Stockpiled tall fescue and livestock performance in an early stage midwest silvopasture system

Using stockpiled forage can substantially reduce livestock feed costs over the winter. However, little is known about utilizing stockpiled forage in an early-stage silvopasture system. This study was conducted to determine if silvopasture production practices utilizing stockpiled forage influence stocker steer performance. The treatments were: (1) stockpiled forage in a non-forested pasture (OPEN) and (2) stockpiled forage in a silvopasture (TREE). Grazing began early December and ended in late February in each of 2 years. Each treatment was replicated three times in a completely randomized design. Forage nutritive value, production, and steer average daily gain (ADG) for the OPEN and TREE treatments were not significantly different as long as the areas occupied by trees was excluded from analyses. When the area occupied by trees was included, the OPEN treatment produced more (P < 0.01) forage than the TREE treatment, with the OPEN producing 3510 kg ha⁻¹ and the TREE producing 2812 kg ha⁻¹. Average daily gain (P = 0.21) was 0.41 kg for the steers in the OPEN treatment and 0.37 kg for steers in the TREE treatment. Gain per ha was significantly different (P < 0.01); the OPEN treatment produced 193 kg of animal gain and the TREE treatment produced 125 kg of animal gain. Exclusion of the area under the tree row from the analysis changed the total gain per ha for the TREE treatment to 148 kg, but was still less (P = 0.01) than the OPEN treatment.     

Soil compaction by grazing livestock in silvopastures as evidenced by changes in soil physical properties

Livestock, pasture, and timber trees are intimately interrelated in silvopastures. Most silvopasture research to date has focused on forage/animal/tree interactions, with less attention paid to animal/soil interactions in silvopastures. While a considerable body of work has been devoted to understanding the effects of livestock trampling on plants and soils in pastures, less has been done for livestock grazing in forests, and even less is available for silvopastures. Three replications of Douglas-fir forest, Douglas-fir/subclover pasture/sheep silvopasture, and subclover/sheep pasture were established in 1989 near Corvallis, Oregon USA. Pastures and silvopastures were grazed each spring during 1990–2001. These plots were sampled in 2002, after 11 years of grazing, and again in 2004 following 2 years without grazing. Soil in the silvopastures had 13% higher bulk density and 7% lower total porosity than those in adjacent forests in 2002. Most of the difference in total porosity was air-filled pores. Average water infiltration rate was 38% less in silvopastures than in forests, however total water stored in the top 6 cm of soil at field capacity was similar. Soil bulk density, total porosity, and air-filled pore space was similar for forests, pastures, and silvopastures after 2 years without livestock grazing. The infiltration rate of silvopasture soils in 2004 had increased to be similar to those of forests in 2002, however, forest soil infiltration rates also increased and continued to be higher than those of silvopastures. Plant production was not sensitive to changes in any of the soil parameters measured. Although livestock grazing did change soil infiltration rates, soil bulk density, and soil porosity, the effects were quickly reversed following cessation of grazing and had little detrimental effect on silvopasture forage or tree production.     

Nitrate and fecal coliform concentration differences at the soil/bedrock interface in Appalachian silvopasture,pasture, and forest

