Tree row spacing affected agronomic and economic performance of Eucalyptus-based agroforestry in Andhra Pradesh, Southern India

The 3 × 2 m spacing currently used for eucalyptus plantations in the state of Andhra Pradesh, southern India does not permit intercropping from the second year. This discourages small landholders who need regular income from taking up eucalyptus plantations and benefiting from the expanding market for pulpwood. Therefore, on-farm experiments were conducted near Bhadrachalam, Khammam district (Andhra Pradesh) for over 4 years from August 2001 to November 2005 to examine whether wide-row planting and grouping of certain tree rows will facilitate extended intercropping without sacrificing wood yield. Eucalyptus planted in five-spatial arrangements in agroforestry [3 × 2 m (farmers’ practice), 6 × 1 m, 7 × 1.5 m paired rows (7 × 1.5 PR), 11 × 1 m paired rows (11 × 1 PR) and 10 × 1.5 m triple rows (10 × 1.5 TR)] was compared with sole tree stands at a constant density of 1,666 trees ha^?1. Cowpea (Vigna unguiculata) was intercropped during the post-rainy seasons from 2001 to 2004, and fodder grasses (Panicum maximum and Brachiaria ruziziensis) were intercropped during both the seasons of 2005. At 51 months after planting, different spatial arrangements did not significantly affect height and diameter at breast height (dbh). Total dry biomass of eucalyptus in different spatial arrangements ranged between 59.5 and 52.9 Mg ha^?1, the highest being with 6 × 1 m and the lowest with 10 × 1.5 TR, but treatment differences were not significant. The widely spaced paired row (11 × 1 PR) and triple row (10 × 1.5 TR) arrangements produced 62–73% of sole cowpea yield in 2003, 59–66% of sole cowpea yield in 2004, and 79–94% of sole fodder in 2005. In contrast, the 3 × 2 m spacing allowed only 17–45% of sole crop yields in these years. The better performance of intercrops in widely spaced eucalyptus was likely because of limited competition from trees for light and water. Intercropping of eucalyptus in these wider rows gave 14% greater net returns compared with intercropping in eucalyptus spaced at 3 × 2 m, 19% greater returns compared with that from sole tree woodlot and 263% greater returns compared with that from sole crops. Therefore, in regions where annual rainfall is around 1,000 mm and soils are fairly good, eucalyptus at a density of 1,666 plants per ha can be planted in uniformly spaced wide-rows (6 m) or paired rows at an inter-pair spacing of 7–11 m for improving intercrop performance without sacrificing wood production.     

Forage production of woody fodder species and herbaceous vegetation in a silvopastoral system in northern Greece

Introduction of woody plants in silvopastoral systems could be an appropriate land-use for the poor sandy soils of the Mediterranean semiarid zone. Forage production of four woody fodder species and herbaceous vegetation in relation to plant spacing and animal (sheep) grazing was studied in a silvopastoral system on such a site in Macedonia, northern Greece. The woody fodder species tested were Robinia pseudoacacia L., Gleditsia triacanthos L., Amorpha fruticosa L. and Morus alba L. They were planted at the spacings 1.5 × 1.5 m,2.5 × 2.5 m and 3.5 × 3.5 m and kept in a shrubby form by topping. They were grazed by sheep (stocking rate of 1.1 sheep/ha/year) in early July and late August of 1992, 1993 and 1994. Among the species Robinia yielded the highest forage production (394 kg/ha). The spacing 1.5 × 1.5 m had the highest (P ≥ 0.05) forage production per area unit (280 kg/ha) while the spacing 3.5 × 3.5 m had the highest forage production per plant (91.8 g/plant). No competition was observed between the woody and the herbaceous plants in the various spacings probably due to topping of the woody species every winter. Percent utilisation of the native herbage dropped as forage of the woody species increased. This revised version was published online in June 2006 with corrections to the Cover Date.     

Variation of soil enzyme activity and microbial biomass in poplar plantations of different genotypes and stem spacings

To improve the productivity of poplar plantations, a field experiment of split-plot design with four tree spacings and three poplar clones was established, and four soil enzyme activities and microbial biomass were monitored in the trial.Soil enzyme activities, in most cases,were significantly higher in topsoil(0–10 cm) than in lower horizons(10–20 cm).Soil cellulase, catalase and protease activities during the growing season were higher than during the non-growing season, while invertase activity followed the opposite trend.Soil invertase, cellulase and catalase activities varied by poplar clone but soil protease activity did not.Cellulase and protease activities in the plantation at 5×5 m spacing were significantly higher than in the other spacings.The highest catalase activity was recorded at 6×6 m spacing.At the same planting density, invertase activity was greater in square spacings than in rectangular spacings.Soil microbial biomass was also significantly affected by seedling spacing and poplar clone.The mean soil MBC was significantly lower in topsoil than in the lower horizon, while MBN showed the opposite pattern.Significantly positive correlations were observed among soil cellulase, protease and catalase activities(p0.01), whereas soil invertase activity was negatively and significantly correlated with cellulase, protease and catalase activities(p0.01).Soil microbial biomass and enzyme activities were not correlated except for a significantly negative correlation between soil MBC and catalase activities.Variations in soil enzyme activity and microbial biomass in different poplar plantations suggest that genotype and planting spacing should be considered when modeling soil nutrient dynamics and managing for long-term site productivity.     

Performance of maize, beans and ginger as intercrops in Paulownia plantations in China

Yield, morphology and specific leaf weight of summer crops maize, beans and ginger were studied in relation to tree proximity and PAR transmissivity in a 7-year old plantation of Paulownia elongata grown at a spacing of 15 m x 5 m in Eastern China. The yield of beans and maize was significantly reduced, compared to controls, at all positions relative to the trees. This yield depression was particularly marked at positions closest to the trees. Beans grown at 2 m from the trees had reduced height and specific leaf weight. These crops would yield more at wider tree row spacings. Ginger gave high yields when intercropped and is an ideal shade crop for these systems. Further research is required on optimisation using a bioeconomic approach. Further agronomic, physiological and biochemical work is required on ginger and other economic members of its family as these appear to have compatibility with dense agroforestry plantings. This revised version was published online in August 2006 with corrections to the Cover Date.     

Improving agroforestry in Nigeria: Effect of plant density and interaction on crop production

The performance of Gmelina arborea forest tree crop and the yields of food crops as affected by their planting distances and crop combinations when intercropped in an agroforestry farm were investigated in six different ecological areas of southern Nigeria. The percentage survival and mean height of Gmelina arborea were not significantly affected by the different planting densities of Gmelina and food crops. However, the yields of yams (Dioscorea rotundata), maize (Zea mays) and cassava (Manihot utilissima) depended greatly (P = 0.01) on the planting densities of these food crops. Yams and maize were found to combine adequately with young Gmelina tree crop at spacings of 1 × 1 m and 2.5 × 2.5 m for the food and forest crops respectively in the areas studied.     

Agroforestry in Europe: a review of the disappearance of traditional systems and development of modern agroforestry practices, with emphasis on experiences in Germany

Agroforestry is a new name for a rather old practice. From a historical point of view, various agroforestry systems existed in Europe, of which the wood pastures (Neolithicum), the Dehesas in Spain (~4,500 years old) and the Hauberg of the Siegerland (established in the Middle Age) are the most prominent. Other widespread systems in Europe were hedgerows, windbreaks and Streuobst (orchard intercropping). Due to mechanisation and intensification of agriculture, trees have been progressively removed from agricultural fields and traditional agroforestry systems slowly disappeared. Today, agroforestry systems are again increasing in interest as they offer the potential to solve important ecological and, especially, biodiversity problems, while at the same time enabling the production of food, wood products and fodder for cattle. Although agroforestry systems offer many advantages, many farmers are sceptical of these systems and are critical and risk-averse with regard to adopting new practices. However, in comparison to traditional systems, modern agroforestry systems can be adapted to current farming practices. By selecting suitable trees and appropriate tree management, high-quality timber can be produced without influencing agricultural crops excessively. In future, agroforestry systems will become increasingly important as they offer the prospect of producing woody perennials for bioenergy on the same land area as food and/or fodder plants, while enhancing overall biodiversity.     

