Radish Planting Date and Nitrogen Rate for Cover Crop Production and the Impact on Corn Yields in Upstate Missouri

Abstract

Cover crops can increase yield of a marketable crop, offer greater yield stability, reduce fertilizer inputs, suppress weeds, and interrupt disease or pest cycles. Producers increasingly look to radish (Raphanus sativus L.) as a cover crop, but integrating it into a cropping system with corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] has been difficult. Radish following wheat (Triticum aestivum L.) may provide more options for farmers. Few studies have tested the effects of nitrogen (N) rates on radish production for a dual purpose cover/forage crop or whether additional N is needed because radish is often used to trap N. This study evaluated radish planting date (1 Aug., 15 Aug., 29 Aug., and 11 Sep. in 2012 and2013) and N fertilizer amount (0, 17, 33, and 67 kg N ha -1 ) on radish heights, chlorophyll content, and biomass production as well as their impact on corn yields the next year (2013 and 2014). Across planting dates and years, non-fertilized controls had shorter radishes than any N rate, while radish chlorophyll content increased as N rates increased. Chlorophyll and biomass content generally did not significantly increase above 33 kg N ha -1 . Radish foliage dry biomass production was 820 to 1670 kg ha -1 greater at the first planting date (1 Aug.) in 2012 and 2013 than the other planting dates. Winter annual weed suppression was greatest at the first planting date in 2012. No differences in winter annual weed suppression were observed in 2013 compared to the other planting dates. Radish planting date did not affect corn yield the following year (2013 and 2014). This study demonstrates the benefits of planting radishes in late summer prior to 1 Sep. and fertilizing with 33 kg N ha -1 for optimum radish biomass production following wheat in upstate Missouri.

Cover Crop Impact on Weed Dynamics in an Organic Dry Bean System

“…In three of the six main siteyears, spring weed biomass following oilseed radish was less than the no-cover control; in 2 site-years it was equivalent, and in 1 site year (2012 MSU) there were more weeds following oilseed radish than in the no-cover-crop control because fall competition with volunteer oat (Avena sativa L.) reduced oilseed radish growth (Table 1). This risk of reduced oilseed radish growth due to competition with volunteer small grain after harvest is not uncommon (Sandler et al 2015). Overall there was no clear relationship between fall radish biomass or percent cover and spring weed biomass in this research.…”

Effect of Sowing Date on Growth and Yield of Four Radish (Raphanus Sativus L .) Varieties

“…An appropriate sowing date helps reduce damage from cold, heat, pests, diseases, and weeds. Growers often manipulate sowing times for better growth and yields (Alam et al, 2010, Sandler et al, 2015. therefore, late planting decreases the most important traits i.e.…”

Fall cover crop nitrogen uptake drives reductions in winter‐spring leaching

“…In Missouri, Sandler et al. (2015) broadcast‐interseeded radish into soybeans and corn at different times in fall but measured consistently higher radish biomass with early planting in only 1 yr with sufficient rainfall. The close relationship between biomass and GDD in our study suggests we avoided growth limitations because we applied manure and because our no‐till drilling is a more reliable seeding method than broadcasting (Fisher et al., 2011; Noland et al., 2018).…”