Pigeon pea: a multipurpose, drought resistant forage, grain and vegetable crop for sustainable southern farms

Pigeon pea: a multipurpose, drought resistant forage, grain and vegetable crop for sustainable southern farms

Summary

Georgia-1 and Georgia-2 pigeonpea no-till planted directly into existing pastures will germinate and produce viable plants, but competition from existing grass limits its value as a mixed-pasture forage. However, when the existing grass is killed or stunted with glyphosate, pigeonpea produces an abundant crop that cattle graze willingly. Provided there is sufficient soil moisture for germination, pigeonpea no-till planted into wheat stubble produces a late-fall forage crop. Pigeonpea germplasm supplied by the International Crops Research Institute for the Semi-Arid Tropics in India was evaluated in a community garden and exhibited wide ranges in growth patterns, including plant architecture and maturity dates.

Objectives/Performance Targets

1. Quantify the effects of pigeon pea variety and plant population on water infiltration and runoff water quantity and quality (Texas AgriLife Research).

2. Evaluate the impact of pigeon pea grain crops on the depletion of soil profile moisture and the growth and yield of subsequent wheat crops.

3. Demonstrate and evaluate the value of pigeon pea as a late season forage crop when intercropped with existing grass pastures or as a post-wheat-harvest crop. Determine if cattle will graze pigeon pea during its pre-flowering growth stage or if they are not attracted to the pigeon pea until it reaches its flowering stage. Determine if there are different patterns and preferences in the way cattle graze white seed versus brown seed pigeon pea varieties.

4. Explore the market for fresh pod and dried bean forms of pigeon pea in the Dallas-Forth Worth area.

5. Host a pigeon pea conference at the Texas A&M University Research and Extension Center in Dallas, Texas to present pigeon pea cropping and marketing options for southern farmers.

Accomplishments/Milestones

Objective 1

Runoff Plots: Limited amounts of runoff data were collected during the third year due to some deterioration of the plots from erosion. Plots are being repaired in order to resume collection of runoff data. Limited data indicated that during the winter months, when there was no standing pigeonpea crop on the plots, there was no significant difference in runoff volume from the various treatments. Since runoff data from natural rainfall was limited and the results were difficult to interpret, we borrowed a rainfall simulator from Mississippi State University that we will use during the final year to collect comparative rainfall data from the five treatments (control, Georgia-1 pigeonpea at low density, Georgia-1 pigeonpea at high density, Georgia-2 pigeonpea at low density, Georgia-2 pigeonpea at high density).

Best management practices: Georgia-2 pigeonpea was incorporated into another study at the Texas AgriLife Research & Extension Center at Dallas dealing with the adoption of best management practices (BMP) to control sediment and nutrient run off from agricultural lands. Georgia-2 pigeonpea was no-till drilled into wheat stubble on June 24, 2009. Drought conditions immediately ensued following planting of the pigeonpea so two weeks after planting, the plots were irrigated with approximately 2cm water. This was enough to induce germination but subsequent rainfall was negligible until the end of July. August growing conditions were favorable and by the end of September, Georgia-2 plants were flowering and starting to fill pods (photos 1 and 2). The following month of October was the sixth wettest October on record with 19 days of measurable rain for a monthly total of 20.4 cm. The preceding month of September had also been atypically wet with a total rainfall of 17.4 cm. Due to the frequent saturated and anaerobic soil conditions combined with predominantly overcast skies, the Georgia-2 plants began to drop leaves and flowers in October and cotton root rot was observed in about 5 to 10% of the population (photo 3). Bean pod bores were another significant problem and the level of damage indicates that this is becoming a serious pest for legumes in Texas and possibly other southern states. Due to the combined effects of excessive rain and bean pod bore, grain yields were extremely low. Data related to the effect of the pigeonpea cover crop on runoff water is still being processed at this time.

Objective 2

Research conducted at the Grazinglands Research laboratory, USDA-ARS, El Reno, Oklahoma was identical to that completed the previous 2008 growing season. Nine one-acre plots were sprayed with Round-up (glyphosphate) herbicide to control weeds. All plots were fertilized with 18-46-0 to provide 24 kg N and 60 kg P205/ha. Pigeonpea varieties were inoculated and seeded into six 1-acre plots at the rate of 25 kg/ha with a no-till drill.

