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Soil Management and Conservation for Sustainable Agriculture and Environment
Study area in the Coastal Mountains of the Araucanía Region, Chile
Nuclear techniques provide essential and value added information and technology for defining and alleviating constraints to intensify and diversify farming systems while ensuring the sustainable use and management of land and water resources.
For example, the SWMCN Subprogramme together with counterparts in Member states determine the effectiveness of soil conservation practices at the area-wide basis and the impact of conservation agriculture on nutrient dynamics and soil quality.
Success story
Fallout radionuclides Cs-137 and Be-7 for evaluating effectiveness of no-tillage systems in Central-South Chile1
The challenge
The process of agricultural intensification has drastically increased soil erosion and associated soil degradation in the coastal mountains of south-central Chile. These problems have prompted a shift from conventional tillage to no-till. However, information is still needed to assess the effectiveness of this shift in reducing soil loss and its consequent environmental impact.
The project
A simplified method for using Cs-137 depth distribution datasets was developed to estimate soil loss under both conventional tillage and no-till system. Be-7 was used to quantify the erosion in order to assess no-till systems with and without burning of crop residues after harvesting, as a result of burning and a period of extreme rainfall.
Main findings
- The fallout radionuclide data showed that 16 years after implementing no-till systems erosion rate was reduced from 11 t ha-1 year-1 to 1.4 t ha-1 year-1. In addition, net erosion associated with crop residue burning and an extreme rainfall event (400 mm in 27 days) as estimated from FRN was approximately 12 t ha-1.
- Comparing these results with those estimated for the medium long term net erosion rate (1.4 t ha-1 year-1) during a prolonged period of no-till without the burning of crop residues, it would appear that burning in autumn is a highly undesirable practice, since it could promote soil loss in the following rainy season.
- These results have been provided to the Chilean Government, indicating that the adoption of a no-till system without burning of crop residues can make crop production in Southern Chile more sustainable and environmentally friendly by reducing diffuse source pollution associated with sediment inputs to the stream network.
1P. Schuller1, D. E. Walling2, A. Iroumé1, A. Castillo1. 1Universidad Austral de Chile, Chile, and 2University of Exeter, United Kingdom.