A major limitation to efficient forage-based livestock production in Appalachia is asynchrony of forage availability and quality with nutritional requirements of the grazer. Producers require dependable plant resources and management practices that improve the seasonal distribution and persistence of high quality herbage, sustainability and environmental integrity of the agricultural landscape. It was hypothesized that inorganic N and fecal coliform concentrations delivered in leachate to the soil/bedrock interface would be lowest in deciduous forest (HF) and highest in pasture (CP) with HF converted to silvopasture (SP) between the two. Piezometers were used to monitor water quality at the soil/bedrock interface under conventional pasture, SP, and hardwood forest. The pasture and SP were rotationally grazed by sheep during the spring to fall grazing season (2004–2008). Geometric mean fecal coliform bacteria concentrations (FC) were greatest in SP (18 FC 100 mL⁻¹) with no difference between CP (7.5 FC 100 mL⁻¹) and HF (5.6 FC 100 mL⁻¹). Mean NO₃-N concentration was lowest in SP (2.3 mg L⁻¹) and greatest in CP (4.4 mg L⁻¹) and HF (4.1 mg L⁻¹), which were not significantly different. Mean NH₄-N concentrations showed different trends with the lowest mean concentration in CP (0.5 mg L⁻¹) and the greatest in SP (2.5 mg L⁻¹) and HF (2.6 mg L⁻¹), which were not significantly different. SP was shown to be a management option in the study area that reduces nitrate leaching, but should be considered cautiously in near-stream areas and near wells where fecal bacteria pollution can be problematic. This study makes an important contribution to our knowledge about interactions between landscape management and environmental quality of the Appalachian region. A diversity of land and forage management options are needed to maximize forage and livestock productivity while protecting surface and groundwater quality of the region.     

<Emphasis Type="Italic">Pinus radiata</Emphasis> and sheep production in silvopastoral systems at Carngham,Victoria, Australia

This long term experiment provides production data for evaluation of combined forestry and livestock systems. Five systems were established in Pinus radiata planted in 1981 (620 mm average annual rainfall). Sheep were introduced in 1984 and trees were pruned in several lifts. Adjusted tree stockings were (1) 60 widely spaced trees ha⁻¹, (2) 200 widely spaced trees ha⁻¹, (3) 200 trees ha⁻¹ in five-row belts, (4) 1,090 trees ha⁻¹ (unpruned) and 815 trees ha⁻¹, and (5) no trees (open pasture). Tree growth, wool production, liveweight gain and pasture production were measured. At year 25, tree diameter under bark at 1.3 m (DBHUB) in Systems 1, 2, 3 and 4 (unpruned) was 46.0, 39.2, 33.5 and 24.1 cm, while volume of bark-free 6-m butt-logs was 49, 117, 86 and 233 m³ ha⁻¹. Inner rows of System 3 belts contained smaller trees than outer rows. Pruned System 4 trees had slightly greater diameter than unpruned trees. Pasture production declined with tree stocking and time, due to shading and competition. Wool production (WP ha⁻¹) and liveweight gain (LWG ha⁻¹) declined linearly from year 9 to 17 with increasing disparity among systems. In 1998 (year 17) WP ha⁻¹ in Systems 1, 2 and 3 was 64, 16 and 43% of that in open pasture. Further analysis is needed to evaluate the financial costs and returns of various systems under particular rotation lengths and market prices.     

A financial analysis of a silvopasture system in southern Mississippi

Silvopasture is reemerging as a land use in the southern US. Alternate land use treatments based on field trials for timber and pasture for beef cattle production were financially evaluated. Multiple-use management aspects of these systems were further illustrated by the addition of fee hunting. Land Expectation Values (LEVs) were lower when silvopasture treatments were compared to steer grazing only. However, silvopasture treatments compared favorably to some grazing treatments. LEVs were higher when silvopasture treatments were compared to commercial forest plantation applications on similar sites. Silvopasture systems promote multiple-use management of the land under an environmentally friendly cropping system whereby certain types of wildlife can thrive. This is particularly relevant in light of recent increases in fee hunting in the South. LEVs were reduced by $289, $200, and $151 ha⁻¹ at discount rates of 5%, 7%, and 9% respectively, when fee hunting was excluded in the recommended silvopasture treatment. The monetary value of a wildlife component in this system can be interpreted as the expected value gained per hectare per rotation in perpetuity when fee hunting is part of the management plan. On average, it represented an 8.6% gain in LEVs for this treatment. Results from this study support the potential for silvopasture applications in the South for private landowners. Cattle grazing of improved forage in commercially productive loblolly pine (Pinus taeda) stands can relieve annual cash flow problems inherent in tree production. This revised version was published online in June 2006 with corrections to the Cover Date.     

