Variations and phenotypic correlation of growth attributes of Calliandra calothyrsus in the Blue Mountains of Jamaica

Forested land cleared for agriculture in the Blue Mountains of Jamaica rapidly loses its productivity leading to further slash-and-burn cultivation and the degradation of more forest. Contour hedgerows of Calliandra calothyrsus Meissner have been shown to reduce water runoff and soil erosion, and products of the species have a wide range of uses in the local farming community. A trial was established at 1550 m in which the locally naturalised population of C. calothyrsus was compared with seven provenances from across the species' ecological range. There was considerable variation between provenances of C. calothyrsus in all the above-ground growth variables measured and, although the local provenance performed moderately well, it was clear that there is potential to improve the suitability of the species for a range of local uses by the introduction of new provenances. One provenance combined high above-ground productivity with low fine root-length density, especially in the inter-hedgerow area: it offers particular potential for use in simultaneous agroforestry systems providing wood and foliage products whilst not imposing high levels of competition with crop plants for below-ground resources. Although there were significant differences between provenances in the distribution of roots between the hedgerow and inter-row areas, they did not differ in the distribution of roots between soil depths. There were only limited differences between provenances in the response of their subsequent growth to harvesting. However, significant block × provenance interactions suggested that the performance of C. calothyrsus provenances may be difficult to predict between sites and farmers should be encouraged to carry out trial planting of a number of provenances to find those which best match their farm environment and needs.This revised version was published online in November 2005 with corrections to the Cover Date.     

Nitrogen fixation capacity in the component species of contour hedgerows: how important?

The choice of an appropriate hedgerow species is one of the most critical decisions in exploiting the value of a contour hedgerow system. The implications of hedgerow species with nitrogen (N)-fixation capacity on hedgerow-crop competition and crop productivity have been widely debated. We examined the agronomic significance of N-fixation by comparing the performance of species representing three classes of hedgerow vegetation: A nitrogen-fixing tree legumeGliricidia sepium), a non-nitrogen fixing tree (Senna spectabilis syn.Cassia spectabilis), and a forage grass (Pennisetum purpureum). The 4-year study investigated the hedgerow biomass and nutrient yields, and their relative effects on the performance of two annual crops commonly grown in alley farming systems, with emphasis on hedgerow-crop interference. The work was done on an Ultic Haplorthox (pH 4.8, organic C 1.9%, total N 0.18%).Senna produced 46% more pruning biomass on an annual basis than didGliricidia; N supplied to the alley crops was similar toGliricidia in the first year of observation, but 20–30% higher in the succeeding years. Upland rice and maize grain yields and total dry matter were unaffected by tree species, but the nitrogen-fixing tree exerted less competitive effects on the annual crops growing in adjacent rows. Grass hedgerows reduced maize yields 86% by the second year, indicating an unsustainable drawdown of nutrients and water. We conclude that hedgerow systems composed of a nitrogen-fixing tree did not exert significant advantages compared to a non-fixing tree species, and that factors other than N-fixation were more important determinants for the choice of hedgerow species.     

Effectiveness of sloping agricultural land technology on soil fertility status of mid-hills in Nepal

Hedgerows with intercropping systems were established at the ICIMOD test and demonstration site at Godawari to assess the effective-ness of Sloping Agricultural Land Technology (SALT) in reducing run-o...     

不同土地利用方式土壤侵蚀与养分流失的模拟试验

采用室内人工模拟降雨方法，研究河北太行山南段低山丘陵片麻岩褐土区3种土地利用方式（草地、坡耕地、刺槐林）土壤侵蚀与养分流失规律，分析土壤养分流失的空间变化以及养分流失与土壤侵蚀的关系，比较流失泥沙中的养分含量与表土和径流中的养分含量变化。结果表明：流失泥沙中的养分含量明显高于径流中的养分含量，也明显高于雨前表土中的养分含量，具有较大的养分富集比；土壤中流失的养分与流失泥沙量具有较好的相关性。     

广林巨尾桉人工林土壤侵蚀和养分流失研究

在2008年7月～2011年12月通过运用径流场观测方法,对广林巨尾桉人工林土壤侵蚀量和养分流失量进行了定位观测.结果表明,与荒地相比,桉树人工林土壤侵蚀量增加了18.86％ ～146.15％,桉树人工林地土壤侵蚀量造林后呈逐年降低的变化趋势;与荒地相比,桉树人工林养分流失量有所增加(5.75％～ 147.12％),但随着桉树的生长明显降低(97.89％ ～99.98％),桉树人工林地各养分流失量的大小排列顺序为K＞N＞Zn＞P＞Cu＞B.     

杉木人工林水土流失及养分损耗研究

１９８４～１９９６年在江西分宜县中国林科院亚热带林业实验中心的３个林场,分别对杉木人工林幼龄林、中龄林及近熟林进行了８组水土保持及养分循环方面多点的试验观测,对杉木人工林水土流失及养分损耗作了研究。结果表明,杉木人工林水土流失以幼林阶段为最大,其次中龄林阶段,最小是近熟林阶段。幼龄林地表迳流量为５４６．０ｍ＾３．ｈｍ＾－２,土壤侵蚀总量为１０５０．０ｋｇ．ｈｍ＾－２,土壤侵蚀量尤为明显;中龄林地表迳流量为５０６．９８ｍ＾３．ｈｍ＾－２;而近熟林地表迳流量为４７７．２５ｍ＾３．ｈｍ＾－２,土壤侵蚀量可略而不计。幼龄林流失有机质５０．０４９ｋｇ．ｈｍ＾－２,养分为３１．５０８ｋｇ．ｈｍ＾－２;中龄林流失有机质为６．０８０ｋｇ．ｈｍ＾－２,养分流失量为２．０９６ｋｇ．ｈｍ＾－２,而近熟林养分流失量为１０．７８４ｋｇ．     

Effects of contour hedgerows on water and soil conservation,crop productivity and nutrient budget for slope farmland in the Three Gorges Region (TGR) of China

Soil erosion has long been recognized as a major environmental problem in the Three Gorges Region (TGR) where slope farming is commonly practiced but the local topography is hilly. In consideration of the poor socioeconomic position of local farmers, low cost hedgerows had been introduced as a soil conservation measure to the TGR in the late 1980s. A collaborative research programme was initiated by the Chinese University of Hong Kong, the Chinese Academy of Science, the Huazhong Agricultural University, and the Bureau of Soil and Water Conservation of Zigui County to study the potential of adopting hedgerows in the TGR. Six experimental plots (10 m × 2 m, gradient = 25°) were constructed at Zigui County, Hubei Province to study effects of hedgerows on erosion, nutrient loss and crop productivity. Results indicated that there were significant relationships between rainfall and runoff, and rainfall and soil loss, respectively. Conventional slope farming could not be considered a sustainable agricultural practice because it resulted in severe erosion and low crop yield. Hedgerows per se seemed not to be effective in reducing soil loss and boosting crop productivity, but performances could be greatly improved when they combined with the use of fertilizers. Current farming and fertilization practices, however, generally did not meet N demands of crops. Results and findings of this paper will contribute towards a technical reference for the promotion and adoption of hedgerows in the TGR.     

丹江口库区大气降雨及森林地表径流特征研究

笔者在2005年8月～2007年7月,对丹江口库区的降雨量进行了每日观测,观测期内降雨集中在6～8月份,且易引起水土流失的暴雨同样出现在这3个月。并在栎类阔叶林、马尾松林、松柏混交林、柑桔园、灌木林和坡耕地(对照)分别建立径流场进行地表径流和土壤侵蚀量的观测,结果表明:坡耕地的径流量、土壤侵蚀量与养分流失量均高于另外5种森林类型,与对照相比,5种森林类型地表径流量可以削减15.21%～61.4%,土壤侵蚀量可以削减54.30%～96.32%。     

Growth of four tree species managed as hedgerows in response to liming on an acid soil in West Sumatra,Indonesia

A hedgerow intercropping study was conducted for 7 years in West Sumatra, Indonesia on an acid and highly Al-saturated soil to determine growth and yield responses of tree hedgerows and upland rice and cowpea intercrops. Three tree species,Paraserianthes falcataria, Calliandra calothyrsus, andGliricidia sepium and a no-tree control were planted at three lime rates with low annual fertilizer inputs of 20 kg P and 50 kg K ha^–1.Paraserianthes andCalliandra grew vigorously, whileGliricidia grew poorly and was replaced after four years withFlemingia macrophylla. After four years,Paraserianthes yields declined due to tree mortality, probably due to intensive pruning.Calliandra andFlemingia were well adapted to intensive pruning (4 to 6 times per year). Gliricidia growth was especially limited by low soil Ca availability and high soil acid saturation.Calliandra andFlemingia yields increased with liming only in the last several years of the study whileParaserianthes did not respond to lime. The species can be tentatively ranked in response to lime as:Gliricidia > Calliandra > Flemingia > Paraserianthes.     

