Rangeland Areas Research Articles

ASAP: A new global early warning system to detect anomaly hot spots of agricultural production for food security analysis

Monitoring crop and rangeland conditions is highly relevant for early warning and response planning in food insecure areas of the world. Satellite remote sensing can obtain relevant and timely information in such areas where ground data are scattered, non-homogenous, or frequently unavailable. Rainfall estimates provide an outlook of the drivers of vegetation growth, whereas time series of satellite-based biophysical indicators at high temporal resolution provide key information about vegetation status in near real-time and over large areas. The new early warning decision support system ASAP (Anomaly hot Spots of Agricultural Production) builds on the experience of the MARS crop monitoring activities for food insecure areas, that have started in the early 2000's and aims at providing timely information about possible crop production anomalies. The information made available on the website (https://mars.jrc.ec.europa.eu/asap/) directly supports multi-agency early warning initiatives such as for example the GEOGLAM Crop Monitor for Early Warning and provides inputs to more detailed food security assessments that are the basis for the annual Global Report on Food Crises. ASAP is a two-step analysis framework, with a first fully automated step classifying the first sub-national level administrative units into four agricultural production deficit warning categories. Warnings are based on rainfall and vegetation index anomalies computed over crop and rangeland areas and are updated every 10 days. They take into account the timing during the crop season at which they occur, using remote sensing derived phenology per-pixel. The second step involves the monthly analysis at country level by JRC crop monitoring experts of all the information available, including the automatic warnings, crop production and food security-tailored media analysis, high-resolution imagery (e.g. Landsat 8, Sentinel 1 and 2) processed in Google Earth Engine and ancillary maps, graphs and statistics derived from a set of indicators. Countries with potentially critical conditions are marked as minor or major hotspots and a global overview is provided together with short national level narratives.

Abiotic factors affect the recruitment and biomass of perennial grass and evergreen shrub seedlings in denuded areas of Patagonian Monte rangelands

Assessing the ability of key species to cope with environmental stresses in disturbed areas is an important issue for recovery of degraded arid ecosystem. Our objective was to evaluate the effect of soil moisture, exposure to UV radiation, and presence/absence of litter with different chemistry on soil N, recruitment and biomass of seedlings of perennial grass (Poa ligularis and Nassella tenuis) and evergreen shrub species (Atriplex lampa and Larrea divaricata) in denuded areas. We carried out a microcosm experiment with soil blocks (28 cm depth) sowed with seeds of the target species, subjected to different levels of litter type (perennial grass-evergreen shrub mixture, evergreen shrub mixture, and no litter), UV radiation (near ambient and reduced UV), and soil water (high: 15–25% and low 5–15%). Periodically, during 6 months, we assessed soil-N (total and inorganic) at two depths and species seedling recruitment at microcosms. Additionally, emerged seedlings of each species were transplanted to individual pots containing soil and subjected to the same previous factors during 12 months. Then, all plants were harvested and biomass assessed. Only inorganic soil-N at the upper soil varied among treatments increasing with the presence of evergreen shrub litter, exposure to ambient UV, and high soil water. Inorganic soil-N, promoted by near ambient UV and high soil water, had a positive effect on recruitment of perennial grasses and A. lampa. Both litter types promoted the recruitment of perennial grasses. Evergreen shrub litter and high soil water promoted the recruitment of L. divaricata. Seedling biomass of perennial grasses increased with high soil water and reduced UV. Ambient UV had positive or null effects on biomass of evergreen shrub seedlings. High soil water increased biomass of L. divaricata seedlings. We concluded that soil water appeared as the most limiting factor for seedling recruitment of all species whereas inorganic soil N limited the recruitment of the small-seeded perennial grasses and A. lampa. Ambient UV had negative effects on seedling biomass of perennial grasses. These complex relationships among abiotic factors and seed and plant traits should be taken into account when planning management actions after disturbances.

