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Since the 1990s, the scientific literature has shown how the technical model of intensification of livestock production is ill adapted to the characteristics of semi-arid climates and the pastoral systems operating in them. While this led to changes in the rhetoric of pastoral development, there have been no significant shifts in its conceptual foundations and working methods. This article analyses the forms of this persistence, its effects and its causes in the Valley of the Senegal River through a study of the introduction of a social business dairy project into the pastoral area surrounding the city of Richard Toll. The industrial dairy producers and the pastoralists mutually use each other for their own ends, thereby reinforcing the discrepancy between their objectives and the logic of their systems. The model of intensification is persistent because it plays a political role in constructing alliances between actors from agribusiness, and because choices about land use and resource access are depoliticised and repeatedly made in their favour. The article underlines the urgency of re-politicising and rethinking the logic behind pastoral development and the challenges it faces, and of deconstructing the rhetoric of reconciling profit with social development which serves mainly to reinforce the role that private businesses play in shaping public action. KEYWORDS: Intensification, Techno-Political Models of Development, Pastoralism, Agribusiness, Middle Valley of the Senegal River, 1. Introduction From the colonial era to the end of the 1990s, the technoscientific model of intensification of livestock production served as an explicit reference for interventions in pastoral development [...]

Soil organic matter (SOM) plays a major role in agricultural and ecological processes. For this reason, accurate quantification of SOM is important for precision agriculture and environmental management. Inexpensive sensor technology could be a potential approach to achieving the accurate prediction of SOM. The objective of this study was to evaluate inexpensive colour sensor (Nix[TM] Pro) data for prediction of SOM in arid and semiarid areas of Iran. A total number of 85 and 152 soil samples from the soil surface (0-20 cm) were collected from the Semnan (arid area) and Qazvin (semiarid area) regions respectively. The nonlinear random forest (RF) method and linear regression were conducted to predict SOM using Nix[TM] pro colour sensor data. The partial least-squares approach was also utilised to reduce the dimensions of the dataset, decrease the number of input variables and avoid multi-collinearity. Soil colour was measured in moist and dry conditions. Root mean square error (RMSE), correlation coefficient (r), r-square ([R.sup.2]), mean square prediction error (MSPE) and ratio of performance to interquartile distance (RPIQ) were used to assess the RF and the linear regression models for prediction of SOM. Moist sample data was used for estimation of the SOM because of the larger correlation between SOM and colour sensor data in moist than dry samples. In estimation of SOM, the RF model represented lower dispersion between the estimated and the actual values of SOM (RMSE = 0.42, 0.43, RPIQ = 2.2, 2.06 and MSPE = 0.19, 0.19 in semiarid and arid regions respectively). In contrast, more dispersion was obtained by applying the linear regression model (RMSE = 0.61 and 0.51, RPIQ = 1.47 and 1.76, and MSPE = 0.39 and 0.26 in semiarid and arid regions respectively). The RPIQ values for linear regression in arid and semiarid areas were 1.76 and 1.47 respectively. Hence, the use of a linear regression model for prediction of SOM in arid areas would result in acceptable reliability; however, its utilisation should be avoided in semiarid areas due to less reliable results. Additional keywords: Inexpensive colour sensor, nonlinear models, soil organic matter. Received 25 October 2018, accepted 8 February 2019, published online 29 March 2019, Introduction Soil organic matter (SOM) has an essential role in various agricultural and ecological processes including the carbon cycle, soil fertility and soil physical interactions involving C[O.sub.2] sequestration (Sullivan et [...]

Physical and hydraulic properties of soil are variable at different spatial scales. This indicates the necessity of understanding spatial patterns of soil properties. Scaling analysis, such as multifractal analysis, has been used to determine the spatial variability of soil properties. There are however limited numbers of studies concerning the applications of multiffactal techniques applied to characterise spatial variability of soil properties in arid lands. The objective of this study was to quantify the scaling patterns of soil properties measured across a transect and to apply multiffactal analysis in arid land areas. A transect with a length of 4.80 km was selected, and soil properties were measured at 0-20 cm depth every 145 m along the transect. The soil properties analysed were: texture (sand, silt, clay), pH, electrical conductivity (EC), bulk density (BD), soil hydraulic properties (saturated hydraulic conductivity [K.sub.s] and the van Genuchten soil water- retention equation's parameters [n.sub.v] and [α.sub.v]), saturated water content ([θ.sub.s]), and the slope of the soil water-retention curve at its inflection point (S). Results showed that the variability of pH and BD was characterised by quasi-monofractal behaviour. Results showed that soil hydraulic properties such as [K.sub.s], [α.sub.n], [n.sub.v], S, and [θ.sub.s] were characterised by higher multiffactal indices in the transects. EC showed the highest tendency to a multifractal type of scaling or the higher degree of multiffactality. Additional keywords: asymmetry index, box-counting method, hydraulic properties, tension infiltrometer. Received 6 October 2015, accepted 22 June 2016, published online 26 September 2016, Introduction Spatial variability is an inherent property of soils. The spatial variability of soil properties results from interactions between the five factors of soil and several physical, mineralogical, chemical, biological, [...]

We used aerial photography from 1954 and airborne LiDAR and imaging spectroscopy from 2008 to infer changes in extent and location of tallstature woody vegetation in 127 [km.sup.2] of subalpine dry forest on the island of Hawai'i (Pohakuloa Training Area), and to identify 25.8 [km.sup.2] of intact woody vegetation for restoration and management. Total cover of woody vegetation was 54.7 [km.sup.2] in 1954 and 58.6 [km.sup.2] in 2008. Approximately 28.9 [km.sup.2] underwent woody vegetation change (22.7%) between 1954 and 2008. Increases in woody vegetation cover occurred in 16.4 [km.sup.2], and 12.5 [km.sup.2] represented reduction of woody vegetation cover (12.9% and 9.8% of the 127 [km.sup.2] study area, respectively). Our findings suggest that 3.9 [km.sup.2] (3.0%) experienced a net increase in woody vegetation cover between 1954 and 2008. Spatial patterns suggest that fires may be the primary driver of reductions in woody vegetation cover. Increases could be due to regeneration of dry forest trees or measurement errors associated with historical imagery. Areas remaining in woody vegetation cover over the 53-yr study interval can be targeted for restoration and management. We discuss challenges to integrating historical photography with contemporary conservation and management in Hawai'i and the Pacific and we outline additional studies that would help to improve estimates. The methods and analysis are general and could be applied to other dryland ecosystems with complex volcanic substrates in Hawai'i and the Pacific., A challenge to conservation and restoration projects is defining management objectives in the context of historical impacts. Whether current patterns represent natural or modified conditions is usually unknown in the [...]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2009.12.014 Byline: Yong Zhong Su (a)(b), Xue Fen Wang (a), Rong Yang (a), Jaehoon Lee (c) Abstract: The rehabilitation of sandy desertified land in semi-arid and arid regions has a great potential to increase carbon sequestration and improve soil quality. Our objective was to investigate the changes in the soil carbon pool and soil properties of surface soil (0-15cm) under different types of rehabilitation management. Our study was done in the short-term (7years) and long-term (32years) desertification control sites in a marginal oasis of northwest China. The different management treatments were: (1) untreated shifting sand land as control; (2) sand-fixing shrubs with straw checkerboards; (3) poplar (Populus gansuensis) shelter forest; and (4) irrigated cropland after leveling sand dune. The results showed that the rehabilitation of severe sandy desertified land resulted in significant increases in soil organic C (SOC), inorganic C, and total N concentrations, as well as enhanced soil aggregation. Over a 7-year period of revegetation and cultivation, SOC concentration in the recovered shrub land, forest land and irrigated cropland increased by 4.1, 14.6 and 11.9 times compared to the control site (shifting sand land), and increased by 11.2, 17.0 and 23.0 times over the 32-year recovery period. Total N, labile C (KMnO.sub.4-oxidation C), C management index (CMI) and inorganic C (CaCO.sub.3-C) showed a similar increasing trend as SOC. The increased soil C and N was positively related to the accumulation of fine particle fractions. The accumulation of silt and clay, soil C and CaCO.sub.3 enhanced the formation of aggregates, which was beneficial to mitigate wind erosion. The percentage of >0.25mm dry aggregates increased from 18.0% in the control site to 20.0-87.2% in the recovery sites, and the mean weight diameter (MWD) of water-stable aggregates significantly increased, with a range of 0.09-0.30mm at the recovery sites. Long-term irrigation and fertilization led to a greater soil C and N accumulation in cropland than in shrub and forest lands. The amount of soil C sequestration reached up to 1.8-9.4 and 7.5-17.3Mg ha.sup.-1 at the 0-15cm layer over a 7- and 32-year rehabilitation period compared to the control site, suggesting that desertification control has a great potential for sequestering soil C and improving soil quality in northwest China. Author Affiliation: (a) Linze Inland River Basin Research Station, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China (b) Key Laboratory of Inland River Eco-hydrology, Lanzhou 730000, China (c) Biosystems Engineering & Soil Science, The University of Tennessee, Knoxville, TN 37996, USA Article History: Received 17 September 2008; Revised 27 August 2009; Accepted 9 December 2009

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2005.08.008 Byline: S. Priyantha Ranjan (a), So Kazama (b), Masaki Sawamoto (a) Abstract: To estimate the freshwater loss in coastal aquifers due to salinisation, a numerical model based on the sharp interface assumption has been introduced. The developed methodology will be useful in areas where limited hydrological data are available. This model will elaborate on the changes in fresh groundwater loss with respect to climate change, land use pattern and hydrologic soil condition. The aridity index has been introduced to represent the variations in precipitation and temperature. The interesting finding is that the deforestation leads to increase groundwater recharge in arid areas, because deforestation leads to reduce evapotranspiration even though it favors runoff. The combined climate and land use scenarios show that when the aridity index is less than 60, the agricultural lands give higher groundwater recharge than other land use patterns for all hydrologic soil conditions. The calculated recharge was then used to estimate the freshwater-saltwater interface and percentage of freshwater loss due to salinity intrusion. We found that in arid areas, the fresh groundwater loss increases as the percentage of forest cover increases. The combined effects of deforestation and aridity index on fresh groundwater loss show that deforestation causes an increase in the recharge and existing fresh groundwater resource in areas having low precipitation and high temperature (arid climates). Author Affiliation: (a) Department of Civil Engineering, Graduate School of Engineering, Tohoku University, Aoba Yama 06, Sendai 980-8579, Japan (b) Graduate School of Environmental Studies, Tohoku University, Aoba Yama 06, Sendai 980-8579, Japan. Article History: Received 29 June 2004; Revised 8 August 2005; Accepted 11 August 2005

Late Quaternary denudation rates are constrained from alluvial fans and tributary watersheds in central Death and Panamint Valleys. Preliminary results suggest that the denudation rate is in part a function of the mean watershed elevation. Rainfall increases semi-logarithmically with higher elevation to about 2500 m where it becomes limited by the regional average maximum moisture content of the air mass. The fan volumes show a power-law relation to the watershed areas. The fan volumes ranged from about 250,000 to 4000 [km.sup.3] and the watershed areas range from about 60,000 to 2000 [km.sup.2]. The upper limit of the denudation rates estimated from small Death Valley fans restricted to the east side of the basin along the Black Mountain frontal scarp range between about 0.03 to 0.18 mm/yr. The maximum is made by assuming most of the elastic accumulation in these Fans followed the last highstand of Lake Manly around 24,000 yr which is the least conservative condition. The upper limit of the denudation rates from the Panamint fans range from 0.04 to 0.20 mm/yr assuming the accumulation mainly postdates OIS-4 ~60,000 yr or OIS-2 ~20,000 yr based on the presence or absence of inset shorelines from the last glacial pluvial maximum. The greater denudation rate associated with the higher mean watershed elevations can mainly be attributed to the greater rainfall at higher elevation. Denudation rotes are about a third or less of the Neogene dip-slip rates reported from nearby active faults consistent with relief increasing during dryer periods. Keywords: Death Valley; alluvial fans; Quaternary: denudation rates: arid processes: Panamint Valley