Description

Chickpeas (Cicer arietinum)
Chickpeas are an annual grain legume. They come in two types, “desi” and “kabuli,” based on seed size, color, and the thickness and shape of the seed coat. (See the USA Dry Pea & Lentil Council’s website at http://usapulses.org for photos illustrating various types of pulses.)

Desi types are usually smaller, angular seeds with thick seed coats that range in color from light tan and speckled to solid black. Desi chickpeas require a specialized seed-coat-removal process if used for human food. The process, called decortication, requires adjusting the moisture level of the seeds to facilitate the mechanical removal of the thick seed coat. The seeds, which after decortication resemble a small yellow pea, are processed into numerous South Asian ethnic food products.

Kabuli types, also known as “garbanzo beans” in the United States, are larger seeds with paperthin seed coats that range in color from white to pale cream-color to tan. In North America, most kabuli chickpeas are marketed as canned chickpeas for salads or as hummus. Kabuli chickpeas are also marketed as dry chickpeas and ground flour.

In the United States, chickpeas are grown primarily in the Pacific Northwest and Northern Plains, with some production in California, the High Plains, and Arizona. Chickpea plants are erect with primary, secondary, and tertiary branching, resembling a small bush. They flower profusely and have an indeterminate growth habit, continuing to flower and set pods as long as conditions are favorable. Pod set occurs on the primary and secondary
branches and on the main stem. The individual round pods generally contain one seed in kabuli types and often two seeds in desi types. Chickpeas have deeper taproots than peas and lentils, which gives them an advantage in moisture-deficient areas.

Lentils (Lens culinaris)
Lentil plants are herbaceous, with slender stems and branches. Plant height ranges from 12 to 15 inches for most varieties, but can vary from 8 to 30 inches depending on variety and environment. Plants have a slender taproot with fibrous lateral roots. Rooting patterns range from a many-branched, shallow root system to types that are less branched and more deeply rooted. The taproot and lateral roots in surface layers of the soil have nodules that vary in shape from round to elongate. Stems of lentil plants are square and ribbed and usually thin and weak. Branches arise directly from the main stem and may emerge from the cotyledonary node below
ground or from nodes above ground. Leaves are relatively small compared to those of other large-seeded food legumes. Pods are oblong, laterally compressed, and approximately ¼ to ¾ inch long and 1/8 to 3/8 inch wide; they usually contain one or two lens-shaped seeds. Seed diameter of varieties commonly grown in the United States ranges from around 1/8 inch to a little over ¼ inch and colors range from light green or greenish red to gray, tan, brown, or black. Purple and black mottling and speckling of seeds are common in some varieties. In the United States, lentils are grown primarily in the Pacific Northwest and Northern Plains. Several market classes of lentils are grown in these regions, based on seed size, cotyledon color, and seed coat coloration.

Dry Peas (Pisum sativum and P. sativum spp. arvense)
Dry peas are a cool-season annual crop produced primarily in the Northern Plains, High Plains, and Pacific Northwest, with scattered production in northern California, Nevada, Arizona, New England, and a few other states. Also known as “field peas,” they differ from succulent peas in that dry peas are marketed as dry, shelled products for either human food or livestock feed, whereas succulent peas are marketed as fresh or canned vegetables. There are two main types of dry peas. One type has normal leaves and vine length of 3 to 6 feet. The second type is semileafless (with modified leaflets) with shorter vine lengths of 2 to 4 feet.

