Vegetables Gardening - Growing Organic Vegetables

Making Nutrients Available to Your Plants – Organic vs Minerals

Manure and compost contain organic compounds, usually including nitrogen, phosphorus, and potassium – the macro, or major elements – and many of the other secondary nutrients and micronutrients that plants need to grow, but no one knows whether or not they are all there, nor in what amounts.

Being organic simply means that the nutrient molecules are attached to other molecules containing carbon, which makes it very difficult for them to be absorbed by plants in that state. They have to be broken apart by bacteria and other soil organisms in a decomposition process.

Another thing that is in manure and compost is ammonia, an inorganic form of nitrogen. This nitrogen is attached to hydrogen, and can be toxic in large quantities. Ammonia is often used as a cleaning product. It is the result of a naturally occurring chemical reaction as things break down in soils and compost piles and if you were to put your head into a Compost Tumbler you would experience it firsthand.

These organic compounds and ammonia are applied to the soil by the organic grower. And microbes, worms, and bacteria living in the soil consume these compounds and break them down. As the organic compounds decompose, the nutrients become available to the plants, but this often takes a significant amount of time, especially in the cool early spring, when you're trying to get your plants growing. This is accomplished by two processes, nitrification and mineralization.

The process of turning ammonia into safe and available nitrogen is called nitrification, which is essentially the oxidation of ammonia. The process starts with proteins and breaks them down to ammonia, and then takes ammonia and adds oxygen to it a couple of times to end up with nitrate. Nitrate (nitrogen plus oxygen - NO3)) is the first of the primary plant nutrients that your plants must have to grow.

The processes that take place in making the other 12 nutrients (phosphorus, potassium, calcium, magnesium, sulfur, zinc, boron, manganese, iron, copper, chlorine, and molybdenum) available to plants are called mineralization. Almost all of these processes also include oxidation reactions, which means that oxygen is used in the process, and the mineral compounds that result include oxygen.

This is important to understand because these oxidation reactions consume the oxygen in your soil. So, the microbes in the soil need oxygen and the plants also need oxygen. Therefore, in addition to the extended time required for decomposition, with competition going on for oxygen, if soil air is limited, the decomposition process suffers, and your plants can suffer as well.

On the other hand, when the grower applies mineral nutrients directly to the soil there is no decomposition or nitrification required, and so the nutrients are immediately available to feed the plants. In addition, the mineral compounds already include oxygen, so there is no competition for available soil air.

And finally, there is no guesswork, and no waste, because the grower knows exactly how much of each of the 13 nutrients that man can provide are being applied to the soil.