Importance of soil health in sustainable agriculture

Importance of soil health in sustainable agriculture

“Agriculture must, literally, return to its roots by rediscovering the importance of healthy soil” 

It has been quite widely recognised since the birth of sustainable agricultural recognition, that the quality of soil is a vital link between the strategies of conservation management practices proposed and the actual achievement in sustainability targets. There has been no question, that centuries of cultivation has depleted soil fertility to the extent that a negative balance of nutrient availability occurs - resulting in nutrient deficiency - humans have withdrawn more than they can return. Displacement of soil and loss of soil by erosion increases the amount of sediments entering river systems along with chemicals drawn off farmlands (pesticides, fertilizers),  so not only would maintenance of soil improve the quality of soil, but also reduce the associated environmental effects (Lynch et al 2002). But how?

The biological component of the soil system has a high dependence on the chemical and physical soil components and hence tends to be a sensitive indicator to degradation processes (Wollongbar Agricultural Institute 2001), so the maintenance of of ‘holding’ soil together has its origins in organic matter. For example, fungal hyphae binds soil particles together into small aggregates, backed by supporting plant roots. Organisms (most commonly the bacteria such as Bacillus & Pseudomonas) within the soil produce polysaccharides that ‘glues’ the soil and stabilises aggregates. Mycorrhizal fungi also contributes to soil aggregate formation and soil stability by tying mineral and organic debris in a network of external hyphae. When looking at maintaining soil stability, understanding the biological components of what holds the soil together is a key step in maintaining soil health and quality, therefore a step forward to sustainability. 

One of the major areas regarding combating soil degradation is assessment. Assessment of soil health is required to identify problem production areas, make realistic estimates of food production and monitor changes in sustainability and environmental quality (Lynch et al 2002). The Food and Agriculture Organization of the United Nations published the Save and Grow (2011) article, augmenting the systematic approaches to agricultural land practices in the effort to sustain soil quality. Some of the approaches are summarised:

• Establishing national regulations for sound husbandry. FAO believe that governments should be prepared to regulate farming practices through policy frameworks, and especially focus on areas that pose serious threats.
• Monitor soil health. FAO has produced methods and tools that farmers of agricultural lands can use to assess and monitor soil quality. 
• Build capacity. Policymakers should make soil health management knowledge-intensive, which could be done through guidelines and greater research.
• Disseminate information and communicate benefits. Modern information and communication technologies should be utilised so effective agricultural techniques can reach farmers. 

A notable case study regarding the management of soil quality has stemmed from the agricultural usage of of land in Latin America. The soils of Brazil’s Cerrado tropical savanna and Amazon rainforest regions are typically oxisols and ultisols - both which are poor in nutrients and acidic. Due to their location, their are subject to high rainfall and consequently erosion if the surface is not protected by vegetation cover. Management of these soils has been designed to conserve or increase organic matter by providing a permanent soil cover, ensuring minimal tillage of the soil. This is part of an SCPI approach, which has recently been adopted by many farmers in such regions in an effort control soil erosion. Through government and educational influence, this form of zero-till farming has now become widespread in Brazil, covering approximately 26 million hectares of oxisols and ultisols (Save and Grow 2011). 

Sustainable management of soil health requires a set criteria for the balance between food production and supporting soil conservation, water flow and quality, crop, livestock and human health. In addition to the proposal of the inclusion of organic matter, the maintenance of continuous vegetative cover and in particular rooting systems will also promote a healthy soil (Kibblewhite et al 2007)  Ultimately, sustainable solutions in regard to soil health depends on the willingness of society to pay for its maintenance.