Photo credit: CGIAR
Soil compaction and loss in water infiltration ability caused by regular soil tillage leads
to impeded drainage and flooding after a thunderstorm in the ploughed field (right) with sugar beet, and no flooding in the no-till Conservation Agriculture field (left).
Photo Credit: Wolfgang Sturny
Agricultural land degradation and its end result of desertification have been receiving considerable attention by the international community in recent decades. However, the general lack of understanding and awareness about the root causes of land degradation persists, thus the slow progress in reversing the alarming trends of land degradation and land abandonment. Worldwide, empirical and scientific evidence clearly shows that soil degradation in agricultural land use and decreasing productivity are closely related to the prevalence of mechanical soil tillage, the agricultural method of using mouldboard ploughs, disc harrows, tines, rotivators, hoes and other mechanical tools to prepare the field for crop production. The reasons behind these practices are to:
- prepare a seedbed for crop establishment;
- control weeds, insect pests and pathogens;
- aerate the soil and distribute plant nutrients; and
- facilitate other farm cultural practices.
Generally associated with the term conventional tillage agriculture, these practices contribute over the long term to:
- destruction of soil structure, loss of soil organic matter, soil biodiversity and soil health;
- exposed soils and landscapes, surface sealing, decreased water infiltration, increased runoff and soil erosion;
- disruption of many important soil-mediated ecosystem functions; and
- loss in productivity, resilience and eventual abandonment of land.
In developing countries, the combination of all these elements is a major driver of food and nutrition insecurity and a host of other related challenges, such as poverty reduction, effective adaptation to climate change, and sustainable and equitable development in general. In industrialized countries, the poor condition of soils and sub-optimal yields due to conventional tillage agriculture are further exacerbated by:
- over reliance on the application of mineral fertilisers, as the main source of plant nutrients; and
- reduction or doing away with crop diversity and rotations, including legumes.
Read the full article: CGIAR