A new approach for land degradation and desertification assessment using geospatial techniques

Abstract. Land degradation reduces the production of biomass and vegetation cover for all forms of land use. The lack of specific data related to degradation is a severe limitation for its monitoring. Assessment of the current state of land degradation or desertification is very difficult because this phenomenon includes several complex processes. For that reason, no common agreement has been achieved among the scientific community for its assessment. This study was carried out as an attempt to develop a new approach for land degradation assessment, based on its current state by modifying of Food and Agriculture Organization (FAO)–United Nations Environment Programme (UNEP) index and the normalized difference vegetation index (NDVI) index in Khuzestan province, southwestern Iran. Using the proposed evaluation method it is easy to understand the degree of destruction caused by the pursuit of low costs and in order to save time. Results showed that based on the percent of hazard classes in the current condition of land degradation, the most and least widespread areas of hazard classes are moderate (38.6 %) and no hazard (0.65 %) classes, respectively. Results in the desert component of the study area showed that the severe class is much more widespread than the other hazard classes, which could indicate an environmentally dangerous situation. Statistical results indicated that degradation is highest in deserts and rangeland areas compared to dry cultivated areas and forests. Statistical tests also showed that the average degradation amount in the arid region is higher than in other climates. It is hoped that this study's use of geospatial techniques will be found to be applicable in other regions of the world and can also contribute to better planning and management of land.

Global effectiveness of group decision-making strategies in coping with forage and price variabilities in commercial rangelands: A modelling assessment

This paper presents a modelling study that evaluated the global effectiveness of a range of group decision-making strategies for commercial farming areas in rangelands affected by temporal variations in forage production. The assessment utilised an integrated system dynamics model (86 equations) to examine the broad and long-term group decision outcomes. This model considers aspects usually neglected in related studies, such as the dynamics of the main local prices, the dynamics of the number of active farmers, the supplementary feeding of livestock, and certain behavioural traits of farmers and traders. The assessment procedure was based on an analysis of the outcomes of the model under 330,000 simulation scenarios.The results indicated that only if all the farmers in an area are either opportunistic or conservative that is, are either responsive or unresponsive to expected profits, the exploitation of the grazing resources were optimal in some senses. A widespread opportunism proved optimal only from an economic viewpoint. However, it is very unlikely that most of the farmers would agree to be opportunistic in practice. By contrast, a widespread conservatism, which in principle is perfectly feasible, proved optimal from economic, social, and ecological perspectives. Notably, it was found that the presence of a relatively small number of opportunistic farmers would suffice to considerably reduce the economic results of widespread conservatism.

Whither the 100th Meridian? The Once and Future Physical and Human Geography of America’s Arid–Humid Divide. Part II: The Meridian Moves East

Abstract The 100th meridian bisects the Great Plains of the United States and effectively divides the continent into more arid western and less arid eastern halves and is well expressed in terms of vegetation, land hydrology, crops, and the farm economy. Here, it is considered how this arid–humid divide will change in intensity and location during the current century under rising greenhouse gases. It is first shown that state-of-the-art climate models from phase 5 of the Coupled Model Intercomparison Project generally underestimate the degree of aridity of the United States and simulate an arid–humid divide that is too diffuse. These biases are traced to excessive precipitation and evapotranspiration and inadequate blocking of eastward moisture flux by the Pacific coastal ranges and Rockies. Bias-corrected future projections are developed that modify observationally based measures of aridity by the model-projected fractional changes in aridity. Aridity increases across the United States, and the aridity gradient weakens. The main contributor to the changes is rising potential evapotranspiration, while changes in precipitation working alone increase aridity across the southern and decrease across the northern United States. The “effective 100th meridian” moves to the east as the century progresses. In the current farm economy, farm size and percent of county under rangelands increase and percent of cropland under corn decreases as aridity increases. Statistical relations between these quantities and the bias-corrected aridity projections suggest that, all else being equal (which it will not be), adjustment to changing environmental conditions would cause farm size and rangeland area to increase across the plains and percent of cropland under corn to decrease in the northern plains as the century advances.

