The Experts below are selected from a list of 30498 Experts worldwide ranked by ideXlab platform
David J Wittry - One of the best experts on this subject based on the ideXlab platform.
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efficacy of grid and zone Soil sampling approaches for site specific assessment of phosphorus potassium ph and organic matter
Precision Agriculture, 2004Co-Authors: Antonio P Mallarino, David J WittryAbstract:Within-field variability of plant-available nutrients often results in different fertilizer requirements across a field. There is uncertainty concerning the efficacy of alternative sampling strategies suitable for site-specific management. This study compared various Soil sampling approaches for P, K, pH, and organic matter (OM) in eight agricultural fields. Soil samples were collected using an intensive 0.2-ha grid-point procedure, and were used to compare less intensive sampling approaches. The approaches were based on 1.2–1.6-ha grid cells (Grid), Soil series of digitized Soil survey maps (SSM), Soil series of detailed Soil survey (1:12,000 scale) maps, elevation zones, and management zones based on various information layers (ZS). The approaches varied in reducing the within-unit Soil-Test variability and maximizing mean Soil-Test Values across sampling units, but none was superior across all fields and nutrients. All approaches were less efficient for P and K than for pH or OM. The Grid and ZS approach were the most effective across all nutrients and fields. However, the Grid approach was more effective for P, the Grid and ZS approaches were better for K and pH, and the SSM and ZS approaches were better for OM. The ZS approach often resulted in fewer sampling zones than the Grid approach, which implies lower Soil Testing costs for producers, but required more knowledge and subjective judgement than a Grid approach to adapt it to field-specific conditions.
R Santhi - One of the best experts on this subject based on the ideXlab platform.
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Soil Test based integrated plant nutrition system for ashwagandha on inceptisols
Indian journal of agricultural research, 2012Co-Authors: S Saranya, R Santhi, K Appavu, K RajamaniAbstract:An experiment was conducted on Vertic Ustropept following Ramamoorthy's Inductive cum targeted yield model to elucidate the relationship between Soil Test Values and response of ashwagandha (Withania somnifera (L.) Dunal) to added fertilizers under Integrated Plant Nutrition System (IPNS). Nutrient requirement and contribution from Soil, fertilizers and FYM were calculated. The percent contribution from Soil, fertilizer and FYM were 19.03, 31.30 and 23.14 for N; 20.26,17.30 and 6.38 for P2O5; 11.08, 62.53 and 30.39 for K2O. Fertilizer prescription equations were developed for ashwagandha and nomograms were formulated based on the equations for a range of Soil Test Values and desired target yield under IPNS. Following IPNS practice (NPK+ FYM @12.5t ha−1), 40, 24 and 30 kg ha−1 of fertilizer N, P2O5 and K2O respectively, could be saved.
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integrated fertilizer prescriptions for beetroot through inductive cum targeted yield model on an alfisol
Communications in Soil Science and Plant Analysis, 2011Co-Authors: R Santhi, A Bhaskaran, R NatesanAbstract:Field experiments were conducted on a Typic Haplustalf Soil of Tamil Nadu by adopting the inductive cum targeted yield model, and fertilizer requirements were quantified for beetroot based on Soil Test and yield target. The basic parameters [nutrient requirement (NR) and contributions of nutrients from Soil (Cs), fertilizer (Cf), and vermicompost (Cvermi)] were computed from the field experimental data. Using these basic parameters, we developed fertilizer prescription equations under the integrated plant nutrition system (IPNS), and nomograms were formulated for the desired yield target of beetroot for a range of Soil Test Values. The quantity of fertilizers that could be contributed by vermicompost at 5 t ha−1 was evaluated as 40, 21, and 30 kg nitrogen (N), phosphorus pentoxide (P2O5), and potassium oxide (K2O), respectively, when applied along with the NPK fertilizers as per Soil Test and desired yield target.
Antonio P Mallarino - One of the best experts on this subject based on the ideXlab platform.
