New livestock production models need to simultaneously meet the increasing global demand for meat and preserve biodiversity and ecosystem services. Since the 16th century beef cattle has been ...produced on the Pampas and Campos native grasslands in southern South America, with only small amounts of external inputs. We synthesised 242 references from peer-reviewed and grey literature published between 1945 and mid-2015 and analysed secondary data to examine the evidence on the ecosystem services provided by this grassland biodiversity hotspot and the way they are affected by land use changes and their drivers. The analysis followed the requirements of systematic review from the PRISMA statement (Moher et al 2009 Acad. Clin. Ann. Intern. Med. 151 264-9). The Pampas and Campos provide feed for 43 million heads of cattle and 14 million sheep. The biome is habitat of 4000 native plant species, 300 species of birds, 29 species of mammals, 49 species of reptiles and 35 species of amphibians. The soils of the region stock 5% of the soil organic carbon of Latin America on 3% of its area. Driven by high prices of soybean, the soybean area increased by 210% between 2000 and 2010, at the expense of 2 million ha (5%) of native grassland, mostly in the Pampas. Intensification of livestock production was apparent in two spatially distinct forms. In subregions where cropping increased, intensification of livestock production was reflected in an increased use of grains for feed as part of feedlots. In subregions dominated by native grasslands, stocking rates increased. The review showed that land use change and grazing regimes with low forage allowances were predominantly associated with negative effects on ecosystem service provision by reducing soil organic carbon stocks and the diversity of plants, birds and mammals, and by increasing soil erosion. We found little quantitative information on changes in the ecosystem services water provision, nutrient cycling and erosion control. We discuss how changing grazing regimes to higher forage allowance can contribute to greater meat production and enhancing ecosystem services from native grasslands. This would require working with farmers on changing their management strategies and creating enabling economic conditions.
Meeting the goals of sustainable growth of food production and reducing rural poverty requires assisting family farmers to develop more productive, profitable, resource efficient and environmentally ...friendly farms. Faced with decreasing product prices and increasing production costs during the last two decades family farmers in south Uruguay tried to maintain their income by intensifying their farms, growing larger areas of fewer crops and increasing the use of irrigation and agrochemicals. Soil degradation was aggravated by this process, limiting crop yields, undermining the farmers’ aim of maintaining their income. A model-aided explorative study had shown that decreasing the area of vegetables, introducing crop rotations, cover crops and manure applications, and including beef-cattle production would be a better strategy. To test this hypothesis, a project was started at the end of 2004 and expanded in 2007, involving farmers, technical advisers and scientists in a co-innovation process that combined systemic diagnosis and redesign of the farm systems, social learning and dynamic monitoring and evaluation. The project involved 14 farms representing a large range of variation in resource endowment. Main problems found on all farms were deteriorated soil quality and low labour productivity, which resulted in low income and high work load. At the end of 2–5years of redesign farmers had been able to implement most innovations planned. Irrespective of endowment with land, machinery, irrigation water or labour resources, re-design increased the per capita family income (FIp) and the income per hour of family labour (IH) on 13 out of 14 farms, by 51% and 50%, respectively, averaged over all farms. Soil organic carbon content had increased on 11 out of 14 farms and estimated erosion rates in vegetable fields had halved. Farmers considered ‘multi-year planning’ the most important change introduced into their practice by the project. They concluded that the role of the extension service agents should change from mere consultants of operational–tactical, crop-centred decisions to supporters of the process of farm planning and evaluation. The project showed that even on commercial farms operating under highly competitive conditions, substantial improvements in economic and environmental indicators can be achieved when a whole farm strategic redesign is elaborated.
•Cow-calf systems on the Campos have low production and net income.•A cow-calf system model was developed to support ecological intensification.•Strategic, tactical and decision-supporting ecological ...techniques are distinguished.•Uruguayan data show poor management control of main events in the production cycle.•The model identifies levers to support systemic learning during co-innovation.
Cow-calf systems utilise grazing of native grasslands for beef cattle propagation and constitute the principal livestock activity in the Pampas and Campos areas. Cow-calf system sustainability is questioned because of their low production levels and negative environmental impact. Ecological intensification has been proposed as a way out that constitutes an alternative to dominant discourses based on increasing external-input use. There is, however, a considerable gap between the availability of scientific knowledge to promote the ecological intensification of cow-calf systems and farmers' practices. This gap between scientific knowledge availability and farmers' practices can be made explicit, and its consequences for systems performance can be explored through a conceptual model. Conceptual models are tools to build a systems view of the interactions among the production system's state variables, farm management, and resulting system performance. In this paper, we develop a conceptual model of cow-calf systems on native grasslands of the Pampas and Campos regions to support the diagnosis and redesign of farm systems towards ecological intensification. We apply the conceptual model to analyse cow-calf systems in Uruguay, drawing on a survey among 250 Uruguayan livestock farmers. Using the model, we show that in Uruguay, the level of implementation of strategic, tactical, and decision-supporting techniques is low. Consequently, most farms have poor control of the grazing intensity and timing of main events in the production cycle. This results in ample room to improve the productive and environmental performance of most cow-calf farms in Uruguay. We distinguished three broad types of cow-calf systems based on the degree of implementation of techniques, the evolution of state variables throughout the year, and productive indicators. These types imply different departure points and strategies for a sustainability transition process. The conceptual model designed in this paper may support the cow-calf systems sustainability transition in the context of co-innovation processes by aiding the interactive diagnosis and redesign of farm systems.
Vegetables are commonly produced with high inputs of pesticides and fertilisers to boost production and meet cosmetic market standards. Yet, reports on the relationships between agrochemical inputs ...and crop productivity are scattered and an overview is missing. We assessed the relationship between pesticide and nutrient inputs and crop productivity for five vegetable crops in the south of Uruguay at field and farm level and explored the relation with farm resource endowment. We analysed crop yield and input use for tomato, onion, sweet potato, and strawberry with a dataset of 82 farms and 428 fields constructed between 2012 and 2017. Clear crop-specific patterns in pesticide and nutrient input levels were found, despite considerable variation across fields within the same crop. Strawberry and long cycle tomato had the greatest pesticide input regarding of the number of applications (20 and 18, respectively) and pesticide load (21 kg AI ha−1). Cumulative nutrient inputs were greatest for long cycle tomato (1127 kg ha−1). The relationships between inputs and yield were weak or non-significant, indicating inefficiencies and overuse of inputs, and there was no agronomical rationale for input use. We found substantial variation in management practices between fields and farms. In several cases, 21% of the fields and 17% of the farms producing onion, strawberry and tomato, attained relatively high yield levels with limited input levels. Yield and input use levels were not related to farm resource endowment. Our findings question the efficiency of the current high levels of pesticide and nutrient inputs in Uruguayan vegetable systems. The inputs may pose environmental and human health risks and in most cases did not increase yields. Learning from positive deviant farmers in combination with guided farm redesign, high-quality extension services, and use of context-specific knowledge and technologies may equip farmers to use more sustainable management practices.
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•Relations between pesticide and nutrient inputs and yields evaluated for 5 crops•No or weak relations between input use and yields•Input use not related to agronomic criteria or farm resource endowment•Several cases stood out by reaching high yields and low input levels.•Results show the need and opportunities for transitions to more sustainable states.
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•We assessed the performance of 280 beef grazing-farms of southern South America.•We built the first beef farm typology of the Río de la Plata grasslands region.•Farms were mostly ...family-run, smallholder, cow/calf type on native grasslands.•Farm structure was not related to economic and environmental performance.•Better environmental performance was achieved by the use of native grasslands.
Worldwide, native grasslands are being converted to non-native pastures and cropland. This process threatens local grassland biomes as well as the livelihoods of farm families that utilize these grasslands.
In the Río de la Plata grasslands region meat production and multispecies native grasslands have coexisted for more than 400 years. Low levels of meat productivity and farm income, however, trigger replacement of native grasslands by crops and leys and threaten the survival of local beef farming systems. We studied the economic and environmental performance of beef farming in the region based on interviews and field measurements on 280 case study farms with the following aims: (a) to identify the multi-functional economic and environmental performance of beef farms across the Rio de la Plata grasslands biome; (b) to identify farms with ‘outstanding’ multi-functional performance; (c) to compare performance levels with those found in other regions; and (d) to discuss the implications of the outstanding farms for the development of new systems of meat production. The representativeness of the case study farms was ascertained by comparing them with a farm typology constructed from survey data of 15,448 beef farms situated predominantly on native grasslands in Argentina, Brazil and Uruguay. We identified seven farm types on the basis of farm size, labour, farm specialization, land use and stocking rate.
