In this project, we propose expanding soybean production and potentially increasing the economic returns to Iowa farmers and industry leaders by a sustainable intensification of the existing cropland.
Our strategy is to apply intercropping practices, which involve the harvest of our main cash crop- soybean- plus the harvest of a second crop in the same field, in the same year, reducing negative environmental costs. Moreover, planting soybean with winter crops, such as small grains, will be a way to take advantage of Iowa’s six-month fallow period. A winter crop can be planted immediately following the soybean harvest of, and it will have a double function as a cash crop and a cover crop, protecting the soil from erosion and nutrient runoff, which are the major causes of water pollution. Another key benefit of intercropping and crop biodiversification is the potential pest control and disease suppression by breaking disease cycles. In summary, there are multiple advantages of intercropping soybean with winter small grains: increased land use efficiency, soil fertility, better pest and weed control, and enhancement of overall crop productivity relative to conventional crop monocultures, which will allow Iowa farmers to implement an “eco continuous soybean system” instead of corn-soybean rotations.
Intercropping practices or relay intercropping consists of two or more crops grown in sequence with some overlap in the growth cycle. In this practice, a winter crop will be planted in the fall, soybean will be inter-seeded into a living winter crop, mature winter crop will be harvested in July, and mature soybean will be harvested in October. Brazil, which overtook the United States as the leading soybean-producing country since 2019, also is applying relay intercropping practices to take advantage of the yield benefits (https://www.embrapa.br/en/sistema-antecipe). These practices will be accomplished using innovative equipment solutions such as those being employed in Brazil and other projects in the US (Finley and Ryan, 2018, Wilson et al., 2019, Ott et al., 2019). Four reasons for this focus on intercropping are: 1- Iowa’s climate is changing. Today the average winter temperature in Iowa is 3 degrees higher than in the last 50 years and the time between the last freeze in the spring and the first one in the fall has increased by about 10 days since the beginning of the 20th century (USDA Midwest Climate Hub). This climate situation may provide an opportunity to establish a second crop. 2- The current global agricultural and food security situation. Due to Russia’s war against Ukraine, there is an imminent necessity for the US to produce more grains and oilseeds, especially wheat, barley, and sunflower. 3- The contribution of researchers (Sallam et al, 2021) and winter breeding programs in MN, MO, OH, and NE, among others (UMN Forever Green Initiative (FGI), Agricultural and Natural Resource Sciences (CFANS), MSU- Winter Breeding Program, etc.) have focused on developing winter-hardy seeds for Midwest farmers. New cultivars allow for greater timing flexibility and decreased inputs resulting in improved profitability of multi-cropping options. 4- The opportunity for growers to diversify their market. Small grains such as barley, oats, triticale and wheat can be excellent forage crops in the form of pasture, hay and silage. The market for barley, in addition to forage and feed grains, includes food grains, malting barley and ethanol.