Light Measurement Methods Related to Forage Yield in a Grazed Northern Conifer Silvopasture in the Appalachian Region of Eastern USA

The Appalachian region is characterized by hilly topography and a humid temperate climate. In most areas agriculture is limited to pasture although the native climax vegetation is a species-diverse forest. Silvopasture systems can help diversify and increase farm income. Information is needed on the yield response of forage grown as an understory crop among trees. The light environment of a conifer silvopasture was characterized by three methods, a hand-held photosynthetically active radiation (PAR) meter for quick measurements over a large area, fixed PAR meters recorded using data loggers for a large number of measurements over time, and hemispherical photography with software to calculate seasonal direct beam radiation. Light data were considered in terms of forage yield. Plots were harvested when forage reached 20–25 cm in height after which the entire area was grazed by sheep. There were limitations to all methods of quantifying radiation environment for predicting yield. Yield decreased linearly with decreased PAR; however, data variability was high and correlations, while statistically significant, were weak. Grazed silvopastures are dynamic with shifting yield patterns in response to the interactions between the spatially variable soil, changing seasonal environment, and spatially variable animal impacts for each grazing event.     

Production and Economics of Native Pecan Silvopastures in Central United States

Riverine silvopastoral practices with native pecan (Carya illinoinensis) are a suitable land use for areas subjected to seasonal flooding in southern and central regions of the United States. Nut, timber and forage production, and the economics of managed pecan silvopastures were examined in southeastern Kansas. During 1981–2000, annual hulled nut production varied between 50 and 1600 kg ha⁻¹ in stands averaging 72 years of age, and ranging in density between 35 and 74 trees ha⁻¹. The nut crop had a pattern of biennial bearing with some exceptions. Tree stem diameter and stand basal area increased linearly with time. Nut production was not related to stand age or tree density, however, suggesting that nut production had reached a steady state level. Merchantable timber yield ranged between 0.25 and 1.35 m³ ha⁻¹ year⁻¹. In pecan silvopastures with a mean tree age of 37 years, forage production varied between 1500 and 4600 kg DM ha⁻¹ in 2001 and 2002. In 2001 only, grass production decreased with decreasing solar radiation within the range of 0.25–0.83 of fraction light transmitted. In both years, the grass understory had acceptable quality for cow-calf production with average crude protein content between 9 and 11.8%, and no evidence of excessive levels of ergoalkaloids from tall fescue. Twenty-seven vascular plants were identified in the understory of which nut sedge (Cyperus esculentus), tall fescue (Festuca arundinacea), wild oat (Avena fatua) and Canadian wild rye (Elymus canadensis) were the most abundant. Economic simulations obtained with the U.S. Agroforestry Estate Model indicated that pecan nut price is the main variable driving economic outputs under current production conditions. Annual cash flows from nut sales had smaller fluctuations than nut yields because of an inverse relation between nut price and yield. Improved timber production appears an option for increasing profitability of pecan silvopastures.     

Nitrate dynamics of forested watersheds: spatial and temporal patterns in North America,Europe and Japan

The relationships of nitrogen biogeochemistry are reviewed, focusing on forested watersheds in North America, Europe and Japan. Changes in both local and global nitrogen cycles that affect the structure and function of ecosystems are described. Within northeastern United States and Europe, atmospheric deposition thresholds of ~8 and ~10 kg N ha⁻¹ year⁻¹, respectively, result in enhanced mobilization of nitrate. High nitrate concentrations and drainage water loss rates up to 22 kg N ha⁻¹ year⁻¹ have also been found near Tokyo. Although atmospheric deposition may explain a substantial portion of the spatial pattern of nitrate in surface waters, other factors also play major roles in affecting the spatial patterns of nitrogen biogeochemistry. Calcium availability influences the composition of the vegetation and the biogeochemistry of nitrogen. The abundance of sugar maple is directly linked to soil organic matter characteristics and high rates of nitrogen mineralization and nitrification. Seasonal patterns of nitrate concentration and drainage water losses are closely coupled with differences in seasonal temperature and hydrological regimes. Snow-dominated forested catchments have highest nitrate losses during snowmelt. Watersheds in the main island of Japan (Honshu) with high summer temperatures and precipitation inputs have greatest losses of nitrate occur during the late summer. Understanding future changes in nitrate concentrations in surface waters will require an integrated approach that will evaluate concomitantly the influence of both biotic and biotic factors on nitrogen biogeochemistry.     

