Model Evaluation for Perennial Grasses in the Southern United States

Overman, A. R.; Wilkinson, S. R.

doi:10.2134/agronj1992.00021962008400030031x

Cited by 20 publications

(16 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Maximum yield (A) depends upon the grass and seasonal rainfall. Nitrogen coefficients were found to be independent of year, in agreement with previous work (Overman and Evers, 1992;Overman and Wilkinson, 1992). Applied N (N 112 ) to achieve one-half maximum yield (y = A/2) depends upon the grass.…”

Section: Discussionsupporting

confidence: 89%

Logistic Response of Bermudagrass and Bunchgrass Cultivars to Applied Nitrogen

1993

Self Cite

View full text Add to dashboard Cite

Models provide a quantitative means to evaluate yield response of forage grasses to applied N and water availability. The objective of this analysis was to estimate model parameters (A, b, c) for bermu· dagrasses and bunchgrasses grown at the same location and during the same time period. The logistic equation was used to relate annual dry matter production to applied N for three bermudagrasses [C)· nodon dactylon L., 'Coastal', 'Alicia', and 'Coastcross-1'] and four bunchgrasses [Eragrostis curvuw (Schrad.) Nees, 'Morpa' and 'Ren· ner' lovegrass; Panicum coloratum L., 'Selection-75' kleingrass, and Cenchrus ciliDris L., 'Strain 18-35' buffelgrass]. Data were from 4 yr of field experiments at Stephenville, TX. Analysis of variance was used to show that the N coefficients b and c were independent of year and climate for each grass, in agreement with recently published results. Applied N required to provide one-half of maximum yield was approximately 150 kg ha -I for bermudagrass and 50 kg ha -I for lovegrass. Variation among years was accounted for in the linear coefficient A, which was then related to rainfall. Bunchgrasses typically had lower A and b, but similar c values compared with bermudagrasses.The logistic model allows estimates of yields in terms of applied N and rainfall, and quantifies the interaction between these two factors. Bermudagrass yielded approximately 45% more dry matter than lovegrass for the same rainfall. Correlation coefficients exceeded 0.95 throughout the analysis.

show abstract

Section: Discussionsupporting

confidence: 89%

Logistic Response of Bermudagrass and Bunchgrass Cultivars to Applied Nitrogen

1993

Self Cite

View full text Add to dashboard Cite

show abstract

“…Application of the logistic model to response of various grasses to applied nutrients, harvest interval, and water availability has been described in numerous publications (Overman et al, 1990 a,b;Overman and Evers, 1992;and Overman and Wilkinson, 1992). The model can be written as:…”

Section: Introductionmentioning

confidence: 99%

Coupling among applied, soil, root, and top components for forage crop production

Overman

1995

Communications in Soil Science and Plant Analysis

View full text Add to dashboard Cite

This analysis establishes linkage among (a) applied nutrients nitrogen (N), phosphorus (P), and potassium (K), (b) available soil nutrients, (c) root dry matter and nutrient content, (d) top dry matter and nutrient content, and (e) leaf area and carbon dioxide (CO 2 ) concentration. It was previously shown that (a) and (d) are coupled by logistic equations with a common response coefficient c between dry matter and plant nutrient uptake with each applied nutrient. As a consequence of the common c, it has been shown that dry matter and plant nutrient removal are coupled by a hyperbolic equation. Furthermore, a model has been developed which includes N, P, and K as inputs. In the present work, (a) and (b) were coupled by a logistic equation as were (a) and (c). It was then shown that plant nutrient removal was coupled to available soil nutrients through a hyperbolic equation. The hyperbolic relationship was also shown to link dry matter between roots and tops, as well as plant N removal between roots and tops. As a consequence of the results above, it was then concluded that root nutrient content is related to available soil nutrient through a hyperbolic equation. The detailed mechanism of this coupling was not identified. Leaf area of soybeans followed a hyperbolic relationship with CO 2 concentration in the canopy.

show abstract

“…The logistic. model has been used to describe yield response of various furagegrasses to applied N (Overman etal., 1990a,b;Overman and Evers, 1992;Overman and Wilkinson, 1992). This model provided high correlation coefficients (R > 0.97) between observed and estimated values of dry matter yields and plant N removal with applied N. The effects of harvest interval and water availability were incorporated into the logistic model for perennial grasses (Overman et al, 1990b).…”

mentioning

confidence: 99%

Estimation of Yield and Nitrogen Removal by Corn

1994

View full text Add to dashboard Cite

A wide variety of mathematical models have been used to relate crop production to management factors such as applied N and water availability. These include power functions and exponential functions. The objective of this analysis was to use an extended logistic model to relate dry matter yields and plant N removal to applied N for corn (Zea mays L.) for three soils in North Carolina. In this model, response of both dry matter yield and plant N removal to applied N were described by logistic equations. Plant N concentration was then related to applied N by the ratio of these logistic equations. Model parameters were estimated by nonlinear regression. Analysis of variance showed that the N response coefficient c was common for dry matter yield and plant N removal for each soil. Overall correlation coefficients of yield and plant N removal with applied N were very high for all three soils (R> 0.99). It was shown that ≈50% of the total dry matter and 80% of total plant N were contained in the grain at all applied N levels. Maximum potential grain yield of 25.9 Mg ha−1 agreed closely with an estimate in the literature of 26.5 Mg ha−1 (500 bushels acre−1). Dependence of plant N concentration on plant N removal was shown to follow a linear relationship. The present model provides a rational basis for coupling of dry matter yield and plant N removal in response to applied N. It can be used in design and management decisions related to agricultural production and environmental quality.

show abstract

Model Evaluation for Perennial Grasses in the Southern United States

Cited by 20 publications

References 0 publications

Logistic Response of Bermudagrass and Bunchgrass Cultivars to Applied Nitrogen

Logistic Response of Bermudagrass and Bunchgrass Cultivars to Applied Nitrogen

Coupling among applied, soil, root, and top components for forage crop production

Estimation of Yield and Nitrogen Removal by Corn

Contact Info

Product

Resources

About