Production of Narrow-Row Direct Harvest White Beans in Ontario
Table of Contents
Recently, the white bean acreage has expanded northward from Huron. Perth arid Middlesex counties and as far cast as the Ottawa V alley. Newer white bean growers tend not to adopt the traditional method of producing white beans; that is planting 70-75 cm rows, hilling through inter-row cultivation, and pulling, windrawing and combining at harvest. Many are using a system of narrow-row planting (15 to 55 cm) and direct combining.
Reasons for adoption of this new production technique are:
Some of these reasons are also convincing experienced white bean growers to explore the narrow-row system. Within four years of its introduction, the bean acreage in narrow-rows and direct-combined had grown to 15 to 20% of the total
There are scycral agronomic advantages that can be attributed to narrow-row crop production. More sunlight is intercepted by the plant canopy before it reaches the soil surface, increasing the potential light energy that can be used in photosynthesis. The crop canopy will close earlier in the season offering greater shading of late-emerging weeds, and reducing the potential for erosion caused by rainfall impaction exposed soil. When the crop is grown in narrow rows, adjacent plants within the row are spaced farther apart and this may reduce within-row plant competition for water and nutrients. This combination of factors often accounts for higher yields in narrow rows compared to wide rows.
Several Ontario research trials indicate a yield advantage by decreasing row widths (Table 1). However, since these plots were hand harvested, this is an indication of potential yields. White beans often pod close to the ground and some of this yield advantage may not be realized due to combine harvest losses.
*Yields are an average of all varieties tested
In Ontario. white beans appear to respond similarly to crop rotation, soil type and drainage, tillage and fertility practices regardless of row width. Refer to OMAF Fact sheet, Growing White Beans in Ontario, for information on these agronomic practices.
New varieties with a more upright architecture and a narrower plant profile are being tested in provincial variety trials. These , new varieties should result in reduced harvest losses from lodging and lower pods (Figure 1).
Choice of variety for narrow-row, direct-combine production should be influenced by maturity, yield potential and white mold tolerance. Producers should choose a variety that is likely to mature in late August or early September. The second most important criteria is white mold tolerance, since this fungus has been found to be more prevalent in narrow-row production. Refer to OMAFRA Publication 296, Field Crop Recommendations for details on current varieties.
Figure 1. New experimental cultivars (right) have an upright architecture compared to traditional cultivars (left).
Due to the nature of the harvest operation, selection of stone-free fields is critical for direct combined beans.
Primary tillage with moldboard or chisel plow should be done when the soil is dry to reduce compaction. Secondary tillage should be minimized to that required to incorporate herbicides and prepare a level, firm seedbed. Efforts to reduce the number of secondary tillage passes will minimize the area covered with wheel tracks and compaction.
Soils high in fertility are necessary are optimum white bean production. Fertilizer needs should be determined by a soil test. Fertilizer should not be applied with the seed, but plowed down or worked in before planting.
White beans are legumes, and under optimal conditions will biologically fix a portion of their nitrogen requirement. Where white bean yields have been low due to bronzing. Low soil organic matter, poor soil structure, or root rots, broadcast and work 50-100 kg/ha nitrogen into the soil before planting. The actual amount used will depend upon the severity of the stress.
White beans, regardless of row width, must be seeded at a uniform depth of 3.5 to 5.0 cm in warm, moist soil to promote rapid and even emergence. Some herbicides require a minimum planting depth to ensure bean safety.
Narrow-row beans may be successfully sown by grain drills or unit
planters. Seed drills should have gentle seed distribution devices,
depth bands or depth gauge wheels and press wheels to ensure uniform
seed placement and seed coverage. Some farmers have assembled unit
planters on a tool bar at narrow row widths in order to achieve
the seeding accuracy of corn planter units. It is advisable to leave
tramlines or tractor-tire skip rows while planting. The objective
is to gain the benefits of narrow rows without the necessity of
planting into soil compacted by tractor tires, or of trampling white
bean plants with postemergent operations such as picking stones
and the application of pesticides and desiccants.
Figure 2. Planting operation.
Most growers follow the seed drill with a roller or packer to improve seed coverage, and to press down stones or ridges of soil thrown up by cultivation equipment or drill disks. This aids harvest by reducing the problem of an uneven soil surface or stones entering the combine, but may increase soil crusting and emergence problems. This step can be delayed until the seeds have germinated and are almost ready to emerge.