Does exceeding the critical loads for nitrogen alter nitrate leaching,the nutrient status of trees and their crown condition at Swiss Long-term Forest Ecosystem Research (LWF) sites?

Nitrogen (N) deposition exceeds the critical loads for this element in most parts of Switzerland apart from the Alps. At 17 sites (8 broadleaved stands, 8 coniferous stands, and 1 mixed stand) of the Swiss Long-term Forest Ecosystem Research network, we are investigating whether N deposition is associated with the N status of the forest ecosystems. N deposition, assessed from throughfall measurements, was related to the following indicators: (1) nitrate leaching below the rooting zone (measured on a subset of 9 sites); (2) the N nutrition of the forest stand based on foliar analyses (16 sites); and (3) crown defoliation, a non specific indicator of tree vitality (all 17 sites). Nitrate leaching ranging from about 2 to 16 kg N ha⁻¹ a⁻¹ was observed at sites subjected to moderate to high total N deposition (>10 kg ha⁻¹ a⁻¹). The C/N ratio of the soil organic layer, or, when it was not present, of the upper 5 cm of the mineral soil, together with the pool of organic carbon in the soil, played a critical role, as previous studies have also found. In addition, the humus type may need to be considered as well. For instance, little nitrate leaching (<2 kg N ha⁻¹ a⁻¹) was recorded at the Novaggio site, which is subjected to high total N deposition (>30 kg ha⁻¹ a⁻¹) but characterized by a C/N ratio of 24, large organic C stocks, and a moder humus type. Foliar N concentrations correlated with N deposition in both broadleaved and coniferous stands. In half of the coniferous stands, foliar N concentrations were in the deficiency range. Crown defoliation tended to be negatively correlated with N concentrations in the needles. In the majority of the broadleaved stands, foliar N concentrations were in the optimum nutritional range or, on one beech plot with high total N deposition (>25 kg ha⁻¹ a⁻¹), above the optimum values. There was no correlation between the crown defoliation of broadleaved trees and foliar concentrations.     

Phosphorus uptake and maize response to organic and inorganic fertilizer inputs in Rubona,Southern Province of Rwanda

Green manure of multipurpose trees is known to be a good source of nutrients to crop. However, most agroforestry species do not have adequate phosphorus (P) in their leaves. Supplementing green manure with moderate dose of P is a beneficial strategy to improve food security in Rwanda. This study examines the effects of Calliandra calothyrsus Meissner, Tithonia diversifolia Hensley A.Gray and Tephrosia vogelii Hook.f. green manure applied independently or in combination with triple super phosphate (TSP) and lime on maize yield and P uptake in the Oxic Tropudalf of Rubona, Rwanda. The treatments were the control, lime at 2.5 t ha⁻¹, TSP at 25 and 50 kg P ha⁻¹, leaf of C. calothyrsus, T. diversifolia, and T. vogelii each at 25 and 50 kg P ha⁻¹, respectively. Leaf shrubs biomass, TSP and lime were applied for four consecutive seasons (2001–2004). The results showed that the combination of green manure with TSP at a rate of 50 kg P ha⁻¹ significantly increased maize yield from 24 to 508% when compared to the control and T. divesifolia combined with TSP was leading (508%). Equally, the same treatments as indicated above showed higher P uptake (15.6–18. 6 kg P ha⁻¹) than the control (5 kg P ha⁻¹) and 65% of maize yields variation was explained by total P uptake. The plant residues quality such as C:N ratio, total plant N, and P significantly influenced the variability of maize grain yields.     

