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

After two years of no-till planting pigeonpea into existing bermudagrass pasture with no supplemental fertilization, it is apparent that germination and stand establishment can vary considerably from year to year. However, stand establishment is improved by stunting existing pasture vegetation with glyphosate prior to planting. Early planting of pigeonpea also allows plants to become better established before competition from existing pasture vegetation limits their growth. Cattle show no discrimination against pigeonpea when introduced into a mixed grass plus pigeonpea pasture. They also grazed pure stands of white or brown seeded pigeonpea, tending to graze first on the pods, flowers and younger leaves, before moving on to older leaves.

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 were established at the Texas AgriLife Research & Extension Center in Dallas in spring 2007. Six treatments were evaluated during 2007 including Georgia-one pigeonpea planted at 50,000 and 100,000 plants per hectare, Georgia-two planted at 50,000 plants per hectare, aerated grass pasture, and unimproved grass pasture. In summer 2008, the aerated pasture treatment was replaced with a treatment consisting of 50,000 plants Georgia-two per hectare because data from the previous year suggested that the Georgia-two variety had reduced runoff from the pre-existing pasture. Although Georgia-two may reduce the quantity of runoff water, there was little difference in the nutrient and sediment content of runoff from the various treatments. Runoff treatments will be continued for a third growing season in 2009. Also near the end of the 2009 growing season, soil samples will be collected to evaluation plant available nutrient concentrations, with particular emphasis on phosphorus and nitrogen. A penetrometer will be used to assess soil compaction for each treatment.

Objective 2

In summer of 2008, nine one-acre plots were established at Grazinglands Research laboratory, USDA-ARS, El Reno, OK. All 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 per hectare. Pigeon pea varieties were inoculated and seeded in 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. 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, and soil moisture was described. This experiment will be repeated in 2009 and 2010 growing seasons.

Objective 3

In the second year of an on-farm research trial in Dallas County, Texas, Georgia-two pigeonpea and was directly seeded into an existing mixed bermudagrass pasture. The seeded area was adjacent to the area that had been planted the previous growing season. Soybean was planted in a similar fashion as pigeonpea for comparison purposes. Pigeonpea and soybean seeds were inoculated and planted at a population density of 50,000 plants/acre. No supplemental fertilizer was applied. The control treatment consisted of the original untreated bermudagrass pasture. Bermudagrass in the pigeonpea and soybean plots was suppressed with a one-quarter application rate of glyphosate applied shortly after planting. Unlike the previous year, when soil moisture was abundant during the first month after planting, seed germination during the second growing season was sparse for the pigeonpea and completely failed for the soybean due to lack of soil moisture. However, a limited pigeonpea stand was established which persevered through the growing season in spite of competition from the existing pasture vegetation. Cattle were not permitted in the study area until October 2008, when they accidentally gained access to the area after failure of the electric fence. The unauthorized entrance of cattle into the study area prevented the estimate of pre-grazing biomass production, but visual observations prior to failure of the fence showed that pigeonpea plants were sparse throughout the study area, but those plants that germinated and survived the dry spring exhibited strong growth after September 1. Cattle completely grazed the study area and there was no evidence of discrimination against the pigeonpea plants, which had been grazed down to the primary stem.

The objectives of the cooperative research with the USDA-ARS was to evaluate two short-season (white and brown seeded) pigeon pea varieties as a forage source for grazing cattle in late summer and early fall, when other sources of forages are limited. In summer of 2008, nine one-acre plots were established at the USDA Grazinglands Research Laboratory in El Reno, OK. Treatments consisted of 1) native pasture, 2) white seeded pigeonpea, and 3) brown-seeded pigeonpea. Pigeon pea varieties were inoculated and seeded in six 1-acre plots at the rate of 25 kg/ha with a no-till drill. Prior to planting, the pigeonpea plots were sprayed with Round-up (glyphosphate) herbicide to control weeds and all plots were fertilized with 18-46-0 to provide 24 kg N and 60 kg P205 ha-1. Cattle (235 kg stocker calves) were introduced for grazing when plant height reached 45 cm. 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. Cattle freely grazed pigeonpea plants and exhibited no aversion to either the white or brown seeded varieties. Cattle tended to graze first on the pods, flowers and younger leaves, before moving on to older leaves.

Objective 4

The Greater Dallas Indo-American Chamber of commerce provided input into the types of pigeonpea that are most suitable to the Dallas area. It is likely that a split pea form would have the greatest market potential in the Dallas Metroplex. An actual survey of potential markets will be conducted in the summer of 2009.

Objective 5

Planning and discussions for an end-of-project conference continued in 2009. Original plans were for a February 2010 conference, but our current plan is to postpone the conference until fall 2010 so that we will have an additional growing season to generate information for the conference. A fall conference will also allow us to include a field visit to actual pigeonpea plots where we can demonstrate pigeonpea varieties and production techniques to conference participants. We hope to attract both international and local participants to the conference. Regional and national interest in pigeonpea continues to increase. Project collaborator, Dr. Srinivas Rao of the USDA-ARS, was recently invited to collaborate with a consortium of 1890 universities (Tennessee State University, University of Virginia, and Alabama A&M University) on introducing pigeonpea to minority farmers in the Southern U.S.

Impacts and Contributions/Outcomes

The primary impact of this project so far has been to introduce a “new” crop to southern farmers in the United States. Although the crop is a staple in some Asian countries and it commonly found in many other countries of the world, it is mostly unknown in the United States. Another major outcome of this project has been the demonstration that cattle will willingly graze pigeonpea plants. Prior to this study, it was commonly believed that cattle would be averse to grazing pigeonpea due to a high content of anti-nutrional compounds. Our research so far has demonstrated that cattle have no aversion to consuming pigeonpea plants, whether they are planted as a stand-alone crop or inter-seeded with existing grassland pastures. Our future research will quantify anti-nutritional compounds in various pigeonpea varieties from India and the United States.

Collaborators: