Crop selection and soil management and long-term soil productivity are interconnected. Many high tunnel soils are:
a) cropped repeatedly to relatively small sets of input-demanding crops,
b) disturbed frequently and intensely by cultivation and preparing for seeding and transplanting, and
c) exposed to persistent foot and equipment traffic.
High tunnel soils also tend to experience potentially troublesome temperature and moisture profiles. As a result, high tunnel soils can:
a) lose structure and become less friable and more compacted,
b) decline in organic matter,
c) increase in salinity, and
d) develop problematic nutrient imbalances and pathogen loads.
These and other challenges can lead high tunnel soils to become less productive – to require greater and greater amounts of cash and effort to maintain marketable yields at desired levels.
Including additional, less demanding cash and non-cash rotation or cover crops in high tunnel production schedules can help maintain soil productivity and offer other benefits.
Five 21 ft x 48 ft high tunnels used intensively in organic vegetable production-related research for 15-21 years are currently being cropped to butternut squash or a mixed-species summer cover crop (cowpea, Italian ryegrass, pearl millet, and sorghum-sudangrass). See representative panels below. The mixed-species cover crop has produced significant amounts of foliar biomass and suppressed weed growth effectively. Its root system is expected to provide multiple benefits. Similarly, squash plant growth and flower production have been excellent and fruit set is encouraging. Nine-hundred pounds of composted dairy manure were spread in each high tunnel on 4/16/24 and lightly incorporated but no fertilizer or crop protectants have been applied since. Both crops have been overhead irrigated (see https://u.osu.edu/vegprolab/crop-environment-publications/installing-an-overhead-irrigation-system-in-a-high-tunnel/).
Sections of other nearby high tunnels have been planted to buckwheat, carrot, Swiss chard, choi, dry bean, edamame soybean, garlic, groundpea (winter cover), kale, lettuce, okra, pepper, sunflower, and/or wheat (winter cover) since October-2023.
Cash crops can be harvested from high tunnels year-round in Ohio. Maintaining the productivity of soils that help make that possible is key. Considering what many cash and non-cash crops can offer to the process is useful.