Benefits of soil sampling

Agricultural consultant and DoneDeal farming blogger Mark McConnell explains how soil sampling can save thousands of euros Whatever type of farming that you are involved in the most important aspect of your farm is your soil. You spend all day every day interacting with your soil and if you don’t soil sample you are farming in the dark. When you soil sample it’s like turning on a huge bright spotlight on your soil and you can see exactly what you are dealing with. The only way that a farmer will know what’s below the ground that he/she is farming is to soil sample. That small piece of paper that you get back that will cost approx. €20 could save you thousands of euros. What makes soil sampling even more beneficial to farmers is the great variation of soil types that exists within counties and then between different areas of the country. There is however a wide variation of soil types and the fertility of soils throughout Ireland. We will have a look at the different types first. There are four main types and these are brown soils, podzol soils, peaty soils and gley soils Brown soils. This is mainly found in the south east and north east of the country stretching from Louth to south Cork to Wexford. They are mainly free draining with air pockets due to the crumb like makeup of the soil. These soils are very fertile and easily worked. Podzol soil. These are also mainly found in the south east and north east of the country. Again these are free draining fertile soils. Peaty soils. Found on the west cost stretching from Donegal to Galway with some pockets in the midlands. Very hard to drain, can be fertile but excellent management needed. Gley soils. Found in the middle spine of the country stretching from Derry to down and as far south as Kerry and north east Cork. Depth of these soils can vary widely from the south of the country to the north of the country. Very fertile but not as easily drained. Holds water in the soil and can become very wet Although the type and drainage qualities of soil can change around the country all soil can be fertile and productive if managed correctly. The most important nutrients in soil are nitrogen, phosphorus and potassium. The levels of these are varied massively from farm to farm and are as a whole are inadequate. The only true way to gage this is to get a soil sample done on the farm. Main benefits of soil sampling Improved yields and economic return Management tool for your fertiliser plan Efficient use of fertiliser Indicate the level of P, K and lime in the soil Environmental benefits Micronutrient requirements of the crop Improved yields and economic return Whether you are growing grass, barley or any crop you need to know what level of soil fertility you are dealing with. We all know the amount of units of phosphorus and potassium per acre that we need to grow the relevant crops but if we don’t know the level of these elements and the ph. of the soil we are going to affect the yield of the crop and in return the money in your pocket. If you can apply the correct level of the different elements based on your soil sampling results you will obtain the highest yield possible per acre and therefore increase your economic return per acre. There will be certain fields that have lower levels of the major elements than others and these fields will struggle to perform. Management tool for your fertiliser plan Every farmer should set out at the start of the growing season with a fertiliser plan for the particular crops that you are growing. This fertiliser plan will detail the correct amount and type of fertiliser to apply to the different fields on the farm and the level of lime that needs to be applied as well. This fertiliser plan affects all aspects of the agricultural enterprise and will also keep the farmer within the limits set out by the Nitrates Directive and prevent a penalty under cross compliance. The fertiliser plan success and effectiveness is based on your soil sample results and cannot exist without samples have being taken Effective use of fertiliser and lime With the increased pressure on farm incomes and the high level of fertiliser prices that farmers are subjected to it is vital that farmers are not applying too much of the wrong product. Your soil sample will tell you what fields need P, K and lime the most and also tell you what fields to target most with your slurry which will reduce your fertiliser usage. You will have fields that will show up a high level of P and K and lime and there can be huge savings on these fields by cutting back on the levels of these elements that are applied. If you haven’t soil sampled you won’t know if your soil is low in lime. If this is the case you could be losing money. If you have your soil at the correct ph. levels it could save you up to 2 bags of Nitrogen per acre. Indicate the level of P (Phosphorus) and K (potassium) and lime in your soil and other trace elements When you get your soil sample back depending on what you have sampled for you will get a sheet of paper back with all the different levels of those elements on it. The lime is measured on a ph. system which tests the acidity of the soil. The more acidic your soil is the more lime you need to raise the level of the ph. The ideal ph. for soil to grow grass is between 6.2 and 6.5 and this correct ph. will release all the necessary elements available to the crop The P and the K are measured on an index system from 1 to 4 Index 1 being too low and Index 4 being too high Environmental benefits When you don’t soil sample as we have already said you are farming in the dark and you could be applying elements to the soil that you don’t need to this is both a waste of money and detrimental to the environment. Soil sampling primarily allows the efficient use of chemical and animal manures on the land. If you apply chemical fertiliser or animal manures to soils that are at an Index 4 for P then you will be applying surplus P and this can then be leached of the soil and into the neighbouring waterways and cause pollution to these waterways and result in algae growth. Soils that have excessive levels of Phosphorus and Nitrates are more likely to leach these elements into the waterways. Soil sampling allows farmers to avoid applying Phosphorus and Nitrogen to areas of the farm that are naturally high in those elements. Micronutrient requirements of the crop A farmer can also get an in-depth soil sample done whereby you get results back on the various trace elements that are present in the soil. These could include Available Phosphate Exchangeable Potassium Exchangeable Magnesium Total Cobalt Total Manganese Total Zinc Total Copper Available Boron Total Kjeldahl Nitrogen Molybdenum (can effect lime requirement by up to 7.5t/ha) These elements can have a serious impact on tillage crops and grazing livestock and affect the tonnage per acre and the quality of the crop. If you have a crop that is healthy and growing well this crop will need fewer inputs to get the desired yield per acre than a crop that is struggling for lack of certain minerals. Doing a soil sample on micro nutrients is effectively shining an even bigger torch on the soil which allows you see even more about your soil that you are farming and hence allows the farmer to be more efficient in the day to day running for the farm. The main thing to remember The point for farmers to remember is that the annual cost of soil sampling is roughly 50 cents per acre per year and if you compare that to the price of fertiliser per acre per year it’s a no brainer. By not soil sampling you are letting money leak down the drain so stop the leak and your farm soil sampled today by your agricultural advisor and start benefiting form more efficient and profitable farming. Tell us about your experience of soil sampling! #Farming