Selecting the right fertiliser to support summer crops
When growing crops for late summer feed, consider soil condition and fertiliser choice to assist with achieving the best results.
Soil testing before sowing is the first step as Ballance Agri-Nutrients Science Extension Officer, Grant Bickley explains. “Utilise soil test information to adjust soil pH and address any shortfall in the nutrient status prior to planting.” As it can take six months to adjust soil pH, factor this in when calculating the expected yield.
Pay attention to available nitrogen (N) test information. ‘’This indicates how much nitrogen the soil can potentially supply throughout the growth of the crop and the amount of nitrogen that is further required to reach the expected yield,’’ says Grant. If cropping former ryegrass and clover paddocks, reasonably high quantities of organic N may be mineralised from the soil following tillage practices during the growing season. Alternatively, if the land has been cropped and cultivated over a number of seasons, its organic N reserves may be low.
The choice of fertiliser and rate of application depends on the sowing method and soil nutrient status. A starter fertiliser with N and phosphorus, like Diammonium Phosphate (DAP), sets up crops well. ‘’Germinating seeds require a readily accessible phosphorus supply to develop healthy root systems with nitrogen to support early growth.’’
‘’Be aware of micronutrient levels, particularly with brassicas which may require boron at planting to avoid brown heart symptoms and to improve yield,’’ advises Grant. Cropzeal Boron Boost contains boron in every granule, delivering the micronutrient more evenly to the crop than is possible by including boron in a fertiliser mix.
Nitrogen side-dressing timing depends on the crop and the season. ‘’It is important for nitrogen to be available to the plant at a time when it will boost canopy growth, increasing the plant’s capacity to convert sunlight into energy,’’ says Grant.
Generally, the first post-emergence dressing can be applied four to six weeks after sowing. With multiple graze crops, further light dressings of N, such as 60 kilograms of SustaiN per hectare, can be applied after grazing.
Consider monitoring crop nitrate levels to reduce the risk of animal health issues. Applying N too late in the season when growth is slowing, can elevate levels.
‘’Where high rates of nitrogen are broadcast, the potential for loss is increased if conditions are not ideal for application,’’ explains Grant. In these circumstances SustaiN can help reduce the loss of N by volatilisation, retaining more of the applied N in the soil to be utilised by the plant.
For a fertiliser recommendation, contact your local PGG Wrightson Technical Field Representative.
During spring, PGG Wrightson account holders who purchase selected Ballance Agri-Nutrients fertiliser can nominate a chosen qualifying cause and $1 for every tonne purchased will be donated. Click here to learn more.
