The effects of nitrogen fertilization and soil properties on mycorrhizal formation of Salix viminalis

The effects of nitrogen fertilization (100, 200 kg N ha⁻¹ per year) and soil properties on mycorrhizal formation on Salix viminalis were investigated at three short rotation plantations on Gleysols and Cambisols (Abbachhof (ABB) and Wildeshausen (WIL) in Germany, Ultuna (ULT) in Sweden). During 3 years the ectomycorrhizal colonization, the composition of ectomycorrhizal morphotypes and the VAM spore density in the soil were analyzed. The ectomycorrhizal colonization was significantly altered due to N-fertilization at all sites. The quality and magnitude of the fertilization effects on mycorrhizal formation on Salix viminalis varied due to the soil properties, i.e. soil texture, soil N content and pH. The WIL site was characterized by sandy soil (low pH, high soil N content), whereas the ABB site was characterized by clayey soil (high pH, low N content). The ULT site was characterized by clayey soil (high pH, high N content). In the unfertilized control plots (C), ectomycorrhizal colonization was higher at WIL than at ABB. Fertilization reduced the ectomycorrhizal colonization at WIL but increased it at ABB. The distribution of the ectomycorrhizal morphotypes was very heterogeneous within the treatments, therefore significant differences were rare. Sporocarps were collected at ABB during one growing period. The sporocarps were mostly from saprophytic species, with exception of the ectomycorrhizal species Inocybe glabripes. Significant effects of N-fertilization on VAM spore density were observed at two of the three plantations. The pattern in VAM spore density was similar to the pattern seen for ectomycorrhizal colonization. Thus, VAM spore density was increased by fertilization at ABB (low soil N) and decreased at ULT (high soil N). The soil properties have been shown to modify the effects of fertilization on ectomycorrhizal colonization and VAM spore density. Therefore, in management practice of short rotation plantations, the benefit of N-fertilization should be evaluated keeping secondary effects caused by changed mycorrhizal formations in mind.     

Evaluation of tropical forage legumes under Pinus caribaea var hondurensis in Turrialba,Costa Rica

A number of tropical forage legume species were sown in Turrialba., Costa Rica, in plots in the open and under an even cover of Pinus caribaea var hondurensis of basal area 30m²/ha. Mean light level under the trees was 18% full sunlight. After 19 months, species showing good shade tolerance and adaptation to local conditions were: Centrosema spp., Desmodium spp., Flemingia congesta, Galactia striata. Species of poor performance in the shade were: Stylosanthes spp., Indigofera hirsuta, Cajanus cajan, Stilozobium sp.. Canavalia ensiformis, an annual, grew well in the shade, as did Lablab purpureus and Vigna unguiculata. It is suggested that further work be done on the shade tolerant species for eventual use as components of silvopastoral systems. Recommendations are made concerning germplasm collections, evaluation methodology and research for silvopasture development.

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Resumen Se sembraron especies diversas de leguminosas forrajeras en Turrialba, Costa Rica, en parcelas al descubierto y bajo una cobertura uniforme de Pinus caribaea var hondurensis con area basal de 30 m²/ha. El nivel medio de iluminación bajo los pinos era 18% del nivel a pleno sol. Despues de 19 meses las especies que mostraron buena adaptación a la sombra eran: Centrosema spp., Desmodium spp., Flemingia congesta, Galactia striata. Especies de bajo rendimiento en la sombra eran: Stylosanthes spp., Indigofera hirsuta, Cajanus cajan, Stilozobium sp., La planta anuál Canavalia ensiformis creció bien bajo sombra, como tambien lo hicieron Lablab purpureus y Vigna unguiculata. Se sugiere que se investiguen las especies mencionadas como bien adaptadas al sombreamiento para uso en sistemas silvopastoriles. Se presentan recomendaciones sobre colecciones de germoplasma, metodologia de evaluación y investigación para el desarollo de sistemas silvopastoriles.

