Soil input recommendations
Arturo Flores
- Interpret soil test reports
- Calculate the required fertilizer to amend soil nutrient deficiencies
- Design fertilizer formulas based on the soil needs and materials available
Make soil input recommendations
One of the big questions in agriculture has been and will be ‘what and how much should I apply to increase yield?’ It is a common question asked by most farmers, with the belief that there is a magic formula to once and for all improve the soil quality and boost yield. However, this is far from being true. As has been discussed throughout this course, soil is a complex and dynamic system. Therefore, improving soil is a holistic process that should consider each one of its factors that could be limiting production. Soil laboratory analysis is an accepted measure performed by farmers around the globe to obtain some insight about what is going on in their soils and use it as a starting point to take management decisions.
The soil test report obtained after analysis may include recommended fertilizer application rates and even recommended products. Nevertheless, this service is not always available or economically accessible for every user. The process of interpreting a soil test report is not rocket science, and with a basic understanding of the overall condition of soil, it is possible for any user to improve the soil quality. It should be noted that a soil test report is not completely accurate and may just represent the condition of the soil where the sample was taken. However, is still valuable to be able to read, understand, interpret and act according to what the report is telling the user. The most important thing to remember when interpreting soil test results, is that soil quality or fertility is not just a matter of nutrient balance, but also about the chemical and physical conditions of soil, including acidity, salinity, and moisture content.
FIRST: Evaluate and improve the physical condition of the soil
Porosity and moisture content are limiting factors that can reduce agricultural productivity. Fine soil textures are good for retaining moisture, but bad for resisting compaction. Conversely, sand and gravel retain low quantities of humidity, but resist compaction better than clays. Compacted soils and not granular structures make root growth, water infiltration and percolation significantly harder. When roots can’t penetrate deep and water sits for too long on the root-zone (0 – 12 in), the root system becomes shallow and relies on the surface conditions to thrive. This is a problem, especially when water has trouble draining away because waterlogging near the surface increases nutrient reduction reactions and changes the chemical soil conditions. As a result, crops are more susceptible to drought and nutrient deficiencies.
Moreover, soil physical conditions can be managed temporarily to better adequate the soil with optimal growing conditions. Artificial drainage, such as tile pipe or cana