FORAGE & GRAZING LANDS Forage Production and Nutritive Value of Selected Pigeonpea Ecotypes in the Southern Great Plains

for use in sustainable forage-livestock production systems in the southern Great Plain region. Stocker cattle production in portions of southern Great Plains Pigeonpea is a summer legume crop grown for grain depends on wheat (Triticum aestivum L.) and warm-season perennial grasses. Nutrient supply is limited in both quantity and quality from in the tropics and subtropics. The crop ranks sixth in late July through November. To determine if pigeonpea [Cajanus the world in production of dryland legumes (Nene and Cajan (L.) Millsp.] could fill this deficit, a field study was conducted Sheila, 1990). Pigeonpea can survive well in degraded from 1996 to 1998. Seasonal forage production patterns, yield, and soil and tolerates moisture stress, perhaps due to its quality of three pigeonpea ecotypes (ICP8151, ICPX910007, and deep root system. It also has potential for use in soil PBNA) were evaluated. Pigeonpeas produced 5 Mg ha 1 dry matter conservation (Sheldrake and Narayanan, 1979). Piby 26 August, with N concentration 20 g kg 1 and digestible dry geonpea has for centuries been used as high-protein matter (DDM) 500 g kg 1. Ecotype ICPX910007 accumulated greatgrain for human food (Whiteman and Norton, 1981) est dry matter in 136 d (16 Mg ha 1 ), followed by ICP8151 (13 Mg and animal feed because it produces large amounts of ha 1 ) and PBNA (9.5 Mg ha 1 ). Mean N concentration for PBNA biomass with high protein content (Pathak, 1970; Wallis was 28.6 g kg 1 as compared with 23.3 and 23.0 g kg 1 for ICP8151 and ICP910007, respectively. Digestible dry matter of PBNA was et al. 1986; Whiteman and Norton, 1981; and Whyte et 614 g kg 1, followed by 576 and 572 for ICP8151 and ICP910007, al., 1953). For example, late-maturing pigeonpeas (265 respectively. Leaf dry matter yield averaged across sampling dates to 340 d after seeding) grown in relatively frost-free and years for all ecotypes ranged from 2360 to 2600 kg ha 1. Leaf areas produced 36 Mg ha 1 of dry matter in Kanpur, quality was similar to that of alfalfa for all ecotypes. Environmental northern India (Singh and Kush, 1981), 52 Mg ha 1 in conditions such as cooler spring and summer temperatures and excess Columbia (Herrera et al., 1966), and 46 Mg ha 1 in rainfall (1997) or extreme drought (1988) reduced yield of all ecotypes. western Australia (Parbery, 1967). Pigeonpea can provide high-quality forage that could be used as a Chemical composition of pigeonpea varies with age, primary or supplementary forage for grazing livestock at a time when maturity, and the proportion of plant components such other forages are less productive. as leaf, stem, flower, seed, and pods. Akinola and Whiteman (1975) measured N concentration of plant parts at different growth stages and reported that 4-wkA goal of grazing programs is to provide highold leaves and stems contained 48 and 27 g kg 1, which quality forage year-round to reduce costs of stordeclined to 36 and 18 g kg 1 at 16 wk, respectively. Cattle ing and purchasing forage or concentrate feeds. No sincarrying capacity of good pigeonpea stands ranged from gle crop has the potential to provide forage year-round. 1.2 to 3.7 animals ha 1 with an average live-weight gain One of the traditional approaches to agricultural proof 1 kg animal 1 d 1 (Kruss, 1932). In Hawaii, Henke duction in the southern Great Plains is based on stocker et al. (1940) suggested that pigeonpea forage was supecattle production, grazing a primary forage source, winrior to grass when compared in terms of gain per animal, ter wheat. Wheat pasture is grazed during the winter and it could carry a higher stocking rate than grass. and early spring. It is often used as a dual-purpose forage Pigeonpea is not grown in the southern Great Plains; and grain crop. Warm-season perennial grasses such as however, it has potential as a productive, high-quality bermudagrass [Cynodon dactylon (L.) Pers.] and old forage during a period when conventional forages are world bluestems (Bothriochloa spp.) provide forage durnot available. The objective was to evaluate the seasonal ing the late spring and early summer. However, highforage production patterns and nutritive value of sequality forage is unavailable from late July through late lected pigeonpea ecotypes during the summer fallow November, when quality and quantity of summer perenperiod of winter wheat. nial grasses have declined and winter wheat is not yet sufficiently established and productive for grazing. MATERIALS AND METHODS Therefore, additional forage resources with the ability to supply forage during the deficit period are needed Studies were conducted during the summer fallow period in a continuous winter wheat production system at the Grazinglands Research Laboratory near El Reno, OK (35 40 N, S.C. Rao and H.S. Mayeux, USDA-ARS, Grazinglands Research 98 0 W, elevation 414 m). Mean maximum and minimum Laboratory, 7207 W. Cheyenne St., El Reno, OK 73036; S.W. Coleman, USDA-ARSSTARS, 22271 Chinsegut Hill Rd., Brookesville, temperatures at this location during the June to September FL 34601-4672. Received 2 July 2001. *Corresponding author (srao@ growing season are 36 C and 20 C, respectively. The longgrl.ars.usda.gov). Abbreviations: DDM, digestible dry matter. Published in Crop Sci. 42:1259–1263 (2002).