Geospatial analyses of local economic structures in the rangeland areas of the Northern Territory, South Australia and Western Australia

We examine the economic structure of Australian local government areas in the Northern Territory, South Australia and Western Australia using economic base theory and location quotients. Whereas the economic base approach is long established, in this paper we extend the three-staged geospatial visualisation method of Blackwell et al. (2017) to two additional state jurisdictions. Focusing on the economic structure of rangeland local government areas, we find that these vary significantly, implying that no single generic development policy is likely to be effective, but rather these need to be crafted individually. We demonstrate that geospatial visualisations of employment location quotients can identify local economic vulnerability as well as opportunity.

How can sedentarised pastoralists be more technically efficient? A case from eastern Inner Mongolia

Technical efficiency (TE) means the effectiveness of production outputs attained for a given level of production inputs. This study examines pastoralist TE and its determinants for 416 pastoralist households from two leagues (prefectures) in eastern Inner Mongolia, a typical rangeland area in China. A one-step stochastic frontier method is applied to analyse data about household livestock production in 2011 to assess opportunities for increasing income and reducing poverty through increased TE. The main results show that pastoralists, in general, did not perform well with currently available technology, with the average TE score just 0.50 out of 1.0. Only about one-fifth (20.2%) of respondents had TE scores >0.7, and the same proportion had a TE score <0.3. More than one-quarter had TE scores in the range 0.3–0.5, and slightly more than one-third had TE scores in the range 0.5–0.7. About 83% of the variation in pastoralist livestock production is explained by the loss of TE. The age of the head of household, available pasture, investment in covered pens and participation in the rangeland rental market were found to influence TE. Encouraging younger pastoralists to enter pastoralism, and enlarging available grazing land through the rangeland rental market or cooperative rangeland use would likely enhance pastoralist performance; promoting investment in covered-pen construction could also improve productivity and alleviate a rangeland degradation cycle, which is pervasive in the study area.

Determinants of Farm Size and Stocking Rate in Namibian Commercial Cattle Farming

Utilizing a data set of 399 Namibian commercial cattle farmers, we provide a detailed empirical analysis of farm management under highly variable rainfall. Particularly, we provide an econometric analysis of what personal characteristics of the farmer, environmental characteristics, and characteristics of the farm explain farm size and choice of stocking rate. There is strong support for the hypothesis that environmental variables such as inter-annual rainfall variability play a vital role in explaining stocking rate, but not in explaining farm size in the sense of rangeland area or cattle numbers. Other major explaining factors for the stocking rate are the farmer’s gender and the number of cattle on farm above a certain threshold given by a fit of the Pareto distribution to the data. Traditional farm size variables like cattle number and rangeland area are not well explained by any of the candidate models constructed, which supports the view that the stocking rate is the central farm management parameter.

Comparison of vegetation properties on the protected and grazed rangeland areas: The case of Kocapınar Rangeland

Bu calisma, Isparta ili Davraz Dagi Kozagaci Yaylasi Kocapinar Merasinda 2011-2012 yillarinda, bazi bitki ortusu ozelliklerini belirlemek amaciyla yapilmistir. Olcumler iki yil suresince haziran ve eylul aylarinda, otlatilan ve korunan mera alanlarinda gerceklestirilmistir. Bitki ile kapli alan tespitinde “transekt yontemi”, kuru ot veriminin belirlenmesinde ise “kuadrat yontemi” kullanilmistir. Mera alanlarinda toplam 30 familya ve 140 bitki taksonu belirlenmistir. En fazla taksona sahip familyalar 25 takson ile Asteraceae, 14 takson ile Lamiaceae, 12 takson ile Brassicaceae ve Fabaceae olarak belirlenmistir. Calisma sahasi bitki ortusunun botanik kompozisyonunda, toplam bugdaygil orani otlatilan alanda %60.9, korunan alanda %58.7, baklagil orani ayni sirayla %14.4 ve %18.0, diger familyalara giren tur oranlari ise %24.7 ve %23.3 olarak bulunmustur. Bitki ile kapli alan oranlari otlatilan alanda ortalama %24.3 olurken, korunan alanda %30.5 olarak tespit edilmistir. Ayrica otlatilan alanda ortalama 3.478 olan mera kalite derecesi, korunan alanda 3.787 olarak belirlenmistir. Toprakustu biyokutle miktari otlatilan alanda ortalama 208.24 kg/da olurken, korunan alanda 256.49 kg/da, toprakalti biyokutle ise sirasiyla 347.88 kg/da ve 454.41 kg/da olarak belirlenmistir. Otlatma kapasitesi 1 ha’lik alan icin otlatilan alanda ortalama 0.39 buyuk bas hayvan birimi (BBHB) olurken, korunan alanda 0.48 BBHB olarak belirlenmistir.

