Soil is an integral component of successful farming- both crop and animal feed production rely on good soils. As a farmer, it’s important for you to ensure that your soil is taken care of well by engaging in farming practices that constantly improve your soil health, water-holding capacity, nutrition, and structure for higher productivity. Soil water holding capacity as one indicator of soil health is the ability of soils to absorb and hold water for plant use.
Soil water holding capacity is a factor of many soil properties and farming practices which can be summarized as soil organic matter content, soil structure, and texture. There is really very little a farmer can do about soil texture, especially in the short run but the preceding factors are easily manageable through appropriate farming practices. Soils with poor texture in regards to soil water holding capacity simply mean soils with a bigger soil particle size which then translates to a lower surface area which reduces the water holding capacity. Farms with this kind of soil can be amended through the addition of organic matter to build enough humus to take up the role of holding soil moisture as well as bind the soil particles together thus reducing the rate of water infiltration.
Enhancing your soil water holding capacity increases your soil’s ability to support crops with higher water uptake rates. Working on your soil water holding capacity will also mean increased resilience to drought- as your soil will be able to store enough water for plant use in cases of low rainfall or drought.
Approaches To Increasing Soil Organic Matter
There are various approaches to increase soil organic matter without interfering with production. It’s important for a farmer to understand the types and qualities of materials for use to improve soil organic matter. This will help farmers to choose the best plant material/animal waste to use. The different approaches to increasing soil organic matter include:
- Cover cropping– Cover cropping is the practice of planting leguminous crops with the main crop to incorporate the plant materials in the soil after biomass formation. Cover cropping enhances the addition of organic matter with high nitrogen content in the soil which not only improves the soil structure but also enhances soil health and nutrition.
- Incorporation of crop biomass– It’s important to ensure that all the crop residues are plowed back into the soil to recycle the nutrients used in growth. This however takes long to decompose and contains less nitrogen as the materials are only incorporated after harvest when the plant has lost most of its nitrogen.
- Application of manure– Animal manure is a very rich source of organic matter when well-composted. Farmers practicing mixed farming have easy access to manure and only need to learn how to compost properly whereas farmers dealing in crop enterprises only are advised to purchase and apply animal manure at least once every three years to build up soil fertility and structure.
- Application of green manure– Green manure can be applied after composting or as mulch. Just like animal manure- green manure acts as a good soil amendment for structure/physical properties as well as fertility and microbial systems.
Improving Soil Water Holding Capacity
Soil structure and texture of soil particles is also important to factor in determining the capacity of soils to hold water and make it available for plant uptake. There are various farming practices that could possibly help you raise your water holding capacity, they include:
- Conservation tillage: Conservation tillage practices such as zero tillage, minimal tillage, and controlled traffic help to reduce the compaction of soils which then increases surface runoff- maintains soil structure through minimal disturbance during cultivation and helps to build soil organic matter and soil life. Reduced compaction also limits the formation of hard pans which would otherwise reduce water retention capacity.
- Intercropping and rotation: Different plants/ crops have different rooting systems, structures, and needs. Crop rotation (with a focus on the crop root system and root structure) is one of the most efficient techniques to naturally deal with hard pans and increase the depth of water percolation into the soil. Shallow-rooted crops should be followed by deep-rooted crops in the rotation cycle to ensure a uniform soil structure.
- Ridging: Ridging can be used in cases where the soil has been heavily compacted to loosen up the hardpan formed more than 30cm deep.
- Avoid cultivating wet soils: During land preparation, it’s important to ensure that timely cultivation is done so that soils are not compacted during plowing. Uncontrolled traffic on the farm, i.e. heavy machinery and livestock should be avoided as wet soils are easily compacted.
Why Is This Important?
Soil health and particularly soil water holding capacity is a critical factor in building a productive and resource-efficient farm. Enhancing your soil water-holding capacity increases your soil’s ability to support crops with higher water uptake rates. Working on your soil water holding capacity will also mean increased resilience to drought- as your soil will be able to store enough water for plant use in cases of low rainfall or drought. This will also reduce soil erosion as surface water runoff will be kept to a minimum.