Relationship between species diversity and biomass of eucalyptus plantation in Guangxi, south China

To reveal the relationship between species diversity and biomass in a eucalyptus (Eucalyptus urophylla × E. grandis) plantation located in the Dongmen State Forestry Farm of Guangxi, south China, 18 sample plots were established and the total biomass, arbor layer biomass and undergrowth biomass of communities were subsequently harvested. The results were as follows: 1) Species richness in eucalypt plantation had remarkable positive correlation with biomass of arbor layer, undergrowth and community (α = 0.001), its correlation coefficients were 0.6935, 0.7028 and 0.7106 respectively. 2) Leaf area index (LAI) had remarkable positive correlation with species richness and undergrowth biomass (α = 0.001). Its correlation coefficients were 0.7310 and 0.6856, respectively. 3) Arbor layer biomass had remarkable correlation with soil organic matter and hydrolysable N, its correlation coefficients was 0.6416 and 0.6203 respectively. Species richness had remarkable correlation with soil organic matter and correlation coefficient was 0.6359. Among them, the correlation was significant at the 0.1 level. Undergrowth biomass had little correlation with nine soil nutrients and correlation coefficients were under 0.4. To sum up, species diversity was advantageous to the promotion of the biomass of the eucalyptus plantation, and the variation of LAI and soil nutrient in small-scales could result in the difference of species diversity and biomass in different sample plots. Translater from Scientia Silvae Sinicae, 2008, 44(4): 14–19 [译自: 林业科学]     

深圳宝安区生态风景林典型造林地土壤养分、微生物和酶活性的研究

深圳市宝安区为了美化城市 ,改善环境 ,计划大力营造具有保护环境 ,以生态效益和社会效益为主的生态风景林。由于人为干扰 ,深圳原有的常绿阔叶林受到严重破坏 ,现以桉树(Ｅｕｃａｌｙｐｔｕｓｓｐｐ .)纯林 ,马占相思 (ＡｃａｃｉａｍａｎｇｉｕｍＷｉｌｌｄ .)林和马尾松 (Ｐ     

江西红壤低丘水土流失发生规律和防治对策

综述江西红壤低丘的主要特征、水土流失原因和水土流失规律,提出防治对策和该研究领域中亟待解决的一些问题.     

不同混交林地土壤养分、微生物和酶活性的研究

研究了不同混交类型林地的土壤养分含量、微生物数量和酶活性。结果表明：各样地养分含量，特别是P含量偏低；各林地微生物中，细菌数量最大，微生物数量和酶活性随林地不同而有较大差异。     

滨海盐碱地枣园土壤酶活性与土壤养分、微生物的关系

对垦利县黄河口镇枣园的土壤酶活性进行研究。结果表明：随土层深度的增加，土壤酶活性下降。脲酶与过氧化物酶、过氧化氢酶极显著正相关，相关系数分别为0．996、0．943；脲酶与多酚氧化酶相关性不大，相关系数为0．377；过氧化氢酶与过氧化物酶呈显著正相关，相关系数为0．911；多酚氧化酶与其他3种酶的相关性不大。土壤酶与土壤养分、pH值、土壤微生物有较强的相关性，其中脲酶与土壤养分、pH值和固氮菌、真菌、细菌的相关性显著，相关系数在0．444以上；多酚氧化酶与土壤养分和微生物的相关系数较小；过氧化物酶和过氧化氢酶与土壤养分、pH值、纤维素分解菌和真菌的相关性显著，相关系数在0．451以上。     

Influence of three plant species with different morphologies on water runoff and soil loss in a dry-warm river valley, SW China

Understanding of the effects of isolated plants with different morphologies on water runoff and soil loss is important for vegetation restoration in arid environments. We selected three representative species (Artemisia gmelinii; Ajania potaninii; Pulicaria chrysantha) of the dry-warm river valley of the upper reach of Minjiang River, SW China to examine these effects. Twenty-five runoff events were recorded using runoff plots at micro scale (<40 cm × 40 cm) on a south facing slope from July through October 2006. A. potaninii had sparse canopy, the smallest leaf area (0.49 ± 0.25 cm²) and specific leaf area (67.8 ± 16.5 cm²/g), and the highest leaf relative water content (27.1 ± 4.4%). It is the most resistant to drought stress. A. gmelinii was the shortest, and had relatively small leaf area (0.55 ± 0.50 cm²) and the densest canopy. P. chrysantha had the greatest leaf area (1.41 ± 0.49 cm²) and most extended canopy (4450 ± 1646 cm²). Dead branches and leaves of A. gmelinii and P. chrysantha commonly fall and collect on the soil surface. Thus they had greater improvements on soil porosity and soil water content, and higher effectiveness in controlling soil loss. However, A. gmelinii had more stable effectiveness in controlling runoff as compared with P. chrysantha. The characteristics such as relatively small leaf area but low height and dense canopy might be one criterion for selecting species to improve soil properties and controlling runoff and soil loss. Differences in soil environments, and runoff and soil loss production capacity for micro-surfaces regulates water and materials redistribution, which emphasizes the importance in designing vegetation restoration pattern.     

