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A Nitrogen‐Phosphorus‐Potassium Model For Forage Yield of Bermudagrass
Author(s) -
Overman A. R.,
Dagan A.,
Martin F. G.,
Wilkinson S. R.
Publication year - 1991
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/agronj1991.00021962008300010057x
Subject(s) - cynodon dactylon , yield (engineering) , phosphorus , mathematics , dry matter , forage , potassium , agronomy , nitrogen , coefficient of determination , zoology , environmental science , statistics , chemistry , biology , physics , organic chemistry , thermodynamics
A logistic equation was used to relate annual dry matter yield of Coastal bermudagrass [ Cynodon dactylon (L.) Pers.] to applied N, P, and K. Yield data from a 4 ✕ 4 ✕ 4 (N ✕ P ✕ K) factorial experiment were analyzed. The second order Newton‐Raphson procedure for nonlinear regression was used to estimate the seven parameters of the model. A correlation coefficient of 0.9884 was obtained with the model for the 64 data points. A response surface for yield as related to N and K at P = 100 kg ha −1 was drawn from the model. Isoquants (constant yield) were drawn for annual yield of 10 Mg ha −1 . A residuals diagram showed no trends, lending further validity to the model. These results have application to agricultural production and environmental quality.