The Latest Dirt
The fall of 2012 marked challenging times for growers when it came to planting and replanting new stock. With the new regulations on the use of fumigants, growers were finding newly planted fruit trees and cane berries were increasingly susceptible to root-lesion nematodes.
The fumigation issue came into focus when the province of B.C.’s Ministry of Agriculture started the Orchard Replant Program. Not only were there few effective and environmentally friendly alternatives to fumigants, but also when fumigation was possible, growers were faced with completing extensive fumigation management programs.
The good news
Fortunately, research soil ecologist Tom Forge, was already working on a solution – and surprisingly he is finding that something growers already make use of may be the answer. He began working on alternatives to fumigation in raspberries in 2009 or 2010, and in 2013 applied some of those learnings to a study on cherry trees.
“Very, very high doses of compost was almost as good as fumigation,” Forge said. “We got the best [plant] growth out of compost [aside from fumigation]. It was much better than the control.”
He explored high doses of poultry manure as well, but found that the increased nitrogen and potentially harmful effects to ground water made it a less desirable option.
Summerland housed the cherry tree tests in an old apple orchard with Skeena on Gisela 6 stock. Five different methods were trialed: no treatment (control); 50 dried tonnes per hectare of compost applied to plots in the tree rows; fumigation; wood chip mulch; and 50 dried tonnes per hectare of compost plus wood chip mulch.
“At the end of our first full growing season in 2014, we found that [the nematode] populations remained low wherever we applied compost,” Forge noted.
Interestingly, in the fumigated plots, the nematode numbers started out low, but by the end of the season were significantly higher than the populations in the composted plots.
The results are promising
“So far we’ve always tried relatively high rates,” Forge said. “It raises the question, what about 25 tonnes? These are avenues we need to explore, but the basic proof of the concept is there.”
Given that many growers are already interesting in amendments for their soil, the potential of commercially viable compost to improve soil quality and the long-term health of new plantings is worth more research.
When the focus on soil is water
Back in 2013 at the Pacific Agriculture Show, DeLisa Lewis, then with the Faculty of Land and Food Systems at UBC, told an audience there was nothing new under the sun in soil management. She noted that the practices of soil tillage, crop rotation, cover crops, organic amendments and mineral amendments are still the core of soil management.
Now that Lewis has returned to farming, just outside of Duncan as the lead farmer at Green Fire Farm, Orchard & Vine wanted to see if her point of view had changed at all, or if it truly was “nothing new under the sun”. It was no big surprise that the sun has been the topic of interest for Lewis this year.
“It’s been a real experience learning again the bio-physical limits of the soil,” she said.
She’s referring, of course, to the extreme lack of water and unusual heat this spring. In her farm’s location well water is the only option and there is no ability to simply turn the tap on and water the earth. The latest big project completed on Green Fire Farm was an irrigation pond and Lewis noted water only recently made it from the pond into the field.
“This year, we’re trying to bring in a 10 acre field of vegetables,” she said. “But you can’t keep soil alive without water.”
The typical work of turning the soil happened in March and April, but with no water, there was no way to move forward. While Lewis often speaks with other farmers about the importance of organic matter in the soil, the conversation this year is specific to the importance of soil water.
“Without that mixture of soil, minerals and water, you’re not going to have anything growing, living.” She said. “It’s just dust.”
It’s a process of life-long learning, she noted and while a lack of water is challenging, she did note it makes weed management easier. ■
