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Yield and Botanical Composition of an Irrigated Grass‐Legume Pasture as Influenced by Fertilization 1
Author(s) -
Rehm G. W.,
Nichols J. T.,
Sorensen R. C.,
Moline W. J.
Publication year - 1975
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/agronj1975.00021962006700010017x
Subject(s) - agronomy , forage , pasture , dactylis glomerata , legume , irrigation , bromus , human fertilization , bromus inermis , soil water , composition (language) , hay , biology , poaceae , ecology , linguistics , philosophy
Irrigated pastures are becoming more important for animal production in several Great Plains and Western states. The majority of fertilization studies have been conducted at sites where surface irrigation practices were used on medium to fine textured soils. This study was designed to evaluate the effect of N, P, and K fertilization on forage production and grass‐legume composition of an irrigated pasture containing bromegrass ( Bromus inermis Leys.), orchardgrass ( Dactylis glomerata L.) and alfalfa ( Medicago sativa L.) on sandy soils irrigated with automated sprinkler systems. Forage yields were recorded for 3 years at two sites and plant separations to determine the grass‐alfalfa composition were made at one of the two sites. The response to increasing levels of N was curvilinear at both sites throughout the 3‐year period. The application of 252 kg N/ha produced maximum yields at the Holt County site, whereas the use of 560 kg N/ha produced the maximum yields at the North Platte site. These N rates produced increases of 4.7 and 7.0 metric tons/ha, respectively. The response to applied P was linear at the Holt County site but had little influence on yields at the North Platte site. Applied K had no influence on forage yields at either site. Fertilization influenced the grass‐legume composition at the Holt County site to some extent, but trends were not consistent for the 2 years. The data show that N rates in excess of 252 kg/ha decreased the percentage of grass in the mixture while increasing the percentage of alfalfa. Since clipping frequency may have had some influence on grass‐legume composition, changes in the percentage of grass and alfalfa in the mixture cannot be entirely attributed to fertilization.