By Delwyn Dickey for Our Land and Water
Improved management of fodder beet crops for winter grazing could decrease runoff and reduce methane and nitrous oxide emissions.
Paddocks of leafy green fodder beet are common around the country during winter, but cattle grazing the high-yielding crop can cause environmental damage, with sediment and nutrients ending up in waterways.
Adopting the strip-till methods widely used in arable farming to maintain soil structure and reduce the loss of nitrogen, phosphorus and sediment to waterways may take some of the guesswork out of fodder beet crop management for livestock farmers.
Tilling a narrow strip of soil about 30cm wide can lead to less soil erosion from wind and rain as most of the soil remains covered. Cultivation, laying fertiliser and seeding are all done with a single pass of the tractor, instead of up to three passes.
After experimenting with strip-till methods for a couple of years on his north Canterbury farm, Jim Earl was pleased with the condition of his paddocks and the yields. This led him to join up with agricultural adviser Meagan Fitzgerald, of agricultural consultancy Tambo, and her team to assess the benefits of the cropping technique more formally.
Funded by the Rural Professionals Fund from the Our Land and Water National Science Challenge, the group plans to measure runoff and nutrient loss from Earl’s strip-till fodder beet paddocks, compared to conventional tillage.
Along with comparing the amount of runoff coming off cropped land using each cultivation method, differences in sediment, nitrogen, and phosphorus losses will also be measured.
Being able to put numbers to the tilling will see any reductions in fertiliser, spray and inputs going into Overseer and onto farmers’ Farm Environment Plans, while maintaining productive yield.
However, with research lasting just six months through this winter, unfortunately the weather in north Canterbury hasn’t been playing ball, Fitzgerald said. “While the crop is already grown there hasn’t been as much rain. No rain, no runoff,” she said.
Financial costs, including inputs, will be compared and a feasibility study will assess whether strip till could be more widely adopted in local farming systems. Getting a handle on what might get in the way of strip till being used more widely will be put under the microscope, including whether agricultural contractors have the right gear for it.
Good fodder beet management practices could also be a bonus for emissions reductions.
Fodder beet is one of just a handful of forage crops that could produce less methane and nitrous oxide when eaten by dairy animals, compared to pasture, but those nitrous oxide reductions can be wiped out if soil become wet and boggy during grazing.
