scholarly journals Testing the Assumption of Normality for pH and Electrical Conductivity of Substrate Extract Obtained Using the Pour-through Method

HortScience ◽  
2007 ◽  
Vol 42 (3) ◽  
pp. 661-669 ◽  
Author(s):  
Eugene K. Blythe ◽  
Donald J. Merhaut
Keyword(s):  
Electrical Conductivity ◽  
Controlled Release ◽  
Goodness Of Fit ◽  
Linear Models ◽  
Empirical Distribution ◽  
Linear Regression Analysis ◽  
Nutrient Release ◽  
Plant Production ◽  
Controlled Release Fertilizer ◽  
Special Cases

The pour-through method is a simple and useful technique for on-site monitoring of pH and electrical conductivity (EC) in container nurseries, and has also been used in numerous research studies focused on substrates, plant nutrition, and plant production. Linear models, including the special cases of analysis of variance and linear regression analysis, are often used for statistical analysis of extract data and are readily available as procedures in statistical software packages. Certain assumptions, including normality of the data values or model residuals, are required to develop valid statistical inferences using linear models. This study evaluated the normality of pH and EC variables using data obtained from 100 extract samples collected weekly over 12 weeks using the pour-through method from a uniform containerized substrate (25 pine bark : 18 peatmoss : 7 sand blend amended with calcium sulfate and top-dressed with Polyon 17N–2.1P–9.1K + micros, a 365-day controlled-release fertilizer, at 10 g/container) in 2.8-L containers. Graphical techniques (histograms and QQ plots) and formal goodness-of-fit tests (tests based on the empirical distribution function, moment tests, and the Shapiro-Wilk regression test) were used to demonstrate methods for assessing normality. The variables pH and EC both exhibited relatively normal distributions. For comparative purposes, the transformed variables ln(pH), 10–pH, and ln(EC) were also evaluated. The latter two variables exhibited significant departures from normality, whereas ln(pH) did not. Average weekly EC exhibited positive correlations with time-lagged, average weekly substrate temperature, suggesting that nutrient release from the controlled-release fertilizer could be more dependent on temperature in the second to fourth weeks preceding extraction than on temperature in the week immediately preceding extraction.

scholarly journals Nutrient Release from Controlled-release Fertilizers in Acid Substrate in a Greenhouse Environment: I. Leachate Electrical Conductivity, pH, and Nitrogen, Phosphorus, and Potassium Concentrations

HortScience ◽  
2006 ◽  
Vol 41 (3) ◽  
pp. 780-787 ◽  
Author(s):  
Donald J. Merhaut ◽  
Eugene K. Blythe ◽  
Julie P. Newman ◽  
Joseph P. Albano
Keyword(s):  
Electrical Conductivity ◽  
Controlled Release ◽  
Nutrient Release ◽  
Low Fertility ◽  
Plant Production ◽  
Production Cycle ◽  
Permissible Levels ◽  
Phosphorus And Potassium ◽  
Acid Substrate ◽  
Controlled Release Fertilizers

Release characteristics of four types of controlled-release fertilizers (Osmocote, Nutricote, Polyon, and Multicote) were studied during a 47-week simulated plant production cycle. The 2.4-L containers containing a low-fertility, acid-based substrate were placed in an unheated greenhouse and subjected to environmental conditions often used for production of azaleas and camellias. Leachate from containers was collected weekly and monitored for pH, electrical conductivity, and concentrations of NH4+ N, NO3–N, total P and total K. Leachate concentrations of all nutrients were relatively high during the first 10 to 20 weeks of the study, and then gradually decreased during the remaining portion of the experiment. Differences were observed among fertilizer types, with Multicote often resulting in higher concentrations of N, P, and K in leachates compared to the leachates from the other fertilizer types during the first half of the study. Concentrations of NO3– and P from all fertilizer types were often above permissible levels as cited in the federal Clean Water Act.

scholarly journals Analytical solution of diffusion model for nutrient release from controlled release fertilizer

2017 ◽  
Vol 890 ◽  
pp. 012078
Author(s):  
Sayed Ameenuddin Irfan ◽  
Radzuan Razali ◽  
KuZilati KuShaari ◽  
Nurlidia Mansor ◽  
Babar Azeem
Keyword(s):  
Controlled Release ◽  
Analytical Solution ◽  
Diffusion Model ◽  
Nutrient Release ◽  
Controlled Release Fertilizer