Fuelwood production from Leucaena leucocephala established in fodder crops at Mtwapa,Coast Province,Kenya

Fuelwood production from a high density leucaena-based fodder production experiment at Mtwapa, Coast Province, Kenya is reported. Leucaena with and without other fodder crops namely, Cassava, Bana and Napier grass, formed the main-plot treatments while leucaena densities ranging from 6,250 to 100,000 ha^–1 planted in single- or double-line planting arrangements formed the sub-plot treatments of the split-plot design used. Each treatment was replicated four times. The experiment was established and maintained without the use of fertilizer, pesticides, irrigation. Hand weeding was done only during the first year.After 2.7 years growth, height and diameter measurements were taken before cutting back the leucaena stems to 0.5 m above ground. Utilizable fuelwood (twigs greater than 0.5 mm diameter) was then sun-dried for 3 months and dry weights taken.Fuelwood yields were significantly reduced by the fodder intercrops. Yield from leucaena intercropped with fodder crops were, on average, 30% lower than yield from sole stands of leucaena. Mean yields of the single-line plantings ranged from 13.7 to 21.2 tons ha^–1. Yield from the double-line plantings were lower (on average 10%) than that of single-line plantings and were as well highly variable. Unlike tree heights, diameters in the single-line planting arrangement were not affected significantly by the fodder intercrops. In the single line plantings, yield of fuelwood from sole stand of leucaena was higher at all in-row spacings than the yield from intercropped leucaena. Increase in in-row spacing of leucaena generally led to reduced yield of fuelwood.Fodder yields of intercropped Cassava, Bana and Napier grasses were near normal in the first year but zero or negligible in the remaining 1.7 years. Implications of the prolonged tree establishment period on fodder yields after opening of the canopy are discussed.     

Soil water competition in a temperate hedgerow agroforestry system in South Africa

An on-farm trial was conducted to determine dry matter production of four fodder tree species and their effect on soil water and maize production. The trees were planted in rows intercropped with maize. The four tree species selected were Acacia karroo Hayne (indigenous fodder tree), Leucaena leucocephala (Lam.) De Wit (nitrogen fixing), Morus alba L. (fodder and fruit), and Gleditsia triacanthos L. (fodder and fuel). Volumetric soil water was measured in the upper 0.3 m of soil in each row of the trial using the time domain reflectometry technique. The neutron probe technique was used for monitoring the water content deeper in the soil. Geostatistical methods were used to analyse treatment differences in the upper 0.3 m of soil. The soil water content did not differ significantly between the maize and tree rows indicating that competition for water in the upper horizon was not the reason for lower maize yields. However, at greater soil depths (75–125 cm) trees in the wide spacing used less water than those in the narrow spacing. Light interception was an important factor in reducing maize yields in the row nearest to the trees. High soil water values recorded during summer indicated that in the current cycle of good rainfall the plants in the agroforestry trial were not stressed. Thus the trees do not compete with the crops for soil moisture in good rainfall seasons. However, this study would need further evaluation for the competition for water for the low rainfall years. Since the trees have access to water at greater depths, they are likely to be more productive into the dry season than shallow rooted crops.     

Nutrient contents of the leaves of the fodder tree Artocarpus Lakoocha Roxb

Artocarpus lakoocha Roxb. of the Moraceae family is cultivated in Nepal as a fodder tree. The crude protein, crude fibre and mineral contents of the fodder tree leaves were investigated during the lopping season from November 1980 to March 1982 at 800 m, 1200 m and 1550 m in eastern Nepal. The crude protein content varied from 122 to 131 g/kg DM and the crude fibre content, which seemed to remain generally low during the lopping season, varied from 171 to 202 g/kg DM. P, K, Mg, S, Mn, Fe, Cu, Zn and B concentrations in the leaves were found to be at levels which would meet the dietary requirements of cattle performing better than those found in Nepal.     