We identified positive deviant farms based on Pareto-ranking and compared these with a classification based on threshold values provided by experts. Out of the 280 farms, 41 were ranked as Pareto-optimal, i.e. outperformed other farms in one or more indicators without being outperformed in other indicators. Out of these, 5 were positive deviants, achieving on average 192 kg LW ha−1 yr−1 of livestock productivity and 201 US$ ha−1 year−1 farm income, having most favourable values for fossil energy consumption, phosphorus balance, carbon footprint and having over 95% of their land under native grassland as a proxy for biodiversity conservation value. Four of these farms belonged to farm types that together represented 55% of the population, suggesting scope for widescale improvement.
Compared to the values reported for the OECD countries the beef farming systems of the Río de la Plata grasslands region consume less energy and positive deviant farms demonstrated approximately average livestock productivity and carbon footprint. Increasing livestock productivity in the Rio de la Plata grasslands region resulted in a stronger decline of the carbon footprint without compromising the current negligible levels of fossil fuel energy use. Further elucidation of management practices that lead to positive deviant performance will require modelling of the interaction of pasture and herd dynamics at farm level and is needed to support targeted policy support for sustainable natural grassland-based beef production in the region.
•Soil cover reduced soil loss from raised beds by more than 98%.•Cover crops led to considerably smaller C-factor values.•Reduced tillage with mulching decreased runoff over 50% and stored more ...water.•Only reduced tillage kept soil erosion below the tolerance limit of 7tha−1y−1.•N nutrition and plant establishment under mulch cover need further attention.
Smallholder vegetable farmers tend to specialize and intensify their production to secure income. In south Uruguay, frequent tillage and little or no inputs of organic matter have resulted in soil degradation that threatens soil productivity and systems sustainability. This study aimed to quantify the impact of tillage, crop residue management, and organic matter incorporation on runoff, soil erosion, water dynamics, and productivity of a raised bed tomato-oat rotation system. A field trial was set up in 2010 and replicated in 2011 in a temperate climate on a fine textured soil including four soil management practices: reduced tillage with a cover crop left as mulch and chicken manure incorporation (RT), conventional tillage with a cover crop used as green manure and chicken manure incorporation (CGM), conventional tillage with chicken manure incorporation (CChM), and conventional tillage system as control (CT). RT decreased soil erosion and runoff by more than 50% compared with the three conventional tillage systems. We proposed a non-linear model to estimate the reduction in runoff due to stubble as a function of rainfall, with locally adjusted parameters. Yields under CChM were the largest both years, and more than 50% greater than under RT. Causes of low yields under RT are most likely poor crop establishment under the organic cover in combination with N immobilization. Compared with CChM water use efficiency under RT was reduced by 43% during the first season, and by 35% under both RT and CGM during the second season. In a dry season, RT increased soil water capture by 20% (45mm) compared with conventional tillage treatments. This is of special interest in these systems as it may result in a larger cultivated area of irrigation-dependent crops on a farm, thus building resilience to climate change. Future research on soil and water conserving practices in vegetable production systems should particularly address crop establishment and N management to avoid yield penalties under reduced tillage.
•Intensive tillage in vegetable systems leads to soil loss and less water capture.•We modelled mulch and tillage effects on runoff on raised bed systems.•Calibration and validation on Mollisols ...revealed high model accuracy.•Uruguayan farmers can save up to 141mmyear−1 of irrigation water on average.
