Does population pressure induce farm intensification? Empirical evidence from Tigrai Region,Ethiopia

The scarcity of land for crop and livestock production is critical in countries with growing populations. The idea that increasing population density leads to natural resource depletion and economic failure, as predicted by Malthus, or rather to farm intensification, as hypothesized by Boserup, motivates this research. This article examines how high population pressure in northern Ethiopia influences smallholders’ farm intensification by applying recursive estimation with a control function approach using data from 518 randomly selected farmers. Although our empirical results are more in favor of the Boserupian hypothesis, the findings also reveal that both Malthusian and Boserupian forces coexist. Consistent with Malthus theory, high population pressure is found to be associated with small farm size and herd size. Population pressure affected both technology use (breed cow, stall feeding, and modern cattle feed) and output supply (milk yield, milk income, and straw output). As predicted by Boserup's theory, the use of modern input and output supply initially increases with increasing population pressure but declines again when population densities pass a critical threshold (800 persons/km²), supporting Malthus’ hypothesis. The estimation results also revealed that both milk and straw supply responded positively to prices. Free grazing and stall feeding are found to be complementary activities. Likewise, crop farm income and off‐farm job have a nonlinear relation with population pressure, implying that both initially increase and then decrease with rising population pressure.     

ECONOMIC THEORY AND SHEEP-CATTLE COMBINATIONS*

This paper deals with the problem of determining the optimum combination of sheep and beef cattle on grazing properties. A major difficulty is that iso-cost functions (production possibility curves) for sheep and cattle are unstable and difficult to estimate because of sheep-cattle-pasture interaction. After discussion of theoretical difficulties consideration is given to practical approaches, based on the iso-cost function concept, which might provide graziers with useful guide-lines. Evidence is presented which suggests that the substitution rate between sheep and cattle with respect to pasture is not constant, and probably varies with stocking rate.     

Long-term effects of crop residues and fertility management on carbon sequestration and agronomic productivity of groundnut–finger millet rotation on an Alfisol in southern India

The data from long-term management and cropping systems experiments are needed to assess changes in soil quality, organic carbon pool, and agronomic sustainability. Thus, a 13-year-old soil fertility management experiment was used to assess the impact of crop residues carbon (C) inputs on SOC stock in a rainfed groundnut (Arachis hypogeae L.)–fingermillet (Eleusine coracana (L.) Gaertn) rotation in semiarid alfisol. The application of farmyard manure (FYM) alone or in a combination with chemical fertilizers contributed to higher amounts of C inputs and subsequently to build up a higher SOC pool. Application of 10?Mg?ha^?1 of FYM and a recommended dose of chemical fertilizer (25:21.8:20.7 and 50:21.8:20.7?kg?N, P, K ha^?1 for groundnut and fingermillet, respectively) increased soil SOC pool by 41.2% to 73.0?Mg?ha^?1 with an increase of 9.3?Mg?ha^?1 over 13 years. Both SOC pool and rates of its sequestration were positively correlated with cumulative C input and sustainable yield index. A minimal input of 1.62?Mg?C?ha^?1?yr^?1 is needed to maintain SOC pool at the antecedent level. Balanced application of NPK fertilizers is needed to reduce and reverse the depletion of SOC pool.     

Nitrogen Management for Profitable Farming with Minimal Environmental Impact: The Challenge for Mixed Farms in the Cotswold Hills,England

A detailed nitrogen (N) budget was constructed for a mixed farm in the Cotswold Hills, England, situated on thin, well drained soils prone to leaching. The study covered all stages of the farm's seven-year rotation and included the removal of the dairy herd. All inputs and outputs of N were measured or estimated and a balanced budget achieved, but only by including relatively expensive measurements of soluble organic nitrogen (SON) leached. Leaching was the main loss process. Given the nature of the soil and the influence of the weather, it would be difficult to reduce losses without drastic reductions in fertiliser inputs or stocking rates. Nitrogen use efficiency averaged 46%. The mean N surplus declined from 141 kg N ha^?1 to 117 kg N ha^?1 with the removal of the dairy herd. However, the farm to which the herd moved had an N surplus of 392 kg N ha^?1. Simple farm gate N budgets were constructed for neighbouring Cotswold farms to encourage farmers to consider ways to improve N use. Implications for policy to reduce losses of N while maintaining farm profitability are discussed.     

基于地块单元的冬小麦遥感估产方法研究

[目的]以高分时序遥感影像为基础数据源,结合土地承包经营权地块数据,对冬小麦遥感估产方法及其精度进行研究和分析。[方法]文章以河南省兰考县为研究区,采用2019年4―5月份的GF-1C和GF-6 2 m PMS遥感影像提取了研究区冬小麦种植空间分布,并在地块单元控制下对冬小麦种植面积进行了修正和精度验证。其最优提取结果的修正阈值为0.93,地块单元内冬小麦总体分类精度为95.66%,Kappa系数为0.89。利用3月7日至5月20日6期GF-1 WFV遥感影像序列NDVI和RVI与冬小麦种植地块单元数据进行空间统计,得出各冬小麦种植地块单元内NDVI和RVI均值,通过分析冬小麦测产地块单元内均值植被指数与产量间的敏感性,提出一种组合均值植被指数的冬小麦遥感估产模型构建方法,通过交叉验证法对不同的估产线性回归模型进行精度评价。[结果]由4个均值植被指数组合变量的多元线性回归模型为最佳,决定系数为0.922 0,预测误差为40.96 g/m~2,预测精度为93.13%。通过该模型得出兰考县冬小麦平均产量为6 047.25 kg/hm~2,较2017年河南省统计年鉴研究区冬小麦平均单产6 001 kg/hm~2有所提高,土地承包经营权地块内和地块外冬小麦总产量分别为2.76亿kg和4 650万kg。[结论]该方法实现了冬小麦估产结果以像元为单位向以地块单元为单位的转变,解决了模型构建时光谱信息与实测产量间对应问题,为利用国产高分卫星进行县域地块尺度遥感单产精准化估算提供了方法支撑。     

Persistence of cattle ranching in the Brazilian Amazon: A spatial analysis of the rationale for beef production

Fed by demand for beef within Brazil and in global markets, the Brazilian herd grew from 147 million head of cattle in 1990 to ≈200 million in 2007. Eighty-three percent of this expansion occurred in the Amazon and this trend is expected to continue as the industry bounces back from a recent agricultural downturn. Intensification of the cattle industry has been suggested as one way to reduce pressure on forest margins and spare land for soybean or sugarcane production, and is the cornerstone of Brazil's plan for mitigation of greenhouse gas emissions. To this end, federal credit programs and research and development activities in Brazil are aligning to support intensification goals, but there is no guarantee that this push for intensification will decrease the demand for land at the forest margin and as result curb CO₂ emissions from deforestation. In this paper we use a spatially explicit rent model which incorporates the local effects of biophysical characteristics, infrastructure, land prices, and distance to markets and slaughterhouses to calculate 30-year Net Present Values (NPVs) of extensive cattle ranching across the Brazilian Amazon. We use the model to ask where extensive ranching is profitable and how land acquisition affects profitability. We estimate that between 17% and 80% of land in the Amazon would have moderate to high NPVs when ranched extensively if it were settled, i.e. if the rancher does not buy the land but acquires it through land grabbing. In addition, we estimate that between 9% and 13% of land in the Amazon is vulnerable to speculation (i.e. areas with positive NPVs only if land is settled and not purchased), which suggests that land speculation is an important driver of extensive ranching profitability, and may continue to be in the future. These results suggest that pro-intensification policies such as credit provision for improved pasture management and investment in more intensive production systems must be accompanied by implementation and enforcement of policies that alter the incentives to clear forest for pasture, discourage land speculation, and increase accountability for land management practices if intensification of the cattle sector is to deter new deforestation and displace production from low-yield, extensive cattle production systems in frontier regions of the Brazilian Amazon.     

ANOTHER LOOK AT ECONOMIES OF SIZE IN CATTLE FEEDING*

This article is an outgrowth of a study that failed to find any economies of size in total cost of feeding cattle. It examines a number of cattle feeding studies that reportedly found economies of size and explains why the author is not willing to accept their findings. This article is not concerned with the external economies of size that may or may not exist in cattle feeding Cet article est le résultat ?une recherche qui n'a pas réussit à trouver de grands économics dans le prix total de ?engraissement de bétail. II examine un certain nombre ?étude sur ?engraissement de bétail que rapporterent (dit-on) de grands economies el il explique aussi pourquoi ?auleur n'est pas prêt à accepter leurs conclusions. Cet article ne se concerne pas avec les economies de grandeur extérieur quipeuvent ou nepeuventpas exister dans ?engraissement du bétail.     