Traditional agroforestry practices in Zimbabwe

Traditional agroforestry systems in the communal areas of Zimbabwe are described. There are systems centered on main fields, on home gardens, on homesites and on grazing areas. In the main fields, the major tree-related management practice is the conservation of preferred indigenous fruit trees. Fruit trees are also the focus of forestry activities around the gardens and the homesite; but here it is the planting of exotic species. In a localized area of Zimbabwe Acacia albida is important in fields. There is almost no use of tree fallows in Zimbabwe. Trees in grazing areas have numerous roles, but at present there is little knowledge about traditional management practices in these areas. In the development of agroforestry systems in Zimbabwe it is suggested that those systems designed to improve fodder production will make a significant contribution to farm productivity because of the importance of cattle in the farming system and the present fodder shortage. Interventions involving the planting of fruit trees are likely to be very successful, as there is much interest in such planting. Another area that needs to be developed is that of tree plantings to improve soil fertility.     

Carbon stocks and biomass production of three different agroforestry systems in the temperate desert region of northwestern China

Carbon sequestration potential of agroforestry systems has attracted worldwide attention following the recognition of agroforestry as a greenhouse gas mitigation strategy. However, little is known about carbon stocks in poplar–maize intercropping systems in arid regions of China. This study was conducted in the temperate desert region of northwestern China, a region with large area of poplar–maize intercropping systems. The objective of this study was to assess biomass production and carbon stock under three poplar–maize intercropping systems (configuration A, 177 trees ha^?1; configuration B, 231 trees ha^?1; and configuration C, 269 trees ha^?1). We observed a significant difference in the carbon stock of poplar trees between the three configurations, with the highest value of 36.46 t ha^?1 in configuration C. The highest carbon stock of maize was achieved in configuration B, which was significantly higher than configuration A. The grain yield was highest in configuration A, but there was no significant difference from the other two configurations. In the soil system (0–100 cm depth), the total carbon stock was highest in configuration C (77.37 t ha^?1). The results of this study suggest that configuration C is the optimum agroforestry system in terms of both economic benefits and carbon sequestration.     

Early growth of Eucalyptus camaldulensis under agroforestry conditions at Mafiga,Morogoro, Tanzania

The growth of Eucalyptus camaldulensis clean weeded, spot weeded and intercropped with maize and beans was studied. At 4 m × 4 m and 5 m × 5 m spacings trees were significantly shorter after 15 months under a conventional spot weeding regime than with clean weeding or intercropping with beans. A satisfactory maize yield (683 kg ha^?1) was recorded from plots with trees spaced at 5 m × 5 m. Plots where trees were spaced at 4 m × 4 m and 3 m × 3 m gave significantly lower yields (444 kg ha^?1 and 283 kg ha^?1, respectively).     

Arbuscular mycorrhizal association of indigenous agroforestry tree species and their infective potential with maize in the rift valley, Ethiopia

Tree species in agroforestry are important source of inoculum for companion agricultural crops. Agroforestry trees can serve as a source of Arbuscular mycorrhiza (AM) inoculants to intercropped annuals. We studied spore abundance, root colonization of Albizia gummifera (J.F. Gmel.) and Croton macrostachyus (Hochst Ex Del.) trees and their effect on colonization of maize. Soil and root samples were collected from field standing trees from under and outside the canopy of trees and maize crops in the main rainy season. The number of spore count was significantly higher under the canopy of A. gummifera (791/100 g of dry soil) and C. macrostachyus (877/100 g of dry soil) trees than outside the canopy (547 and 588/100 g of dry soil, respectively). The level of root colonization of C. macrostachyus (45 %) was higher than A. gummifera (41 %). Root colonization of maize crops grown under the canopy of A. gummifera and C. macrostachyus trees was significantly higher than outside the canopy (P < 0.001). Maize seedlings grown on non-sterilized soils collected under and outside the canopy of A. gummifera and C. macrostachyus trees recorded higher root colonization, plant height, shoot and root dry weight than grown on sterilized soils (P < 0.001). The percentage of AM colonized roots of Zea mays seedlings was significantly positively correlated with the number of spore counts for field soils. The rhizospheres of indigenous agroforestry perennial species are important source of inoculum for annuals. The integration of perennials and annuals in an agroforestry system enhances the maintenance of soil quality in the tropics.     

