• Authors:
    • Dalal, R. C.
    • Page, K. L.
    • Pringle, M. J.
    • Allen, D. E.
  • Source: The Rangeland Journal
  • Volume: 32
  • Issue: 2
  • Year: 2010
  • Summary: The accurate measurement of the soil organic carbon (SOC) stock in Australian grazing lands is important due to the major role that SOC plays in soil productivity and the potential influence of soil C cycling on Australia's greenhouse gas emissions. However, the current sampling methodologies for SOC stock are varied and potentially conflicting. It was the objective of this paper to review the nature of, and reasons for, SOC variability; the sampling methodologies commonly used; and to identify knowledge gaps for SOC measurement in grazing lands. Soil C consists of a range of biological materials, in various SOC pools such as dissolved organic C, micro- and meso-fauna (microbial biomass), fungal hyphae and fresh plant residues in or on the soil (particulate organic C, light-fraction C), the products of decomposition (humus, slow pool C) and complexed organic C, and char and phytoliths (inert, passive or resistant C); and soil inorganic C (carbonates and bicarbonates). Microbial biomass and particulate or light-fraction organic C are most sensitive to management or land-use change; resistant organic C and soil carbonates are least sensitive. The SOC present at any location is influenced by a series of complex interactions between plant growth, climate, soil type or parent material, topography and site management. Because of this, SOC stock and SOC pools are highly variable on both spatial and temporal scales. This creates a challenge for efficient sampling. Sampling methods are predominantly based on design-based (classical) statistical techniques, crucial to which is a randomised sampling pattern that negates bias. Alternatively a model-based (geostatistical) analysis can be used, which does not require randomisation. Each approach is equally valid to characterise SOC in the rangelands. However, given that SOC reporting in the rangelands will almost certainly rely on average values for some aggregated scale (such as a paddock or property), we contend that the design-based approach might be preferred. We also challenge soil surveyors and their sponsors to realise that: (i) paired sites are the most efficient way of detecting a temporal change in SOC stock, but destructive sampling and cumulative measurement errors decrease our ability to detect change; (ii) due to (i), an efficient sampling scheme to estimate baseline status is not likely to be an efficient sampling scheme to estimate temporal change; (iii) samples should be collected as widely as possible within the area of interest; (iv) replicate of laboratory analyses is a critical step in being able to characterise temporal change. Sampling requirements for SOC stock in Australian grazing lands are yet to be explicitly quantified and an examination of a range of these ecosystems is required in order to assess the sampling densities and techniques necessary to detect specified changes in SOC stock and SOC pools. An examination of techniques that can help reduce sampling requirements (such as measurement of the SOC fractions that are most sensitive to management changes and/or measurement at specific times of the year, preferably before rapid plant growth, to decrease temporal variability), and new technologies for in situ SOC measurement is also required.
  • Authors:
    • Sun, Y.
    • Dowd, S.
    • Acosta-Martinez, V.
    • Wester, D.
    • Allen, V.
  • Source: Applied Soil Ecology
  • Volume: 45
  • Issue: 1
  • Year: 2010
  • Summary: Bacterial tag-encoded FLX amplicon pyrosequencing of the 16S rDNA gene was used to evaluate bacterial diversity of a clay loam soil (fine, mixed, thermic Torrertic Paleustolls) after 10 years under an integrated livestock (beef)-cotton ( Gossypium hirsutum L.) production system compared to continuous cotton in a semiarid region. In the integrated system, cattle alternatively grazed a perennial warm-season grass [ Bothriochloa bladhii (Retz) S.T. Blake] paddock and small grains grown in two paddocks of a wheat ( Triticum aestivum L.)-fallow-rye ( Secale cereal L.)-cotton rotation. Areas excluded from grazing in the integrated system were also evaluated. Maximum observed number of unique sequences operational taxonomic units (OTU) at 3% dissimilarity level (roughly corresponding to the species level) corresponded to 1200 and 1100 at 0-5 and 5-15 cm depths, respectively. Predominant phyla (up to 65% of abundance) at 0-5 and 5-15 cm in this soil were Proteobacteria, Actinobacteria and Gemmatimonadetes. Proteobacteria were predominant in soil under all components of the integrated livestock-cotton system compared to continuous cotton whereas Bacteroidetes were predominant under continuous cotton. Firmicutes (i.e., Clostridia) and Chlorofexi (i.e., Thermomicrobia) were more abundant in soil under fallow periods of the rotation compared to under cotton (Rye- Cotton-Wheat-Fallow or continuous cotton) or grass (i.e., pasture). The lowest OTUs were detected in soil under fallow periods of the rotation (Wheat- Fallow-Rye-Cotton) compared to the other treatments. Grazing effects were significant for Actinobacteria, Proteobacteria and Chlorofexi. Compared to the continuous cotton system, this study revealed significant changes in bacterial phyla distribution under integrated livestock-cotton systems for a semiarid soil after 10 years. Positive correlations were found between certain bacteria ( Proteobacteria, Firmicutes, Chloroflexi, Verrucomicrobiae and Fibrobacteres) and the activities of alkaline phosphatase and beta-glucosidase or beta-glucosaminidase.
  • Authors:
    • Pire, E.
    • Boccanelli, S.
    • Lewis, J.
  • Source: CIENCIA E INVESTIGACION AGRARIA
  • Volume: 37
  • Issue: 2
  • Year: 2010
  • Summary: Agriculture has been practised in the Argentine Pampa Region for more than a century. This long history of disturbance has strongly modified the native vegetation of the region. Some original species have disappeared or its area has been remarkably reduced. The objective was to evaluate vegetation changes over time after the abandonment of agriculture practice. Our hypothesis was that over time vegetation in this region will evolve towards a "flechillar" ( Stipa spp. community) similar to the original vegetation. The experiment was conducted at Zavalla (Santa Fe) Argentina (33degrees01′S, 60degrees53′W and 50 m.a.s.l.). Vegetation evolution was studied during 15 years (1982-1997) after abandonment, considering four initial crop situations (i.e. wheat, soybean, pasture and tillage). Periodically, we measured species cover and abundance in 60 subplots. Data was analyzed using multivariate methods. We identified several groups corresponding to two very well defined successional stages. The first group was very small, and showed predominance of annual species; the second group showed a reduction or almost disappearance of annuals and an increase in perennials such as Baccharis salicifolia (Ruiz & Pav.) Pers. and Sorghum halepense (L.) Pers. accompanied by Carduus acanthoides L. Therefore, a secondary succession was developed, with a first stage of annual species dominance followed by long life cycle species. However, even after 15 years there was no reversion of the vegetation to the original community.
  • Authors:
    • Bosede, A.
  • Source: African Journal of Agricultural Research
  • Volume: 5
  • Issue: 5
  • Year: 2010
  • Summary: An assessment of fertilizer use and other integrated practices was carried out with two hundred farmers selected by stratified random sampling from twenty villages in Kano and Katsina States of Nigeria. The farming system was mixed farming (legume-cereal-livestock mixture), as a strategy both to address nutrient management as well as their livelihoods (both food and income security). The major crops comprised maize, sorghum, millet, rice, soybean, groundnut and cowpea. The average farm size was 7.4 ha and livestock comprised an average of 14 goats, 15 poultry birds, 7 sheep and 9 cattle. An average of 63 kg fertilizer was applied per ha of land relative to about 649 kg of fertilizer requirement per hectare of the crops grown, very low relative to Asia and some other African countries such as South Africa, Malawi, Benin and Ethiopia. The livestock mix provided substantial farmyard manure for fertilizing the soils and supplemented farm drought animals/animal traction while the crop residues (legumes and cereals) provided feeds for the livestock. It was found that fertilizer use multiplies the returns on farmers' output by a factor of 2.1-14.6, which was relatively higher than previous findings (IFDC, 2002) for the same crops in Nigeria, but crop yields were comparatively less for other Sub-Saharan and Asian countries. The observed higher response coefficient could be explained by the use of organic/farmyard manures and other soil conservation practices. Farmers exploit land and the natural fertility of the soil through continuous cropping and poor fertilization (organic and inorganic). Critical environmental issues emanating from these are soil nutrient depletion, soil degradation by erosion, weed and pest invasion, all culminating in sustained low productivity. It was therefore concluded that sustained growth in agricultural productivity without environmental exploitation and degradation cannot be achieved unless efforts to enhance farmers' fertilizer use and organic fertilization are taken seriously. Efforts should be put in place to correct fertilizer market inadequacies, particularly to monitor the quality standard and guarantee farmers' access to fertilizers, as well as encourage National research and extension programs to emphasize economic use of basic local materials for effective fertilization of farmers' fields, reduced vulnerability to nutrient loss and drought, and increased agricultural productivity.
  • Authors:
    • Wruck, F.
    • Feigl, B.
    • Bernoux, M.
    • Cerri, C.
    • Raucci, G.
