Abstract

Feed production is an important contributor to the environmental impacts caused by livestock production. In Portugal, non-dairy cattle are commonly fed with a mixture of grazing and forages/concentrate feed. Sown biodiverse permanent pastures rich in legumes (SBP) were introduced to provide quality animal feed and offset concentrate consumption. SBP also sequester large amounts of carbon in soils. Here, we used a comparative life cycle assessment approach to test the substitution of concentrate through installation of high-yield SBP. Using field data for the Alentejo region in Portugal, we compare the global warming potential of a baseline scenario where cattle is fed in low-yield, semi-natural pastures supplemented with feeds that vary in the ratio of silage to concentrate, and a second scenario where the feed is substituted with high-yield SBP. Although SBP use more fertilizers and machinery, this replacement avoids the emission of about 3 t CO2eq/ha even after SBP stop sequestering carbon. Using crude fiber to establish the equivalence between scenarios leads to higher avoided impact, owing to the fact that the fiber content of SBP is also higher. SBP can avoid 25% emissions from beef production per kg of live animal weight.

Highlights

  • The agri-food sector is responsible for a high share of direct and indirect environmental impacts [1]

  • Livestock production, including feed production, is a major contributor to the world’s total greenhouse gas (GHG) emissions [2,3,4]. This is the result of energy use in food production [5], fertilizer production [6], carbon loss due to direct and indirect land transformation and occupation [2,7], and methane (CH4) and nitrogen oxide (N2O) emissions [2]

  • The HF ratios are mostly dominated by the maize forage (70% of total mass), while in the LF feed, the proportion is more diluted among all ingredients, which leads to more variance in nutritional values

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Summary

Introduction

The agri-food sector is responsible for a high share of direct and indirect environmental impacts [1]. Livestock production, including feed production, is a major contributor to the world’s total greenhouse gas (GHG) emissions [2,3,4] This is the result of energy use in food production (mostly fossil fuels consumed in machinery used for agricultural operations) [5], fertilizer production [6], carbon loss due to direct and indirect land transformation and occupation [2,7], and methane (CH4) and nitrogen oxide (N2O) emissions [2]. Sown biodiverse permanent pastures rich in legumes (SBP) are a mixture of selected high-yield legumes and grasses that provide quality animal feed [9,10,11] These pastures have been developed since the 1960s in Portugal, with the main objective of increasing grassland productivity and sustainable stocking rates, by sowing mixes of up to 20 species/cultivars of legumes and grasses [10,12]. The majority of the area of SBP (over 90%) was installed in the agricultural region of Alentejo; namely in highly important “Montado” areas, an agro-forestry landscape of high biodiversity value [15]

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