HORIZON INTERNATIONAL SOLUTIONS SITE

Problem Overview:

Soil degradation and desertification due to human activities such as agriculture, fuel wood collection, and high intensity pastoralism.

Soil degradation has become a crucial concern for many communities since soil is an integral part of almost all terrestrial ecosystems and plays an important role in sustaining livelihoods through food and agricultural production. Semi-arid and arid areas (drylands) are increasingly susceptible to chemical and physical deterioration, such as salinization and crusting of topsoil, as well as soil displacement from water and wind erosion. Drylands, such as the one in this study, are characterized by desert conditions, namely nutrient deficient soils, low moisture content and high salinity concentrations, and extremely vulnerable to degradation due to slow recoveries from disturbances. Due to these qualities, many dryland areas are more susceptible to desertification, rendering the soil infertile and nutrient and water deficient. Human activities, such as intensification of agriculture, fuel wood collection, and high intensity pastoralism, can accelerate physical processes (i.e, water and wind erosion) and exacerbate desertification.

Background:

By incorporating an integrated approach to farming and water management, Pyneham farm in Frankland, Australia, has overcome problems caused by land degradation to create a more sustainable system. The newly established farming system, known as integrated whole farm -- whole landscape planning, has not only helped combat desertification, but also helps restore biodiversity in an area which previously experienced vast forest depletion for agricultural expansion.

This approach aims to achieve total control of water movement and use by performing water management activities at the catchment scale, not just within the boundaries of the individual farmer’s property. Thus, the strategy is community-based and requires both co-operation and co-ordination among all farmers in the catchment area. This problem, however, can be further aggravated by some water management practices which do not focus on water distribution and flow. Waterlogging can become a particular problem as a result, especially in areas that experience extreme rainfall and drought.

Pyneham farm is located in a subhumid area with a mean annual rainfall of 580 mm and where soils are highly podsolic and lateritic (i.e., low water activity). Such conditions often lead to perched aquifers, waterlogging and increased salinization and sodification problems during the rainy months. Wind and water erosion as well as forest clearance had also previously reduced the quality and quantity of groundwater for the farming community. In a response to this depleted water source, the community had previously developed dams to improve water levels; however, this had only expanded waterlogging problems.

The key factors in implementing and managing this scheme are a series of drains to control the nature and rate of water movement after rainfall events and tree planting which provides a way of utilizing deep moisture. First, interceptor drains were dug in the slopes of the upper and middle parts of the catchment in order to capture surface runoff that would otherwise drain rapidly to the lower catchment areas, inducing a waterlogged effect. The drains, following the contours of and slightly cutting through to the clay horizon, then run across the soils at a gradient of approximately 0.25%. In other words, these drains in the upper levels of the soil prevent water from saturating the clay zone in the lower level of the soil, but allowed water to percolate to greater depths without causing waterlogging. Once the water has drained following the rainfall event, it is stored in dams for domestic stock and irrigation purposes.

The soil dug to form the drain, by bulldozer, grader or hand, is then banked up on the downslope side and flattened to provide an excellent surface for tree planting. The trees are then planted in a series of four rows on each bank. 38 tree species were planted, the most dominant being Spotted gum (Eucalyptus maculata), Wandoo (Eucalyptus wandoo), Golden wreath wattle (Acacia saligna) and Tagasaste. Wandoo and Golden wreath wattles were planted in the middle rows of the windbreaks to provide nectar for birds and insects, and to create a more diverse wildlife habitat. The trees are advantageous for several reasons. First, they act as windbreaks. Second, since they follow the contour-hugging drains they can also protect crops and livestock against wind and harsh weather. Third, the tree roots withdraw water from great depths to further reduce the waterlogging problem. And finally, the trees can help restore biodiversity in the area by again protecting the native flora and fauna in the area from wind and weather disturbances and providing wildlife corridors throughout the area. For example, the reappearance of the native orchids has been documented. These windbreaks reduce the effect of large farms on reducing wildlife populations but also protect the crops from livestock trampling and attract birds for pest management. Furthermore, the outer row of trees in the windbreaks is planted with tagasaste or tree lucerne, which acts as a fodder for livestock during drought periods.

In addition to tree planting and drainage use, stubble mulching has also been practiced on the farm for 15 years and soil acidity problems are being corrected with lime and sodicity with gypsum. Organic fertilizers, organic matter residue and chisel ploughing are also used to reduce nutrient mobility and encourage earthworm activity.

Benefits:

This diversified approach to agriculture has enhanced the economic viability of the farm through an improved environment and restoration of degraded lands. Livestock carrying capacity has increased and more fertile land is now available for cropping. An economic analysis of the farm has concluded that gross margins for crops are more than double the local average and for sheep almost four times the average. One Frankland farmer stated that his gross income increased by 25% in one year. By controlling the rate and nature of water flow on the farm, the farmers have improved water quality in the area by minimizing salinization while simultaneously finding a solution to the waterlogging problem. The windbreaks have also enhanced biodiversity in the area by protecting both the flora and fauna from wind erosion and helped restore the natural tree species which had once been removed from the area.

Constraints:

While there have been significant ecological and agricultural benefits from adopting the whole farm approach, there are several constraints which might inhibit replication of the project. The first is the cost of implementation. This can be overcome by implementing the project in stages rather than all at once. Since the farming strategy can only be successful on a community basis and requires community participation, the second constraining is the difficulty in convincing all farmers in the catchment area to adopt the strategy. This constraint should provide greater impetus to educate the community on the disastrous effects of waterlogging to both the farmer’s livelihood and ecosystem, and how this strategy can effectively improve biodiversity, soil quality, and agricultural production in a short period of time.

Status:

The strategy has been implemented for 15 years at Pyneham farm and has subsequently been adopted by 20 other farmers in Western Australia, both in the immediate vicinity of Frankland and further afield.

Submitted by:

Clare Parker
Email: cparker@rona.unep.org
United Nations Environment Programme
2 UN Plaza, Rm. DC2-803
New York, NY, 10017
USA