Integration of agroforestry with sustainable grazing systems can enhance tree cover in a given landscape. This integration could have a significant economic and ecological impact especially in ...dryland farming systems. Despite this, the integration is challenged by the lack of combined adoption of both agroforestry and sustainable grazing.
In this study, we first examined the factors that determine the integrated adoption of controlled grazing (CG) and multipurpose fodder trees (MFT). More importantly, we investigated whether the integrated adoption of CG and MFT enhances tree cover in dryland farming systems.
Based on primary data collected from a randomly-selected sample of farm households, we used an IV approach to probe into the integrated effect of adopting CG and MFT on tree cover. On the other hand, the bivariate probit model was used to identify the factors that affect the adoption of both CG and MFT.
On average, adopters of both CG and MFT were found to have higher levels of tree abundance and density on their farms. Our model analysis indicates that these higher levels of tree abundance and density are positively related to the integrated adoption of CG and MFT. While the integrated adoption of CG and MFT had a stronger effect, separate adoption of CG or MFT was also correlated with tree abundance. These results generally indicate the importance of integrated silvopastoral systems not only as sustainable livestock management systems but also as promoters of vegetation (tree cover).
Given the economic and ecological importance of the integrated adoption of CG and MFT, factors that were found to influence integrated adoption including access to improved livestock breeds, skill development (both agroforestry and livestock management training), and agricultural services (such as irrigation and water sources) could give policy a useful direction for targeting and promoting the uptake of such integrated silvopastoral systems both for improving farmers' livelihoods and ecological sustainability.
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•We examine whether integrated adoption of multipurpose trees and controlled grazing enhances tree abundance and density•Adopters of both controlled grazing and multipurpose trees have significantly higher tree abundance and density•The higher average tree abundance & density is correlated with integrated adoption of multipurpose trees & controlled grazing•Integrated silvopastoral systems are important not only as sustainable livestock systems but also as promoters of vegetation
In pasture-based grazing systems, urine deposition is the major source of the greenhouse gas nitrous oxide (N2O). Livestock treading damage and high soil water contents increase the risk of N2O ...emissions. Duration controlled grazing (DCG) practices that are implemented in response to soil water conditions above a threshold may therefore provide an effective means of reducing greenhouse gas (GHG) emissions from dairy farms. The objective of this study was to evaluate the potential decrease in GHG emissions from dairy farms when implementing DCG when soil water content is above a specific threshold (akin to ‘wet’ days). We used the DairyNZ Whole Farm Model and APSIM model to assess the cost-benefit of implementing DCG to reduce total N2O and manure-derived CH4 emissions from dairy farms. We modelled scenarios on poorly drained or imperfectly drained soils in four regions of New Zealand including Waikato, Manawatu, Canterbury and Southland, where the grazing time on wet days was 0, 13, 17 or 21h per day. Emissions were estimated using a refined version of New Zealand's current national greenhouse gas inventory methodology. Our analysis suggested that reducing the grazing time from 21h to 0, 13 or 17h per day when soils were wet could reduce annual N2O and manure-derived CH4 emissions by up to, respectively, 12, 9 or 5% on farms with poorly drained soils. The 13h per day grazing duration was the least costly, particularly if there were >150 ‘wet’ days per year. In contrast, for dairy farms on imperfectly-drained soils, DCG increased emissions, suggesting this management approach for reducing GHG emissions is not suitable for these soils.
•Grazing pastures when soils are wet increases N2O emissions from cow urine•Duration controlled grazing (DCG) was applied when a soil ϴv threshold was reached.•Different durations were assessed for farms on poorly and imperfectly drained soils.•For poorly drained soils, DCG reduced N2O and manure-derived CH4 emissions.•For imperfectly drained soils, DCG increased N2O and manure-derived CH4 emissions.