An Econometric Model of the Colombian Beef Sector: 1950–1970

Recent theoretical and empirical studies of beef cattle producers by Barros, Jarvis, Nores, Reutlinger, and Yver have focused on producers' supply response assuming cattle represent consumption goods and capital goods. To differentiate producer price response for cattle sold as consumption goods and cattle retained as capital goods requires data on herd and slaughter age-sex structure. This has limited the range of econometric work which could be carried out in many developing countries. This study utilizes a time series of the Colombian cattle herd which was recently constructed by Rivas and Valdes and which has the necessary age-sex and slaughter data to develop a complete system of structural equations representing the simultaneous determination of demand and supply for Colombian cattle over the 1950–1970 period.     

Soil CO2 emission and carbon budget of a wheat/maize annual double-cropped system in response to tillage and residue management in the North China Plain

To investigate the impacts of tillage and crop residue managements on soil CO₂ emission and C budget in a wheat (Triticum aestivum L.)/maize (Zea mays L.) double-cropped system in the North China Plain (NCP), a field experiment was conducted consisting of four treatments: tillage with crop residues retention (CT+), tillage with crop residues removal (CT?), no-till with crop residues retention (NT+), and no-till with crop residues removal (NT?). Daily soil CO₂ fluxes changed with crop growing stage and peaked during the most vigorous growth of period, fluxes in maize season were higher than those in wheat season. Compared to the tilled soils, cumulative CO₂ emissions were significantly lower under no-till treatments. The largest cumulative CO₂ emission occurred under CT+ (65?g CO₂-C m^?2 y^?1) and the smallest was under NT+ (39?g CO₂-C m^?2 y^?1). After 5 years of the experiment, soil organic carbon (SOC) sequestration were greater with crop residues retention (CT+ and NT+) than with crop residues removal (CT? and NT?), the maximum SOC stock was in NT+ (5940?g C m^?2) while the minimum was in CT? (3635?g C m^?2). NT+ could help to mitigate CO₂ emission in the annual wheat/maize double-cropping system of the area.     

Valuing remnant vegetation in Central Queensland using choice modelling

In the Desert Uplands region of Central Queensland, many pastoralists are clearing vegetation in order to improve cattle grazing production. A choice modelling study was undertaken to provide estimates of the benefits of retaining remnant vegetation that are appropriate for inclusion in a cost benefit analysis of tighter clearing restrictions. Attributes included in the choice model were reductions in the population size of non-threatened species, the number of endangered species lost to the region, and changes in regional income and employment. A nested logit model was used to model the data in order to avoid violations of the independence of irrelevant alternatives condition. The estimated benefits are reported for several tree clearing policy regimes that are more stringent than those currently applied.     

The drivers of sugarcane expansion in Goiás,Brazil

Between 2003 and 2013, sugarcane area expanded six-fold, from 142,000 ha to 847,000 ha, in Goiás State and the Federal District, Brazil. And while there has been much research on land-use dynamics of sugarcane expansion in established sugarcane growing regions, little is known about the dynamics associated with its expansion in sugarcane frontiers like Goiás. Understanding these dynamics provides critical information for environmental, economic, and political decisions. Here, we investigate the agricultural land-use change dynamics associated with sugarcane production in Goiás and interrogate the relationship between biophysical, institutional, and logistical factors associated with sugarcane expansion. Our results demonstrate that pasture is seven times more likely to be converted to sugarcane than soy, and most new sugarcane area was not sourced in native Cerrado vegetation. Although there exist few biophysical limitations to sugarcane expansion, capital, infrastructure, and institutions constrain production. Lastly, we show that areas where soy is currently cultivated may be converted to sugarcane in the future given the expansion of transportation and sugarcane infrastructure. Thus, we suggest incentivizing the cultivation of sugarcane on degraded pastures and supporting increased pasture stocking rates to ensure continued protection of both natural vegetation and food production while supporting the expansion of sugarcane in the state.     

