粒径较小，预计较高的持水能力）可能会牵连改进增长，是已开展至今的日期和分析的数据不允许进一步改善树木生长锯末治理地块的原因解释。致谢： 设立这个项目在1994年和1995年的资金提供了从加拿大的绿色计划，由授予加拿大森林服务。自1996年以来，持续测量已成为可能，由卑诗省的森林。对这个项目的支持也提供了由载波木材。由马修提供现场援助，和科林彼得斯在计划的安排和后续的测量。