An efficient dairy system, that implemented a combination of nitrogen (N) leaching mitigation strategies including lower N fertilizer input, standing cows off pasture for part of the day in autumn ...and winter (stand-off), and importing limited amounts of low protein supplements was evaluated over four consecutive years of a farmlet study. This efficient system consistently demonstrated a lower measured annual N leaching of 40 to 50% compared with a baseline system representing current practice with no mitigations. To maximize return from this system fewer cows but of higher genetic merit were used resulting in an average decrease in milk production of 2% and operating profit by 5% compared with the baseline system. The magnitude of the N leaching reduction from mitigation strategies was predicted in pre-trial modelling. Using similar mechanistic models in a post-trial study, we were able to satisfactorily predict the trends in the observed N leaching data over the four years. This enabled us to use the calibrated models to explore the contributions of the different mitigation strategies to the overall leaching reduction in the efficient system. In one of the years half of the leaching reduction was achieved by the ‘input’ component of the strategy (less feed N flowing through the herd from lower fertilizer use, less grass grown, and low-protein supplement use), while the other half was achieved by the stand-off strategy. However, these contributions are determined by the weather of a particular year. We estimate that on average stand-off would contribute 60% and ‘input’ 40% to the reduction. The implication is that farmers facing nutrient loss limitations have some current and some future technologies available to them for meeting these limitations. A shift towards the mitigations described here can result in a downward trend in their own N-loss metrics. The challenge will be to negate any reductions in production and profit, and remain competitive.
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•Dairy farmers are asking for ways to reduce N leaching but increase production and profit.•We tested N leaching mitigations on actual farms over several climate years.•Modelling helped design the farms and interpret the results.•In the mitigated farm N leaching was consistently lower by 40 to 50%.•Pasture-based dairy farmers have options to reduce their N leaching footprint.
To elucidate the effects of grazing intensity and grazing time on plant diversity and community structure, as well as the successional differentiation in an alpine meadow, a controlled grazing trial, ...with six grazing intensities on an alpine meadow was conducted in the eastern Qilian Mountain region for four years. Using species accumulation curves, RDA ordination and variance decomposition, we analyzed the changes in proportion of dominant species, richness, abundance, as well as the life forms of plant communities under grazing disturbance. Both the grazing intensity and grazing time had a significant effect on these dominant species, richness, abundance, as well as the life forms in the plant community (P<0.01). More detailed results showed that: (1) The richness and abundance of plant species were highest in the light grazing plot, and these increased as time passed. In the heavy grazing plot, the abundance of plant species decreased as time passed, but the richness of these species did not change significantly. (2) The abundance of Gramineae and Umbelliferae were negatively and significantly correlated with the duration of grazing treatments, whereas Plantaginaceae and Geraniaceae were positively and significantly correlated with the grazing intensity. Over time, the abundance of bunch-type plants decreased and other life forms of plants have increased. With the increase in grazing intensity, the plants' abundance with the rosette type did not change, but other life forms of plants decreased. The results of variance decomposition indicated that grazing disturbance has had greater effects on life forms and plant populations, followed by the changes in the dominant species and their abundance, with lesser effects on the richness of the species. Grazing intensity had a greater effect than the duration of the grazing treatment had. The results of PCA showed that the climax community in both the lowest and the highest grazing intensity plots had changed over time. In the sample plots with light grazing intensity, the plant community changed to an Elymus nutans+Poa crymophila community, but later changed to a Melilotoides ruthenicus+Kobresia humilis community under heavy grazing.
To elucidate the effects of grazing intensity and grazing time on plant diversity and community structure, as well as the successional differentiation in an alpine meadow, a controlled grazing trial, ...with six grazing intensities on an alpine meadow was conducted in the eastern Qilian Mountain region for four years. Using species accumulation curves, RDA ordination and variance decomposition, we analyzed the changes in proportion of dominant species, richness, abundance, as well as the life forms of plant communities under grazing disturbance. Both the grazing intensity and grazing time had a significant effect on these dominant species, richness, abundance, as well as the life forms in the plant community (P<0.01). More detailed results showed that: (1) The richness and abundance of plant species were highest in the light grazing plot, and these increased as time passed. In the heavy grazing plot, the abundance of plant species decreased as time passed, but the richness of these species did not change significantly. (2) The abundance of Gramineae and Umbelliferae were negatively and significantly correlated with the duration of grazing treatments, whereas Plantaginaceae and Geraniaceae were positively and significantly correlated with the grazing intensity. Over time, the abundance of bunch-type plants decreased and other life forms of plants have increased. With the increase in grazing intensity, the plants' abundance with the rosette type did not change, but other life forms of plants decreased. The results of variance decomposition indicated that grazing disturbance has had greater effects on life forms and plant populations, followed by the changes in the dominant species and their abundance, with lesser effects on the richness of the species. Grazing intensity had a greater effect than the duration of the grazing treatment had. The results of PCA showed that the climax community in both the lowest and the highest grazing intensity plots had changed over time. In the sample plots with light grazing intensity, the plant community changed to an Elymus nutans+Poa crymophila community, but later changed to a Melilotoides ruthenicus+Kobresia humilis community under heavy grazing.
