This week we will be fully launching into the final preparations for next year’s strawberry crop. The two acre field that we will be planting into at the end of November has been fallow for the last month after we harvested one spring crop of broccoli and other mixed vegetables from it. After the initial round of tillage—two passes with a “ripper” to break up any deep compaction followed by alternating passes with a chisel plow and a disc-harrow—we will level the field to make sure it drains properly during the winter. After the field is level we spread gypsum, which provides calcium and sulfur to the strawberry plants and can help to loosen our heavy clay soils. After the “gyp” is spread, we make two final passes with the chisel plow and ring roller before setting out the irrigation pipe. For the most part, strawberry beds around here are “listed” (or shaped) when the soil is “wet” which helps them to hold their shape better when they are formed up. Four hours or so of water through the sprinklers followed by a 7-10 day waiting period to allow the water to be deeply absorbed usually results in perfect soil conditions.
Listing strawberry beds is the one farm operation that we contract with an outside company for. They use large, GPS guided tractors that are capable of making beds that are much straighter and deeper that we would be able to. It’s an impressive sight to see. The operator simply sets the first two waypoints, and the tractor does the rest—making perfectly straight beds four at a time.
This year we will be using the ASD (anaerobic soil disinfestation) technique that we have described in previous newsletters. As part of this approach, when the soil moisture is correct and we have removed the irrigation pipes, we spread rice bran—9 tons per acre to be exact. Just before the contract company comes in to list beds we make a final pass with the rototiller implement to thoroughly incorporate the rice bran before the beds are shaped up. As soon as the beds are finished, we use a special implement that buries drip lines on top of the beds and then we lay down the plastic mulch. This is where the ASD process begins. As soon as the beds are finished we connect the drip lines and thoroughly saturate the field. With the rice bran as a food source, anaerobic bacteria thrive in these conditions and over the next two weeks the entire microbial community in the soil is altered in a way that greatly suppresses pathogens that harm strawberry plants. Strawberries, like everything else, can use all the help they can get.
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