A range of row widths from I8 to 55 em is available for planting but 18 cm and 35 cm row widths are most common. Yield differences between these narrow-row widths are small and inconsistent (Table 1).
Recent studies have shown that harvesting losses can be reduced if seeding rates are increased for narrow rows, even though biological or potential yield was similar across a range of seeding rates. However, producers should be aware that higher seeding rates can increase both white mold severity, and competition for moisture and nutrients.
Recommended seeding rates for wide row (70 em) white beans are approximately 250,000 plants per hectare and should be increased to 375,000-640,000 viable seeds per hectare for 18 to 36 cm wide rows. Seeding rates should be based on seeds per hectare rather than kg.-'ha, since seed size can vary greatly, depending upon variety and the seasonal growing conditions under which the seed was produced (Table 2). To aid in planting a specific number of seeds per hectare, many companies provide the number of seeds per kilogram or pound.
Adjust seeding rates based on seed quality, seed germination, accuracy and dependability of planting equipment, seedbed and soil moisture conditions, and susceptibility of soil to crusting.
Stresses on the plant may cause stunting, uneven and delayed maturity.dramatically affecting seed yield and quality. Stunting of plants caused by stress such as root rot, soil compaction or potato leaf hopper feeding results in pod set close to the ground and high machinery harvest losses Delayed or uneven ripening causes problems in harvesting a quality white bean Situations of soil compaction, uneven emergence.herbicide damage, wheel traffic over bean plants or weather stress during the growing and harvest season can cause uneven ripening of beans These stresses can be reduced by avoiding compaction of soils, planting high quality seed at a uniform depth into adequate moisture and using proper rates of herbicides and fertilizer and avoiding overlaps Very little can be done to prevent unwanted secondary vegetable growth resulting from weather stress and often chemical desiccation is required.
When growing and weather conditions favour the incidence at white mold, yields will generally be reduced more in narrow-row fields The denser canopy reduces air flow and retains moisture lower which enhances the development and spread
Yield results from a severely infested variety trial are reported in Table 3.
White mold was present throughout the trial and all varieties had significantly more mold in the narrow rows. Despite yield losses some varieties have superior tolerance to white mold damage than other varieties.
Growers should select varieties with some mold tolerance if they suspect this disease may be a problem. Refer to OMAF Publication 296, Field Crop Recommendations for variety tolerance to white mold. Producers maybe able to reduce white mold pressure and rnore consistent achieve a uniform stand by switching to intermediate row widths (35-50 crns as opposed to solid-seeding (I8 cm)
White mold can most effectively be controlled by fungicides applied with ground equipment during the early bloom period. For currently recommended fungicides and for scouting procedures in establishing spray thresholds, consult Publication 296. Field Crop Recommendations or the Factsheet Fungal Diseases of Field and Snap Beans, Agdex 255/630.
The most serious insect affecting field beans is the potato-leaf Hopper. This insect injects saliva while sucking sap from the Plant. A toxin in the saliva causes stunting of plant growth and "hopper burn'"; tight curling of the leaves and yellowish-to-brown leaf tips and edges. The hopper burn will reduce yields and harvestability of the smaller plant. For more information and control for recommendations for the potato leaf-hopper, refer to Publication 296. Field Crop Recornmendations, or the Factsheet White Bean Insects, Agdex 142/622.
Narrow-row beans are equally susceptible to yield and quality loss from weed competition as are wide-row beans (see Factsheet Growing White Beans in Ontario) But narrow-row plantings demand a different weed management strategy. Narrow planted beans will form a plant canopy over the row car her and offer more competition against annual weeds than do beans in wide rows. However, inter-row cultivation in row spacings less than 50 em is difficult and may actually hinder direct harvest operations by pulling up stones or forming ridges of soil Mechanical weed control is generally restricted to preplanting secondary tillage and preemergent and postemergent rotary hoeing, so the emphasis is on chemical control For current recommendations on herbicide and herbicide combinations necessary to control a broad spectrum of weeds, consult Publication 71 Guide to Weed Control.
Perennial weeds, such as quackgrass, Canada thistle and field bindweed, should be controlled In the previous crop or stubble Sometimes inter-row cultivation could salvage a crop overrun with perennial weeds, but chemical control of the same weeds requires precise timing and often repeated and expensive treatments. If the use of postemergence pesticides is anticipated, tramlines should be established at planting. Trampled bean plants usualy recover. but will be slower to ripen causing uneven maturity and poorer quality beans.