Revealing channel controlled nutrient release mechanism of bio-oil polymer coated controlled-release fertilizer

2021 ◽  
Vol 173 ◽  
pp. 114096
Author(s):  
Bochao Wei ◽  
Jiaquan Jiang ◽  
Chengxiang Gao ◽  
Lidan Zhang ◽  
Yaowei Zhan ◽  
...  
Keyword(s):  
Controlled Release ◽  
Nutrient Release ◽  
Release Mechanism ◽  
Controlled Release Fertilizer ◽  
Bio Oil

Rapid and Low-Cost Method for Evaluation of Nutrient Release from Controlled-Release Fertilizers Using Electrical Conductivity

2018 ◽  
Vol 26 (12) ◽  
pp. 4388-4395 ◽  
Author(s):  
Eduardo Lopes Cancellier ◽  
Fien Degryse ◽  
Douglas Ramos Guelfi Silva ◽  
Rodrigo Coqui da Silva ◽  
Mike John McLaughlin
Keyword(s):  
Electrical Conductivity ◽  
Controlled Release ◽  
Low Cost ◽  
Nutrient Release ◽  
Controlled Release Fertilizers

scholarly journals Hydroponic Fertilizer Supply for Basil Using Controlled-release Fertilizer

HortScience ◽  
2020 ◽  
Vol 55 (10) ◽  
pp. 1683-1691
Author(s):  
Fernanda Trientini ◽  
Paul R. Fisher
Keyword(s):  
Controlled Release ◽  
Nutrient Release ◽  
Nutrient Content ◽  
Water Soluble ◽  
Plant Performance ◽  
Small Scale ◽  
Single Application ◽  
Fresh Weight ◽  
Controlled Release Fertilizer ◽  
Shoot Fresh Weight

Small-scale hydroponics is a growing urban horticulture trend, but nutrient solution management remains a challenge for small growers. The objective was to investigate the potential to use controlled-release fertilizer (CRF) to simplify nutrient management in small-scale hydroponic systems. Three experiments were conducted with the goal of a single fertilizer application during the crop cycle of basil (Ocimum basilicum). Nutrient release curves were quantified by adding prills to water and measuring nutrient content weekly in the solution for CRF products without plants. In all seven products tested (Osmocote Bloom 2–3M, Osmocote Plus 3–4M, E-Max Calcium Nitrate 2–3M, Agrocote MAP 3–4M, E-Max Keiserite 3–4M, E-Max K-Mag 2–3M, and Agrocote SOP 3–4M) an initial rapid release was followed by a plateau, but release rates differed between products varying from 100% (MgSO4) to 60% release [(NH4).(H2PO4)] over an 11-week evaluation period. Total nutrient content in two commercial N–P–K CRF products (3–4 months 15N–3P–10K and 2–3 months 12N–3.1P–14.9K) provided lower Ca and Mg compared with a typical hydroponic solution based on water-soluble fertilizer (WSF). A subsequent experiment evaluated plant growth response using the same two commercial CRF products (single application) or a WSF (replaced weekly) in growth chamber environment. Plants grown for 4 weeks under CRF treatments yielded less than half the shoot fresh weight of plants grown with WSF and exhibited symptoms of Ca deficiency and micronutrient toxicity (confirmed with tissue analysis). Electrical conductivity (EC) of CRF solutions increased over time indicating excess dose compared with plant uptake, reaching a maximum of 5.4 dS·m−1. Nutrient release curves from the first experiment were then used to estimate product release and create a single-application nutritional program based on a customized “Blend” developed from CRF macronutrients plus WSF micronutrients. Plants were grown hydroponically with two dosages of Blend (1X and 2X) and compared with a commercial WSF with weekly replacement of solution. Blend 2X and WSF treatments had similar shoot fresh weight (241 and 244 g/four plants, respectively) with healthy plant appearance and tissue nutrient levels generally within published survey ranges for basil. Commercial CRF products designed for soil or container production were unsuitable for hydroponics, but acceptable plant performance with the customized CRF Blend demonstrated proof-of-concept for a single CRF application.

scholarly journals Machine Learning Model for Nutrient Release from Biopolymers Coated Controlled-Release Fertilizer