Comparing the environmental impacts of pasture-based and confinement-based dairy systems in Nova Scotia (Canada) using life cycle assessment

A life cycle assessment (LCA) of dairy systems in Nova Scotia was conducted to compare environmental impacts of typical pasture and confinement operations. Data on material and energy inputs and outputs of these systems were obtained from local researchers and industry, and life cycle impacts in 11 categories were quantified. Use of concentrate feeds, N fertilizers, transport fuels and electricity were dominant contributors to environmental impacts. Somewhat surprisingly, grazing cows for five months per year (typical of pasture systems in Nova Scotia) had little effect on overall environmental impact. Scenario modelling suggests, however, that prolonged grazing is potentially beneficial. Compared with total confinement, a seven-month grazing scenario performed better in seven of the environmental impact categories evaluated with greatest potential improvements associated with acidification potential, ozone depletion potential, human toxicity and fresh water ecotoxicity. In contrast, land use was the only category in which an increased reliance on pasture is predicted to result in a marked increase in environmental impact.     

Investigating improved pasture productivity change on the New South Wales tablelands

The productivity of improved pastures in Australia's southeastern grazing regions is now believed to be in a state of long-term decline. As yet, there is little economic evidence to support this perception. The analysis reported in this paper seeks to examine improved pasture Productivity change from an economic standpoint in a major Australian grazing area. The analysis rests on the central proposition that the Productivity of the livestock enterprises is a direct reflection of pasture productivity. Using both index number and econometric methods, the results indicate that while the annual growth in livestock and hence, improved pasture productivity has been positive over the period, there has been a significant decline in legume pasture productivity. Because these pastures comprise the bulk of improved pastures, the livestock Productivity of all improved pastures has declined in recent years. In contrast, the growth in livestock productivity from the perennial grass pastures continues to be high. The main reasons for legume pasture livestock productivity decline appear to be various important biological Problems and the long-term decline farmers' terms-of-trade.     

DUMMY VARIABLES: AN APPLICATION IN CATTLE PRICE ANALYSIS

Price variation demands the attention of most Alberta cattle producers and marketing agents. This study sought to identify and measure the effects of certain pertinent variables in the marketing system. Cattle prices on different markets–terminals and auctions–were compared. Comparisons in pricing among three different areas–namely, the Grande Prairie region, Central Alberta, and Southern Alberta–were also drawn. Among the variables hypothesized affecting cattle prices, class, grade, and weight were most important for both feeder and slaughter cattle. Low prices were associated with the presence of horns and also with a “full” condition. Producers, therefore, stand to gain by paying attention to “fill,” dehorning, and castration of male calves. An official grading system for feeder cattle should be instituted, and the optimum weights at which to sell feeder and slaughter cattle should be ascertained. La variation des prix est une préoccupation importante pour tous ceux qui sont concernés par la raise en marché du boeuf, qu'il s'agisse des éleveurs, ou des agences de raise en marché. Cette étude vise à identifier certains facteurs, et à en mesurer ?influence sur la mise en marché. On a compareé les prix du bétail dans les grands pares publics et dans les encans locaux. Pour fins de comparaison, une liste de prix a été dressée pour les trois régions suivantes: Grande Prairie, le centre ainsi que le sud de ?Alberta. Parmi les facteurs affectant le prix du bétail, on remarque que la classe, la catégoire et le poids, sont ceux qui influencent le plus le prix des bovins. ?étude a démontré que généralement les prix sont plus éléves pour les animaui sans comes et à jeun au moment de la vente. Les élevéurs auraient done avantage à?mineur la nourriture avant la vente. Il serait preferable aussi ?enlever les comes et le castrer les veaux males. On devrait aussi instituter un systéme officiel de classification des bovins ?engraissement, qui serait utile pour déterminer les poids optima de vente des bovins ?engraissement et du bétail destiné aux abattoirs.     

