Sheep grazing in young oak Quercus spp. and ash Fraxinus excelsior plantations: vegetation control, seasonality and tree damage     

P. M. McEvoy  J. H. McAdam 《Agroforestry Systems》2008,74(2):199-211

An experiment was carried out where sheep were grazed in temporary fenced paddocks at a stocking rate of 178 LSU ha⁻¹ in a 5-year old broadleaf plantation of oak (Quercus spp.) and ash (Fraxinus excelsior) (1.5 m spacing) on fertile, former lowland pasture in Northern Ireland. The grazing regime was rotational and intensive, with two grazing periods of 5 days in February and October 2001. Results showed that a significant proportion of the rank herbage height was removed within the first 24 h of livestock introduction. Herbage biomass was reduced by approximately half after 5 days. Sward height in grazed plots remained significantly lower than control plots for over 6 months after cessation of grazing, whilst biomass remained significantly lower for over 4 months after cessation of grazing. No significant tree damage to either oak or ash was measured during the February grazing trial, however significant damage to the lateral branches of both oak and ash was observed in the October grazing trial. Leader damage did not occur on trees greater than 152 cm. Ash was more commonly browsed than oak. Annual height increment of both tree species was unaffected by grazing, but annual stem diameter increment was significantly reduced in both oak and ash in February grazed plots. Oak trees in both February and October grazed plots were found to have a significantly smaller annual increase in canopy diameter than those in control plots. Results are discussed with regard to practical implementation of controlled grazing in young broadleaf forestry plantations on fertile, lowland soils.  相似文献   

A comparison of pod production and insect ratings of 12 elite Prosopis alba clones in a 5-year semi-arid Argentine field trial     

Mauricio Ewens  Peter Felker 《Forest Ecology and Management》2010

Semi-arid adapted nitrogen fixing trees of the genus Prosopis have been extensively used in Argentina for soil improvement, luxury quality lumber production and sweet (35% sucrose) pods for humans and livestock. Due to the great demand of Prosopis alba for lumber, erect, tall, high pod producing trees of this species have been greatly overharvested, leading to erosion of the gene pool. A previous progeny trial with 57 half sib families identified 12 trees with promise for rapid growth, high production of pods and sweet pods. This trial, on a site with a salinity of 8.6 dS m⁻¹ EC and a pH of 7.7, examined clones of these 12 trees in a randomized complete block trial with 8 single tree replications for height, basal diameter, canopy height and diameter, production of pods, sensory characteristics of the pods, disease resistance and insect resistance. In the 5th year of production and 7th year from planting, three clones produced more than 50 kg pods per tree versus 32 kg for check. At this 10 m × 10 m spacing, this yield of 5000 kg/ha compares favorably to many other semi-arid crops, especially given the unfavorable salinity and pH. In contrast to genetic improvement in pod production, the clones had lower diameter, height and canopy growth than the check. The lower biomass production may be due to fibrous root system produced from cuttings, since some of the clones blew over in high winds but none of the checks produced from seed blew over. Companion seed orchards of salt tolerant clones may provide rootstock for these high pod production clones. Significant differences in insect and disease resistance of the clones were observed and full sib crosses were made to study the genetics of the resistance. All clones had good sensory properties for use in human food. This is the first replicated trial with multipurpose clones useful for lumber and human food. The annual diameter growth rates ranged from 2.8 to 4.1 cm year⁻¹ which was estimated to produce an internal return of approximately 20% from lumber alone.  相似文献   

Comparison of marker- and pedigree-based methods for estimating heritability in an agroforestry population of Vitellaria paradoxa C.F. Gaertn. (shea tree)   总被引：1，自引：0，他引：1  

J. -M. Bouvet  B. Kelly  H. Sanou  F. Allal 《Genetic Resources and Crop Evolution》2008,55(8):1291-1301

We implemented a regression-based method between pairwise relatedness estimated from markers and phenotypic similarity to estimate heritability of traits related to leaf size and morphology in a wild tree population (Vitellaria paradoxa C.F. Gaertn.: shea tree). We then compared the results with heritability estimated with a classical pedigree-based method. We tested both approaches in an agroforestry population of this tree species, a very important one and abundant in the Sudano-Sahelian zone of Africa. Twelve microsatellite loci were used to estimate pairwise relatedness after selection of estimator coefficients based on Monte Carlo simulation. The regression-based method applied to 200 individuals did not display a significant trend with physical distance between trees for relatedness as well as for actual variance of relatedness. In consequence, estimates of narrow-sense heritability of traits related to leaf size were not significant. The pedigree-based method using a progeny test with 39 families and 15 individuals per family from the same population showed high and significant estimates of narrow-sense heritability for the same traits (h² = 0.36–0.95), demonstrating a marked genetic variation within the population. This discrepancy between methods stresses the poor performance of the molecular marker-based method. This can be explained by the absence of fine-scale structure within the agroforestry population of shea trees, other parameters being consistent with recommended values. The regression-based method does not seem well adapted to the agroforestry tree population. New experiments in tree populations and theoretical approaches are needed to evaluate the real potential of the marker-based methods.  相似文献   