    • Carvalho, J.
    • Cerri, C.
  • Source: Soil & Tillage Research
  • Volume: 110
  • Issue: 1
  • Year: 2010
  • Summary: Changes in land use can result in either sources or sinks of atmospheric carbon (C), depending on management practices. In Brazil, significant changes in land use result from the conversion of native vegetation to pasture and agriculture, conversion of pasture to agriculture and, more recently, the conversion of pasture and agriculture to integrated crop-livestock systems (ICL). The ICL system proposes a diversity of activities that include the strategic incorporation of pastures to agriculture so as to benefit both. In agricultural areas, for example, the implementation of ICL requires the production of quality forage for animals between crops as well as the production of straw to facilitate the sustainability of the no-tillage (NT) management system. The objective of this study was to evaluate the modifications in soil C stocks resulting from the main processes involved in the changes of land use in Amazonia and Cerrado biomes. For comparison purposes, areas under native vegetation, pastures, crop succession and ICL under different edapho-climatic conditions in Amazonia and Cerrado biomes were evaluated. This study demonstrated that the conversion of native vegetation to pasture can cause the soil to function either as a source or a sink of atmospheric CO 2, depending on the land management applied. Non-degraded pasture under fertile soil showed a mean accumulation rate of 0.46 g ha -1 year -1. Carbon losses from pastures implemented in naturally low fertile soil ranged from 0.15 to 1.53 Mg ha -1 year -1, respectively, for non-degraded and degraded pasture. The conversion of native vegetation to agriculture in areas under the ICL system, even when cultivated under NT, resulted in C losses of 1.31 in six years and of 0.69 Mg ha -1 in 21 years. The conversion of a non-degraded pasture to cropland (soybean/sorghum) released, in average, 1.44 Mg of C ha -1 year -1to the atmosphere. The ICL system in agricultural areas has shown evidences that it always functions as a sink of C with accumulation rates ranging from 0.82 to 2.58 Mg ha -1 year -1. The ICL produces soil C accumulation and, as a consequence, reduces atmospheric CO 2 in areas formerly cultivated under crop succession. However, the magnitude of C accumulation in soil depends on factors such as the types of crops, the edapho-climatic conditions and the amount of time the area is under ICL.
  • Authors:
    • Gamzatov, I.
    • Muslimov, M.
  • Source: Kormoproizvodstvo
  • Issue: 12
  • Year: 2010
  • Summary: Continuous green fodder conveyor production system allows quality fodder supply during the grazing season. Field trials were conducted in Dagestan, the North Caucasus, Russia, with Red Steppe cattle. Data are tabulated on sowing dates and period of use of fodder crops, i.e. natural pastures, winter rape, winter rye + winter vetch, pea-oat + vetch-oat, regrowth of perennial grasses after hay cutting, Sudan grass, maize and maize + Sudan grass, sorghum, regrowth of Sudan grass and sorghum, maize sown after winter cereals grown for green fodder, maize and sorghum grown for silage for additional feed rations, winter rye after pea + oat, squash, pumpkin, fodder watermelon and fodder beet, and regrowth of natural pastures and meadows. The importance of natural pastures and drought resistant plants, such as sorghum crops, for production of high yield of fodder in dry conditions of Dagestan is considered.
  • Authors:
    • Guimaraes Junior, R.
    • Marchao, R.
    • Moraes Neto, S.
    • Vilela, L.
    • Pulrolnik, K.
  • Source: Boletim de Pesquisa e Desenvolvimento - Embrapa Cerrados
  • Issue: 276
  • Year: 2010
  • Summary: The trees may improve the productivity of an agroecosystem, influencing the characteristics of soil, microclimate, hydrology and biological components associated. However, there is little information on the tree species most suitable for use in the system of integration crop-livestock-forest (SiLPF). In this context, the objective of this work was to evaluate the initial growth and survival of tree species native and exotic in different space arrangements and plant density in SiLPF in Planaltina, DF. The planting of seedling trees was conducted between January and March 2009. O design of treatments was randomized blocks with three replications of five treatments: control (tillage/grazing), native (two rows of trees and spacing between alleys of 12 m), Eucalyptus cloeziana (7 rows of trees and spacing between alleys of 22 m), Eucalyptus urograndis (2 rows of trees and spacing between alleys of 12 m) and Eucalyptus urograndis (2 rows of trees and spacing between alleys of 22 m). Among the alleys of forest species was planted sorghum in March 2009 and soybeans in December 2009 in no-tillage system with recommended fertilizer for the crop. There was no significant difference in survival between the treatments. Among the species studied native cedar species was less growth in height, while the guapuruvu, angico red mahogany and had the highest growth. Guanandi registered the worst performance and is not recommended in areas with high water deficit.
  • Authors:
    • Avcioglu, R.
    • Soya, H.
    • Demiroglu, G.
    • Kir, B.
  • Source: Turkish Journal of Field Crops
  • Volume: 15
  • Issue: 2
  • Year: 2010
  • Summary: This study was conducted in the experimental fields of Field Crops Department of Agriculture Faculty in Ege University, Bornova, Izmir-TURKEY under Mediterranean environmental conditions in the years, 2003-2009. Three legumes (Medicago satire, Lotus corniculatus and Trifolium resupinatum) and four grasses (Bromas inermis, Festuca erundinaceae, Dactylis glomerate and Arrhenatherum elatius) with Sanguisorha minor were sown in rows 15 cm apart and tested for some yield and quality characteristics under cattle grazing regime. Medicago satire and Festuca erundinaceae were the permanent and most successful legume and grass in the mixture in terms of botanical composition and cover traits throughout the experimental years. With respect to dry matter and crude protein yield characteristics, same components of the mixture also performed very well and have been evaluated as recommendable for all resembling Mediterranean environments. It was also suggested that Lotus corniculatus and Arrhenatherum elatius, both exhibiting stable and sustainable dry matter and crude protein yield contribution to overall performances of the sward, should be included in this type of Mediterranean pasture mixture. The general performance of this rotation pasture mixture was quite sustainable and suggested to utilize the sward economically for another couple of years.
  • Authors:
    • Tischew, S.
    • Reisinger, E.
    • Luick, R.
    • Jedicke, E.
    • Metzner, J.
  • Source: NATURSCHUTZ UND LANDSCHAFTSPLANUNG
  • Volume: 42
  • Issue: 12
  • Year: 2010
  • Summary: Extensive Grazing and Requirements for the new Agricultural Policy - Promotion of biological diversity, climate protection, water balance and landscape aestheticsThe near-natural pasturing of our cultural landscape stands for a modern, multi-functional agriculture. Many farms with grazing animals have an important share in effectively implementing the European challenges to protect biological diversity, climate and water. The subsequent paper - supported by numerous associations - makes proposals for a better establishment of extensive grazing in the funding guidelines of the Common Agricultural Policy (CAP) of the EU after 2013. Existing instruments are to be advanced in the following areas:On extensively grazed grasslands it should in future be possible to generally activate payment claims of the 1(st) column, and to combine them with aid programmes of the 2(nd) column. In order to reduce the risks of reclaims for the applicants the sites are to be identified by a specific code with an "integrated administration and control system", and the implementation of the measures is to be controlled according to nature conservation criteria.In the context of the 2(nd) column the study recommends the expansion of agri-environmental measures - including better co-financing by the EU, additional incentives and contract periods of up to 20 years.Additionally landscape management programmes have to be established on the basis of the Regulation of the EAFRD (Art. 57) - including invested-related measures which are not covered by agri-environmental schemes.The comprehensive counselling of the farms aims to promote a better integration of extensive grazing, ensuring the optimal combination of measures of the 1st and 2nd column.The study recommends the following measures which are particularly eligible: (a) extensive all-year continuous grazing with cattle and horses, (b) conversion of arable fields into extensively grazed grasslands in flood areas and on fen soils, and (c) biotope management with sheep and goats.
  • Authors:
    • Neffati, M.
    • Belgacem, A. O.
    • Visser, M.
  • Source: Grass and Forage Science
  • Volume: 65
  • Issue: 1
  • Year: 2010
  • Summary: When grass species are used to reseed depleted drylands, grazing is often prescribed during the establishment phase. Total protection from grazing often leads to the presence of persistent weed species and is hard to accept by land users keen to graze reseeded land as soon as possible. The particular case of reseeding arid Mediterranean cereal fallows with one native grass species, Stipa lagascae (Stipa), in Tunisia was tested. Seedlings, derived from two different seed sources (selected and bulk), and volunteer annual weed species underwent four different cutting treatments to ground level (early cut, late cut, early and late cuts and no cuts). No effect of any of the treatments on seedling survival or dry matter mass of Stipa seedlings was found. It was concluded that Stipa seedlings are indifferent to the presence of annual weed species and can tolerate more than one cut during the year of establishment. In the context of the study, early grazing of reseeded fallows is worth investigating further.