A cheap change in grazing rotation can make a dryland farm soak up far more of the rain that falls on it, a farmer-led New Zealand project has found. In Catch the Rain, funded by Beef + Lamb New Zealand (BLNZ) and led by Quorum Sense, extending pasture recovery periods almost doubled infiltration rates on average within nine months on three farms, compared with control areas.

For non-irrigated sheep and beef farms rainfall is the key resource, but rain only helps if the soil can absorb it; otherwise it runs off. More than 60 farmers across the South Island and lower North Island took part through workshops, interviews and trials, and 11 tested practical, low-cost ways of improving infiltration on their own land.

Three approaches were tried: longer recovery periods, a biostimulant to support soil biology, and more diverse pastures. Farmers compared a standard 30-day rotation with recovery periods of 60 to 90-plus days, and the longer rest gave the strongest result — a change that fits existing systems without capital spending. "Farmers don't necessarily need major investment to make a difference," said Dr Suzi Keeling, BLNZ's head of science and research.

The biostimulant trials, using a Biomarinus fish hydrolysate, raised infiltration by about a third within nine months on three farms, and soil analysis showed more abundant and active fungi. The diverse-pasture trials were less conclusive: infiltration fell during the trial, reflecting the short-term disruption of pasture renewal, and the longer-term benefit is still to be assessed.

"Being part of Catch the Rain opened up a totally different way of looking at soil for us," said Banks Peninsula farmer Will Johns, citing visual soil assessments and the link between soil structure and infiltration. Science lead Dr Gwen Grelet said it was encouraging to detect measurable changes in soil function in under a year from simple management, while cautioning that the small farmer-led trials should not be generalised without testing across more farms, soils and climates.

Source: Farmers Weekly NZ