Reduced tillage and mulching may bring about new production systems that combine better soil structure with greater water use efficiency for vegetable crops grown in raised bed systems. These are especially relevant under conditions of high rainfall variability, limited access to irrigation and high soil erosion risk. Here we evaluate a novel combination of empirical models on water interception and infiltration, with a soil-water balance model to evaluate water dynamics in raised bed systems on fine Uruguayan soils to analyze the effect of reduced tillage, cover crops and organic matter addition on soil physical properties and water balance. In the experiment mulching increased water capture by 9.5% and reduced runoff by 37%, on average, leading to less erosion risk and greater plant available water over four years of trial. Using these data we calibrated and evaluated different models that predicted interception+infiltration efficiently (EF=0.93 to 0.95), with a root mean squared error (RMSE) from 0.32 to 0.40mm, for an average observed interception+infiltration of 28.8mm per day per rainfall event. Combining the best model with a soil water balance resulted in predictions of total soil water content to 1m depth (SWCT) with RMSE ranging from 4.5 to 10.3mm for observed SWCT ranging from 180.4 to 380.6mm. Running the model for a four-year crop sequence under 10 years of Uruguayan historical weather revealed that reduced tillage required on average 141mmyr−1 less irrigation water than conventional tillage combined with organic matter application, thus enabling a potential increase in irrigated area of vegetable crops and crop yields. Results also showed the importance of inter-annual rainfall variability, which caused up to 3-fold differences in irrigation requirements. The model is easily adaptable to other soil and weather conditions.
▶ Seven farm types were defined for the vegetable farming systems of South Uruguay. ▶ An innovative quantitative method for farm typology identification was developed. ▶ The method facilitates the ...inclusion of expert knowledge. ▶ The method is applicable to support a qualitative up-scaling of model results.
The effectiveness of quantitative system approaches, aimed at exploring options for sustainable development, can be improved by integrating farm typologies and participatory methods. An innovative method of quantitative identification and characterization of farm typologies was developed, whose advantages are the straightforward communication of results to stakeholders and rapid graphical selection of representative farms. The method is presented through an application to a large census dataset of specialized vegetable production systems of South Uruguay. Seven farm types were characterized that mainly differed for availability of off-farm labour, mechanization endowment and irrigation. Farm types can be used to complement a model-based exploration aimed at designing options for sustainable development of the farming systems. The potential of the method to support the up-scaling of farm level results to study the impact of different livelihood strategies at the regional level is discussed.
► SOC depletion due to cropping was 43% in coarser and 32% in finer textured topsoils. ► SOC increase after systems re-design was 9–12% in the finer textured topsoils. ► SOC was positively correlated ...with available water capacity. ► AWC increased by 8.4mm for every 10gkg−1 of SOC increase to 20cm depth. ► Improved cropping systems contributed to increased soil moisture supply capacity.
Loss of ecological functions due to soil degradation impacts viability of crop production systems world-wide, particularly in vegetable cropping systems commonly located in the most productive areas and characterized by intensive soil cultivation. This paper reports soil degradation caused by intensive vegetable farming, and its reversibility after two to five years of drastic changes in soil management on 16 commercial vegetable farms in south Uruguay. Changes in soil management included addition of green manures and pastures in rotations of vegetable crops, use of animal manure, and erosion control support measures (terracing, reducing slope length, re-orientation of ridges). Soil degradation caused by vegetable farming was assessed by comparing soil properties in 69 vegetable fields with values at reference sites located close to the cropped fields. Effects of the changes in soil management in the 69 fields were assessed by comparing soil properties at the start and to those at the end of the project. Compared to the on-farm reference sites, the vegetable fields contained 36% less SOC, 19% less exchangeable potassium, water stable aggregates with an 18% smaller geometric mean diameter, and 11% lower plant-available soil water capacity. Phosphorus availability was 5 times higher under vegetable cropping compared to the on-farm reference. Phaeozems (Abruptic) revealed greater degradation (44% less soil organic carbon (SOC)) than Vertisols (24% less SOC) and Phaeozems (Pachic) (21% less SOC). After two to five years of improved soil management, SOC concentration in the upper 20cm increased by on average 1.53gkg−1 (12%) in the Phaeozems (Abruptic) and 1.42gkg−1 (9%) in the Phaeozems (Pachic). SOC in Vertisols increased only by 0.87gkg−1, most likely due to their greater initial SOC concentration. Topsoil carbon sequestration was on average 3.4Mgha−1 in the Phaeozems. Multiple linear regression showed the quantity of incorporated amendments, the initial amount of SOC and the clay content to explain 77% of the variability in yearly changes of SOC. Available water capacity increased significantly with SOC particularly due to more water retention at field capacity, resulting in an increase in available water capacity in the first 20cm of soil of 8.4mm for every 10gkg−1 of SOC increase. Results are discussed in relation to perspectives of soil degradation reversal in the long term.
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