Research Project Year: 2014
Nearly 15,000 acres were devoted to sweet corn production in New England in 2012. Because sweet corn is an herbicide-, fertilizer-, and water-intensive crop, research must be done to develop production systems that can reduce inputs and tillage. This project aims to improve sustainable and profitable production of early sweet corn in the Northeast by integrating the benefits of forage radish cover crops and no-till production. Two experiments will measure the precocity, fertility, and weed suppression in early sweet corn provided by fall forage radish cover crops.
Forage radish has been planted as a catch crop, to scavenge residual nitrate from the soil after a main season cash crop. However, recent research shows that forage radish can provide many more benefits. Fall-planted forage radish cover crops have shown successful suppression of winter annual weeds, suppression of spring pre-plant weed growth, and reduction of soil compaction. The seedbed following forage radish is relatively weed-free and residue-free, therefore optimal for direct seeding in a no-till system. By combining the weed suppression of a winter-killed forage radish cover crop with reduced tillage practices it may be possible to decrease production costs and environmental risks incurred by chemical herbicides and mechanical tillage.
This research will use two experiments to evaluate whether forage radish cover crops could be an innovative and integral part of sustainable production methods for profitable no-till sweet corn. In late August 2014, forage radish cover crops were planted at the University of Massachusetts Crops and Animal Research and Education Center, in South Deerfield, MA. Each experiment is a 4x4 Latin square, with 4 treatments in 4 replicates randomized in each direction. In Experiment 1, four different cover crop mixes were planted:
- 100% forage radish,
- 70% oats/30% forage radish (by weight)
- 30% peas/40% oats/30% forage radish
- 0% cover crop (as a control)
These cover crop mixes were selected to compare the effects of forage radish and other cover crop species on weed suppression and rate of decomposition. Forage radish alone will have the least surface residue and high weed suppression. Oat/forage radish mixes will have a higher C:N ratio and will decompose more slowly than pure forage radish, thereby shifting the synchrony between the N release of the cover crop and N demand of the corn. Pea/oat/forage radish mixes may benefit from some nitrogen fixation by the peas.
Weed population and cover crop biomass will be measured at regular intervals in both the late fall, before winter-kill, and in early spring. Soil temperature, water infiltration, and soil compaction will be measured in spring before planting. A single variety of sweet corn will be no-till planted when the soil reaches 12˚C for three consecutive days.
Three nitrogen fertilizer treatments will be used to evaluate the synchrony between nutrient release from decomposing cover crop and the uptake by sweet corn. Soil tests will be taken at planting and harvest, in addition to nitrogen sufficiency tests (Pre-Sidedress Nitrate Test and Corn Stalk Nitrate Test). Sweet corn date of maturation, marketable yield and ear quality will be assessed.
In Experiment 2, the same cover crop treatments were planted at the same date in neighboring plots. Weed management treatments will be:
- chemical herbicide,
- no-till mechanical cultivation.
Weed population and weed biomass will be measured in the late fall, in early spring, at corn planting, and at corn harvest. Sweet corn marketable yield and quality will be assessed.