SOIL & PLANT NUTRITION IN NATURAL & CONVENTIONAL

FARMING SYSTEMS: A COMPARISON.

Andrew Wild

The soil is any country’s greatest asset. It is the lifeblood of its people. In Australia we have seen huge advances in agriculture and the opening up of new land for us to farm. However, with this we have seen large problems of soil degradation in many forms, some so severe as to render the land useless.

As with any problem it is important to get at the crux of the matter if we are to solve it. In Agriculture I feel we are only covering up the problems with band-aid measures. The most important factor in reversing soil degradation in Australia and to make Agriculture more sustainable is a shift to Natural Soil & Plant Nutrition, or basically, naturally fertilising our soils.

There are many other measures we can take which will help immensely, but this single aspect can rectify a lot of the problems. What is the difference between conventional and natural fertilisers? Essentially artificial fertilisers are water soluble and natural fertilisers are not. It may sound simple but this essential difference turns out to be much more complex. Artificial (chemical) fertilisers are treated with either an acid or alkaline process to make the essential elements more 'readily available. They are water soluble 'salts' of the elements in question - a situation that does not occur in natural soil habitats.

Because artificial fertilisers are water soluble, each time the plant takes a drink it takes in nutrients whether it wants it or not (Imagine the 'salt' mixed with water). This leads to a force-feeding effect and an imbalance of nutrients in the plant. Due to the extra moisture to fiber-ratio you get problems of frost or drought damage. It creates a need for the plant to receive water at regular intervals. Plants grown this way are more susceptible to pest and disease attack.

Most people do not fertilise their lawn, they just water and mow it. How does it grow? In a natural situation a plant takes nutrients and water from the soil via its roots and from the air. Where do the nutrients come from? They come from the broken down organic matter (dead leaves & roots, manures etc) in the soil. This organic matter is broken down to form a stable colloid called Humus, by microbes and bacteria in the soil. Humus is a crucial component of our soils as it holds onto nutrients and stops their leaching. It also has great water holding capacity. Good compost is an example of humus. The plant is able to take nutrients from the Humus and clay particles not in a forced way, but triggered by natural factors such as sunlight.

Humus in our soils is like a sponge. It retains moisture and nutrients very well, which means less leaching of nutrients and greater water holding capacity. The thicker the sponge (humus) the more, moisture and nutrients the soil is able to hold.

By feeding the plant naturally with minerals and nutrients that are not water soluble, we encourage the roots of the plant to go down deep in search of sub-soil nutrients and moisture. The plant develops many more of the smaller, white feeder roots which take up nutrients. A plant with a larger, more fibrous root system will mean that there is more organic matter in the soil when the crop is harvested. Or, when the plant dies it is turned into humus by the microbes and bacteria in the soil for use in the next crop.

By increasing the organic matter and humus content in our soils, we are able to achieve many benefits. These include:

1.) Increasing the moisture retaining capacity

2.) Increasing nutrient availability

3.) Decreased effects of erosion

4.) Increased porosity of soil

5.) Create a better soil structure

Microbes in the soil are a crucial component of living soils. By increasing the microbial activity of our soils we are able to;

I.) Break down organic matter into humus more quickly

2.) Increase the availability of nutrients

3.) Create a better soil structure

4.) Create a better, more fibrous and penetrating root structure in our plants.

Examples of the types of bacteria which are of benefit are:

1.) Rhizobium Bacteria - Nodulate on roots of leguminous plants, which provide nitrogen for the soil. (Commonly known).

2.) Mycorrhizal Fungi - increase the uptake of minerals, especially phosphorus.

- Secrete plant growth hormones

- Protect plant from infection by pathogens

3.) Pseudomonas Bacteria - Help build soil structure by secreting legumes, which hold the soil together.

MINERALS.

Minerals and trace elements are important not only for good soils but also for animal health. One of the main reasons why bacteria and microbes fail to function in the soil is because of a lack of trace elements. Many farmers throughout Australia have realised the importance of balanced minerals and trace elements for their animal health and nutrient availability. Building up a good balance of minerals and trace elements is the first step a farmer should take. It is the foundation of the soil, just like the importance of having a good foundation to your house.

A soil containing a balance of major nutrients such as calcium, magnesium, phosphorus etc and trace elements will provide a good soil structure, allowing soil aggregation, porosity and excellent nutrient availability. Coupled with a soil thriving with microbes, the plant develops a healthy, fibrous root system. A soil, which has a poor mineral balance and low humus levels, is compacted and this leads to low nutrient availability, poor water infiltration and reduced microbial action.

Thee are 4 major points to remember in creating our soil to be more healthy, fertile and productive, and therefore more sustainable. It's easy to remember them as the 4 M's

1.) Minerals

2.) Microbes

3.) Mulch

4.) Moisture

These four are the basis for long-term soil fertility and healthy production of foodstuffs. There is no question that the farmers who have gradually changed their fertiliser regime to a one that incorporates these factors have benefited greatly.