农林复合系统防尘效应的研究   总被引：7，自引：0，他引：7  

孟平  宋兆民  张劲松  马秀玲 《林业科学》1998,34(2):11-16

本文以农林复合生态系统气候特征及防尘效应进行了研究。结果表明,在沙质土壤类型区,农林复合生态系统具有较高的动力和水文效应,是减少降尘的直接原因,防风效能愈强,防尘效果愈好,农林复合生态系统能够有效地减少尘埃输送量,同时能减少降尘量达２０％～６０％;防风效能,乱流交换强度,土壤湿度是决定降尘量大小的主要因子。  相似文献   

光照亏缺对橡胶-作物农林复合系统中作物生产力的影响     

黄坚雄  潘剑  周立军  袁淑娜  林位夫 《中国生态农业学报》2020,28(5):680-689

为探明农林复合系统中光照亏缺对不同间作作物生产力的影响,以橡胶-豆薯和橡胶-花生农林复合模式为研究对象,测定光照强度、作物生物量、光合生理等指标,研究光照亏缺对不同喜光间作作物生产力的影响及可能的影响因素。结果表明,复合系统中间作区域的光照强度日变化呈单峰型,间作区域平均光照强度为裸地对照的51.3%～59.0%。间作作物的产量显著低于相应单作处理(P0.05);间作豆薯产量可达22.9 t×hm~(-2),为单作处理的85.3%;而间作花生产量仅为单作处理的39.2%。光照亏缺环境对间作豆薯和花生不同位置叶片的RuBisCO活性没有显著影响,但显著提高叶绿素(特别是叶绿素b)含量,降低类胡萝卜素含量(P0.05),其光合能力亦低于相应单作处理。复合系统中间作豆薯叶面积高于单作豆薯,而间作花生叶面积则较单作花生显著降低59.1%～88.4%(P0.05)。综上所述,豆薯比花生更适合在橡胶-作物农林复合系统中进行间作,间作豆薯应该是通过维持较高的叶面积来捕获光能并制造更多的光合产物,从而维持相对较高的生产力。  相似文献   

Long-term effects of intensive rice–wheat and agroforestry based cropping systems on build-up of nutrients and budgets in alluvial soils of Punjab,India     

Salwinder Singh Dhaliwal  Rama Krishna Naresh  Maninder K. Walia  Raj K. Gupta  Rajveer Singh 《Archives of Agronomy and Soil Science》2020,66(3):330-342

ABSTRACT

A detailed study was conducted to investigate the long-term effects of rice–wheat and poplar-based agro-forestry systems existing on a large area for last 25 years on the distribution of macro as well as micronutrients in surface soils, as well as their profiles. To achieve these objectives, profile soil samples (0–150 cm) were collected from 10 randomly scattered locations each from rice–wheat and poplar-based agro-forestry systems and analyzed for various physico-chemical properties. The results of our investigation revealed that pH, EC, OC available N, P and K reported significantly higher levels in agro-forestry as compared to rice–wheat system. On the other hand, DTPA-extractable and total Zn, Cu, Fe and Mn were significantly higher in D1 (0–15 cm), D2 (15–30 cm) and D3 (30–45 cm) depths of rice–wheat system which may be attributed to the reduced conditions prevailing during rice crop. Nutrient budgeting also assessed the impact of crop removal and fertilizer inputs along with recycling of crop residue and leaf litter. Also, the build-up of available nutrient status in surface layer (0–15 cm) and soil profiles (0–150 cm) continuously under these two systems helped in maintaining agricultural sustainability and soil fertility over a long period of time.  相似文献   

