Agronomic Advice For Spring

Looking forward with low milk prices it is important to make your dollar go as far as possible. With the price of some fertilizers dropping such as urea, the questions asked generally revolve around what to do for silage season. Each farm will be different depending on fertilizing history, but there are a few good options to consider.

The cheapest option going forward is straight urea, but you must take into account what nutrients you are removing with silage. Average figures for a 3 tonne/DM/ha silage crop shows that you can remove up to 120 kg of Nitrogen (N), 12kg of Phosphorus (P) and 50 kg of Potassium (K) and 10 kg of sulfur (S). Now these figures can depend on how much grass you grow, the more silage you take off the paddock the more nutrients you need to replace.

For this season, when locking up a paddock for silage I suggest to apply straight urea @ 100kg/ha. Optimum time for cutting (weather dependant) has been shown to be 41 days after last grazing. This is a balance between quantity and quality, again this will vary from farm to farm. If your paddocks are deficient in potassium I would recommend using a mix of 2/3 Urea, 1/3 MOP (sometimes referred to as red and white) and apply at 150kg/ha. It is important to remember plants have what is called luxury uptake of potassium which means that the plant will continue to take up more than it needs if the nutrient is readily available. There is also the issue of high potassium levels in your silage (and Hay) which can have animal health issues when feeding. For that reason apply no more than 50kg of Potassium (100kg of MOP) in one application. If you also require phosphorus look at some the booster products which are an N,P,K,S blend and apply at the rate depending on your needs.

After a silage cut, if there is sufficient soil moisture for regrowth, I would look to top-dress again this time with a mix of N, P, K and S. Maximising regrowth will be important to continue grazing good quality pasture until the season finishes. If soil moisture is limited and regrowth is limited, you are not going to get the short term benefit of the fertilizer and it may be worth holding off until your initial autumn application.

November is a good time to do your soil tests. It gives you time to be able to look at the results and put a plan together for the coming growing season when the autumn break occurs. This will allow you to calculate maintenance levels and also if capital applications are required, to build fertility levels. You can also do a nutrient budget to be able to accurately assess what nutrients you require after taking into account the nutrients you import and export on your farm.

In relation to summer crops, there are different options out there. At the end of the day it is finding the option that best suits your requirements. Factors to consider when choosing what to sow include: when do you need the feed; do you want one or multiple grazings; can the crop be irrigated; do you want to be able to cut the crop for silage or hay if an excess occurs; and what is going to happen to the crop in autumn, are you going to resow it to pasture or do you want the crop to continue into the autumn and winter months. It may be the case that you plant a number of different crops to suit your feed requirements in the summer months.

When working up a paddock a fine seed bed with good soil seed contact is a must. Paddocks sown with a small seed such as a brassica can have poor germination results if the seed bed is rough. This is important in regards to soil seed contact. Well soil seed contact is the same. The conditions need to be right to achieve optimum germination.

Every farm is different so the best way to find out what works for you is to seek advice.

Gerard Murphy Sales, Nutrition and Agronomy Consultant

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