Pulse crops are the edible seeds of legume plants that are harvested as dry grains.¹ Currently, the United Nations Food and Agriculture Organization (FAO) has classified 11 types of pulses including dry beans, dry peas, dry broad beans, chickpeas, lentils, cow peas, pigeon peas, lupins, pulses nes, Bambara beans, and vetches.¹ While this list does not encompass all pulses, it does comprise of the most widely known.
Pulse crops are grown in 173 countries around the world in hundreds of varieties.¹ It’s estimated that we have been consuming pulses for more than 11,000 years—dating all the way back to 8th century BC.² It’s grown to become a healthy, sustainable source of protein around the world.
Producing high-yielding, quality pulse crops requires a strong understanding of their growth throughout production. A deep understanding of each stage of development will help you better manage the crop from planting to harvest. Certain fertility decisions are only effective at specific stages of development, and factors like the climate and soil conditions can impact the evolution of growth. Thus, it is important to better understand a pulse crop’s growth stages and development cycle to make more informed management decisions while meeting your productivity and profitability goals. Knowing what stage of growth your crops are in will also allow you to better manage their health, assess crop quality, and determine the best time to harvest.
The stages of pulse development can be broken into two parts: vegetative and reproductive. Click through each of the MORE buttons below to learn about each stage.
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VE – Germination and Emergence
The seeds will begin to absorb water about 24-48 hours after planting if enough moisture is available. As water uptake begins, a radical root emerges forming a taproot, anchoring the seed to the ground. The hypocotyl (the initial seedling stem) forms and straightens, pulling the seed coat up through the soil. During this stage, the cotyledonary node is visible.
V1 – Cotyledon
Cotyledons are the first visible structures above the ground. A unifoliate is the first true leaf produced. During this stage, the cotyledon and unifoliate are visible above the soil.
V2 – First Trifoliate
During this stage, the first trifoliate is formed. This is the second true leaf and has three leaflets. As the plant is grows it produces alternately arranged trifoliate leaves from the main stem and branches. Within this stage, photosynthesis is enough to meet all energy requirements by the seedling.
V3 – Bifoliate
At this stage, the third true leaf is unfolded at the third node and the tendril is present. Root nodulation by nitrogen-fixing bacteria should be initiated by this stage and will begin supplying nitrogen to the plant. Rapid development of initial leaves can provide greater energy to developing nodules and improve nitrogen fixation.
Vn – Multifoliate
During this stage, the pulses have more leaves developing and unfolding from the stem. Cells that will become flowers and eventually seeds are being initiated at V3 and beyond, and yield potential is being determined. Stress at this stage can reduce the total yield potential.
R1 – Early Bloom
Flowering occurs from axillary buds on the main stem and branches. It proceeds acropetally from lower to higher nodes. At this stage, flowers begin to open at one or more nodes. Stress at this stage and beyond can cause flowers to abort and reduce yields.
R2 – Full Bloom
Most of the flowers are open on nodes 10-13 of the basal primary branch. Approximately 50 percent of the plants in the field will be in bloom.
R3 – Early Pod
The developing pods are visible on the plants during the early pods stage. The pods are at nodes 10-13 of the main branch on about 50 percent of the plants in the fields.
R4 – Flat Pod
The pods during this stage are on nodes 10-13. They have reached their full length but are mainly flat. The seeds inside these pods are less than half of the pod area but can be felt as a bump between the fingers. Stress during seed fill will reduce seed size and final yield.
R5 – Full Seed
During this stage, seeds inside the pods begin to swell and completely fill the pod cavity. The leaves will start yellowing and the lower pods have turned yellow to golden brown.
R6 – Physiological Maturity
During this stage, the moisture content is 30 percent or below. Nearly 80 percent of the plant has changed from yellow to brown in color, but the top of the plant may still be green with seeds fully formed and not juicy. Seed pods on the bottom-third of the plant are tan to brown in color and are hard to the touch. Seeds in the middle third of the plant are full-sized, are light green to tan in color and are firm. The top third of the plant has only 50-57 percent color change with no immature seeds.
R7 – Full Maturity
Nearly 90 percent of the pods on the plant have turned tan to brown in color. The seed moisture ranges from 20-30 percent. The crop is ready to harvest when seed moisture is below 20 percent and 90 percent of the pods on the plant are golden-brown in color.
Planting Tips
Soil temperature has a direct impact on growth—temperatures above 82°F (27.8°C) can negatively impact growth.³ Early planting is often encouraged with March becoming a common time of year to plant.
Seeding depth should be considered—large pulses can be seeded deeper into the soil than small pulses.⁴
Soil moisture is critical—pulse seeds require three times more moisture to complete germination than other crops.³