Macroinvertebrate communities in riverine systems of buffer areas of protected wildland, rangeland and city areas: implications for conservation of riverine systems on urbanising watersheds.

Riverine systems in developing countries continue to be degraded by anthropogenic pressures such as urbanisation. The responses of biota in watersheds surrounding a drainage divide may provide critical information that is required to protect the ecological condition of riverine systems. This study assessed the spatial variation of selected environmental variables together with macroinvertebrate communities in upper reaches of riverine systems across different land use categories of the Bulawayo region. Based on an a priori selection criterion, studied sites were grouped following an urban-wastewater disturbance gradient comprising of (i) heavily polluted city sites, (ii) moderately disturbed rangeland sites and (iii) less disturbed sites of the buffer areas of protected wildland. Most of the studied environmental variables and the macroinvertebrate community assemblages were significantly (ANOVA, p<0.05) different and degraded within the city areas. In this study, the variance of environmental variables known to be associated with organic pollution like increased nutrients, embeddedness by particulates, salinity, COD, conductivity, turbidity and reduced dissolved oxygen was found to be related with the variation of macroinvertebrate communities across the studied sites. Besides affirming the effectiveness of macroinvertebrate-based bioassessment approaches, the results of our study demonstrate that an aggressive riverine protection policy that prohibits the discharge of poor-quality urban effluents and preservation of the less disturbed riverine systems needs to be part of the larger urban planning and regulatory framework in urbanising watersheds.

A Case of Echinococcosis: Surgical Management of Hepatic Hydatid Cyst

Echinococcosis is a parasitic infection, also known as hydatidosis, caused by of the tapeworm Echinococcus. In regions endemic to cystic echinococcosis the World Health Organization reports incidence rates over 50 per 100,000 person-years. It is globally distributed and commonly seen in regions with pastoral and rangeland areas. Humans are accidental intermediate hosts through ingesting food and water contaminated with the parasites eggs. The species Echinococcus granulosus causes cystic echinococcosis predominately affecting the liver. A 34 year old female Yemeni immigrant, presented with the chief complaint of right upper quadrant abdominal pain, and slightly elevated transaminases. An abdominal CT with contrast noted a 10.1 X 9.3 cm cyst in the superior right hepatic lobe. Using ultrasound guidance cyst 500 ml of colorless fluid was aspirated from the cyst. Cytology demonstrated parasitic structures with hooklets consistent with Echinococcus. She was treated with a 10 day course of Albendazole, however she continued to have persistent abdominal pain. Repeat CT and US revealed recurrence of the cyst with findings concerning for daughter cyst formation. Based on World Health Organization staging criteria treatment options included; repeat cyst aspiration or surgical resection with concomitant Albendazole. In light of the cystic septations noted on MRI surgery was favored and she underwent hepatic segment VII resection with the encapsulated cyst. She had an uneventful recovery with normal hepatic function and was discharged home with 4 weeks of albendazole therapy. Repeat ultrasound 2 months post op revealed no evidence of recurrent cyst formation. The diagnosis of hepatic hydatid cysts requires a high degree of clinical suspicion and knowledge of the subtle signs and symptoms of the disease. Early diagnosis and appropriate treatment prevents complications of the disease including pressure symptoms, cyst leakage, cholangitis and anaphylaxis. Treatment options are dependent on the stage of the hydatid cysts, and surgery should be considered for patients who have not responded to medical management and have evidence of cyst criteria not amenable to percutaneous drainage. Rates of recurrent infection are significantly lower after radical surgical procedures however follow up is still recommended for up to 5 years post treatment with periodic imaging.Figure: Cut sections of the single hepatic cyst with multiple concentric membranes and yellow scoleces.Figure: Admission CT abdomen and pelvis with contrast shows right hepatic lobe cyst measuring 10.1 x 9.3 cm.Figure: MRI w contrast demonstrating the floating membranes.