In the past, many farmers have resorted to direct harvesting in an effort to salvage the bean crop when field conditions are too wet for pulling and withdrawing. Often the bean plants had suffered substantial weathering and farmers experienced low yields and high harvest losses However, when timely direct combining is intended as part of a narrow row managernent system with modern harvest equipment, a high yielding, high quality crop may be harvested.
The combine should be equipped with a flexible floating cutter bar adjusted to clip the bean plants as close in the ground as possible This minimizes the cutting of low hanging pods and associated harvest loss Knife sections and guards most be properly maintained and replaced when necessary. The knife must cut cleanly and quickly to avoid shaking the dry bean plants, splitting pods and shattering beans. Shattering losses at the cutter bar increase as pod moisture decreases.
New and modified equipment has been developed to minimize harvest losses. Specialized air reels are available to assist in moving the crop quickly off the knife and back into the cylinder The minimizes the buildup of cut bean plants on the knife and subsequent shatter losses The air blast keeps weeds and bean plant off the knife. offering better cutter bar visibility without shoving stones into the header Research studies at Centralia College of Agricultural Technology hale measured a 50% reduction in header loss as compared to a standard pickup reel. Another new development features air tubes incorporated into a revolving reel or others set out In front of a standard reel
Many farmers have successfully rnodified their standard pick-up reel by attaching flaps of heavy belting or stiff plastic to brush beans plants off the knife and into the header. Some farmers have welded triangular shaped lifters to the cutter bar guards to leaf bean branches and pods before the stalk is cut thereby reducing stubble loss.
Often yield and quality can be improved by modifying the harvest pattern in an uneven maturing or weedy crop. Direct combining does not oblige one to follow rows, so clean, mature areas can be harvested separately from weedy, green areas. Harvest can he delayed in these uneven areas until they mature or are Treated with a desiccant. Never contaminate a sample of clean, dry white beans with green. Stained wet beans from poor areas of the field. Modifying the harvest pattern for a lodged crop may increase yields. Harvesting against the direction of lodging or clipping the field on an angle allows harvest of leaning branches and low hanging pods and may reduce stubble losses by up to three fold.
Harvest loss with convention1 pulling and windrowing might range from 3-12%.. but is not obvious or easily determined since loose beans are mixed and/or covered with soil and bean straw. Harvest losses with direct harvesting are quite obvious and may discourage growers. Losses have been seen to range from 5% to 18% depending upon equipment modifications, operator experience and skill and timeliness of harvest. Determine harvest losses routinely to evaluate new technologv, modifications or adjustments to your combine. Calculate losses by consulting the Factsheet Measuring Soybean Harvesting Losses, Agdex 141,'745.A loss 100 kg/ha equals 48 beans/m2 (100 pounds/acre = 5 seeds/square foot).
Figure 3. Harvest operation.
Ideally, beans should be harvested when seeds arc 18% moisture. Leaf drop is complete, stems are dry and fields are free of green weeds. Green bean leaves and weeds will stain seed coatsand at high moisture levels, any dirt taken into the combine will be ground into the seed coat resulting in permanent discolouration. In the case of imrnature bean plants and weeds in wide row beans, plants are pulled and windrowed and allowed to dry down in the windrow before combining. For direct combining beans, farmers should consider applying a desiccant, such as R.eglone, if there are green weeds and uneven maturity or secondary growth of beans. Refer to Publication 75 Guide to Weed Control it seldom pays to wait for a second set of blossoms to produce pods, since the first set may suffer considerable weathering damage in the interim.
Bean quality may actually be superior by direct combining compared to conventional harvest techniques. Mud tagging arid dirt staining is reduced due to smaller amounts of soil accompanying the beans through the combine. Likewise, beans tolerate wet weather far longer when standing in rows than when lying in the windrow. Often those beans in the bottom pods are the first to sprout and discolour with wet weather, yet they are not harvested in a clipping operation.
The daily acreage harvested by direct cutting may be only I /3 to I /2 that of a similar combine threshing bean plants lying in the windrow. But, once over direct harvesting replaces the additional machinery and manpower required to conventionally pull, windrow and thresh beans.
Threshing, handling, shipping, storage and marketing operations are identical to that for wide row been production. Consuit the Factsheet Growing White Beans in Ontario, Agdex 142 or Coloured Beans in Ontario, Agdex 142/ 10.
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