印度西部5种热带干落叶林中凋落物中生物元素和返回到绿叶中的季节性变化(英文)

本文对印度西部5种热带干落叶林中凋落物里生物元素的季节性变化和它们返回到新鲜叶中季节性变化进行研究。对5个树种:阿拉伯金合欢(Acacia nilotica L.)、金合欢(Acacia leucophloea Roxb.)、柚木(Tectonagrandis L.f.)、绒毛野独活(Miliusa tomentosa Roxb.)和紫矿(Butea mono-sperma Lain.)中凋落物的成熟叶、枝和再生部分的N、P、Ca、Mg、K和Na的浓度,以及老叶和幼叶中浓度间的关系进行调查。对这些树种的总干物质进行记录,并分析它们所含的N、P、Ca、Mg、K和Na的含量。其中阿拉伯金合欢叶子中N的含量最高,而金合欢的叶子里Ca和Mg含量最高。叶中含P最多的是阿托伯金合欢、金合欢和紫矿,而含P最少的是柚木和绒毛野独活。K和Na含量在这些树种中没有明显的区别。观察发现,N、P和K的浓度随季节变化大,但Ca和Mg则不然。唯有钾在所有树种中都是最稳定的,吸收N和P可以用于来年新叶的生长。从老叶和凋落物中吸收的营养会支持新叶的生长,并增加土壤的肥力。图1表4参30。     

广西扁桃适生区土壤碳氮磷生态化学计量特征

为探究广西扁桃适生区土壤碳(C)、氮(N)、磷(P)生态化学计量特征及其对环境因子的响应,采用野外调查与室内分析相结合的方法,对广西南宁、百色等扁桃适生区的土壤有机碳(SOC)、全氮(TN)、全磷(TP)及环境因素进行研究.结果表明,广西扁桃适生区土壤有机质的矿化作用慢,但土壤P表现为净矿化,具有较高的有效性.土壤C︰...     

造林对乌海露天煤矿复垦地土壤养分和碳库的影响

目的 明确矿区复垦地造林前后土壤碳库的变化及土壤养分对碳库的影响。 方法 以造林前的荒草地和造林后的新疆杨林地为研究对象,研究复垦地造林前后土壤无机碳库、活性有机碳库、慢性有机碳库、惰性有机碳库和养分的变化规律和相互关系以及各养分指标对碳库的贡献率差异。 结果 表明,除NN（硝态氮）外,造林后土壤养分和碳库各组分含量均有所上升。林地土壤TN（全氮）、AN（铵态氮）、TP（全磷）、AP（速效磷）、TK（全钾）和AK（速效钾）的含量相较于草地分别增加了29.27%、17.21%、23.08%、27.04%、51.18%和53.19%,而土壤NN含量下降了71.84%。造林后土壤SOC（有机碳）、POC（颗粒物有机碳）、NPOC（非颗粒物有机碳）、DIC（可溶性无机碳）、DOC（可溶性有机碳）、MBC（微生物量碳）和HC（还原性糖碳）含量相较于造林前分别上升了50.35%、62.46%、22.56%、113.53%、230.23%、274.63%和72.54%。复垦地土壤无机碳库与活性有机碳库之间呈显著正相关性,与慢性有机碳库和惰性有机碳库之间无显著相关性。土壤养分因子共能解释40.7%的碳库变量,其中K对土壤碳库的贡献率最高。相关性分析也表明TK和AK与各形态碳组分之间均存在显著正相关关系。 结论 综合分析认为造林能够明显改善和提高乌海露天煤矿复垦地土壤养分含量和碳库水平,这为进一步深入研究造林对干旱荒漠区露天煤矿复垦地土壤质量和生态功能的影响提供了理论和实践基础。     

不同抚育措施对油茶林土壤养分 微生物及酶活性的影响

对常宁地区不同抚育措施油茶林的土壤养分、微生物及酶活性进行了测定和分析。结果表明:各林分间土壤养分、微生物数量和酶活性存在较大差异。同一林分土壤养分、微生物数量和酶活性随取样深度的增加逐渐降低。锄抚林地在土壤养分、微生物总数和酶活性方面明显高于未抚育和刀抚林分。相关分析表明,这3种林分的土壤养分(有机质、全氮、碱解氮和速效磷)与微生物数量及酶活性之间存在相关关系;细菌数量和脲酶活性与土壤有机质、全氮、碱解氮和速效磷等主要养分指标呈显著或极显著正相关;过氧化氢酶和蔗糖酶活性与土壤养分指标间相关性不强。     

杉木连栽幼林生长量、营养元素和土壤肥力的比较

结果表明：杉木连栽引起林地肥力减退，土壤地力衰退程度与前茬林生长周期有关。头茬杉木林周期短（14a）的二耕土上连栽的杉木长势较好，头茬杉木林周期长（24a）的二耕土上连栽的杉木幼树长势极差。林地施肥后并没有促进杉木幼树恢复生长。原因在于杉木幼树根系受到土壤中有毒物质毒害，根系腐烂，不能从土壤中吸收养分。建议采取生物工程措施解决杉木连裁地力减退问题。