Plant-community characteristics of bahiagrass pasture during conversion to longleaf-pine silvopasture

Silvopasture is considered a sustainable agroforestry practice as a result of benefits the system offers for biodiversity, economic returns, and environmental quality. However, little is known about temporal and spatial dynamics of forage species composition of pastures being converted to silvopasture. Research objectives were to determine (1) the response of forage species composition to a young longleaf pine (Pinus palustris Mill.)-bahiagrass (Paspalum notatum Flugge) silvopasture versus open bahiagrass pasture, and (2) the impact that alley position relative to trees has on forage species composition in a young longleaf pine-bahiagrass silvopasture. The research was conducted in a randomized complete block design with three replications from 2003 to 2007 at Americus, Georgia, USA in a longleaf-pine silvopasture established in 2000 in an existing bahiagrass pasture and an adjoining bahiagrass open-pasture. Silvopasture forage-species composition was measured within alleys. Plant community diversity was greater in the silvopasture versus open-pasture early in the growing season, but open-pasture had greater diversity during the later growing season. Alley position in silvopasture also had a significant effect on understory forage species composition. This study indicated that conversion of bahiagrass pasture to longleaf-pine silvopasture in the Southern Coastal Plain can influence plant-community characteristics by the time trees are six to seven years old.     

Forage production and nitrogen nutrition in three grasses under coconut tree shades in the humid-tropics

Reduction in forage production (FP) under trees in the humid tropics is well known, but information on how different levels of nitrogen (N) fertilizer influence FP under trees is meager. The present study reports effects of four N fertilizer levels (0, 60, 80 and 120 kg ha⁻¹ N) on net soil N mineralization rate (NMR) and soil moisture (SM), FP, shoot biomass/root biomass ratio (SB/RB), N concentration in SB, N uptake and nitrogen use efficiency (NUE) of three grasses [guinea (Panicum maximum Jacq.), para (Brachiaria mutica (Forssk) Stapf) and hybrid-napier (Pennisetum purpureum Schumach.)] under three canopy positions [under canopy (UC, representing high shade), between canopy (BC, representing low shade) and open] of coconut trees (Cocos nucifera L.) in a coconut based silvopastoral system in the humid tropical climate of South Andaman Island of India. The study was performed for two annual cycles (2005–2006 and 2006–2007). The hypotheses tested were: (1) FP would decline under tree shades, both in N fertilized as well as no N fertilized conditions, when SM was not growth limiting in the open. However, amount of decline in the FP would depend on grass species and intensity of shades i.e., higher was the shade greater would be the decline; (2) N fertilizer would increase FP under tree shades, but the increase depended on grass species, intensity of shades and amount of N applied. Amount of N applied, however, would not annul the shades effects when SM was not growth limiting in the open. The study revealed that the tree reduced light 59% under UC and 32% under BC positions, but the N fertilizer levels increased NMR by 11–51% under UC and 3–44% under BC positions compared to the open. SM did not differ across the canopy positions. Under all situations, FP of all grasses declined under UC (47–78%) and BC (18–32%) positions compared to the open; the decline was greater in Hybrid-napier than Guinea and Para grasses. Forage production of all grasses increased with N fertilizer increments under all canopy positions reaching 32 t ha⁻¹ dry matters for hybrid-napier at 120 kg ha⁻¹ N in the open. Both guinea and para grasses outyielded hybrid-napier grass under UC but not under BC or in the open. N concentration in the forage (SB) also increased as N fertilizer level increased. These observations support our hypotheses and suggest that forage production under coconut palms can be increased by the application of N fertilizer with both guinea and para grasses being more productive than hybrid-napier grass under the high shade. Where light conditions are better, hybrid-napier would produce more forage than the other species.     

