Alfalfa grown for seed on drylands is planted in rows, usually two to three feet (60 to 90 centimetres) apart; cultivation between rows is required during the first year. Alfalfa is also grown for forage where favourable. This practice builds nitrogen and organic…
…plants may be propagated by seeding, grafting, layering, or cutting. In seeding, seeds are usually planted in either a commercial or home nursery in which intensive care can be given for several years until the plants are of a size suitable for transplanting on the desired site. In soil layering,…
…best time and depth of seeding and planting is an effective cultural practice that reduces disease impact. Shallow planting of potatoes may help to prevent Rhizoctonia canker. Early fall seeding of winter wheat may be unfavourable for seedling infection by wheat bunt teliospores. Cool-temperature crops can be grown in soils…
…by the use of pathogen-free seed grown in arid regions. Examples of diseases controlled by this method include bacterial blights of beans and peas, black rot of crucifers, and bacterial spot and canker of tomato. Seed treatment with hot water at about 50 °C (120 °F) is also effective for…
Growth, flowering habits, and light requirements on the one hand, and management problems on the other, determine the most satisfactory planting plan for a fruit- and nut-growing enterprise. There is a trend toward use of dwarfing stocks, growth control chemicals, or…
There are many variations on these methods. Watch different equipment in action on farms and at farm shows. Every piece of equipment is different, and individual farm needs depend on the management system in use.
Broadcasting by ground: This is the most popular and accurate seeding method and may be done using spinners, drop tubes or air pressure. The most critical factor is accurately metering seed before it is spread. Make sure the seeding pattern is appropriate for complete and even ground cover. Different seeds have varying spread patterns based on their respective weights, and heavier seeds spread further than lighter seeds. This can cause difficulties when heavier and lighter seed mixtures are applied. Broadcast seeders may be mounted on ATV’s, tractors, tillage tools or other implements.
Accurate seeding equipment calibration is essential for applying cover crop seeds. Calibrate a seeder each time a different type of seed is used and routinely during the season. Use the following steps as a guide to calibrating a broadcast seeder:
Frost-seeding: Seeding a cover crop into an established crop in late winter to very early spring. Example: Seeding red clover into wheat in March.
Broadcasting by air: Cover crops can be applied from a broadcast seeder mounted on an airplane. This practice works well for larger seeds like rye and wheat, but is not recommended for small clover or grass seeds. Broadcasting by air allows for the overseeding of an existing crop or for planting when soils are too wet for ground seeding, although seed germination might be slower and a higher seeding rate may be needed.
Cover crop seed application is as important as commercial seed application and the method used will effect seed germination rate and stand quality. Using equipment that allows accurate application at the correct rate will save money and help ensure sufficient cover. Since cover crop seed sizes and weights vary, it is important to match equipment to both the seed and management practice.
Incorporation: Cover crop seeds produce better stands with shallow soil incorporation. Excellent results can be obtained by combining broadcast seeding with a cultivator or other incorporating tillage tool. The combination chosen depends on when seeding takes place and what management practices are in effect. Most cover crop seeds are very small and do not need much soil cover, just good seed-to-soil contact.
With increasing seeding rates, seed costs of course increase. Table 2 shows the cost of seeding each cover crop at the three rates – while rye is one of the most inexpensive cover crops, hairy vetch is much more expensive. Considering the cost, it is important to give it optimum conditions for success, such as planting it early and inoculating the seed.
Despite low emergence, cereal rye was a productive cover crop when established by late-season broadcast interseeding. When broadcast interseeding cereal rye into corn, we found that a seeding rate of 90 lb/ac produced the most biomass in the spring. When broadcast interseeding into soybean, a seeding rate of 60 lb/ac produced the same amount of biomass as higher seeding rates. Vetch biomass production was low and was the same at the seeding rate of 40 lb/ac than at the higher seeding rates. Vetch needs to be established earlier than the mid-to late September seeding dates in our study.
When it comes to selecting a seeding rate for broadcasting cover crops, there is little research-based information. Broadcast seeds do not have good seed-soil contact which reduces the seeds’ ability to take up water necessary for germination. Thus, stand counts of broadcast cover crops are often lower than those of drilled cover crops. Could increasing the seeding rate overcome low stand counts and improve cover crop productivity?
On average, in rye plots, 13% of broadcast seed emerged, with stand counts of 6 plants/sq ft. In vetch plots, 30% of seed emerged, and there were about 5 plants/sq ft. Rainfall within a week after broadcasting is critical for good establishment and was greater at the eastern site than at the south-central site. As a result, more seeds emerged at the eastern site. Stand counts increased with increasing seeding rates.
Figure 1 shows cover crop biomass production where broadcast interseeded into corn. Rye produced more biomass than vetch, on average 1,500 lb/ac. Rye biomass increased with the greater seeding rates, but the difference between the medium and high seeding rate was not significant. For vetch, increasing the seeding rate did not improve biomass production which was 400 lb/ac. Vetch should be planted earlier for better productivity. Figure 2 shows biomass production of the cover crops broadcast interseeded into soybean. Rye was more productive than vetch (2,100 lb/ac and 500 lb/ac) but increasing the seeding rates did not change biomass production of either rye or vetch.
Cover crops tended to produce more biomass when established in soybean than in corn, but this was not statistically tested. Rye in corn stubble showed signs of not receiving enough light, as it was lighter in color, had longer stems, and fewer tillers than rye in soybean stubble (see figure 3). Fall tillering is associated with greater spring biomass and may be the reason why cover crops planted into soybean were more productive than those planted into corn. Rye can also compensate for low stand counts by tillering, which explains the lack of response to increased seeding rates. On the other hand, the greater amount of residue and taller stalk remaining in corn fields may preserve more soil moisture and may protect from wind, thus benefitting cover crops in dry and cold sites (figure 4).
We tried to answer this question by carrying out field experiments at the Eastern Nebraska Research and Extension Center near Mead and the South-Central Agricultural Laboratory near Clay Center in 2016/2017 and 2017/2018 in corn and soybean fields under no-till management. Our cover crops were cereal rye, variety Elbon, and hairy vetch, variety not stated. The research plots measured 20 by 30 feet, so we broadcast by hand instead of using equipment.