Agriculture ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 538
Author(s):  
Sayed Ameenuddin Irfan ◽  
Babar Azeem ◽  
Kashif Irshad ◽  
Salem Algarni ◽  
KuZilati KuShaari ◽  
...  
Keyword(s):  
Machine Learning ◽  
Controlled Release ◽  
Surface Hardness ◽  
Nutrient Release ◽  
Learning Model ◽  
Mechanistic Modeling ◽  
Release Time ◽  
Controlled Release Fertilizer ◽  
Machine Learning Model ◽  
Controlled Release Fertilizers

Recent developments in the controlled-release fertilizer (CRF) have led to the new modern agriculture industry, also known as precision farming. Biopolymers as encapsulating agents for the production of controlled-release fertilizers have helped to overcome many challenging problems such as nutrients’ leaching, soil degradation, soil debris, and hefty production cost. Mechanistic modeling of biopolymers coated CRF makes it challenging due to the complicated phenomenon of biodegradation. In this study, a machine learning model is developed utilizing Gaussian process regression to predict the nutrient release time from biopolymer coated CRF with the input parameters consisting of diffusion coefficient, coefficient of-variance of coating thickness, coating mass thickness, coefficient of variance of size distribution and surface hardness from biopolymer coated controlled-release fertilizer. The developed model has shown greater prediction capabilities measured with R2 equalling 1 and a Root Mean Square Error (RMSE) equalling 0.003. The developed model can be utilized to study the nutrient release profile of different biopolymers’-coated controlled-release fertilizers.

scholarly journals Reaction-Multi Diffusion Model for Nutrient Release and Autocatalytic Degradation of PLA-Coated Controlled-Release Fertilizer

Polymers ◽  
2017 ◽  
Vol 9 (12) ◽  
pp. 111 ◽  
Author(s):  
Sayed Irfan ◽  
Radzuan Razali ◽  
KuZilati KuShaari ◽  
Nurlidia Mansor
Keyword(s):  
Controlled Release ◽  
Diffusion Model ◽  
Nutrient Release ◽  
Controlled Release Fertilizer

scholarly journals (59) An Examination of Irrigation Volumes and Controlled-release Fertilizer Application Methods and Rates to Reduce Nursery Container Leachate and Fertilizer Use

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 997B-997
Author(s):  
Peter Purvis ◽  
Calvin Chong ◽  
Glen Lumis
Keyword(s):  
Electrical Conductivity ◽  
Controlled Release ◽  
Fertilizer Application ◽  
Peat Moss ◽  
Regression Curve ◽  
Controlled Release Fertilizer ◽  
Fertilizer Use ◽  
Sphagnum Peat Moss ◽  
Physocarpus Opulifolius ◽  
Application Methods

Plug-rooted liners of common ninebark [Physocarpus opulifolius (L.) Maxim.] were grown in 6-L nursery containers filled with 73% composted pine bark, 22% sphagnum peat moss, and 5% pea gravel (by volume). Plants were fertilized with Polyon (Nutryon) 17–5–12 (17N–2P–5K) 6-month controlled-release fertilizer at various rates (2.5, 4.5, 6.5, and 8.5 kg·m-3) pre-incorporated, topdressed, or dibbled (placed under the liner at potting). Plants were trickle-irrigated daily with low (0.4-L), middle (0.8-L), or high (2.0-L) volumes of water to maintain leaching fractions of <0.15, 0.25–0.35, or >0.60, respectively. Regression analysis indicated that growth of ninebark increased from 30 to 109 g/plant with increasing rates of incorporated fertilizer (mean over irrigation volumes), from 27 to 71 g/plant with topdress and from 59 to 103 g/plant with dibble. Electrical conductivity (EC, mean over five dates) of the leachate throughout the season was highest with dibble (0.85 dS·m-3), intermediate with incorporated (0.81 dS·m-3), and least with topdressed (0.76 dS·m-3). With low irrigation volumes, growth of ninebark increased from 42 to 81 g/plant with increasing rates of fertilizer (mean over methods), and from 39 to 105 g/plant with middle or high volumes (common regression curve). With low irrigation volumes, leachate EC increased from 0.74 to 0.94 dS·m-3 with increasing rates of fertilizer, and from 0.75 to 0.81 dS·m-3 with middle or high volumes.

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