Homegrown research is helping fodder beet live up to its promise.
Fodder beet has attracted great interest in recent years, with increasing amounts of this high energy and potentially high yielding crop planted for late autumn and winter feed.
But while efficient use of nutrients can maximise fodder beet’s high yield potential and return, it is a relatively new crop in New Zealand, meaning farmers have largely relied on overseas or historical advice.
To better understand the crop’s nutrient requirements in order to optimise yields, a Sustainable Farming Fund project involving Ballance Agri-Nutrients and other partners has investigated fertiliser management and crop establishment, both of which can affect fodder beet yields.
The project looked at the impacts of different rates and timings of nitrogen (N), potassium (K) and boron (B) application. Trials were carried out at sites (including dairying, arable cropping and sheep and beef, as well as irrigated and rain-fed conditions) across five of the main fodder beet production regions.
Results indicated fodder beet is a luxury feeder of N, meaning N should be applied prudently. As N application rates increased, so did crop N uptake and N concentration, but yield did not consistently increase. Yield response to N fertiliser varied across sites in the first year of the study, with responses seen between 100 and 200 kilograms per hectare (kg/ha) of added N, while three sites had no response to added N. The second year of the study showed similar results, with peak N response up to 100 kg/ha of added N.
Overall it was concluded that in most cases, adding up to 100 kg N/ha should suffice to optimise yield. Splitting N applications between sowing and canopy closure will help achieve optimal yields but applying a third application was shown to have little benefit in terms of additional yield. The response to N fertiliser varied depending on the amount of available N already in the soil, highlighting the value of soil testing to avoid wasting money applying N unnecessarily.
Looking at the application of K, the crop was found to take up large amounts of K (related to the amount applied), but as with N, this did not necessarily affect yield. Both rate and timing of K application were found to have no effect on yields, indicating that across the trial sites, soil levels were sufficient to meet K requirements. Soil testing is also important for K, and adding up to 100 kg K/ha at low K soil test levels – with a Quick Test K (QTK) less than five – will ensure sufficient K. If QTK is greater than five, adding K will not affect yield so it can be withheld.
The application of B was also found to have no effect on yield in the trial, however, it should still be added due to its importance for crop health. Deficiencies of this essential micronutrient can result in brown heart and abnormal bulb development.
Applying the results
The Ballance fodder beet profile test, taken before sowing to a depth of 150 millimetres (mm), will determine levels of available N, K and B, as well as phosphorus (P), pH, sulphur (S), sodium (Na) and magnesium (Mg).
Land just out of pasture has higher levels of available N, up to 300 kg N/ha. Previously cropped land typically has available N levels of around 100 kg N/ha and fertiliser N requirements of around 100 kg N/ha. About half of this should be applied with the base or starter fertiliser before or at sowing, with the remainder applied as post-emergence N at canopy closure. Some or all of the base or starter N can be applied as DAP or Cropzeal Boron Boost at drilling, but this must be in a separate box to the seed to avoid direct contact in the soil. The best choice for post-emergence N is SustaiN. If K is required, potassium chloride (potash) can be applied with the base dressing before sowing.
Article supplied by Ballance Agri-Nutrients