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This study evaluates the potential for pasture improvement and restoration at two silvopastoral sites. We used a total of 16 wild legume species under different management systems (rhizobial inoculation, mycorrhizal inoculation, sheep penning, and sheep penning with mycorrhizal inoculation), at two mountain sites in Sierra Nevada Natural Park (Granada, southern Spain). The first site, Soportújar, had higher soil fertility and rainfall than the second, Lanjarón. Forage yields in Soportújar ranged from 265 to 8970 kg DM ha¿1, Vicia amphicarpa, Vicia monantha, Vicia disperma and Lathyrus clymenum being the most productive species. Mycorrhizal inoculation resulted in higher forage yields for Lens nigricans, V. disperma and Vicia lutea. Seed yields were low, ranging from 5.9 to 1234 kg ha¿1. Forage yields in Lanjarón were lower, ranging from 46 to 1415 kg DM ha¿1; and the most productive species were V. monantha, V. disperma, Lathyrus cicera and Medicago rigidula. Sheep penning alone and together with mycorrhizal treatment resulted in greater forage yields for most of the species studied, although differences were only significant for V. disperma, V. monantha and Lathyrus sphaericus. Seed yields ranged from 0.4 to 60 kg ha¿1. In conclusion, we recommend V. monantha, V. disperma and L. cicera followed by V. amphicarpa and L. clymenum (in wetter more fertile sites) and M. rigidula (in drier sites), as they seem to be the best adapted to the pedoclimatic conditions of Sierra Nevada Natural Park. Increasing nutrients in the soil (by sheep penning) and promoting nutrient assimilation (by mycorrhizal inoculation) may be effective strategies for increasing pasture biomass in silvopastoral sites., This work has been funded by the National Parks Autonomous Agency (OAPN, Spanish Ministry of Agriculture, Food and Environment) through the project “Investigaciones sobre la flora forrajera natural en mejoras de pastos, restauración forestal y silvicultura preventiva con ganado: una experiencia piloto en Sierra Nevada” (Ref. 748). We would like to thank Baltasar del Pozo for managing the sheep penning, Mycovitro who donated the Glomigel, and Manuel Fernández-López and Pablo Villadas who provided the rhizobium inocula for this study.

Several wildfire prevention programs in southern Europe are currently using livestock grazing for the maintenance of fuelbreaks. This silvopastoral management is valued for being sustainable and effective in reducing fuel loads, but few studies have analyzed other impacts linked to fuelbreak grazing. This paper reports on an experiment performed within the wildfire prevention program in Andalusia (southern Spain) with the aim of clarifying and quantifying the effect of fuelbreak grazing on herbage biomass, ground cover, herbage species composition, and growth of holm oak saplings. The study site, located in a semiarid Mediterranean environment, was grazed by a shepherded sheep flock from February to June in three consecutive years at a similar stocking rate. Livestock consumed between 33 and 68 % of herbage production in the different years, and the greatest fuel reduction (remaining dry matter of 200 kg ha−1) was registered in Year 2, when rainfall and herbage production was lowest. Ground cover was significantly affected by grazing: on average, the percentage of bare soil increased three-fold, while herbage cover was reduced by a quarter. The botanical composition of herbage varied remarkably between years, but very little between Grazed and Non-Grazed areas within each year. Non-browsed holm oak saplings became progressively larger than browsed ones, differences only reaching clear statistical significance at the end of the three experimental years. At this time, the volume of browsed saplings was 47–56 % smaller than that of non-browsed holm oaks, even though the former had also grown significantly in the course of the experiment.

We evaluate the forage yield and quality, species composition, and carrying capacity of oats and oat-vetch as fodder-cover crops, grown in almond orchards, under mineral or organic fertilizer and three harvesting regimes (“grazing,” “hay,” and “grain plus straw”). Also, we show preliminary results of almond yield. Differences in yield due to mineral and organic fertilization were only 9%. The carrying capacity was similar for all treatments. The almond yield was greater when the cover crop was removed early as “grazing.” Therefore, oats and oat-vetch could be used as cover crops in almond orchards if removed early by livestock grazing.

Atriplex halimus L. is a valuable fodder shrub that has been widely used in arid Mediterranean regions. However, its response to several cumulative years of grazing management remains uncertain. Accordingly, we conducted a three-year experiment in south-eastern Spain to analyze the influence of repeated seasonal (winter-spring) sheep browsing on young A. halimus plants. Shrub growth, fodder and wood production, plant compactness and shoot moisture content were assessed through regular monitoring of the size of shrubs, sampling of summer shoots, and destructive procedures at the end of the experiment. Shrubs were on two closely located sites but where soil quality and water availability were different. At the better location, browsed shrubs grew less and were significantly smaller (P < 0.001) than the non-browsed saltbushes. In contrast, differences between groups were minimal where the growth conditions were poorer. In all cases, shrubs resprouted vigorously and maintained fodder production throughout the experiment. Browsing affected shrub structure, resulting in smaller but more compact plants (2.20 vs. 1.24 g dm−3, P < 0.001), but their proportion of fodder remained similar. The spring grazing increased shrub-shoot moisture content in the summer (62.5% vs. 56.0%, P < 0.001). Overall, this species responded very positively to repeated seasonal grazing.