Fall-planted peas – peas planted in the fall with a tolerance to winter temperatures – of the green and yellow market classes have been released for both feed markets and, more recently, for food markets. Fall-planted peas also show promise as a cover crop in all regions of North America. Austrian winter peas are raised for forage and specialty feeding applications. Fall-planted peas provide producers with significantly improved yields, possible adaptability to drought or summer season heat due to earlier bloom dates, earlier harvest potential, and longer-term nitrogen fixation for better soil health. Fall-planted pea acres are expected to expand across current
growing regions and to provide additional pulse acres in summer fallow/winter wheat rotations. Depending on the variety, dry peas start flowering after a specific number of nodes are reached
and flowering continues until moisture or nitrogen deficiency brings it to an end. Dry pea varieties have either a determinate or indeterminate flowering habit. Determinate varieties mature in 80 to 90 days, indeterminate varieties in 90 to 100 days. Dry pea harvest begins in late July (for spring-planted peas), when pods are dry and seed moisture is 8% to 18%, depending upon the growing region. They are combined directly in the field. A timely harvest is important to avoid post-maturity disease, seed bleaching, and seed shatter

Crop Stages in Brief
This section summarizes the general activities and production considerations in pulse crops at each crop stage. Activities and considerations specific to management of weeds, diseases, insects, nematodes, and vertebrate pests are discussed in the section devoted to that pest under Pulse Pests and Management Options, following this section.

Pre-Plant
Pulses are often grown in rotation with other crops. As rotation partners, pulses offer several agronomic and economic advantages. Cereal crop yields often increase when planted after legumes because cereal pest cycles have been disrupted. Legume crops enable use of different herbicides than the cereal crops to clean up grassy weeds. Legumes conserve soil moisture and limit soil erosion by offering an option other than summer fallow. Finally, pulses increase the nitrogen content of the soil.

Field history and crop rotation are important pest management considerations in pulse production, particularly with respect to weeds. The decision to grow pulses in a given field is typically made one to three years in advance to allow for proper site preparation, rotation partner selection, and plant-back considerations. Weed control is critical in pulses because they are slow to establish, produce limited vegetative growth, and do not compete strongly with weeds. A carefully considered crop rotation scheme, which may include chemical fallow, can help decrease weed populations. Grass weeds are easier than broadleaf weeds to manage in pulses,
therefore pulse growers tend to avoid fields with a history of broadleaf perennial weed problems.

Many herbicides used in small-grain production may persist in the soil, resulting in pulse crop injury and yield loss. Rotational intervals depend in part upon how long herbicides remain in the soil. Factors that affect herbicide persistence include soil pH, moisture, temperature, texture, and organic matter. In areas with a dry climate and short growing season, herbicides generally degrade slower than in warmer, moister areas. Sulfonylurea herbicides persist longer in higher pH soils. When soil pH exceeds 7.5 to 7.9, sulfonylurea residues may remain in the soil much longer than described on the label. Under such conditions, a field bioassay is required the year
before seeding pulses. Pulses are best grown following a cereal rather than a crop that can harbor pulse diseases such as botrytis, powdery mildew, aphanomyces root rot, and fusarium root rot caused by species
specific to pulses. Pulse crops are susceptible to diseases that can overwinter in the soil and in stubble. These considerations are important in management of weeds and diseases and in minimizing residual herbicide injury to the crop.

Planting
Variety selection at planting is critical to the success of the crop. It is imperative that varieties with general adaptation to the region be identified as well as varieties that best counter the stresses in a given field. End uses and markets need to be considered as some varieties fit very specific market niches. As new varieties are developed, testing programs to assure their performance in each region will be needed.

Lentils, dry peas, and desi chickpeas are cool-season crops that can be seeded early into cool soils (40°F); kabuli chickpeas require warmer soils (46-50°F). The rate at which the soil warms affects early crop vigor, which in turn affects the plants’ tolerance of weeds and diseases. Pulse crops can be planted under conventional, minimum-till, or no-till production systems. Direct seeding techniques and low-till and no-till techniques can be very effective for pulse production. Extended rotations are especially important in direct seeding systems to reduce the spread of disease from intact residues on the soil surface and to allow for a slower breakdown of residual herbicides.