Effects of clump spacing on nutrient distribution and root activity of <Emphasis Type="Italic">Dendrocalamus strictus</Emphasis> in the humid region of Kerala,peninsular India

The humid agroclimatic conditions of Kerala, India permit the cultivation of an array of bamboo species of which Dendrocalamus strictus Roxb. (Nees.) is an important one on account of its high growth rate and multiple uses. Stand density, a potential tool in controlling the productivity of woody ecosystems, its effect on growth and root distribution patterns may provide a better understanding of productivity optimization especially when bamboo-based intercropping options are considered. Growth attributes of 7-year-old bamboo (D. strictus) stands managed at variable spacing (4 × 4 m, 6 × 6 m, 8 × 8 m, 10 × 10 m, 12 × 12 m) were studied. Functional root activity among bamboo clumps were also studied using a radio tracer soil injection method in which the radio isotope ³²P was applied to soil at varying depths and lateral distances from the clump. Results indicate that spacing exerts a profound influence on growth of bamboo. Widely spaced bamboo exhibited higher clump diameters and crown widths while clump heights were better under closer spacing. Clump height was 30% lower and DBH 52% higher at the widest spacing (12 × 12 m) compared to the closest spacing (4 × 4 m). With increasing soil depth and lateral distance, root activity decreased significantly. Root activity near the clump base was highest (809 counts per minute, cpm; 50 cm depth and 50 cm lateral distance) at 4 × 4 m. Tracer study further showed wider distribution of root activity with increase in clump spacing. It may be concluded that the intensive foraging zone of bamboo is within a 50-cm radius around the clump irrespective of spacing. N, P and K content in the upper 20 cm was 2197, 21, and 203 kg/ha respectively for the closely spaced bamboo (4 × 4 m) which were significantly higher than corresponding nutrient content at wider spacings. About 50% of N, P and K were present within the 0–20 cm soil layer, which decreased drastically beyond the 20 cm depth. The results suggest that stand management practices through planting density regulation can modify the resource acquisition patterns of D. strictus which in turn can change growth and productivity considerably. Such information on root activities, spatial and temporal strategies of resource sharing will be helpful in deciding the effective nutrition zone for D. strictus. Further, the study throws light on the spatial distribution of non-competitive zones for productivity optimization yields, especially when intercropping practices are considered.     

Effect of gap size on mid-rotation stand structure and species composition in a naturally regenerated mixed broadleaf forest

This paper is an assessment of the effect of gap size on stand structure and species composition 48 years following treatment in a mixed broadleaf upland forest. Established in 1960, the study tests three circular openings, 15.2 m (0.02 ha), 45.7 m (0.16 ha), and 76.2 m (0.46 ha). Forty-eight years following treatment (2008) basal area, top height, and quadratic mean diameter were significantly lower in 15.2 m openings. Maple (Acer spp.) species had the highest mean importance value across treatments (0.40). Trends suggest that species composition of dominant and codominant trees among opening sizes may have been influenced by shade tolerance adaptations of the species groups present. Whereas 15.2 m openings were dominated by shade tolerant maple species, 45.7 and 76.2 m openings produced a mixture of commercial species including shade intolerant species such as yellow-poplar (Liriodendron tulipifera L.), trees of intermediate shade tolerance like oak (Quercus spp.), and shade tolerant maple. Data further suggest the density of overstory oak was highest in the intermediate opening size (45.7 m), while yellow-poplar increased in the larger opening sizes. Evaluation of species shifts between 1981 and 2008 showed that relative basal area of maple increased across all treatments. Relative basal areas from 45.7 to 76.2 m openings suggest declines in yellow-poplar and other non-commercial species were balanced by increases in oak and maple.     

Growth and yield responses of cotton (<Emphasis Type="Italic">Gossypium hirsutum</Emphasis>) to inorganic and organic fertilizers in southern Malawi

Fertilizer trees, the nitrogen-fixing legumes, such as gliricidia (Gliricidia sepium) and tephrosia (Tephrosia spp.) have been used to improve soil fertility for higher crop yields in nitrogen deficient soils. Many studies have focused on how these fertilizer trees improve maize yield, but there has been a dearth of information on the effect of fertilizer tree species on cotton growth and yield. A study was undertaken for two cropping seasons (2012/13 and 2013/14) with the objective of assessing IRM 81 cotton growth and yield responses to tephrosia and/or gliricidia biomass with or without inorganic fertilizer application. Boll opening significantly varied (P < 0.0001) with treatments and early boll opening was observed in plots where only inorganic fertilizer was applied. Higher lint yield (mean of 1397 kg/ha) was obtained in the second cropping season than in the first cropping season (480 kg/ha) and the application of gliricidia biomass with fertilizer gave the highest lint yield (2121 kg/ha). The lowest lint and seed yields were obtained from plots where tephrosia biomass only was applied. It is concluded that the use of gliricidia biomass with inorganic fertilizer improved cotton yields. The high amount of gliricidia biomass (due to prolific coppicing) applied contributed to higher cotton lint yields with reduced rates of inorganic fertilizer application, making gliricidia-cotton intercropping a cost-effective option to smallholder farmers.     

Potential of the APSIM model to simulate impacts of shading on maize productivity

A number of agroforestry models have been developed to simulate growth outcomes based on the interactions between components of agroforestry systems. A major component of this interaction is the impact of shade from trees on crop growth and yield. Capability in the agricultural production systems simulator (APSIM) model to simulate the impacts of shading on crop performance could be particularly useful, as the model is already widely used to simulate agricultural crop production. To quantify and simulate the impacts of shading on maize performance without trees, a field experiment was conducted at Melkassa Agricultural Research Centre, Ethiopia. The treatments contained three levels of shading intensity that reduced incident radiation by 0 (control), 50 and 75% using shade cloth. Data from a similar field experiment at Machakos Research Station, Kenya, with 0, 25 and 50% shading were also used for simulation. APSIM adequately simulated maize grain yield (r² = 0.97) and total above-ground biomass (r² = 0.95) in the control and in the 50% treatments at Melkassa, and likewise in the control (r² = 0.99), 25% (r² = 0.90) and 50% (r² = 0.98) treatments at Machakos. Similarly, APSIM effectively predicted Leaf Area Index attained at the flowering (r² = 0.90) and maturity (r² = 0.94) stages. However, APSIM under-estimated maize biomass and yield at 75% shading. In conclusion, the model can be reliably employed to simulate maize productivity in agroforestry systems with up to 50% shading, but caution is required at higher levels of shading.     

Optimizing Tapping-Tree Density of Rubber (<Emphasis Type="Italic">Hevea brasiliensis</Emphasis>) Plantations in South China

Tapping-tree density in rubber plantations affects the production of dry rubber. Farmers can estimate rubber productivity when they know with certainty the number of tapping trees within a plantation and can therefore increase productivity through optimized planting schematics. Historical data on planting distance between trees and between rows, planting density (trees/ha) and tapping-tree density (number of trees under tapping for latex harvest per hectare) from 1952 to 2014 have been collected for plantations in the Hainan, Yunnan and Guangdong provinces of South China. A plantation survey was conducted to collect more detailed data on current tapping tree and planting densities in various plantations in the three provinces. Planting density and row spacing are found to have increased with rubber tree planting time and plant spacing to have declined from 1952 to 2014. Tapping-tree density of rubber plantations from 1955 to 1995 in South China ranges from 270 to 345 tree/ha, averaging 300 trees/ha. Strong typhoons and cold snaps are important drivers of fluctuations in tapping-tree density. The factors driving tapping-tree density are similar across the three provinces but the degree of change differs between provinces. Tapping panel dryness (due to tapping beyond the natural limit of the rubber tree productivity), severe wind damage and cold damage are the major factors resulting in loss of tapping trees in plantations in South China. These results suggest that a combination of environmental management for extreme weather and targeted breeding could improve tapping-tree density in rubber plantation and therefore dry rubber yield per unit area.     