Biomass,and carbon and nitrogen pools in a subtropical evergreen broad-leaved forest in eastern China

Subtropical evergreen broad-leaved forest is the most widely distributed land-cover type in eastern China. As the rate of land-use change accelerates worldwide, it is becoming increasingly important to quantify ecosystem biomass and carbon (C) and nitrogen (N) pools. Above and below-ground biomass and ecosystem pools of N and C in a subtropical secondary forest were investigated at Laoshan Mountain Natural Reserve, eastern China. Total biomass was 142.9 Mg ha⁻¹ for a young stand (18 years) and 421.9 Mg ha⁻¹ for a premature stand (ca. 60 years); of this, root biomass was from 26.9 (18.8% of the total) to 100.3 Mg ha⁻¹ (23.8%). Total biomass C and N pools were, respectively, 71.4 Mg ha⁻¹ and 641.6 kg ha⁻¹ in the young stand, and 217.0 Mg ha⁻¹ and 1387.4 kg ha⁻¹ in the premature stand. The tree layer comprised 91.8 and 89.4% of the total biomass C and N pools in the young stand, and 98.0 and 95.6% in the premature stand. Total ecosystem C and N pools were, respectively, 101.4 and 4.6 Mg ha⁻¹ for the young stand, and 260.2 and 6.6 Mg ha⁻¹ for the premature stand. Soil C comprised 23.8–29.6% of total ecosystem C whereas soil N comprised 76.9–84.4% of the total. Our results suggest that a very high percentage of N in this subtropical forest ecosystem is stored in the mineral soil, whereas the proportion of organic C in the soil pool is more variable. The subtropical forest in eastern China seems to rapidly accumulate biomass during secondary succession, which makes it a potentially rapid accumulator of, and large sink for, atmospheric C.     

Cumulative Forage Production, Forage Quality and Livestock Performance from an Annual Ryegrass and Cereal Rye Mixture in a Pine Walnut Silvopasture

Annual ryegrass (Lolium multiflorum Lam.) and cereal rye (Secale cereale L.) pastures can extend the grazing season in the lower Midwest. There is little data from this region on the productivity of these forages in a silvopasture system. Our objective was to determine the forage and livestock production from annual ryegrass/cereal rye in a silvopasture versus an open (non-forested) system. This study was conducted near New Franklin, MO, USA. The treatments were (1) annual ryegrass/cereal rye planted into a 6- to 7-year-old stand of pitch pine (Pinus rigida Mill.) × loblolly pine (Pinus taeda L.) hybrids and black walnut (Juglans nigra L.) (TREE treatment) and (2) the same forages planted into pastures without trees (OPEN treatment). Marshall annual ryegrass and cereal rye were no-till seeded at 22 and 67 kg ha^-1 of pure live seed, respectively, on 18 September 2000 and 30 August 2001. Treatments were replicated three times in a randomized complete block. In March 2001 and 2002, three beef heifers were assigned to each pasture and rotationally grazed until early June. Cumulative forage production and quality were measured for each treatment. Cumulative forage production in the TREE treatment was reduced by approximately 20% compared to the OPEN treatment. However, beef heifer average daily gain and gain ha^-1 were equal for both treatments. Beef producers using a annual ryegrass/cereal rye in a silvopasture system likely would not sacrifice livestock production when hybrid pine and black walnut trees are 6- to 7-year-old when compared to an open pasture. Contribution of the Missouri Agricultural Experiment Station and the University of Missouri Center for Agroforestry. This work was funded through the University of Missouri Center for Agroforestry under cooperative agreements AG-02100251 with the ARS and CR 826704-01-0 with the US EPA. The results presented are the sole responsibility of the authors and/or the University of Missouri and may not represent the policies or positions of the ARS or EPA.     