Clean cultivation is a common practice in rainfed orchards; however, it may have detrimental effects on soil properties. This study examines the effect of different soil management systems on physical, chemical, and biochemical properties in a hypercalcic Calcisol in rainfed almond orchards (Prunus dulcis (Mill.) D.A. Webb) in SE Spain. Four types of soil management (main-plot treatments) were compared to a frequently tilled orchard system (FT: three or four tillages per year). The four types of soil management were: fencing (SF) of a flock of 130 sheep in 0.4 ha and grass cover was kept throughout the growing season; native vegetation (NV) that was allowed to grow; cover crop (CC) composed of legumes and crucifers; and reduced tillage (RT) comprising autumn and spring chisel ploughing. Each type of soil management was split into two grazing treatments (subplot treatments): with and without grazing. Our results supported the hypothesis that clean cultivation, i.e., FT, has deleterious effects on soil properties compared with managed groundcover. Compared with FT treatment, at the end of the experiment, the rest of treatments had higher wet aggregate stability (except the SF treatment), soil organic carbon (10.6 g kg−1 vs. 5.4 g kg−1, mean groundcover treatments vs. FT), total nitrogen (1.35 g kg−1 vs. 0.83 g kg−1, mean groundcover treatments vs. FT), available potassium (332 mg kg−1 vs. 187 mg kg−1, mean groundcover treatments vs. FT), and dehydrogenase (2.6 μg INTF g−1 h−1 vs. 1.9 μg INTF g−1 h−1, mean groundcover treatments vs. FT), arylsulphatase (12.8 μg PNP g−1 h−1 vs. 6.5 μg PNP g−1 h−1, mean groundcover treatments vs. FT), β-glucosidase (569 μg PNP g−1 h−1 vs. 300 μg PNP g−1 h−1, mean groundcover treatments vs. FT), and phosphatase activity (394 μg PNP g−1 h−1 vs. 220 μg PNP g−1 h−1, mean groundcover treatments vs. FT). Grazed plots had higher water content in soil (10 g H2O kg soil−1 vs. 9.4 g H2O kg soil−1, grazed vs. not grazed plots) and greater levels of arylsulphatase (12 μg PNP g−1 h−1 vs. 11 μg PNP g−1 h−1, grazed vs. not grazed plots), β-glucosidase (582 μg PNP g−1 h−1 vs. 491 μg PNP g−1 h−1, grazed vs. not grazed plots), and phosphatase activity (396 μg PNP g−1 h−1 vs. 345 μg PNP g−1 h−1, grazed vs. not grazed plots), in late spring, and this is attributed to the reduction of evapotranspiration and to the stimulation of root activity by means of plant defoliation. In conclusion, under the conditions of this study, managements including grass cover improved physical, chemical and biological properties of soil compared with frequent tillage, particularly when grass was early removed by grazing., This work has been financed by Desarollo Agrario y Pesquero (Consejería de Agricultura y Pesca, Junta de Andalucía) through the project 92.162, and a FPU-MECD grant to M.E. Ramos.

Fallows constitute an important grazing source for livestock in semiarid environments. This work proposes two methods to improve fallow pastures quality in SE Spain consisting of (i) seeding a fallow (seeded fallow, SF) with a mixture of fodder species (Moricandia arvensis, Vicia ervilia and Medicago sativa cv. Aragon), and (ii) using sheep for introducing these fodder species in a fallow while manuring (“seeded-manured” fallow, SMF), this consisting of fencing sheep for 5 days, after seed ingestion, in a fallow plot. To evaluate the performance of these methods, we compared the yield, fodder quality, and botanical composition of the SF and SMF for two growing seasons (2006 and 2007). Biomass yield in 2006 was greater in the SMF than in the SF, but similar in 2007; additionally, moderate grazing in 2006 did not affect yield in 2007. Crude protein content was greater in SF whereas SMF had a higher lignin content. The species seeded in the SF showed a high self-reseeding ability as indicated by the decrease in weed percentage in 2006 (50%) with respect to 2007 (25%), V. ervilia being the most abundant. In SMF, weeds constituted from 94 (2007) to 99% (2006) of the total biomass, indicating low establishment success of the prescribed species from sheep dung. To assess the potential ability of sheep to introduce fodder species into fallows, we quantified seed recovery after gut passage and potential seedling establishment in greenhouse conditions was also examined. Low seed recovery and low seedling establishment were detected. M. arvensis registered the highest values of seed recovery (2.7%), while M. sativa and the highest seedling-establishment percentages under greenhouse conditions (0.49%). In conclusion, this study suggests that seeding a fallow with a mixture of fodder species, and using sheep for introducing these fodder species in a fallow while manuring may improve fallow pastures quality in semiarid Mediterranean environments. Nevertheless, hardseeded species should be used when introducing new high fodder quality species into pastures by means of livestock dejections.

