Protecting the soil surface from rain and wind with crop residues or living plants is key to building soil health and preventing erosion (Reicosky, 2015). In the Red River Valley (RRV), any remaining corn residue is usually tilled into the soil in preparation for soybean planting. Traditional tillage operations, while preparing a good seed bed, leaves the soil surface vulnerable to crusting and erosion (DeJong-Hughes et al., 2011). The flooding-prone lacustrine soils of our region make transitioning to reduced or no-tillage difficult, especially managing previous corn residue with a high C:N ratio that is slow to decompose in our often-frigid region (Alghamdi and Cihacek, 2022). Corn residue can be difficult to plant into, or even become stuck in the furrow or “hair pinned”, preventing good seed-soil contact (Holshouser and Pitman, 2009). Planter modification options may help farmers in the RRV transition to no-till through improved residue management at planting, in particular for soybean following corn grain crops.
Susterre (a start-up company and Grand Farm partner) has developed a planter modification system that uses extremely high pressure (60,000 PSI) water jets to cut through crop residue or compacted soil immediately ahead of the seed. This modification is primarily designed for residue-management to improve seed-soil contact, and results in consistent planting depth even in heavy residue. Our intent is to compare Susterre’s planter technology to a more typical no-till planter, owned by NDSU, in varying levels of corn residue (augmented by the surrounding area) as well as a winter rye cover crop. We hypothesize that water-jet planting technology will improve emergence rates and produce a more consistent soybean stand, which has potential to impact end of season yield.
In addition to yield outcomes, there are environmental benefits to reducing tillage and protecting the soil surface (O’Brien et al., 2022). In addition, residues help conserve soil moisture. We will measure several outcomes of interest in this realm, including greenhouse gas emissions from each treatment, soil nitrate, soil compaction, and soil water. Tillage increases microbial respiration by aerating the soil, so we expect reduced CO2 emissions from soil in reduced tillage treatments, but additional crop residue may increase emissions (Campbell et al., 2014).
The proposed study focuses on a specific climate-smart management practice and would provide useful information to ND farmers, including both soybean-productivity outcomes (objective 1) and sustainability outcomes (objective 2). Climate-smart agriculture is a balancing act that must prioritize sustainable improvement of yield, while building resilience and reducing emissions.
Literature Cited:
Alghamdi, R.S., and L. Cihacek. 2022. Do post-harvest crop residues in no-till systems provide for nitrogen needs of following crops? Agron. J. 114(1): 835–852. doi:10.1002/agj2.20885.
Campbell, B., L. Chen, C. Dygert, and W. Dick. 2014. Tillage and crop rotation impacts on greenhouse gas fluxes from soil at two long-term agronomic experimental sites in Ohio. J. Soil Water Conserv. 69(6): 543–552. doi: 10.2489/jswc.69.6.543.
DeJong-Hughes, J., D. Franzen, and A. Wick. 2011. Reduce Wind Erosion for Long Term Productivity. Univ. Minn. Ext.
Holshouser, D., and R. Pitman. 2009. Equipment Considerations for No-till Soybean Seeding. Va. Coop. Ext. (Publication 442-456).
O’Brien, P.L., B.D. Emmett, R.W. Malone, M.R. Nunes, J.L. Kovar, et al. 2022. Nitrate losses and nitrous oxide emissions under contrasting tillage and cover crop management. J. Environ. Qual. 51(4): 683–695. doi: 10.1002/jeq2.20361.
Reicosky, D.C. 2015. Conservation tillage is not conservation agriculture. J. Soil Water Conserv. 70(5): 103A-108A. doi: 10.2489/jswc.70.5.103A.
Brief Description of Proposed Research:
The proposed research would take place at the Grand Farm Innovation Campus in 2024. Susterre will provide access to their space in Casselton, as well as technical assistance, their modified planter, and a tractor in order to operate it. The study would be a randomized complete block design with four replications and a split-plot arrangement. Treatments include residue levels (n = 5; No additional residue, winter rye cover crop, augmented corn residue, consistent with a 100 bu ac-1, 200 bu ac-1, and 300 bu ac-1 corn grain crop) and planter technology (n = 3; Susterre Planter with jets on and off, NDSU Planter). Corn residue levels will be manipulated in fall 2023 following corn grain harvest, to allow the augmented residue treatments to settle over the winter and mimic true wet-residue conditions in the spring.
Objective 1. Compare soybean productivity outcomes between a traditional no-till planting system and a planter modified with high-pressure water jets to cut through residue.
Soybean productivity outcomes will primarily be measured through soybean seed yield, measured by harvesting the middle 5-ft of each plot with the NDSU Soil Science Almaco Plot Combine. Seed moisture and test weight will be measured for a subsample from each plot. Early season outcomes are of interest when comparing planting technology, so we will measure soil temperature in the furrow immediately following planting, and take daily emergence counts in all treatments. Final stand count will be measured as well.
Objective 2. Assess sustainability outcomes between planting treatments and residue levels.
Sustainability outcomes will include soil moisture early-season, greenhouse gas emissions, soil nitrates, and penetration-resistance. Gravimetric water will be taken by hand throughout the growing season, to capture differences in moisture due to crop residue levels and cover crop treatments. Greenhouse gas emissions (N2O, CH4, and CO2) will be monitored every-other week for 10 weeks. Metal rings will be placed in each plot after planting, and PVC caps will be placed on top of the rings at the start of each sampling timepoint. The flux of gasses will be measured through at least 3 air samples, which will then be analyzed with a Gas Chromatograph. Soil nitrate levels will be tested at two depths (0-15cm and 15-60cm) in each plot, in both the spring and fall. Penetration-resistance will be measured in both spring and fall as well, using a hand-held penetrometer.
For both objectives, appropriate statistical analysis (mixed-model ANOVA) will be conducted to compare treatment means for all measurements.