For best results, follow the recommendations in this section on selecting a site, seeding management, residue management and fertilization. For control of weeds, please seed Weed Control.
Selecting a Site
Proper field selection and preparation for dry beans provides seed with the best environment for rapid germination and emergence allows roots to grow quickly and absorb nutrients, as well as providing the conditions necessary for good weed control and proper irrigation.
Dry beans require warm, moist soil conditions for germination and emergence.
The soil must be prepared so it warms rapidly, but still retains as much moisture as possible. Fall plowing is preferred because it conserves more moisture than spring plowing. Freezing and thawing during winter tends to reduce soil clods.
Choose land that is moderately firm, level, and free of clods and trash.
Ensure adequate moisture in the seeding zone.
Soils, especially heavy clay types, must be worked at the right moisture to avoid producing a lumpy seedbed and soil compaction.
The field must be properly prepared to provide seed with the best environment for rapid germination and emergence, allow roots to grow quickly and absorb nutrients, and provide the conditions necessary for good weed control and proper irrigation.
Avoid excessive tillage — it’s not only costly, but can cause compaction that interferes with water drainage and root penetration. It also has a tendency to dry out the seedbed.
Avoid compacted wet soils, as they tend to warm slowly and cause delays in germination and emergence.
Maintain good records
Keep good records on herbicides used in previous crops – some leave residues that will injure the dry bean crop. Always read the herbicide label and pay close attention to re-cropping restrictions.
DRY BEAN SEEDING RECOMMENDATIONS
Use seed with both high germination and vigour.
Dry bean is very sensitive to a number of seed-borne diseases – it is critical to plant disease-free seed.
Purchasing seed from areas isolated from commercial production will ensure seed is disease-free.
Ensure seed lots contain sound, whole seed and that seeds have few hairline cracks.
Bean seed is very fragile – take care to ensure the seed coat is not cracked during handling or seeding, as bean seed with cracked seed coats will not germinate, resulting in a decreased plant population.
Managing the moisture of the seed can also reduce mechanical damage. Seed with a moisture content of at least 14% is less prone to cracking.
Bean plants are not frost tolerant, so seeding should not begin until the likelihood of frost has passed (in southern Alberta, this normally results in a seeding date between May 20 and May 25).
Having epigeal germination means the growing point and cotyledons are both above-ground, making them particularly vulnerable to late spring frosts. Seeding much later than June 5 puts dry beans at risk of early fall frosts.
The crop must be completely mature before the first fall frost, or crop quality will suffer.
Ideal soil temperature for germination of dry bean is 15˚ C – seeding when soil temperatures are below 12˚ C will result in slower emergence and weaker plants.
Cool, moist soil provides an ideal environment for insects and disease, resulting in damage to young seedlings.
Bean seed should be placed into warm, moist soil to a depth of 1 to 2.5 inches (2.5 to 6 cm).
Seeds planted too shallow risk drying out as the relatively large bean seed requires quite a bit of moisture to hydrate. If planted too deep, plants struggle to emerge and are more prone to seedling diseases.
Bean plants crowded in rows can help break through heavier soils if pushing at the same time. Even germination makes the timing of all operations easier throughout the growing season and harvest.
Dry bean is generally grown as a row crop – space rows so that cultivation and harvesting equipment can be used efficiently (row spacings vary from 22 to 30 inches (56-76 cm), with 24 inches (61 cm) being most common).
Dry beans can be successfully grown when planted with air drills and seeders on narrower row spacing (6 to 12 in), and are referred to as solid seeded when grown this way. Given the large difference between row spacing in these two systems, different management practices are followed.
Narrow row crops should produce higher yields, but high disease pressure (particularly white mould) and higher harvest losses result in lower yields compared to wide row crops.
Solid seeded bean requires much higher seeding rates, and care is needed to obtain a uniform seeding depth and to minimize seed damage.
Seeding rate should be targeted between 95-100,000 plants per acre.
The number of seeds per pound will vary between varieties and types (as well as from year to year), so do a seed count with all lots.
SEEDING RATES FOR PLANTING ROW CROP DRY BEANS
Specialized row crop equipment is used to plant beans in rows 70 to 90 cm (30 to 36 in) apart.
Given the precise placement and metering of row crop seeders, dry bean seeding rates are targeted to obtain a precise number of viable seeds per acre.
While ideal plant stand densities will vary somewhat based on bean type, most target 100,000 plants per acre, or 18 seeds per metre of row. This works out to around 40 to 50 pounds per acre (lb/ac) of seed, depending on the size of the seed.
SEEDING RATES FOR SOLID SEEDING
When beans are seeded using air seeders and air drills on narrower row spacing, several adjustments are made to the row cropping system:
Populations are adjusted to take advantage of the more even distribution of plants across the ground.
Determinate bush-type varieties are chosen that resist lodging better and have higher pod set for harvest.
Extra care to reduce seed damage when being handled and put through the seeders and drills.
Tramlines should be considered to avoid damage when spraying that can result in delayed beans, complicating harvest timing.
When grown on narrower rows, bean plants are not as crowded and are more evenly distributed across the field. This means seeding rates can be adjusted to take advantage of the reduced in-row competition.
Seeding rates tend to be heavier and will increase seeding costs in solid seeding systems, compared to row crop seeding.