Frequent tillage has been widely used in rainfed orchards in SE Spain in order to impede weed establishment and to increase water reposition in the soil profile. However, this practice may lead to soil degradation by decreasing structural stability, organic carbon content and microbial activity. This work examines the effect of different cover crop managements and frequent tillage on soil physical, chemical and biological properties in almond orchards in SE Spain. Two cover crops (oat – Avena sativa L. and oat-vetch – Vicia sativa L.) with two fertilization managements (mineral and organic) and three harvesting regimes (grazing in mid May, hay in early June, and grain-straw in mid July) were compared to a frequently tilled orchard system (three or four tillages per year). Most parameters were sensitive to soil management. Wet aggregate stability, total organic carbon, total nitrogen, carbon:nitrogen ratio, phosphatase, and β-glucosidase activities increased with cover crops, whereas the soil–water content declined, especially for the grain-straw treatment. The kind of fertilizer affected the available P content, which was higher for mineral fertilizer, and influenced the β-glucosidase activity, which augmented for the organic fertilizer. Livestock dejections depressed phosphatase activity, and increased WSC and available P. This study suggests that cover crops in semiarid environments improve soil quality compared to frequently tilled management, by increasing the organic matter content, improving the chemical and physical fertility of the soil, and enhancing the soil biological activity. Only higher water extraction by the plants could affect the orchard development and/or productivity; however, early cover crop removal would minimize possible yield losses.

The purpose of the present study was to determine the effect of a single nonprescribed fire on species community composition, woody and herbaceous species diversity, carrying capacity, density of dominating shrubs, and their resprouting capacity after fire. For short and long-term evaluations, two sites were chosen in a private extensive cattle ranch: (1) unburned areas and (2) burned areas. The forage total cover before fire (initial stage) was 54%; this cover decreased in burned areas to 13% (1986) and to 25% (2000), mainly due to a reduction in forage shrub cover. The cover of Atriplex lampa (zampa), the dominant forage shrub, decreased from 17.0 to 0.20% in 1986 after fire, and 15 years later this value remains constant (0.33%). The same area showed a carrying capacity, expressed in hectares per large stock unit (LSU), of 10 ha LSU−1 by 1986 and 17 ha LSU−1 by 2000, whereas in unburned areas it was 7 ha LSU−1, similar to prewildfire. All selected species that had been cut, simulating the action of fir...

Coronilla juncea is a leguminous shrub native to semi-arid regions of the Mediterranean Basin, particularly south-eastern Spain, and is browsed by livestock such as sheep and goats. We provide here information about this source of forage: allometric regression equations (phytovolume vs. total and forage phytomass), nutritive value and seed germination. The regression equations calculated were highly significant (r2= 0·86 for volume/total phytomass and 0·93 for volume/forage phytomass, p < 0·001). The values recorded for the in vitro digestibility of dry matter and organic matter were 65·93% and 62·13%, respectively. The optimum temperature for seed germination was 10°C. Scarification in goat rumen for 24 h increased the overall germination rate of fruit with pericarp although in sheep rumen overall germination decreased slightly. We suggest that this fodder shrub be included in programmes for land management and the rehabilitation of degraded semi-arid-to-arid ecosystems.

A comparison was made of plant cover, carrying capacity and diversity in areas of Monte vegetation at the Biosphere Reserve of Nacunan, Mendoza, Argentina, in 1982, 1984 and 1995. Treatments applied in 1981 were: control (untreated plots), selective hand-cutting, roller-chopping, and root-plowing. By 1995, woody cover was lower in root-plowed plots (27%) than in the others treatments (41–51%), and herbaceous cover was similar in treated (28–39%) and untreated areas (26%). Carrying capacity of treated areas (6–8 ha per Large Stock Unit (LSU)) was higher than in the control areas (12 ha LSU−1). Woody species diversity, quantified by the Shannon index, for both areas was similar in the study period (0·62), except in root-plowed sites in 1982 (0·0) and 1995 (1·3). Herbaceous species diversity was similar on treated (0·81) and untreated sites (1·2) in 1995. We could recommend less drastic treatments to improve carrying capacity.

This study provides data on plant density, vegetation cover, total and forage phytomass for the main rangelands and shrubs of a ‘pilot zone’ (Almeria, Spain) in the south-east of Spain. Carrying capacity has been calculated for each rangeland, and for two different levels of energy requirements: maintenance (from 0·29 to 1·28 goats ha −1 ) and production (from 0·20 to 0·88 goats ha −1 ). The nutritive value was determined for the most representative shrubs in the area