Carbon sequestration of modern Quercus suber L. silvoarable agroforestry systems in Portugal: a YieldSAFE-based estimation

Modern alley cropping designs, with trees aligned in rows and adapted to operating farming machinery, have been suggested for Europe. This paper explores the potential for adoption of cork oak (Quercus suber L.) agroforestry in Portugal and estimates the potential carbon sequestration. Spatial modeling and Portuguese datasets were used to estimate target areas where cork oak could grow on farmland. Different implementation scenarios were then modeled for this area assuming a modern silvoarable agroforestry system (113 trees ha^?1 thinned at year 20 for establishing 50 trees ha^?1). The YieldSAFE process-based model was used to predict the biomass and carbon yield of cork oak under low and high soil water holding capacity levels. Approximately 353,000 ha are available in Portugal for new cork oak alley cropping. Assuming implementation rates between 10 % of the area with low soil water capacity (60 mm: 15 cm depth, coarse texture) and 70 % of the area with high soil water holding capacity (1,228 mm: 200 cm depth, very fine texture), then carbon sequestration could be 5 × 10⁶ and 123 × 10⁶ Mg CO₂ respectively. Due to higher yields on more productive land, scenarios of limited implementation in high productivity locations can sequester similar amounts of carbon as wide implementation on low productivity land, suggesting that a priori land classification assessments can improve the targeting of land and financial incentives for carbon sequestration.     

Shrub yield and fodder quality variations in a non-tropical dryland environment in West Asia

Integration of shrubs into the smallholder crop-rangeland-livestock farming systems in non-tropical dry areas could reduce feed gaps, rangeland degradation and desertification, but data on yield and fodder quality of most native and exotic shrubs are scanty. The study aimed at identifying shrubs for dryland agroforestry based on agronomic and fodder quality attributes. Fodder and wood yield, percent fodder (FBR) and fodder quality of 26 non-legume shrubs were determined from 6 to 8 months regrowth in north-west Syria. Seed yield was estimated from plants that were not cut. Fodder (31–87 Mg DM ha⁻¹), wood (16-2064 Mg DM ha⁻¹) and seed (0-132 Mg DM ha⁻¹) yield, FBR (24–87%), fodder concentrations of crude protein (69–195 g kg⁻¹.), acid detergent lignin (ADL) (24–109 g kg⁻¹), acid detergent fiber (ADF) (102–267 g kg⁻¹), neutral detergent fiber (NDF) (214–526 g kg⁻¹), in vitro organic matter digestibility (IVOMD) (391–526 g kg⁻¹), and in vitro gas production after 24 h of incubation (25–39 ml 200 mg⁻¹ DM) varied (P < 0.05) among the shrubs. Atriplex halimus-halimus and A. herba-alba from Spain, A. canescens, A. ploycarpa and A. lentiformis from USA, A. halimus and A. herba-alba from Syria and A. nummularia from Australia and South Africa had greater potential for development of dryland agroforestry technologies. The promising shrubs could be integrated into the rangeland-crop-livestock systems in non-tropical dryland environs to provide fodder, fuel-wood, shade, medicine, stabilize sand-dunes, and sequester carbon; thereby contributing to mitigation of rangeland degradation and global warming; if major constraints to adoption of fodder trees such as agronomic problems, low multipurpose value, land shortage and quality seed supply could be overcome.