Pulse crops generally follow winter wheat or spring barley. Cereal stubble that is plowed or chiseled in the fall is cultivated for weed control and herbicide incorporation, then harrowed and rolled. (Pulse beds are also rolled after planting, which is discussed in the “Preemergence” section below.) Growers try to avoid excessive tillage in the spring to prevent drying out the seedbed. Most pulse seeds can emerge from deep seeding depths due to their large size. However, deep seeding is not required, provided that the seed is accurately placed in firm, moist soil. Seeding depth is also determined by herbicide incorporation depth. In direct-seeding systems, the seed is
placed at a shallower depth than systems utilizing pre-tilled soils, as soil moisture is usually much higher in untilled soils. Direct seeding and low-till and no-till methods have distinct advantages. Mulch from surface residue changes surface ecology. The soil aeration changes, which in turn facilitates water passthrough and favors certain organisms. The resulting improved soil tends to promote plant health, and healthy plants are better able to resist pest pressure. There are, however, a few drawbacks to direct seeding and low-till/no-till techniques. Pulse crops grown under these systems have a greater reliance on non-selective herbicides such as glyphosate (Roundup Ultra). Low-till and no-till systems limit the ability to incorporate pesticides, which is required with some herbicides. Also, the untilled residues remaining on the soil surface from the previous crop may tie up residual herbicides, rendering them ineffective.

Preemergence
After planting, pulse crop beds are rolled to smooth the soil surface. This field operation improves the harvesting of low-hanging pulse pods by reducing harvest losses and breakage of sickle section and guards, and improves harvest rate. Rolling is done anytime from immediately after seeding up to the 5- to 7-node stage in lentils and up to the 5-leaf stage in peas. Chickpea beds are rolled prior to emergence only.

Emergence to Harvest
Pulse crops have a low growth habit and low pod set. This affects the practicality of mid- to lateseason mechanical weed control and often necessitates specialized attachments for combine headers to allow mechanical harvest. Some lentils and dry peas are swathed or desiccated prior to harvest due to uneven maturity or weed infestation, an operation that also requires specialized combine attachments. Chickpeas may be swathed prior to harvest, but this is less common. Fields are inspected prior to harvest for variety characteristics and certifiability of seed.

Harvest
Harvest of pulse crops takes place once the crop has matured and dried out to a certain moisture level. Harvest date depends upon crop and region (see Activity Tables, Appendix A). Drying usually occurs naturally, but desiccant herbicides may be used in years with warm, wet springs and cool, wet summers that promote luxuriant plant growth. Under such conditions the crop will continue to flower and set pods and weeds will continue to grow as long as moisture is available. If growers wait for natural dry down to occur under such high-moisture conditions, they risk pod shattering, sprouting, seed coat slough, and seed bleaching. Sometimes application of desiccants is limited to “green spots” within a field. In years when weeds are less threatening, dry peas and lentils are mechanically swathed or direct combined. Timely harvest of dry peas and lentils is critical to avoid post-maturity disease.

Post-Harvest, Shipping and Storage
Even though peas and chickpeas produce a limited amount of crop residue, they develop one of the best seedbeds for subsequent crops with direct-seed cropping systems. The high nitrogen to carbon ratio of pulses provides a nitrogen benefit to non-legume crops in the system and reduces the need for nitrogen fertilizer application. Following removal of the crop, typical operations include: sampling for certified seed, applying perennial weed controls, heavy harrowing to manage residue (in some regions), fertilization for the next season’s crop, and pre-plant chemical application and incorporation for the next crop. After the crop leaves the field, it is stored (warehoused) and monitored. Seed moisture must be carefully controlled (typically in the range of 12 to 14%) to prevent storage molds, spoilage, heat damage, insect damage, and unintentional germination. Moisture is tested several times during the first few weeks of storage to maintain proper levels and to prevent seed sweating. If moisture levels are too high, bin aeration may be employed. Aeration cools and dries the seed to forestall
storage problems. It is important to make sure the fan size is appropriate to the bin size and the crop. Grain dryers are sometimes used on chickpea, but they must be used with extreme caution because they may cause mechanical and thermal damage to the crop.

Crop Cycles Per Year