A simple production function model for variable density growth and yield modeling

1984 ◽  
Vol 14 (6) ◽  
pp. 783-788 ◽  
Author(s):  
Sun Joseph Chang
Keyword(s):  
Site Index ◽  
Yield Function ◽  
Variable Density ◽  
Growth And Yield ◽  
Planting Density ◽  
Annual Increment ◽  
Yield Data ◽  
Growth Functions ◽  
Basic Model ◽  
Growth And Yield Modeling

This paper proposes a logarithmic–reciprocal yield function that improves upon the function proposed by Nautiyal and Couto (J. C. Nautiyal and L. Couto. 1982. Can. J. For. Res. 12: 452–458) by allowing forest crops starting with different stocking levels to eventually approach the same volume and peaking of the current annual increment (CAI) at different ages of the stands. The function is then used to fit yield data generated from Smalley and Bailey's study (Smalley, G. W., and R. L. Bailey. 1974. U.S. For. Serv. Res. Pap. SO–96) that shows wobbles in CAI and changes in yield as a result of changes in planting density. The basic model is then expanded by incorporating site index to account for local differences in productivity. Finally, compatible growth functions that can be estimated with log differences in yield instead of instantaneous growth are also derived.

A Growth and Yield Model for Improved Eastern Cottonwood Plantations in the Lower Mississippi Delta

1991 ◽  
Vol 15 (4) ◽  
pp. 213-216 ◽  
Author(s):  
Quang V. Cao ◽  
Kenneth M. Durand
Keyword(s):  
Populus Deltoides ◽  
Mississippi Delta ◽  
Basal Area ◽  
Site Index ◽  
Growth And Yield ◽  
Annual Increment ◽  
Yield Model ◽  
Eastern Cottonwood ◽  
Volume Yield ◽  
Growth And Yield Model

Abstract A compatible growth and yield model was developed based on remeasurement data collected from 183 plots on unthinned improved eastern cottonwood (Populus deltoides Bartr.) plantations in the lower Mississippi Delta. The Sullivan and Clutter (1972) equation form was selected for predicting cubic-foot volume yield and projecting volume from site index and initial age and basal area. Yield equations explained 97% and 94%, respectively, of the variations in total outside bark and merchantable inside bark volumes. Mean annual increment of merchantable volume culminated between 8 and 15 years, depending on site index and initial basal area. South. J. Appl. For. 15(4):213-216.

scholarly journals  Modelling of tree diameter growth using growth functions parameterised by least squares and Bayesian methods

2012 ◽  
Vol 58 (No. 6) ◽  
pp. 245-252 ◽  
Author(s):  
R. Sedmák ◽  
L. Scheer
Keyword(s):  
Least Squares ◽  
Bayesian Methods ◽  
A Priori ◽  
Nonlinear Least Squares ◽  
Yield Function ◽  
Growth And Yield ◽  
Diameter Growth ◽  
Tree Diameter ◽  
Growth Functions ◽  
Future Growth

The purpose of this paper is to present a new growth and yield function (denoted as KM-function), which was empirically derived from the cumulative density function of the Kumaraswamy probability distribution. KM-function is theoretically well disposed for the prediction of future growth; however, the function also has other theoretical features that make it useful also for retrospective estimation of the past growth frequently used in biological analyses of growth in the initial life stages. In order to demonstrate the practical applicability of the KM-function for growth reconstruction, an investigation of the accuracy of five-year retrospective projections of the real tree diameters obtained by stem analyses of 35 beech trees was done. Bias and accuracy of the new function were compared with bias and accuracy of some well-known growth functions on the same database. Compared functions were parameterised in two ways: by the method of nonlinear least squares and Bayesian methods. Empirical validation of the KM-function confirmed its good theoretical properties when it was used for retrospective estimation of the tree diameter growth. The valuable knowledge of this research is also a finding that the incorporation of a great deal of a priori known facts about the growth of trees and stands in natural conditions of Slovakia into Bayesian parameter estimation led to a decrease in the bias and magnitude of reconstruction errors.  