Incentivizing sustainable rangeland practices and policies in Colombia’s Orinoco region

Livestock grazing, along with agriculture, are key drivers of deforestation and land degradation that subsequently affect ecosystem service provision in the tropics. Although environmental and agricultural policies may curtail these negative effects, information is needed on how specific programs and instruments could be used to incentivize ranchers into adopting rangeland practices to achieve land conservation. We examine what encourages livestock ranchers to adopt more sustainable rangeland practices with various technical and conservation attributes in Colombia’s Orinoco region. First, we analyze a management alternative based on an improved pasture (IP) approach traditionally used in tropical South America, and another practice that promotes silvopastoral systems (SP) that better sustain the long term provision of ecosystem services. Second, we assess the influence that technical assistance and conservation payment instruments can have on the adoption of the IP or SP programs. Using expert-based elicitation, questionnaires, choice experiments, and econometrics, we found that when either SP or IP management alternatives include a complete technical assistance program (CTAP), emphasizing forage or cattle production, the propensity to adopt the conservation focused SP alternative significantly increases. The SP alternative with CTAP for cattle production was valued by ranchers at $290 ha/year and the CTAP prioritizing forage production was valued at $233 per ha/year. Nonetheless, a basic technical assistance program for cattle production using the IP alternative was valued at $128, but when including the CTAP, the value increased to $262. Adopting conservation practices in the form of compensation payments for not grazing portions of their land in the SP was valued by ranchers at an average of $8 and $10 in the IP. Our findings show that decisions to adopt conservation oriented rangeland practices and policies are not strictly based on monetary payments for ecosystem services alone, but also on technical support.     

175 years of adaptation: North Scandinavian Sámi reindeer herding between government policies and winter climate variability (1835–2010)

Unmanaged wild reindeer populations tend to follow cyclical behaviour, and domesticated reindeer populations often show cyclical behaviour, too. In this contribution, we intend to use the long-term development of two areas in northern Scandinavia to explore how externally imposed policies and winter climate variability have influenced the reindeer herd size and pasture state. We do this by comparing the development in two areas that are rather similar ecologically: Torneträsk in northernmost Sweden and Kautokeino (Vest-Finnmark) in northernmost Norway.Climatic and ecological studies as well as commons theory have been useful tools for understanding the inherent socio-ecological dynamics. Especially the time from 1850 to 1940 includes several short periods when historical sources document combinations of events such as (1) closure of national borders to cross-border herding migrations, (2) relocations of herder households, (3) overutilization of lichen pastures, (4) catastrophic winters, and (5) forced herd reductions. The high number of incidents and actions during this era makes it challenging to disentangle causes and effects.Our main findings are based on the documented effects of international events and consequent government policies and actions in Fennoscandia from 1852 to 1921 which had dramatic consequences, including excessive numbers of reindeer and people in northernmost Sweden, leading to more or less forced relocation southwards in Sweden with cascading effects in large parts of Sápmi. We have found clear indications that this contributed to overutilization of lichen pastures and beyond any reasonable doubt must also have reinforced the effects of several of the documented catastrophic climatic events, especially in areas like Torneträsk to where many families from Finnmark were relocated. From the first border closure in 1852 to the Second World War it thus seems as if the shocks from the political events were the main factor determining the development of reindeer herding in large parts of Sápmi. The political and administrative history is well documented. Our climate data are a unique compilation of climate events based on multiple sources during two centuries, which contribute to the validity of our findings. Our pasture state data from the late-1800s are also based on several sources which support each other.Two new factors influencing the general cyclical pattern have arisen more recently. Motorization has increased the possibilities for intense pasture utilization and the amplitudes between minimum and maximum herd sizes, while supplementary feeding has the potential to limit the effects of winter climate variability and lichen overutilization.     

From weed to wealth? Prospects for medic pastures in the Mediterranean farming system of north-west Syria

