As a three-year Ministry for Primary Industries’ Sustainable Farming Fund project to identify agronomic solutions for fodder beet came to an end in August, project leader John de Ruiter delivered a seminar covering the key messages resulting from the trial.

John says the project was supported by Foundation for Arable Research, several key seed and fertiliser companies both financially and with field technical assistance – and Plant and Food Research administered the trial with him at the helm.

“We’ve come away from this with extensive data on nutrient requirements from numerous trial sites research, and a sound Good Practice Guide for growing fodder beet,” says John.

“The focus was on fertiliser management, in particular nitrogen, potassium and boron, and their effect on yield and profitability.

“Potential yields of 35 tonnes DM per hectare were possible in perfect growing conditions and with high crop health. However, yield in the range of 20-32t DM/ha were typically achieved with on-farm trials.”

Field test sites were set up across the country on differing soil types. Detailed field work compared regional differences in crop productivity under varying rates and timing of N and K fertiliser, and effect of disease and weeds on production levels.

“Fodder beet is an excellent feed but needs to be managed well to achieve the best outcome from production and environmental perspectives,” says John.

In the final year, demonstration blocks of fodder beet managed by farmers in Waikato, Whanganui, Mid-Canterbury and Southland were compared with Good Management Practices derived from trial work in previous seasons.

The comparisons showed farmers were achieving good results with similar yields and profit margins to the GMP treatments.

John says the following key messages emerged from the three years of trials.

Firstly, there is no yield response above 100kg/ha of total N applied in fertiliser. Soil N tests prior to cultivation can be used to refine N inputs.

Timing of N application is important – 50 per cent at sowing and 50 per cent before canopy closure.

And, there is no effect of potassium fertiliser on crop yield, so limit the application of K to less than 100kg K/ha, especially if the crop is grazed. Less K can be applied if a soil test shows Quick test K values < 5, and none if QTK >5 levels.

In trials, boron rate and timing of application had no effect on yield or incidence of B deficiency symptoms. And, farmers need to maintain a healthy canopy through monitoring and control of foliar diseases to maximise yield. Plus, prevent carry-over of disease by not sowing successive crops of fodder beet. “Future work needs to address significant issues with crop health appearing in fodder beet crop,” says John.

“Our aim of increasing yield was hindered by the disease problems in most crops. However, we have a better understanding of the crop requirements for fertiliser and the practices required for sustainable management.”

The findings of the research, and the Good Practice Guide, with nutrient recommendations for fodder beet can be viewed on the DairyNZ website: www.dairynz.co.nz