Improving the Efficiency of Use of Agricultural Land in the Republic of Kazakhstan

The agricultural lands have a special legal regime and are subject to the protection aimed at limiting the seizure of these lands, preserving and increasing their fertility. The area of lands of this category in the structure of land Fund accounts for 100.8 million hа, or 38.6% of used land. Their share in the land Fund of the regions ranges from 70-75% (North-Kazakhstan, Akmola region) to 10-20% (Kyzylorda, Atyrau region). It is mainly related to different climatic conditions and vast areas of desert and semi-desert rangelands.

Phytogeographical distribution of roadside flora along the plain to mountainous natural areas (Northern Khorasan Province, Iran)

Exploring the phytogeographical distribution of roadside flora in natural areas provides several original insights into plant dispersal. The roadside flora of the Irano–Turanian rangelands was studied in the northeast of Iran, along about 600km of asphalt road. Sampling was performed in homogenous physiognomic-physiographic units along the altitudinal gradient from the plain to the mountainous areas. In a stratified random design, 38 sites on 12 asphalt roads were sampled, and 330 plant taxa of different chorotypes were identified. The altitudinal distribution of the chorotypes was examined fitting generalized linear models (GLM) and generalized additive models (GAM). The results showed that native uni-regional taxa (Irano–Turanian elements) were the dominant chorotype of the roadside habitats in the rangeland areas. The altitudinal response curve of multi-regional (bi-regional to quadri-regional) chorotypes reflected climatic conditions in their contributing phytochoria. Quadri-regional taxa, with an optimum of the Gaussian response curve at mid-altitudes, reflected a moderate climate. The proportion of endemic species (3.6%) was high compared to the pluri-regional (4.6%) and the cosmopolitan taxa (1.2%). While the pluri-regional taxa increased with altitude, cosmopolitan species decreased monotonically and were absent from the high altitudes. This study revealed the importance of the mid-altitude roadsides, both as a refuge for local endemic species and as a bed for local weeds and regional alien species.

An investigation on the effect of land use land cover changes on surface water quantity

Abstract The present study is an attempt to show how changes in land use and land cover would change the quantity of surface water resources in a river basin in northwestern Iran. In order to detect the changing trend of surface water quantity in the river basin, the long-term statistic data of sediment load and river discharge were gathered over the period between 1987 and 2013. For land use change detection of the river basin, the land use land cover maps of the study area in the years of 1987, 1998, 2002, 2009, and 2013 were prepared from Landsat satellite images using supervised classification method. The changing trend of river discharge showed a significant and positive relationship with rain-fed agriculture (R2 = 0.8152), poor rangeland (R2 = 0.7978), and urban areas (R2 = 0.8377). There was also a strong negative correlation between water discharge and irrigated agriculture (R2 = 0.7286) and good rangeland (R2 = 0.8548). In conclusion, increasing the area of rain-fed agriculture, good rangeland (type IV), and urban land uses, due to their effects on increasing the runoff, have caused an increase in the water flow of Zanjanroud River.