Grazing practices in rangelands are increasingly recognized as a management tool for environmental protection in addition to livestock production. Long term continuous grazing has been largely ...documented to reduce pasture productivity and decline the protective layer of soil surface affecting environmental protection. Time-controlled rotational grazing (TC grazing) as an alternative to continuous grazing is considered to reduce such negative effects and provides pasture with a higher amount of vegetation securing food for animals and conserving environment. To research on how the grazing system affects herbage and above ground organic materials compared with continuous grazing, the study was conducted in a sub-tropical region of Australia from 2001 to 2006. The overall results showed that herbage mass under TC grazing increased to 140% in 2006 compared with the first records taken in 2001. The outcomes were even higher (150%) when the soil is deeper and the slope is gentle. In line with the results of herbage mass, ground cover under TC grazing achieved significant higher percentages than continuous grazing in all the years of the study. Ground cover under TC grazing increased from 54% in 2003 to 73%, 82%, and 89% in 2004, 2005, and 2006, respectively, despite the fact that after the high yielding year of 2004 herbage mass declined to around 2.5 ton ha^(−1) in 2005 and 2006. Under continuous grazing however there was no significant increase over time comparable to TC grazing neither in herbage mass nor in ground cover. The successful outcome is largely attributed to the flexible nature of the management in which grazing frequency, durations and the rest periods were efficiently controlled. Such flexibility of animal presence on pastures could result in higher water retention and soil moisture condition promoting above ground organic material.
The annual quantities of nitrate-N (
-N) and total N (TN) leached from mole and pipe drained dairy pastures on a Pallic soil, were reduced by an average of 52% and 42% (p < .05), respectively, by ...standing cows off pasture to ruminate and rest after grazing (Duration-controlled grazing, DC), compared to the standard grazing management (SG) of leaving cows at pasture between milkings. For the SG treatment, measured
-N leached was 13, 8 and 21 kg N ha
−1
and total N leached was 18, 13 and 26 kg N ha
−1
in 2009, 2010 and 2011, respectively. Annual surface runoff contained <1 kg
-N ha
−1
y
−1
and <3 kg TN ha
−1
y
−1
. The deposition of urine in the autumn period had the greatest influence on the quantity of
leached in winter drainage. DC grazing is a practical method to reduce N leaching from grazed dairy pastures.
Standing cows off pasture after 4 hours of grazing (duration-controlled (DC) grazing) was researched over 3 years (2008-2011) to compare the losses of nutrients in drainage and surface runoff water ...with losses under standard grazing (SG). Pasture growth rates, nutrient concentrations and apparent intake by cows were used to model nutrient removals from, and returns to, pasture. Pre- and post-grazing covers and apparent pasture intakes were similar for both treatments. Quantities of N, P and K returned to the DC plots in excreta and effluent were 34%, 0% and 45% less than those returned to SG plots. This reduction in nutrient returns was associated with a nil, 20% and 9% decrease in annual pasture growth on the DC plots in the three respective years. Reductions in annual pasture growth under DC grazing may be avoidable if nutrient removals are balanced with returns in effluent and fertiliser.
Livestock grazing influences arid rangelands greatly with important effects on vegetation dynamics. Two areas traditionally grazed by sheep and goats in southern Tunisia were sampled to evaluate the ...vegetation response to grazing management. A continuous grazing (CG) area was sampled in March 2007. A 2000 ha exclosure that had been rested for 3 years (2004–2007), grazed for 2 months (July and August 2007), and then rested for 7 months (September 2007 to February 2008) was sampled before and after grazing, and again after the 7 months’ rest. Results show that vegetation dynamics in arid rangelands respond strongly to changes in grazing management. Our results suggest that even previously overgrazed rangelands are resilient and are able to recover if given rest periods. In the studied Tunisian rangeland that has been moderately or lightly grazed, we found that recovery improved faster compared with continuously grazed. In practice, excluding grazing livestock and the use of a rotational grazing system are available ways to restore vegetation affected by CG. Therefore, a stocking rate not exceeding the carrying capacity is vital to maintain grazing operations under changing conditions and sustain rangeland resources over the long term. Increased stocking rates generally promote rangeland degradation.
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