     

Perennial crop-based agroforestry systems in Northeast Brazil

Land use systems in the Northeast Region of Brazil are dominated by large holdings and extensive cultivation of perennial crops such as cashew, coconut, carnauba wax palm, babaçu palm and so on. The common feature which links these crops is the silvopastoral system of livestock (chiefly cattle, sheep and donkeys) grazing under them. Agrosilvicultural systems involving cultivation of annual subsistence crops, and in some instances other perennials, in the stands of these perennial crops is also common. The paper presents the available information on the management, production, rate of growth, economic importance, etc. of these agroforestry systems involving cashew, coconut and carnauba palm. These systems are of considerable merit in the environmental, agricultural and socio-economic conditions of Northeast Brazil. However, practically no research nor even systematic data collection has been done on these so that there is an almost total lack of information on them. In order to improve the systems, they should be studied in detail and research undertaken on various components (crops, trees and livestock) individually as well as the system as a whole. Selection of suitable species of grass and other herbaceous crops, appropriate management techniques for both overstorey and understorey species in relation to the age of the overstorey species, optimal stocking rates of animals, etc. have to be determined so as to enable plantation owners and operators to realize the full potential of these systems.     

Surgical repair of a full-thickness ear pinna defect in a horse

A 5-year-old gelding used for showing was presented for surgical repair of a full-thickness 15 mm diameter defect in the right pinna, which had occurred as a delayed complication following laser excision of a sarcoid. The defect had resulted in progressive deformity of the ear, and the horse was considered at risk of further injury if the defect became entrapped on a fixed object. Two artificial dermis meshes were inserted to encourage the formation of granulation tissue across the defect, and a commercially available skin expander was implanted adjacent to the site. Eighteen days later, a second surgery was performed to remove the skin expander and to mobilise a local rotational skin flap to close the defect. Both surgeries were performed under standing sedation and local anaesthesia. The site healed well, avoiding further potential trauma to the ear and deformity due to tissue contracture at the site, although some deformation of the lateral aspect of the cartilage remained.     

坐标旋转订正对农田林网水热通量测算精度的影响

农田防护林的特殊结构使附近农田地表大气运动形成了特有的动力学和热力学效应,影响着周边物质和能量交换过程。坐标旋转订正方法的选择成为提高农田防护林水热通量测算精度的核心问题,选取2012年3月9日至5月7日共60 d的防护林网内农田的涡动相关观测数据,对相关湍流特征及能量闭合率等关键参数进行坐标旋转订正并进行比较,结果表明:(1)在整个试验过程中,采用平面拟合法进行坐标旋转时,当订正参数的计算周期小于15 d时,x-z平面内旋转角度有一定的波动,而在计算周期大于15 d后,则基本维持在-2.8°左右。采用二次旋转法订正的x-z平面内旋转角度受原始水平风向的影响始终很大;(2)2种坐标旋转方法对于三维风速的处理结果基本一致,在风速较大的情况下,需要考虑坐标旋转方法的选择对结果的影响。二次旋转方法订正后的垂直风速全部为零,平面拟合方法订正后的垂直风速接近于0;(3)平面拟合订正后摩擦风速基本与订正前一致,而二次旋转方法订正后的结果增大了将近5%;(4)平面拟合方法对显热通量及潜热通量的订正误差较小,二次旋转方法则分别将原始测得值提高了5%左右;(5)防护林网通量的能量闭合率经过平面拟合订正后提高了17%,而经过二次旋转法订正后则提高了30%。总之,坐标旋转方法可以对观测设备倾斜引起的误差进行订正,订正后的结果比订正前更精确。二次坐标旋转方法因为可以订正较短时间段内的单组数据,比较适用于下垫面情况变化较快时的观测;平面拟合方法适用于观测系统及其周围环境在整个测量过程中相对稳定时的观测。二次旋转方法对防护林网水热通量订正更好。     

Effects of intercropping systems of trees with soybean on soil physicochemical properties in juvenile plantations

