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Vol. 22 No. 3 - July 2016

Silvopastoral Systems and Biodiversity

By: F.J. Solorio and S.K. Basu*

The most common threat to biodiversity is the fragmentation of natural habitats. With the increase in human population the demand for food grains and other food items like milk and meat has also increased, which has led to the loss of forests for the expansion of the agricultural frontier and pastures, mainly in the tropics. The loss of forests is one of the principal negative impacts on biodiversity, due to the expansion of the agricultural frontier, mainly in the tropics. Silvopastoral Systems can become an effective tool to mitigate this problem, because of its multiple benefits and ecosystem services, coupled with increased productivity in livestock systems production.

Silvopastoral systems (SPS) are an agroforestry systems orientated mainly for livestock production. It also aims at providing environmental and soil benefits, including biodiversity aspects. Biodiversity is a key aspect in the sustainability of the agriculture production systems and hence for maintaining a SPS work in an integral way. Although, biodiversity depends on the structural heterogeneity of the land vegetation, SPS, is composed of a multistrate vegetation with a diversity of herbaceous and woody species that create heterogeneity for increased below- and above-ground biodiversity. Trees and shrubs provide habitat and food for diverse types of birds and bees, and, at the same time, birds and bees play a fundamental role in natural reforestation and vegetation restoration through seed dispersal.

Silvopastoral Systems provide a number of ecosystem services including carbon sequestration, biodiversity conservation, soil enrichment, air and water quality maintenance, and regulation of microclimate (Table 1).

Table 1. Ecosystems services from silvopastoral systems.



Nutrient Cycling

In an SPS plant nutrients are in a state of continuous, dynamic transfer. Plants take up nutrients from the soil and use them for metabolic processes. In turn, plants return nutrients to the soil either naturally as litter, or through root senescence.

Carbon sequestration

SPS represent an important alternative to the recovery of degraded areas and have high potential for carbon (C) sequestration. Net carbon flux and primary productivity increases significantly due to integration of different woody species with grasses.

Biological N Fixation

A long-term, more sustainable and cost-effective solution to pasture degradation is the addition of vigorous forage legumes to the pasture to boost soil N levels by biological N fixation. Leguminous nitrogen fixing-fodder species can fix >150 kg N/ha/yr (equivalent to 320 kg urea/ha/yr), some of which is cycled to the pasture via animal dung and urine during grazing.

Greenhouse gas mitigation

Methane emission from ruminants is one of the sector´s largest greenhouse gas emissions. SPS is one of the most important approaches to offsetting agricultural emission through improving animal diet quality and using forage rich tannin species.

Microclimatic conditions

The shade within silvopastoral systems reduces temperature and ameliorates environment and is beneficial for better animal performance. Shade has been useful in increasing milk yields of dairy cattle and liveweight gains of feed cattle in hot climates,

Recovering degraded land

SPS with fast-growing leguminous nitrogen-fixing trees can, in a short to medium time, recuperate degraded land. The litter stocks and soil C and N stocks in SPS indicate that the use of leguminous trees can increase efficiency in re-establishing the nutrient cycling processes of the systems. These results also show that recovering degraded land with this technique is effective in sequestering carbon dioxide from the atmosphere at high rates.

Biological diversity

SPS with a diversity of multipurpose species growth generate a rich habitat that increases the number and variability of living organisms (below and above the soil). In the above-ground level, diversity of insects and birds increases which is beneficial for the productivity of SPS, while in the belowground layer worm and beetle species thrive due to increase in the soil humidity created by the trees and shrubs grown in the SPS.


*UFL, Lethbridge, AB, Canada. E-mail ssolorio@correo.uady.mx

This article has been reproduced from the archives of EnviroNews - Newsletter of ISEB India.

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