Most orchard, vineyard, cropping and pasture soils we work with need some dry soil corrective fertiliser applications to supply major nutrients such as N, P, K, Mg, Ca and S. We almost always find that lime is required at least once a year to supply Ca, the main nutrient required in big volumes by all plants and usually not found in sufficient available quantities in our soils.

Fertiliser applications are about balance

Following a soil test we will make a fertiliser recommendation that aims to set out the major nutrients required to achieve the desired balance of these nutrients in your soil. Ratios between nutrient elements are important for long term soil productivity so applying just one particular fertiliser such as Nitrogen to promote pasture growth isn’t an option.

And remember we’re not trying to remedy a soil’s total mineral imbalances in one go, as this will be extremely expensive and probably not particularly successful anyway. You can imagine a drug addict quitting drugs cold turkey and the problems with the resulting withdrawal symptoms. It’s the same with your soil.

The goal is to identify what is most out of balance and necessary for microbe and plant growth, and then provide that first. Since calcium and phosphorous are crucial for plant growth and are not elements that microbes can convert from the air as they can nitrogen, we tend to focus on those in annual capital fertiliser applications.

When is the ideal time to make dry soil corrective fertiliser applications?

We have found that the most appropriate time to make soil corrective fertiliser applications such as Lime is generally in autumn. These are the reasons why:

• Autumn application on cropping land (following harvest of the previous crop) provides time for the applied fertiliser to be biologically decomposed or activated so that the applied nutrients are incorporated into the soil microbial biomass and therefore likely to be available to the next crop in the following spring.
• There is likely to be enough moisture from autumn rain to facilitate the microbial activity and plant uptake that is necessary to make the most of the valuable nutrients applied in the form of dry fertiliser. If conditions are very dry it would pay to delay the autumn fertiliser application until it rains.
• In a cropping situation, leftover crop residues from the previous harvest will be cultivated (incorporated) into the soil at the same time as the dry fertiliser application. This provides more microbial food in the form of the crop residues as well as the nutrients required in the form of fertiliser to balance the requirements of the soil microorganisms while they are digesting the crop residue.
• In pasture and crops you will always get the maximum benefit from the nutrients applied in the fertiliser when your plants are growing rapidly. By applying fertiliser during the autumn flush of growth you will generate even more plant growth while making sure the nutrients applied are incorporated into the plants and soil microbiology. This improves the efficiency of fertiliser use and minimises losses of highly soluble nutrients such as N and K through leaching.
• Achieving the correct balance between Ca and Mg (7:1) will improve the soil structure which reduces compaction and improves soil drainage. This makes spring operations on the land much easier, reduces weed growth and reduces the compaction caused by livestock in wet conditions.