Growth habit will also affect seeding rates. Indeterminate vine-type beans will require lower seeding rates than determinate bush-type, as the plants vine more and will cover the ground more quickly. Some air through the canopy is important to reduce diseases, so too heavy of a seeding rate is discouraged.
Seeding rates should be calculated for the specific seed lot, based on the seed size. Generally targeting 45 plants per metre squared (four plants per square foot) on solid seeding dry beans is a good target.
A major concern and consideration when solid seeding beans is maintaining seed quality.
Beans are very susceptible to mechanical damage and damaged beans can develop a condition termed baldhead, where only the cotyledons and stem emerge but no leaf development follows.
SEEDS PER POUND
1,300 – 2,300 seeds per pound.
Thousand Kernel Weight (TKW) varies within market classes and between market classes, in general ranging from 200 – 350 grams/1000 seeds.
Recommended soil temperature of 18˚C.
Seeding within this time also generally means soil temperatures are warmer. Ideally, soil temperatures should be at a minimum of 12°C for quick germination and growth.
At cooler temperatures these processes will be much slower, increasing the risk of seedling diseases, and delaying the time to emergence.
If soil moisture is too low to initiate germination of this large-seeded crop, an irrigation prior to seeding followed by a light tillage operation is strongly recommended
Irrigating after seeding often reduces soil temperature below that required for bean germination – this low temperature may increase both the incidence of fungal diseases of the root system and the chance of damage to the seed (and germinating seedling) by insects.
TYPE OF EQUIPMENT
Vacuum or air precision planters provide the most uniform seed drop per foot of row and minimize the amount of seed required, thus reducing the cost of seed per acre and minimizing inter-plant competition.
If using an air drill to seed beans: To reduce damage operate at as low of fan and air speed as possible, while still ensuring even distribution across the air drill. It can be difficult to get even distribution, as often there are gaps in the row followed by heavy density if distribution is not even.
Some drills can be modified with seed deflection pads in manifolds to reduce cracking. Using conveyors when possible, rather than augers, will also help.
If sown in wide rows with traditional planters, rolling is not necessary.
If using an air drill (solid seeding) rolling may improve germination and promote even emergence.
Rolling should only be done before crop emergence.
Germination testing is one method for evaluating seed lots for quality.
Germination addresses the seed’s ability to develop into a normal, healthy plant under favourable field conditions.
This testing can be misleading because seed may germinate well in the lab due to optimum conditions being present or to the fact that the seed has every opportunity to develop into a normal healthy seedling.
Vigour testing, another method, assesses the seed’s potential to withstand unfavourable field conditions by assessing certain factors that influence seed quality.
While vigour results represent the lowest germination obtained from the lot, germination testing represents the highest result. Actual field germination would normally fall between the two.
VARIABLES IMPACTING SEED QUALITY
Germination and vigour are influenced by the physiological well-being and anatomical completeness of the seed plus its interaction with a wide range of environmental conditions.
Seed vigour is affected by:
seed size and weight
mechanical integrity and soundness
deterioration, aging, and stage of maturity
In years where unfavourable weather conditions prevail, it is best to combine a vigour test with a germination test to determine seed quality and performance more accurately.
Be sure germination results include adequate categorization of the seedling defects and the seedling’s ability to survive adverse conditions.
It’s impossible to predict post-seeding conditions with a vigour test, so seed is placed under a variety of stressful conditions, simulating climatic conditions as closely as possible, including:
Under these conditions, the seed must demonstrate the ability to germinate into a vigorous seedling.
Seed vigour is measured by the Electrical Conductivity Test to assess mechanical damage and evaluate seed lots that remain vigorous during storage.
Dry bean is very susceptible to mechanical injury, such as cracking and chipping, either at harvest or during processing, especially if the moisture level is below 14%.
Mechanical injury, such as small seed coat cracks, results in rapid water intake that leads to dead seed cells – this dead tissue then becomes a source of food for invading pathogens.
Vigour tests must be combined with germination tests to predict field performance.
The seed may also require 1000 seed weight and disease tests to completely assess the seed’s total quality.
Most bean seed purchased in southern Alberta is pre-treated with a fungicide. It is also beneficial for the grower to treat the seed with an insecticide as well to protect against two insects that cause damage to bean seed and seedlings: wireworm and corn root maggot.
Use proper straw and chaff management in the fall before seeding a dry bean crop is critical.
Heavy straw conditions can create seeding problems such as hair pinning with disc openers or plugging between the shanks of an air seeder.
Hair pinning refers to a condition where the seed is pushed down onto the straw layer by the opener, creating a wicking effect, where there is poor seed-to-soil contact and, as a result, patchy or poor germination of the dry bean crop.
Thick layers of chaff may also cause phytotoxicity to the next crop.
Phytotoxicity is the phenomenon of reduced growth and yields of the next year’s crop due to toxic compounds leached from the residue and/or microbial activity that produces toxic compounds during breakdown of the residue.
DIRECT SEEDING CONSIDERATIONS
Direct seeding is usually defined as seeding into standing stubble, but can also be referred to as reduced tillage.
Even and wide distribution of residue with a durable straw chopper and chaff spreader is vital.
To avoid plugging shanks, stubble height should be the same or less than the shank spacing of the seeding tool.
Proper rotational planning can also assist in managing heavy residue: