Selecting Appropriate Best Management Practices After Harvest
As wheat, canola and other annual crops continue to be harvested across Ontario, producers are often left with the question of “what do I do with this field now?”. Deciding on cover crops, tillage, nutrient applications or “just leave it alone” management activities can be overwhelming. There are numerous best management practices recommended in Ontario, however, that doesn’t always mean that every practice is a best fit for each operation.
Anytime that decisions are being made in regard to field management – both before and after harvest – the initial question should be “What am I trying to accomplish?”. Goals can include trying to increase organic matter, fix more nitrogen, break up soil compaction, reduce erosion potential or improve weed control. Having a clear goal can make it easier to decide appropriate best management practices.
Evaluating BMPs for Your Operation
It is important to consider all aspects of a best management practice before implementing, however there are some on-farm metrics that need to be captured first. Ensuring that soil tests are up to date is the first and arguably, most important step for field management. Samples should be updated every 3-4 years. Sampling fields this time of year creates a larger window to soil sample, get results back and make any fall field applications of lime or nutrients to be applied if needed. Soil pH needs to be in range of 5.5 to 7.0 prior to applying any organic amendments or manures to optimize nutrient availability.
For operations that have livestock, considerations for manure management and feed inventories can also be an important part of the decision-making process. Current manure samples, accompanied by recent soil tests, can best direct manure application rates and timing. Farms concerned about feed inventories heading into winter can consider annual forage crops after cereal harvest, such as oats to bolster inventories. Fall manure applications can be done before and after cover crop seeding, however it is important to be aware of your soil fertility plan, and to reduce the risks of any manure runoff potential.
If manure is not a feasible option, it may be of interest to explore the many organic amendments and compost alternatives across the province. When considering organic amendments (or purchased manure), it is important to consider both the immediate and long-term effects (e.g., benefits and consequences) that may occur. For example, calculating the cost per pound of nutrients can be an effective way to select the best amendment. One product may cost more per tonne but need fewer tonnes per acre for the desired nutrient level. Others may be located at a further distance, and additional trucking can increase the cost quickly. OMAFA’s AgriSuite offers many tools and calculators, including the Organic Amendment Calculator and the Crop Nutrient Calculator. These tools can be helpful in planning rates, considering crop removal and nutrient availability. They also allow users to use their own costs to calculate estimated per acre applications and economic values.
Cover crops are a common management practice planted after cereal and canola harvest. The Midwest Cover Crops Council Cover Crop Decision Tool helps selecting the best option for a field. Some cover crops may be sensitive to herbicides that were applied earlier in the growing season, or even possibly in the previous year. Information on this can be found on the Crop Protection Hub. Other cover crops, such as turnips or radishes, should be carefully considered in in crop rotations that have canola; negative crop rotation pest and disease issues could occur.
It is also critical that prior to planting a cover crop, a plan for crop termination is in place. Termination can be either fall or spring, and can be overwinter kill, tillage or chemical, however, it should be multi-pronged and well thought out. Some cover crops, such as oats, typically do winterkill, however, they have survived to spring before, highlighting the importance of having a termination plan (and/or a back up plan). Failing to terminate a cover crop in a timely fashion can create heavy, wet mats of crop residue that are difficult to till, retain soil moisture well into spring, and can make spring field preparation and planting challenging.
Planning for fall field management can be overwhelming at times and possibilities can be endless. While some decisions need to be made or adjusted at harvest (sometimes weather can create challenges), including them into your annual and multi-year crop plans can take the pressure off decision making in the moment. Knowing when soil sampling needs to be done, where you’d like to put manure in an ideal year, or which soils could use an application of an organic amendment can make it easier to accomplish on-farm goals and manage time constraints each year. Consulting with your agronomist and other team members can help avoid potential issues with field decisions and optimize both labour and financial resources.
