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Rhizome Characteristics and Canopy Light Interception of Grazed Rhizoma Peanut Pastures
Author(s) -
OrtegaS. J. A.,
Sollenberger L.E.,
Bennett J.M.,
Cornell J.A.
Publication year - 1992
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1992.00021962008400050009x
Subject(s) - grazing , canopy , interception , rhizome , pasture , dry matter , loam , agronomy , biology , zoology , botany , horticulture , soil water , ecology
‘Florigraze’ rhizoma peanut ( Arachis glabrata Benth.) is a promising pasture legume for warm climates. In 1988 and 1989, the effect of grazing management on rhizoma peanut canopy light interception (LI) and the role of rhizome reserves in regrowth were studied on a Sparr fine sand (loamy, siliceous, hyperthermic Grossarenic Paleudults). Treatments were replicated twice and included all combinations of three levels of residual dry matter (RDM; 500, 1500, and 2500 kg ha −1 ) and four grazing cycle lengths (GC; 7, 21, 42, and 63 d between grazings, including a 0.5 to 2‐d grazing period). Data were analyzed by fitting multiple regression equations starting with a second order polynomial model. Canopy LI before grazing ranged from 24 to more than 90% and was lowest for low RDM and short GC treatments, while canopy LI after grazing ranged from 9 to 79% and increased at a decreasing rate as RDM increased. When grazed to 500, 1500, and 2500 kg ha −1 , RP required an average of 49, 24, and 12 d to reach 85% LI. At season‐end 1989, rhizome mass (range of 450‐4100 kg ha −1 ) and total nonstructural carbohydrate (TNC; range of 58‐210 g kg − ) concentration were lowest at low RDM and short GC, increased with increasing GC when RDM was low, and changed only slightly with changes in GC at RDM above 1700 kg ha −1 . Low postgraze light interception and depletion of rhizome mass and total nonstructural carbohydrate with close grazing suggest that reserves were mobilized for rhizoma peanut regrowth. In contrast, postgraze light interception and rhizome mass and reserve status remained high when residual dry matter was 1700 kg ha −1 or greater suggesting that residual leaf area was primarily responsible for regrowth under more lenient grazing.