Optimizing sowing density-based management decisions with different nitrogen rates on smallholder maize farms in Northern Nigeria

2020 ◽  
Vol 56 (6) ◽  
pp. 866-883
Author(s):  
Adnan Aminu Adnan ◽  
Jan Diels ◽  
Jibrin Mohammed Jibrin ◽  
Alpha Yaya Kamara ◽  
Abdulwahab Saliu Shaibu ◽  
...  
Keyword(s):  
Nutrient Management ◽  
Fertilizer Application ◽  
Growth And Yield ◽  
Planting Density ◽  
Economic Returns ◽  
Yield Data ◽  
N Fertilizers ◽  
Scenario Analyses ◽  
Maize Varieties

AbstractIn this study, the CERES-Maize model was calibrated and evaluated using data from 60 farmers’ fields across Sudan (SS) and Northern Guinea (NGS) Savannas of Nigeria in 2016 and 2017 rainy seasons. The trials consisted of 10 maize varieties sown at three different sowing densities (2.6, 5.3, and 6.6 plants m−2) across farmers’ field with contrasting agronomic and nutrient management histories. Model predictions in both years and locations were close to observed data for both calibration and evaluation exercises as evidenced by low normalized root mean square error (RMSE) (≤15%), high modified d-index (> 0.6), and high model efficiency (>0.45) values for the phenology, growth, and yield data across all varieties and agro-ecologies. In both years and locations and for both calibration and evaluation exercises, very good agreements were found between observed and model-simulated grain yields, number of days to physiological maturity, above-ground biomass, and harvest index. Two separate scenario analyses were conducted using the long-term (26 years) weather records for Bunkure (representing the SS) and Zaria (representing the NGS). The early and extra-early varieties were used in the SS while the intermediate and late varieties were used in the NGS. The result of the scenario analyses showed that early and extra-early varieties grown in the SS responds to increased sowing density up to 8.8 plants m−2 when the recommended rate of N fertilizers (90 kg N ha−1) was applied. In the NGS, yield responses were observed up to a density of 6.6 plants m−2 with the application of 120 kg N ha−1 for the intermediate and late varieties. The highest mean monetary returns to land (US$1336.1 ha−1) were simulated for scenarios with 8.8 plants m−2 and 90 kg N ha−1, while the highest return to labor (US$957.7 ha−1) was simulated for scenarios with 6.6 plants m−2 and 90 Kg N ha−1 in the SS. In the NGS, monetary return per hectare was highest with a planting density of 6.6 plants m−2 with the application of 120 kg N, while the return to labor was highest for sowing density of 5.3 plants m−2 at the same N fertilizer application rates. The results of the long-term simulations predicted increases in yield and economic returns to land and labor by increasing sowing densities in the maize belts of Nigeria without applying N fertilizers above the recommended rates.

Comparing site productivity of mature fire-origin and post-harvest juvenile lodgepole pine stands in Alberta

2004 ◽  
Vol 34 (6) ◽  
pp. 1181-1191 ◽  
Author(s):  
Shongming Huang ◽  
Robert A Monserud ◽  
Thomas Braun ◽  
Hugh Lougheed ◽  
Olenka Bakowsky
Keyword(s):  
Lodgepole Pine ◽  
Total Yield ◽  
Site Index ◽  
Rate Of Change ◽  
Growth And Yield ◽  
Annual Increment ◽  
Projection System ◽  
Post Harvest ◽  
Pine Stands ◽  
Fire Origin

Twenty-two paired-plot sample locations were revisited to re-examine the site indices of mature fire-origin and adjacent post-harvest juvenile lodgepole pine (Pinus contorta var. latifolia Engelm.) stands occurring on the same physiographic sites. The post-harvest juvenile stands followed harvesting and drag scarification, whereas the mature fire-origin stands received no stand treatment. Results showed that the site index of post-harvest juvenile stands was 27% to 35% higher than that of the mature fire-origin stands. Calculation of the rate of change in site index indicated that the site index estimates of post-harvest stands were stable after 5 years breast height age was reached. This suggests that the increase in site index in post-harvest stands is not a short-term artifact, but a sustained gain that will be maintained over time. Simulations of post-harvest yield based on the Alberta growth and yield projection system (GYPSY) for lodgepole pine suggested that the increase in post-harvest site index will likely result in substantial gains in the mean annual increment and total yield of post-harvest lodgepole pine stands in the study area. The results of this study indicate that post-harvest lodgepole pine stands are growing significantly faster than their fire-origin counterparts on equivalent sites.

scholarly journals Use data from permanent sampling points in growth and yield modeling

2007 ◽  
Vol 31 (1) ◽  
pp. 59-69 ◽  
Author(s):  
Alexandre José Pereira ◽  
Helio Garcia Leite ◽  
João Carlos Chagas Campos ◽  
Agostinho Lopes de Souza
Keyword(s):  
Eucalyptus Grandis ◽  
Basal Area ◽  
Site Index ◽  
Minas Gerais ◽  
Growth And Yield ◽  
Western Region ◽  
Independent Variables ◽  
Yield Modeling ◽  
Sampling Points ◽  
Growth And Yield Modeling