Three, one-acre plots were established without seeding with pigeon pea to serve as controls. After seeding, 3 X 3 m enclosures were installed in each plot to prevent grazing. Two neutron probes were installed in each plot (grazed and un-grazed areas) to determine soil water use with and without grazing. Cattle (235 kg stocker calves) were introduced for grazing when plant height reached 45 cm (photo 4). Cattle were weighed before grazing initiated and on 15 d intervals until most of the leaves were stripped. Final weight of cattle was recorded for each treatment.

Neutron probes readings were recorded just before seeding and at 15 d intervals during the growing season in order to evaluate the effect of pigeonpea on soil profile nutrient depletion.

The experiment will be repeated again in the 2010 growing season.

Objective 3

No on-farm demonstrations were conducted during the 2009 growing season due to logistical problems with equipment. At the Texas A&M Research & Extension Center in Dallas, Georgia-1 and Georgia-2 varieties were planted for the third year into existing pasture. Runoff data was addressed under objective 1. In terms of overall plant growth, Georgia-1 tended to produce more aboveground biomass than Georgia-2. The primary reason for greater biomass with Geaorgia-1 versus Georgia-2 was greater plant survival during the period from September to November. It is likely that the Georgia-1 pigeonpea variety was better adapted to surviving the extremely wet conditions prevalent during September to October 2009. Both Georgia-1 and Georgia-2 lost a significant part of their population stand from August to November, but the loss was greatest for Georgia-2.

Objective 4

Meetings were held with Harry Iyer of the Greater Dallas IndoAmerican Chamber of Commerce to reevaluate and redefine the objectives of marketing portion of the SARE grant. During summer 2010, Mr. Iyer will hire a student to conduct a market evaluation for pigeonpea in the Dallas Metroplex. The focus will be on identifying the demand for pigeonpea in the Dallas Area as well as other regions in the US and to identify how pigeonpea produced in the US can supply part or all of the market demand.

Objective 5

Planning is still underway for a Pigeonpea Conference/Field Day to be held in late fall 2010.

• Pigeonpea stand in wheat stubble on September 30, 2009 (June 24 planting date).
• Root rot in pigeonpea crop on BMP plots.
• Runoff collection apparatus for pigeonpea in BMP plots (9-30-2009).
• Cattle grazing Georgia-2 pigeonpea at USDA Grazinglands Research Laboratory in El Reno, Oklahoma.

Impacts and Contributions/Outcomes

Interest in pigeonpea, both as a forage for cattle and as a pulse crop for humans continues to grow in the Southern United States. This project has focused on evaluating several on-farm uses for pigeonpea, with the greatest efforts directed towards its use as forage for cattle. After several growing seasons with variable rainfall patterns, we have learned that direct seeding pigeonpea into existing pastures has limited potential to produce significant quantities of forage (photos 5 and 6). However, cattle are quite willing to graze pigeonpea and the long growing season for pigeonpea allows it to remain green and palatable to cattle late in the fall when warm-season grass pastures have declined due to drought and cooler temperatures. In 2009, we were also able to establish a successful stand of Georgia-2 pigeonpea by no-till drilling the seed into wheat stubble in late June. This demonstrated that a late planting of pigeonpea can supply a significant amount of fall forage for cattle.

Although the crop is a staple in some Asian countries and it commonly found in many other countries of the world, pigeonpea is mostly unknown in the United States. Therefore, a new effort was initiated in 2009 to introduce the urban population to pigeonpea. To that end, sixteen varieties of pigeonpea obtained from the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) was planted in replicated plots at the Education Community Garden at the Texas AgriLife Research and Education Center in Dallas (photo 7).

• Mid-summer stand of Georgia-2 pigeonpea direct seeded into existing pasture.
• Pigeonpea germplasm evaluation in the Education Community Garden at the Texas AgriLife Research & Extension Center in Dallas.
• Late fall stand of Georgia-2 (foreground) and Georgia-1 (background) pigeonpea direct seeded into existing pasture.

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