Double-cropping effects of Brassica carinata and summer crops: II. Effects of winter cropping history on subsequent summer crop production

Abstract

There is an opportunity for crop farmers in the Southeast United States (SE US) to increase income by producing carinata during the winter following summer crop production. However, a major limitation to the use of carinata as a winter annual in the SE US is the lack of information on double-cropping with summer commodity crops common to the region. Considering that integrating carinata into cropping systems common to the region could impact productivity of those systems, it is critical to quantify the potential effects of carinata on existing cropping systems. To this end, a study was conducted in Jay, Florida for three years to evaluate the effects of winter cropping history (carinata vs. fallow) on the productivity of subsequent summer crops including cotton, peanut, sorghum, and soybean. Treatments (winter carinata vs. winter fallow) were laid out in a randomized complete block design with eight replications. Data were collected on infiltration; plant population; plant canopy height; aboveground biomass; and yield. Infiltration rates, determined within a week of carinata harvest, were affected by winter cropping history, being greater in former carinata plots than former fallow plots. Carinata harvest coincided with the timely planting of cotton and peanut which resulted in these summer crops being sown three to four weeks later than their typical sowing window for the SE US. Winter cropping history (including the winter fallow control) did not influence commodity crop (cotton, peanut, sorghum, and soybean) yields when all summer crops were planted at the same time, as in a double-crop scenario. Regarding the combined productivity of winter (carinata vs. winter fallow) and summer crops, carinata-cotton, carinata-peanut, carinata-sorghum, and carinata-soybean systems were necessarily more productive than their winter fallow counterparts due to no crop production in the fallow during the winter cropping years. Overall, results from this study showed that carinata can successfully replace winter fallow, and can be double-cropped with summer-planted sorghum and soybean with no adverse effect on yield. Double-cropping carinata caused a delay in timely planting of cotton and peanut, and represents a limitation that may hinder its adoption in the SE US until such time a faster-maturing carinata cultivar can be developed.