This study was carried to evaluate the efficiency of the Bitterlich method in growth and yield modeling of the even-aged Eucalyptus stands. 25 plots were setup in Eucalyptus grandis cropped under a high bole system in the Central Western Region of Minas Gerais, Brazil. The sampling points were setup in the center of each plot. The data of four annual mesurements were colleted and used to adjust the three model types using the age, the site index and the basal area as independent variables. The growths models were fitted for volume and mass of trees. The efficiency of the Bitterlich method was confirmed for generating the data for growth and yield modeling.

Growth and yield of okra (Abelmoschus esculentus (L.) Moench) grown in the marginal upland area of Sta. Rita, Samar as influenced by different planting densities and mulching materials

2017 ◽  
pp. 44-54
Author(s):  
Zenaida Gonzaga ◽  
Warren Obeda ◽  
Ana Linda Gorme ◽  
Jessie Rom ◽  
Oscar Abrantes ◽  
...  
Keyword(s):  
Bare Soil ◽  
Abelmoschus Esculentus ◽  
Growth And Yield ◽  
Planting Density ◽  
Rice Hull ◽  
Plastic Mulch ◽  
Lady’S Finger ◽  
Materials Used ◽  
Set Up ◽  
A Minor

Okra or Lady’s finger, botanically known as Abelmoschus esculentus (L.) Moench, is a tropical and sub-tropical indigenous vegetable crop commonly grown for its fibrous, slimy, and nutritious fruits and consumed by all classes of population. It has also several medicinal and economic values. Despite its many uses and potential value, its importance is under estimated, under-utilized, and considered a minor crop and little attention was paid to its improvement. The study was conducted to evaluate the effects of different planting densities and mulching materials on the growth and yield of okra grown in slightly sloping area in the marginal uplands in Sta. Rita, Samar, Philippines. A split-plot experiment was set up with planting density as main plot and the different mulching materials as the sub-plot which were: unmulched or bare soil, rice straw, rice hull, hagonoy and plastic mulch. Planting density did not significantly affect the growth and yield of okra. Regardless ofthe mulching materials used, mulched plants were taller and yielded higher compared to unmulched plants. Moreover, the use of plastic mulch resulted to the highest total fruit yield. The results indicate the potential of mulching in increasing yield and thus profitability of okra production under marginal upland conditions.

Growth and Yield of Wheat under Irrigation by Sugar Mill’s Wastewater

2014 ◽  
Vol 24 (1-2) ◽  
pp. 211-218
Author(s):  
PK Kundu ◽  
TK Acharjee ◽  
MA Mojid
Keyword(s):  
Grain Yield ◽  
Fertilizer Application ◽  
Wastewater Irrigation ◽  
Growth And Yield ◽  
Sugar Mill ◽  
Yield Data ◽  
Full Dose ◽  
Sugar Mills ◽  
Irrigation Treatments ◽  
Mixed Water

The possibility of using sugar mill’s wastewater/effluent in irrigation was evaluated by investigating the effects of wastewater on growth and yield of wheat (Triticum aestivum cv. Prodip). The experiment was conducted at North Bengal Sugar Mill site in Natore during December 2011 to March 2012. Three irrigation treatments (I1: irrigation with fresh/tubewell water, I2: irrigation with a mixture of fresh and wastewater at 1:1 ratio and I3: irrigation with wastewater) under a main factor and three fertilizer treatments (F0: no application of fertilizer, F1: half dose fertilizer and F2: full dose fertilizer) under a sub factor were evaluated. The experiment was laid out in a split-plot design with three replications of the treatments. Wheat was grown with three irrigations totaling 14 cm applied at 4, 26 and 43 days after sowing (DAS). Important growth and yield data of the crop were recorded. The highest grain yield of 1.829 t/ha was obtained under mixed water irrigation and the lowest grain yield of 1.469 t/ha was obtained under wastewater irrigation. The three irrigation treatments, however, provided statistically similar (p = 0.05) grain yield. For the interaction between irrigation and fertilizers, mixed water irrigation and full dose fertilizer application (I2F2) provided significantly higher grain yield (2.757 t/ha) than all other treatment combinations. The second highest yield, produced under freshwater irrigation and full dose fertilizer (I1F2), was statistically similar to the yield under wastewater irrigation and full dose fertilizer (I3F2). Results of this experiment thus exposed good prospects of irrigating wheat by sugar mills’ wastewater.DOI: http://dx.doi.org/10.3329/pa.v24i1-2.19174 Progress. Agric. 24(1&2): 211 - 218, 2013

scholarly journals A Novel Approach to Modelling Stand-Level Growth of an Even-Aged Forest Using a Volume Productivity Index with Application to New Zealand-Grown Coast Redwood