Evaluating the Effects of Government Policy and Drought from 1984 to 2009 on Rangeland in the Three Rivers Source Region of the Qinghai-Tibet Plateau

The Three Rivers Source Region of the Qinghai-Tibet Plateau is a key area that has extensive impacts on much of the population and economy of China as well as several Southeast Asian countries. The rangeland in this area has undergone degradation, the driving factors of which have been extensively investigated in previous studies. However, the effect of policy on rangeland was not analyzed by subdividing the study period according to the timing of the rangeland policies. The role of dry conditions during the process of degradation has not been studied. Therefore, the period from 1984 to 2009 was subdivided into five periods according to the timing of the relevant government policies based on long-term field investigation. The mean annual normalized difference vegetation index (NDVI) and its relationship to dry conditions, policy, temperature, precipitation, and moisture index were analyzed for the five periods. According to our analysis, dry conditions mainly occurred in non-vegetation-growing months, and they did not affect the status of the rangeland. The privatization of rangeland and livestock caused the number of livestock to increase, resulting in a decrease in the mean annual NDVI from 1984 to 1993. The policies of “Green-to-Grain” and eco-migration caused livestock numbers to decrease and the NDVI to increase after 1994. Physical factors such as temperature, precipitation, and moisture also affected the status of the rangeland. Increased temperature had positive effects on rangeland in most areas, but its effect was offset by increased numbers of livestock from 1984 to 1993. Precipitation had positive effects only in drier areas in which the precipitation in the vegetation-growing months was less than 400 mm. In general, the policies of “Green-to-Grain” and eco-migration improved the status of rangeland, and helped improve sustainable use of the rangeland. The methods used in this study could be applied to other case studies of rangeland. Governments should continue to implement compensation policies to maintain the improved condition of rangeland in the area and expand those policies to other rangeland areas.

Applying the concept of resilience to pastoralist household data

This article explores the concept of resilience as outlined in a recent World Bank publication that applies the concept to rangeland areas in Africa. The paper does not attempt to speak to all of the dimensions of resilience and debates about the concept’s applications to pastoral ecology and rangelands. Instead, we utilize a panel data set from northern Kenya and southern Ethiopia that has been analysed in other published studies to reconsider it from a resilience perspective. We show how different livelihood groups in the region are impacted by climate, disease, market, conflict, and land use shocks in a time characterized by a drought phase and a recovery phase. In many cases, there are livelihood-specific impacts of these shocks, and these help explain long-term herd dynamics and pastoralist poverty traps. Our analysis then turns to different ways of measuring resilience and finds that measurements of combined income and asset thresholds provide the most convincing outcomes. We further assess some broader opportunities and innovations that have the potential to enhance resilience in the drylands. Finally, different policy relevant steps that can be taken to enhance resilience are discussed in the context of the considerable heterogeneity in livelihood strategies which occurs in African rangelands.

Aridity and Overgrazing Have Convergent Effects on Ecosystem Structure and Functioning in Patagonian Rangelands

AbstractOver 65% of drylands are used for grazing of managed livestock. Understanding what drives grazing effects on the structure and functioning of rangelands is critical for achieving their sustainability. We studied a network of 239 sites across Patagonian rangelands (Argentina), which constitute one of the world's largest rangeland area. We aimed to (i) evaluate how aridity and grazing affect ecosystem structure and functioning and (ii) test the usefulness of the landscape function analysis (LFA) indices (stability, infiltration and nutrient cycling) as surrogates of soil functioning. Aridity decreased species richness and the cover of palatable grasses but increased the cover of palatable shrubs. Grazing pressure negatively impacted the cover of palatable grasses and species richness but did not affect the cover of shrubs. Aridity had direct and indirect negative relationships with the LFA indices. Grazing pressure had no direct effects on the LFA indices but had an indirect negative effect on them by affecting vegetation structure. The LFA indices were positively and negatively correlated with soil organic carbon and sand contents, respectively, suggesting that these indices are useful proxies of soil functional processes in Patagonian rangelands. Our findings indicate that aridity and overgrazing have convergent effects on the structure and functioning of ecosystems, as both promoted reductions in species richness, the cover of palatable grasses and soil functioning. Rangeland management activities should aim to enhance species richness and the cover of palatable grasses, as these actions could contribute to offset adverse effects of ongoing increases in aridity on drylands. Copyright © 2017 John Wiley &amp; Sons, Ltd.