Precipitation chemistry at a high elevation forest in central Taiwan

High elevation ecosystems are particularly sensitive to environmental change. Mountain agriculture is extending to areas at high elevations in Taiwan but the effects on nutrient cycling of the surrounding ecosystems are largely unknown. We examined precipitation chemistry at Piluchi Experimental Forest in central Taiwan to evaluate the contributions of local air pollution and long-range transport of air pollutants on nutrient cycling at this seemingly remote forest. Sea-salt aerosols and anthropogenic pollutants resulting from long-range transport of air pollutants and mountain agriculture activities are the key factors affecting precipitation chemistry at Piluchi Experimental Forest. Precipitation chemistry was dominated by ions of oceanic origin in the summer and by anthropogenic pollutants SO₄ ²⁻, NO₃ ⁻ and NH₄ ⁺ in the winter and spring, the northeast monsoon season. The much higher concentrations of S and N in the northeast monsoon season than the summer suggest a substantial contribution from long-range transport as the prevailing air masses moved from inland China and passed over the industrialized east coast of China before arriving in Taiwan. The very high concentration of NH₄ ⁺ (22 μeq L⁻¹) in the spring, when the local application of N-containing fertilizers was high, signifies the influences of mountain agriculture. Despite very low concentrations relative to other sites in Taiwan, annual input of NH₄ ⁺ (3.6 kg ha⁻¹ year⁻¹), NO₃ ⁻ (7.2 kg ha⁻¹ year⁻¹) and SO₄ ²⁻ (10 kg ha⁻¹ year⁻¹) via precipitation was substantial suggesting that high elevation ecosystems of Taiwan are not free from the threat of atmospheric deposition of pollutants.     

Modeling forage growth in a Midwest USA silvopastoral system

Tree effects on understory pasture growth in a silvopastoral system were modeled by explicit simulation of tree canopy light and rainfall interception, evapotranspiration, and nutrient uptake. The algorithms to model these effects were incorporated into a multispecies grazing simulation model, GRASIM, to form the Silvopasture GRASIM model (SGRASIM). The new model was evaluated using forage biomass data and soil moisture data collected from a silvopasture field experiment with black walnut (Juglans nigra L.). The SGRASIM model performed well in simulating the growth of three competing dominant forage species (orchardgrass [Dactylis glomerata L.], Kentucky bluegrass [Poa pratensis L.], and tall fescue [Festuca arundinacea (Schreb.)] in the pasture both under tree canopy and in open pasture (linear regression of observed on simulated biomass for the species gave r ² values above 0.97). Model growth parameters for forage under tree canopy, compared with those for an open pasture, bear testament to the shading effects from the forest canopy in terms of reduced photosynthetic efficiency, increased leaf area ratio, and photosynthate partitioned to aboveground biomass. The new model reasonably followed the soil moisture time series in the upper soil layer (0–30 cm), where the bulk of the forage roots reside.     

Nitrogen budget of a rehabilitated forest on a degraded granitic hill

Rehabilitated forests established about 100 years ago on denuded lands in a hilly granitic area are widespread in the Kyoto–Osaka area, the second largest megalopolis in Japan. From 2001 to 2003, we monitored the annual nitrogen (N) budget of a rehabilitated forest watershed dominated by Quercus serrata and Ilex pedunculosa. The ion concentrations of bulk rain in the watershed were similar to those of other watersheds in Japan. The annual bulk rain input of N ranged from 5.1 to 6.3 kg N ha⁻¹ year⁻¹, and the N deposition from throughfall and stem-flow ranged from 7.5 to 8.2 kg N ha⁻¹ year⁻¹. Estimated annual outputs of N from the stream ranged from 3.3 to 10.6 kg N ha⁻¹ year⁻¹. These results indicate that the amount of N deposition in this area is less than that in urban Tokyo (>10 kg N ha⁻¹ year⁻¹), but the N output of the watershed is comparable with that of the Tokyo area. We discuss the characteristics of N dynamics in rehabilitated forests, focusing on the biogeochemical processes of this watershed.     

Thirteen-year monitoring of liming and PK fertilization effects on tree vitality in Norway spruce and European beech stands

The chemical fertility of the forest soils in the Belgian Ardenne is threatened by acidifying and eutrophying deposition and by the nutrient removal due to timber harvesting. Experiments were launched to evaluate the ability of liming and fertilization to improve foliar nutrition, maintain or restore crown condition and promote tree growth. In 1995, 10 liming and fertilization trials were installed in even-aged stands of European beech (5) and Norway spruce (5) distributed throughout the Ardenne. In each stand, two treatments were tested: liming with 3,000 kg ha⁻¹ of dolomitic limestone and liming plus fertilization with 0 to 800 kg ha⁻¹ of rock phosphate and 0 to 350 kg ha⁻¹ of K₂SO₄. Between 1995 and 2006, the foliar Ca and Mg status of spruce and beech trees improved in the limed stands, which limited significantly but did not prevent the decline in crown condition triggered by the summer drought in 2003. For spruce, liming also increased the increment in basal area. The additional fertilization increased the foliar nutrition in P but had no significant effects on soil chemistry and tree vitality.     

Cattle distribution and behavior in southern-pine silvopasture versus open-pasture

Shade present in silvopasture systems could reduce heat stress associated with microclimatic conditions that characterize warm-weather portions of the year on the Coastal Plain of the Southeast USA. Objectives of this research were to: (1) quantify diurnal distribution patterns of landscape use and behavior of cattle in loblolly-pine (Pinus taeda) silvopasture versus open-pasture landscapes, and (2) relate observed differences in landscape use and cattle behavior patterns between the two pastures to differences in microclimatic conditions, and forage quantity and quality. The research was conducted in Chipley, Florida USA within a 5-ha cell of a loblolly-pine-bahiagrass (Paspalum notatum) silvopasture (tree age 20 year), and a 5-ha open bahiagrass pasture with unlimited access to an adjacent 1-ha wooded area. One-day observations of diurnal distribution and behavior of cattle were conducted in March, June, and September 2007; microclimatic conditions were measured, and forage quantity and quality were estimated within each landscape. Cattle utilized the landscape more evenly in the silvopasture versus the open-pasture and this difference was mainly attributed to reduced solar radiation recorded in the silvopasture. Grazing was the dominant behavior in the silvopasture while loafing was dominant in the open-pasture. Shade present in silvopasture appeared to reduce heat stress for cattle grazing during warm-weather portions of the year on the Coastal Plain of the Southeast USA. Further study is needed to determine how this reduction in heat stress influences cattle performance in southern-pine silvopasture, and the nature and extent of the interactions among animal distribution and behavior, microclimatic conditions, and forage characteristics in these systems.     

Pasture production under different tree species and densities in an Atlantic silvopastoral system

We studied the effect of six tree species planted at six different densities on pasture production seven years after establishment. Annual and seasonal pasture production was studied every six months, over three years. Pasture production was lower under conifer trees (Pseudotsuga menziesii (Mirb.) Franco, Pinus pinaster Aiton, Pinus radiata D. Don) than under broadleaved trees (Betula alba L., Quercus rubra L. and Castanea sativa Mill.). Annual pasture production under Pseudotsuga menziesii and Pinus pinaster decreased progressively starting from 952 trees ha⁻¹, while decline in herbage production under Pinus radiata began to occur at 427 trees ha⁻¹. Tree density effect on pasture production was detected at 2,000 trees ha⁻¹ for all of the deciduous species studied. This effect on pasture production was more important in the first six months of the year (June sampling), while from June to December herbage production was less affected by tree density. The tree effect became more noticeable over time, with the last sampling showing the inverse relationship between tree density and herbage production most clearly. Seven years after tree establishment, pasture production was quite consistent under tree densities between 190 trees ha⁻¹ and 556 trees ha⁻¹ and declined remarkably from 556 trees ha⁻¹ to 2,500 trees ha⁻¹. The study also indicated that by the sixth growing season, annual pasture production under different tree species is inversely correlated with tree leaf area index.