Forests ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1155 ◽  
Author(s):  
Mark O. Kimberley ◽  
Michael S. Watt
Keyword(s):  
New Zealand ◽  
Growth Model ◽  
Growth Models ◽  
Stand Density ◽  
Site Index ◽  
Growth And Yield ◽  
Productivity Index ◽  
Site Quality ◽  
Spatial And Temporal Variation ◽  
Coast Redwood

Empirical growth models are widely used to predict the growth and yield of plantation tree species, and the precise estimation of site quality is an important component of these models. The most commonly used proxy for site quality in growth models is Site Index (SI), which describes the mean height of dominant trees at a specified base age. Although SI is widely used, considerable research shows significant site-dependent variation in height for a given volume, with this latter variable more closely reflecting actual site productivity. Using a national dataset, this study develops and describes a stand-level growth and yield model for even-aged New Zealand-grown coast redwood (Sequoia sempervirens). We used a novel modelling approach that quantifies site quality using SI and a volume-based index termed the 300 Index, defined as the volume mean annual increment at age 30 years for a reference regime of 300 stems ha−1. The growth model includes a number of interrelated components. Mean top height is modelled from age and SI using a polymorphic Korf function. A modified anamorphic Korf function is used to describe tree quadratic mean diameter (Dq) as a function of age, stand density, SI and a diameter site index. As the Dq model includes stand density in its formulation, it can predict tree growth for different stand densities and thinning regimes. The mortality model is based on a simple attritional equation improved through incorporation of the Reineke stand density index to account for competition-induced mortality. Using these components, the model precisely estimates stand-level volume. The developed model will be of considerable value to growers for yield projection and regime evaluation. By more robustly describing the site effect, the growth model provides researchers with an improved framework for quantifying and understanding the causes of spatial and temporal variation in plantation productivity.

scholarly journals Liming Effects of Sawdust Ash and Lime on Sunflower (Helianthus annuus L.) Yield in Acidic Soil of Southeastern Nigeria

2019 ◽  
pp. 1-11
Author(s):  
C. V. Ogbenna ◽  
V. E. Osodeke
Keyword(s):  
Soil Ph ◽  
Chemical Properties ◽  
Exchange Capacity ◽  
Acidic Soil ◽  
Soil Chemical Properties ◽  
Growth And Yield ◽  
Available Phosphorus ◽  
Yield Data ◽  
Southeastern Nigeria ◽  
Head Weight

Aim: A pot experiment was carried out to determine the effect of sawdust ash and lime (Ca(OH)2) on soil characteristics and yield of sunflower in acidic soil of southeastern Nigeria. Study Design: The experiment was laid out in split-plot design, using sawdust ash (0, 1, 2, 3, 4 t ha-1) as the sub plot and lime (0, 0.5, 1.0, 1.5 t ha-1) as the main plot. Place and Duration of Study: Study was conducted outdoors at Michael Okpara University of Agriculture Umudike, Nigeria, during the 2010 planting season. Materials and Methods: Treatment combinations were applied to the 60 buckets containing soil, mixed thoroughly and watered adequately. After 1 week of treatment application, two sunflower seeds were planted and later thinned to one seedling per bucket. Plant growth and yield data were collected. Pre planting and post-harvest soil samples were collected and analyzed for soil properties. Results: Results showed that with the exception of organic carbon there was significant effect of treatments on all soil chemical properties. Lime and sawdust ash (SDA) as single and combined treatments significantly increased total nitrogen (P=0.05), available phosphorus (P<0.010), and base saturation (P<0.012). The interaction between SDA and lime significantly (P=0.05) increased total exchangeable bases and effective cation exchange capacity, while soil pH was significantly increased (P=0.05) by single applications. The increases in soil chemical properties led to significant positive response of the sunflower. With the exception of number of leaves, other plant parameters (Plant height, stem diameter, head weight, 50 seed weight, head diameter) had significant increases for sawdust ash alone at P=0.05. Correlation studies showed positive significant relationship between soil pH and sunflower yield. Conclusion: The study showed that sunflower performed best at the combination of 3 tha-1 SDA and 1.5 t ha-1 lime producing a mean head weight of 45.4 g.

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