The intercropping system of tree with soybean in juvenile plantations, as a short-term practice, was applied at Lao Shan Experimental Station in Mao’er Shan Forest of Northeast Forestry University, Harbin, China. The larch (Larix gmelinii)/soybean (Glycine max.) and ash (Fraxinus mandshurica) intercropping systems were studied in the field to assess the effects of the intercropping on soil physicochemical properties. The results showed that soil physical properties were improved after soybean intercropping with larch and ash in one growing season. The soil bulk density in larch/soybean and ash/soybean systems was 1.112 g·cm⁻³ and 1.058 g·cm⁻³, respectively, which was lower than that in the pure larch or ash plantation without intercropping. The total soil porosity also increased after intercropping. The organic matter amount in larch/soybean system was 1.77 times higher than that in the pure larch plantation, and it was 1.09 times higher in ash/soybean system than that in the pure ash plantation. Contents of total nitrogen and hydrolyzable nitrogen in larch/soybean system were 4.2% and 53.0% higher than those in the pure larch stand. Total nitrogen and hydrolyzable nitrogen contents in ash/soybean system were 75.5% and 3.3% higher than those in the pure ash plantation. Total phosphorus content decreased after intercropping, while change of available phosphorus showed an increasing trend. Total potassium and available potassium contents in the larch/soybean system were 0.6% and 17.5% higher than those in the pure larch stand. Total potassium and available potassium contents in the ash/soybean system were 56.4% and 21.8% higher than those in the pure ash plantation. Biography: FAN A-nan (1972–), female, Ph. Doctor in Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, P. R. China.     

CamFlores: A FLORES-type model for the humid forest margin in Cameroon

A FLORES-type model in the Simile modelling environment is being developed for three villages in the Humid Forest Benchmark area of southern Cameroon. The modelling project seeks to investigate the effects of introduction of new crop varieties and improved farming systems on the long-term maintenance of stable mosaics of forest and agriculture, within the context of the international Alternatives to Slash and Burn programme. Biophysical data have been collated, and socio-econnomic and tenure data have been acquired in spatially-explicit ways. Maps of land-cover at village and benchmark scale are being prepared from detailed and semi-detailed satellite imagery, using a nested legend system that allows linking of maps at different scales. These data enable the initial construction and parameterisation of the model, and will permit the extrapolation of the results of modelling from the villages to the benchmark, and ultimately to the whole of the Congo Basin humid forests. The prototype version of the model involves 10 households and about 500 land patches, and includes the three agricultural systems dominant in the southern more forested portion of the Benchmark (mixed food-fallow systems, forest melon fields, cocoa plantations) with no rental, sale or other transfer of land. Decision-making at the household level is essentially modelled deterministically, and labour productivity is assumed to be constant between households. This model is now complete, and once it has been adjusted and suitably parameterised, it will be applied to real data from the three test villages. This will require the addition of new farming systems, the introduction of modes of permanent or temporary transfer of land, and modification of the decision model to render it more realistic. The work described in this paper is a part of a project funded by the European Union through ICRAF and hosted at the IITA Humid Forest Ecoregional Centre, Cameroon. The assistance of Valentina Robiglio (JPO GIS specialist), especially in preparation of land-cover maps and in collection of socio-economic data, is gratefully acknowledged, as is the work of IITA ASB village facilitators in collection of field data. The cooperation of IITA, IRAD, CIFOR and ICRAF scientists in providing data for the model and periodically reviewing progress with the modelling process was essential to the progress achieved thus far.     

Studies withGliricidia sepium for crop/livestock production systems in West Africa

This paper reports for progress of research onGliricidia sepium conducted by the Humid Zone Programme (HZP) of the International Livestock Centre for Africa (ILCA) at Ibadan in Southwest Nigeria in the period 1982–1986. It examines the biological characteristics of the species, with respect to growth, flowering and seed production, and analyses its potential for improving crop production (through soil fertility maintenance) and livestock production (through production of improved fodder). Integration ofGliricidia into cropping systems is necessary for optimum realisation of its crop improvement quality. The alley farming system is presented in the paper as one means of achieving sustainability in crop production through integration of trees, such asGliricidia, into cropping systems. The use ofGliricidia in Intensive Feed Gardens, for production of leguminous fodder is also described as an alternative production system. The paper finally reports on experiences with local farmers in on-farm research and development for the integration ofGliricidia andLeucaena into local farming systems. It ends with a suggestion for more research, targetted specifically at improvement of the species and its utilisation.     

Crop yields of rice and wheat grown in rotation as intercrops with three tree species in the outer hills of Western Himalaya

Studies on tree crop interaction under rainfed condition in Dehradun valley were conducted for 13 years during 1977 to 1990. Grewia optiva (Bhimal), Morus alba (Mulbery) and Eucalyptus hybrid were tried along with rice (CV: Akashi) — wheat (CV: RR-21) rotation. One-year-old tree seedlings of the above tree species were planted in line, 5 m apart in N-S direction, in July 1977, in the middle of the plot (size 20 m × 20 m). Eucalyptus was first harvested in 1987. Grewia optiva, Morus alba and coppice of Eucalyptus were harvested in 1990. All tree species had depressing effect on crop yields. Eucalyptus had maximum effect in depressing crop yield till the first harvest and had least effect thereafter. From 1987 onwards, Morus alba affected rice most, while wheat was mostly affected by Grewia optiva. The depressing effect on an average varied from 28 to 34% depending upon the species.Distance of tree line from the crop significantly affected the crop yield upto a distance of 5 m and there was 39% decrease in crop yield upto 1 m, 33% from 1–2 m, 25% from 2–3 m and 12% from 3–5 m distance. Annual removal of lops and tops from trees partly compensated the deficit. Grewia optiva could produce 1.08 t ha^–1 yr^–1 of branches and 0.26 t ha^–1 yr^–1 of leaves (air dry) and 1.28 t ha^–1 yr^–1 of branches and 0.28 t ha^–1 yr^–1 of leaves were obtained from Morus alba. Wood (ADT) produced by the trees was 33.6 t ha^–1 from Eucalyptus, 9.5 t ha^–1 from Grewia optiva and 11.6 t ha^–1 from Morus alba.     

Structure and function of traditional agroforestry systems in the western Himalaya. II. Nutrient cycling

Budget of nutrient in plant and soil, and their rates of recycling in three types of traditional agroforestry systems in mid elevations of the western Himalaya were studied. Concentration of nitrogen and potassium was significantly higher in fruits and leaves than in branches, boles, and litter. Grewia optiva, an important fodder tree, was found to be rich in potassium, vegetable crops in nitrogen, and weeds in phosphorus. Maximum store of nutrients was estimated in aboveground biomass of agrihortisilvicultural system: nitrogen 532, phosphorus 40, potassium 461, calcium 400, and magnesium 298 kg/ha; it was closely followed by that in agrihorticultural system, and both these had sbout 2-fold higher nutrient stock as compared to agrisilvicultural system. In the case of the former two systems, considerable quantity of nutrients up to nitrogen 169, phosphorus 14, potassium 165, calcium 97, and magnesium 65 kg/ha, for example in agrihortisilvicultural system, was recycled through debris of crops and weeds, and tree leaf litter, while the recycling rate was almost half in agrisilvicultural system. Through ‘harvest’ potassium was depleted in the largest quantity from the system, followed by nitrogen, magnesium, calcium, and phosphorus; much higher loss occurred through agricultural and/or horticultural edible parts as compared to fuel and fodder biomass. For example, the loss through agricultural crops and horticultural fruits for nitrogen in agrihortisilvicultural system was up to 75 percent and 38 percent respectively of the total annual uptake. This heavy loss makes the system unstable from a nutrient point of view particularly for nitrogen and potassium until external inputs are added through organic and inorganic fertilizers. Agrihortisilvicultural system is remarkably efficient in view of biomass productivity for fuel, fodder and fruits, and also from nutrient point of view provided losses through harvest are compensated externally.