Soil Testing and Fertiliser Application By Sophie

Soil Testing for cotton crop Soil testing in the agriculture industry is the analysis of an soil sample to determine nutrients. An soil analysis service should provide independent laboratory analysis, soil health which includes estimating soil fertility, monitoring soil fertility, evaluating Fertiliser program and root disease (optional) and interpretation and professional advice. The 13 essential mineral nutrients for cotton crop includes Nitrogen (N), Phosphorus (P), Potassium (k), Magnesium (Mg) , Calcium (Ca) , Sulfur (S), Boron (B), Copper (Cu) , Chlorine (Cl) , Iron (Fe) , Molybdenum (Mo) , Manganese (Mn) and Zinc (Zn).

Cotton crop nutrition Cotton farmers need to do soil testing to establish which nutrients are deficient, Then add the necessary Fertiliser, ensuring that the crop has adequate nutrition which is critical to maximizing yield, But with the Fertiliser making up 9 – 21 per cent of cost of production, nutrition efficiency is important.

Cotton requires a good supply of Macro and Micro nutrients to support the high yields. Most soils require the application of Nitrogen and also Phosphorus, and some cotton crop farmers will likely need to supply potassium. Fertiliser applications reflect on the amount of certain nutrient being placed in the soil before planting. Farmers should apply approximately 230- 300 kilograms of Nitrogen per hectare which matters depending on the soil testing. However, not all Fertiliser is taken up by the plant, the average Fertiliser recovery is around 50% for Nitrogen and Potassium Fertilisers.

Nutrient Supply The supply of nutrients for a cotton crop is controlled on the soil nutrient reserves and nutrient added as an Fertiliser. The soil before planting, a routine soil tests is a part of crop management which can provide an indication of the fertility level in the soil. Once the soil nutrients levels are determined then Fertiliser requirements can be more accurately calculated for the yield which is something you would take for consideration.

Nutrient Removal A significant amount of nutrient is removed from the cropping system in harvest of the seed cotton. The high yielding cotton in the Australian production system leads to the removal of large amounts of nitrogen (N) , phosphorus (P) , and potassium (K) from the soil.

Having the correct Fertiliser? There are different types or forms of Fertiliser that can be used e.g. manures, compost, granular Fertilisers, anhydrous ammonia (gas), and liquid Fertiliser A local example in the Forbes district was to apply MAP, Potassium and Nitrogen. There are different varieties of Fertiliser that could be used for example Manures and composts, granular Fertilisers, anhydrous ammonia (gas)and liquid Fertiliser. The type of Fertiliser you use should be matched to the paddocks needs.

Having the correct rate? The Fertiliser rate will depend on the type of Fertiliser being used, when it Is being applied and how much of each nutrient that needs to be required. The composition of the Fertiliser which is the percentage of each nutrient in the Fertiliser that will dictate just how much of the product you will need to apply to meet the crops requirements. The rate is determined by soil analysis after performing soil testing.

Having the correct time? The timing of the Fertiliser application is determined by the production system, soil conditions and type of fertiliser being used. The wise thing to do is to apply after July to reduce the risk of substantial losses through densification and leaching. Apply 3 weeks before planting to prevent seed damage.

Placing the fertiliser in the correct place? There are various methods of fertiliser application. These include: fertilisers that are applied to the soil pre- planting at a depth of 300mm. Applying Fertilisers too close to the plant line may cause seed damage leading to salt or toxicity effects. Fertiliser being too far from the seed can cause a loss of Nitrogen (N), called denitrification which is the most important loss of nitrate –N in irrigated cotton crops and can easily lead to loss of greater than 50 per cent. Removal of seed cotton is when most the crop N is removed from the cotton crop, especially in high yielding crops.

Nitrogen Fertiliser Use Efficiency (NFUE) The Nitrogen Fertiliser use efficiency is a simple measure that enables growers to gauge how well they are using the Fertiliser N that they have applied. NFUE = (kg/ha) Lint produced (kg/ha)N Fertiliser applied)

Bibliography Introduction to irrigated cotton production ,18th may 2016, http://www.monsanto.com/global/au/products/documents/introduction%20to%20irrigated%20cotton%20production.pdf Wikipedia the free encyclopeida,18th may 2016, https://en.wikipedia.org/wiki/Soil_test (Jemalong field day) 16th march 2016 Soil Management and Soil Testing for Irrigated Cotton Production,2nd June 2016, http://ag.arizona.edu/crop/cotton/soilmgt/soilmanagement.html#testing Abbeys book, 2nd June 2016 The land, 2nd June 2016 Australian cotton production manual 2015, 2nd June 2016