Using and encouraging the natural cycling of plant nutrients is a great way to increase the efficiency of your farming operation. Rather than buying in nutrients in the form of fertiliser, we may as well make full use of the nutrients that already available to us to nourish the soil.

Are you using all of your leftovers?

When growing a crop, only a portion of the crop is generally harvested and sold. The majority of the crop plant actually gets left behind in or on the field. These leftovers form a very important source of carbohydrate for the soil micro-organisms. An added advantage is that because they used to be living examples, crop residues also contain all of the essential plant nutrients in approximately the proportions needed.

This means that it is essential to incorporate the crop residues into the soil as soon as possible after harvesting. In this way you can maximise use of the carbohydrates, energy and nutrients that exist in the crop residue. Making sure the residue is incorporated into the top 100mm of soil is equally important because it makes sure as much of the leftovers as possible is in contact with the soil and is therefore accessible and of most benefit to soil microorganisms.

How to get the most of your crop residues

We generally encourage the application of a stubble digester to the crop before it is cultivated. This stubble digester provides microbial foods and stimulants which encourage faster breakdown of the crop residues. We also normally apply some N to ensure nutrient levels are balanced.

This is because the plant residue being digested has a C:N ratio of between 20:1 and 80:1, while the microbes have a C:N ratio of between 3:1 and 20:1. Adding Nitrogen brings the C:N ration down and makes the residue more palatable to soil microbes.

Encouraging the breakdown of crop residues in your soil ensures the soil nutrients that weren’t used in the harvested part of the plant are recycled and used to help create new season growth. Don’t waste crop residues by leaving them sitting on top of the ground as they tend to lose the carbon and nitrogen value if not incorporated quickly.

In reality it’s free fertiliser, so use it wisely to increase your soils productivity.