孟加拉国Dinajpur农林复合区内不同树种和作物种中丛枝菌根分布和孢子群落多样性的研究     

M. A. U. Mridha　P. P. Dhar 《林业研究》2007,18(2):91-96

从孟加拉国Dinajpur地区采集了不同农林复合区内树种和作物种,对采集植物的丛枝菌根多样性进行了研究.在3个取样地采集了18种植物的根和根际土,取样地和被采取植物分别为：取样地Dashmail为黄豆树 （Albizia procera Benth.）、小指椒 （Capsicum frutescens L）、姜黄（Curcuma domestica Vahl）、印度黄檀 （Dalbergia sissoo Roxb.） 和大叶桃花心木（Swietenia macrophylla）5种植物; 取样地Kantaji为姜黄（C.Domestica）、印度檀 （D.Sissoo）、赤桉 （Eucalyptus camaldulensis Dehnn.）、石梓（Gmelina arborea （Roxb） DC） 和水稻 （Oryza sativa L.） 5种植物; 取样地Ramsagar为姜黄（C.Domestica）, 印度檀 （D.Sissoo）, Litchi chinensis Sonn.和水稻.在取样地Dashmail,植物丛枝的分布范围在36%-79%,其中分布最高的是小指椒,达到79%,而C.Domestica仅占36%.取样地 Kantaji丛枝的分布范围在33%-70%之间,其中分布最高的是石梓,达到79%,而O.Sativa分布最低,仅36%.取样地 Ramsagar丛枝的分布范围在35%-70%之间,印度檀丛枝分布在该地最高, 达70%,而水稻丛枝在该地的分布最小,仅35%.在采样地Dashmail,每100克干土中所含采样植物丛枝菌根孢子群落54-140个;孢子群落最多的是印度檀（140/100g dry soil）,最低的是姜黄（C.Domestica） （40/100g dry soil）.在采样地Kantaji,孢子群落在63-221/100g dry soil,石梓具有的群落最高,为221/100g dry soil;印度檀为63/100g dry soil.在采样地Ramsagar, 所具有的最高和最低群落分别是 160/100g dry soil （D.Sissoo）和69/100g dry soil（L.Chinensis）.土壤Ph值与土壤中丛枝分布和菌根孢子群落无显著相关性.Simpson多样性指数和Shannon多样性指数在取样地Kantaji 的印度檀土壤中最高;而在取样地Ramsagar的水稻土壤中最低.研究表明孟加拉国Dinajpur地区丛枝菌根的存在、树种和作物种中的营养性质、丛枝菌根的必要性和贡献以及复合农林植物生长与丛枝?  相似文献   

Effects of phosphorous fertilizer on seedlings growth and nodulation capabilities of some popular agroforestry tree species of Bangladesh   总被引：1，自引：0，他引：1  

Mohammad Belal Uddin Sharif Ahmed Mukul Mohammed Abu Sayed Arfin Khan Mohammed Kamal Hossain 《林业研究》2007,18(4):283-286

An experiment was conducted to assess the effect of Phosphorous （P） fertilizer （i.e. TSP or triple super phosphate @ 80 kg/hm^2） on seedling growth and nodulation capabilities of three potentially important agroforestry tree species （Acacia auriculiformis, Albizia lebbeck and Albizia procera） of Bangladesh. The study was conducted in nursery beds with six-month-old polybag seedlings ofA. auriculiformis, A. lebbeck and A. procera. The effects of P fertilizer on seedling growth and nodulation were compared with that of the seedlings grown in control （i.e. unfertilized soil）. The observations revealed that the seedling growth was enhanced significantly with the application of P fertilizer. The growth was found more pronounced in A. auriculiformis, whereas it was not apparent and shows depressed growth in case ofA. lebbeck. The study also suggests that the nodulation in terms of nodule number and size was also increased significantly with the application of P fertilizer.  相似文献   

Factors determining the occurrence of the agroforestry system withAcacia mearnsii in Central Java     

Luciënne M. Berenschot  Bram M. Filius  Soedarwono Hardjosoediro 《Agroforestry Systems》1988,6(1-3):119-135

In 1922, the colonial government introducedAcacia mearnsii in the tobacco-growing region of Wonosobo. Soon this species was accepted by the local people who developed an agroforestry system based on a rotation ofA. mearnsii and agricultural crops. Now, the growing of the black wattle is becoming less popular. To study the prospects for this agroforestry system 143 farmers from 5 villages were interviewed. The functions of this agroforestry system are the production of fuelwood and bark (which contains tannin for the leather industry), soil conservation and soil improvement. The following factors affectA. mearnsii growing: population density (which affects farm size and demand for domestic fuelwood), tobacco-processing (which requires fuel), topography and commercialization. If current trends continue, the contribution of the functions of this agroforestry system to welfare will not be sufficient to compete successfully with subsistence and cash crops like potatoes and tobacco. Therefore,A. mearnsii cultivation is expected to decline further. This article was written within the framework of the cooperation between the two departments in the Forestry and Nature Conservation (FONC) project sponsored by the Netherlands University Foundation For International Cooperation (NUFFIC).  相似文献   

核桃中药材不同复合经营模式土壤肥力综合评价   总被引：1，自引：0，他引：1  

肖良俊  谢正万  张传光  杨根林  缪福俊  吴涛  宁德鲁 《东北林业大学学报》2021,49(1):91-95

选择核桃与5种中药材的复合经营模式,即核桃+滇黄精(H+H)、核桃+云木香(H+M)、核桃+白及(H+B)、核桃+滇重楼(H+C)、核桃+秦艽(H+Q)及以核桃林(CK)为对照,2.5 a后对6种经营模式土壤的pH值,有机质、全量元素、速效元素和矿质元素质量分数进行测定比较分析,并采用灰色关联分析对6种经营方式进行土壤肥力综合评价。结果表明:在土层深(h)0相似文献