Medic (Medicago spp.) pastures are widely grown in rotation with dryland cereal crops in Mediterranean climate zones of Australia. Attempts since the 1960's to introduce this system to Mediterranean west Asia and north Africa (the native region of medic) have not lead to significant adoption; farmers in the region recognize medic, but as a weed and natural pasture plant. This first detailed economic evaluation of the rotational medic system was conducted using a whole-farm linear programming model based on the agricultural system of north-west Syria. The model represents in detail impacts of rotation on yields, labor requirements of alternative farm activities, availability of family and hired labor, subsistence income requirements, livestock feed sources and uses at different times and a choice of sheep stocking rates. Biological data for the analysis are based on a large six-year cropping and grazing experiment near Aleppo on terra-rossa soil with rainfall mainly in winter and averaging about 330 mm annually. The trial compared a dryland medic-wheat system and traditional two-year rotations of wheat with: fallow, watermelon, lentil and vetch. Results indicate that, given current prices and yields from the trial, medic is less profitable than traditional rotations. The model was used to investigate situations in which medic would be economically preferred. Selection of a medic rotation by the model was found to be particularly sensitive to the area of the farm and the price of labor. On small farms, labor availability per hectare is high, favouring the production of labor intensive crops such as lentil and watermelon. On larger farms, labor costs of these enterprises are substantial, increasing the relative profitability of medic, especially if labor prices increase. Interestingly, the relative desirability of medic is more sensitive to its impact on subsequent wheat crops than to the level of pasture production. We also found that modest increases in the prices of sheep products (especially milk) have a major impact on the economic performance of medic. These insights will allow improved focusing and targeting of future research and extension activities.     

Patterns and processes of pasture to crop conversion in Brazil: Evidence from Mato Grosso State

The rate and location of cropland expansion onto cattle pastures in Brazil could affect global food security, climate change, and economic growth. We combined mapping, statistical modeling, and qualitative methods to investigate patterns and processes of pasture to crop conversion (P2C) in Mato Grosso State (MT), Brazil, a globally important center of agricultural production. P2C land constituted 49% of cropland expansion from 2000 to 2013. For a random sample of ̃250 m pixels in MT, we estimated a regression model skilled at predicting P2C land in the rest of the state as a function of cattle ranching suitability, cropping suitability, and P2C conversion costs. Surprisingly, just 1/7 of pasture agronomically suitable for cultivation had undergone P2C. Hedonic regressions revealed that agronomic characteristics of land were associated with less than 20% of the variation in cropland suitability. Instead, the majority of the variation stemmed from a combination of proximity to agricultural infrastructure, characteristics of neighboring lands, and time fixed effects. The weak relationship between agronomic characteristics of land and P2C location suggests a less certain future for P2C than projections made with agronomic models. Consequentially, complications may arise for greenhouse gas mitigation policies in Brazil predicated on widespread expansion of cropland on pasture vs. natural areas. Our follow-up qualitative research shows that because P2C has often involved land rentals or sales, poorly functioning land institutions may have constrained P2C. Locally poor land quality, omitted from agronomic P2C predictions, can either catalyze or constrain P2C by limiting returns to ranching, farming, or both. Interventions to control rates and locations of P2C should take these insights into account.     

Investing in Perennial Pasture Improvement: A Real Options Analysis

In investment analysis, uncertainty and irreversibility can undermine net present value (NPV) as a decision rule since the option to delay investment may have value. We apply the real option theory of investment to the pasture investment decision facing livestock producers in southwest Western Australia. In 2006, livestock producers thinned their herds as pasture availability dwindled due to extreme drought conditions. This left producers with a unique opportunity to either establish new perennial pastures for their cattle or utilize volunteer annual pasture and invest in more sheep breeders. In either case, large and irreversible investments fraught with multiple sources of uncertainty implies that one can gain useful insights by casting the investment problem in a real option context. The results suggest that required rates of return for each investment alternative are about 1% to 1.5% higher than standard NPV would suggest with sheep production having the lower required rate of return.     

Optimal management of annual ryegrass (Lolium rigidum Gaud.) in phase rotations in the Western Australian Wheatbelt*

Lucerne (Medicago sativa L.) helps to prevent soil salinisation in the Western Australian Wheatbelt by reducing recharge to saline water tables. There is broad consensus, though, that it is not sufficiently profitable to motivate producers to plant it at the intensity at which considerable off‐site benefits would be conferred. This paper employs a multiple‐phase optimal control model to explore the value of this perennial pasture for the management of herbicide‐resistant annual ryegrass (Lolium rigidum Gaud.) in a crop–pasture rotation, given the difficulty of observing this value in practice. The availability of selective herbicides for efficient weed control is found to determine whether or not it is profitable to adopt lucerne pasture under optimal management. Herbicide resistance requires producers to employ costly, non‐selective treatments for in‐crop weed control. Thus, it motivates the adoption of perennial pasture in which cost‐effective forms of control can be implemented. Moreover, this result is robust to feasible changes in the current economic environment.