Choice Options to Meet Household Food Security in the Cattle Corridor of Uganda

This study identified the major options adopted by households in the rangelands of Uganda to meet their food needs, the factors that affect their choices and barriers to making use of various choices. A cross-sectional survey using semi-structured questionnaires was administered among 180 pastoral households in selected rangeland area of Uganda. The options identified include restocking animals, changing planting dates, soil conservation, harnessing new technologies, planting trees and buying food stuffs. Analysis of results from the multinomial logistic model indicated that age, level of education, size of household, years in current location, farm income, non-farm income, livestock ownership, access to extension services and climate and weather information were key determinants of farmers’ choice of options to realize household food security. The major perceived barriers to choice options were lack of information on alternative options, poor technologies, climate variability, inadequate land, high food prices and low income. The analysis of choice of options to meet household food security suggests a number of different policy options such as strengthening production facilitation options available to pastoral communities including among others access to affordable credit, investing in yield-increasing technologies, introduction of livestock species that are better suited to drier conditions, raising awareness on climate related variations, creating opportunities for off-farm employment, encouraging pastoralists to grow more crops, and investing in irrigation.

Optimizing land use pattern to reduce soil erosion

Soil erosion hazard is one of the main problems can affect ecological balance in watersheds. This study aimed to determine the optimal use of land to reduce erosion and increase the resident's income of Qushchi watershed in West Azerbaijan province, Iran. Income and expenses for the current land uses were calculated with field studies. Damages resulting from the soil erosion were estimated by soil depth equal to the specified land uses. For three different options including the current status of land uses without and with land management, and the standard status of land uses, multi-objective linear programming model was established by LINGO software. Then the optimization problem of the land use was solved by simplex method. Finally, the best option of land use was determined by comparing erosion rate and its cost in each scenario. Then the circumstances and the recommended conditions were compared. The results indicated that the current surface area of current land uses is not suitable to reduce erosion and increase income of residents and should change in the optimum conditions. At the optimum level, there should change horticulture area of 408 to 507 (ha), irrigated land area of 169 to 136 (ha) and dry farming of 636 to 570 (ha), while conversion of rangeland area not indispensable. In addition, the results showed that in case of the optimization of land use, soil erosion and the profitability of the whole area will decrease 0.75% and increase 3.68%, respectively. In case of land management practices, soil erosion will decrease 42.27% and the profitability increase 21.39% while in the standard conditions, soil erosion will decrease 60.95% and profitability will increase 24.20%. The results of the sensitivity analysis showed that the changes in the horticulture and range land areas have the greatest impact on the increasing profitability and reducing soil erosion of Qushchi watershed. So, it is recommended using Education and Extension to promote the importance of land management to understand how proper use of the land.

Nitrogen balance in Australia and nitrogen use efficiency on Australian farms

The amount of reactive N in soils on the Australian continent appears to be increasing, mainly because of biological N-fixation by permanent pastures in the dryland farming zone. This gain is partly offset by N-mining by crops, which we estimate have removed between one-fifth and one-quarter of the original soil N. The vast areas of non-agricultural land and arid rangelands appear to be in neutral N balance and the relatively small area of intensive agriculture is in negative balance. There are regional N losses from the sugar and dairy industries to groundwater, estuaries and lagoons, including the Great Barrier Reef. Fertiliser N application is increasing, and is likely to increase further, to compensate for the soil-N mining and to meet increasing crop yield potential, but fertiliser-N represents a relatively small fraction of the Australian N balance. The dryland farming zone utilises the largest amounts of native and fertiliser N. The average fertiliser application to dryland cereals and oilseeds, 45 kg N ha–1, is low by international standards because of the small N-demand by dryland crops and because there are no subsidies on crops or fertiliser that promote overuse. The efficiency of N-use is relatively low, for example about 40% of fertiliser N is recovered in the aboveground parts of dryland wheat and the rest is retained in the soil, denitrified or otherwise lost. We suggest further research on fertiliser-application methods to increase crop recovery of fertiliser, as well as research to reduce the surplus N from permanent pasture.