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efficacy of grid and zone Soil sampling approaches for site specific assessment of phosphorus potassium ph and organic matter
Precision Agriculture, 2004Co-Authors: Antonio P Mallarino, David J WittryAbstract:Within-field variability of plant-available nutrients often results in different fertilizer requirements across a field. There is uncertainty concerning the efficacy of alternative sampling strategies suitable for site-specific management. This study compared various Soil sampling approaches for P, K, pH, and organic matter (OM) in eight agricultural fields. Soil samples were collected using an intensive 0.2-ha grid-point procedure, and were used to compare less intensive sampling approaches. The approaches were based on 1.2–1.6-ha grid cells (Grid), Soil series of digitized Soil survey maps (SSM), Soil series of detailed Soil survey (1:12,000 scale) maps, elevation zones, and management zones based on various information layers (ZS). The approaches varied in reducing the within-unit Soil-Test variability and maximizing mean Soil-Test Values across sampling units, but none was superior across all fields and nutrients. All approaches were less efficient for P and K than for pH or OM. The Grid and ZS approach were the most effective across all nutrients and fields. However, the Grid approach was more effective for P, the Grid and ZS approaches were better for K and pH, and the SSM and ZS approaches were better for OM. The ZS approach often resulted in fewer sampling zones than the Grid approach, which implies lower Soil Testing costs for producers, but required more knowledge and subjective judgement than a Grid approach to adapt it to field-specific conditions.
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evaluation of excess Soil phosphorus supply for corn by the ear leaf Test
Agronomy Journal, 1995Co-Authors: Antonio P MallarinoAbstract:The P concentrations of ear leaves at silking are often used to assess P status of corn (Zea mays L.). The ear-leaf Test has been evaluated for its ability to detect P deficiencies, but little attention has been given to its ability to quantify excess P supplies. The quantification of high P supplies is important for both economic and environmental reasons and because fertilization has increased P supplies of many Soils to levels where additional yield responses are not likely. Grain yields and tissue samples were collected from 41 site-years corresponding to 2 long-term and 24 short-term P-response trials from 1980 to 1990. The sites included a wide variety of Soil types, Soil-Test P Values, and management practices. Phosphorus fertilization increased corn yields at 13 site-years and leaf P concentrations at 24 site-years. Fertilization increased leaf P concentrations at 85% of the Soils where fertilization increased yields but at only 46% of the Soils where fertilization did not increase yields. The determined critical concentration range for the leaf Test, based on various models fit to relationships between yields and leaf P concentrations, was 2.3 to 2.5 g kg -1 . This range is below or within the lower range of previously published critical concentrations for this Test. Leaf P concentrations increased curvilinearly with increasing Soil-Test Values, and there were small or no increases at high Soil-Test Values. This trend, together with the failure of fertilization treatments to increase leaf P concentrations at many high-Testing Soils, indicates limited luxury uptake of P in the leaves. The results of this study show that the ear-leaf Test does not evaluate excess Soil P supplies appropriately and is not a reliable diagnostic tool for regions having abundant high-Testing Soils. The inappropriate evaluation of excess P and the high variability in leaf P concentrations due to growth factors other than P availability limit the value of this Test to the diagnosis of severe P deficiency.
Lars Stoumann Jensen - One of the best experts on this subject based on the ideXlab platform.
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long term fertilisation strategies and form affect nutrient budgets and Soil Test Values Soil carbon retention and crop yield resilience
Plant and Soil, 2019Co-Authors: Frederik Van Der Bom, Jakob Magid, Lars Stoumann JensenAbstract:AimsThe aim of this study was to evaluate the effects of long-term mineral and organic fertilisation on crop performance and Soil fertility.MethodsThe Long-Term Nutrient Depletion Trial (Denmark) was used to analyse changes in concentrations of Olsen-P, exchangeable potassium (K) and Soil carbon (C). Yield responses (2010-2016) were evaluatedmaking use of an early-season temperature model, fertilisation practices were evaluated by nutrient budgets, and nitrogen use efficiency by calculation of apparent recovery (ANR) in subplots receiving mineral N.ResultsOlsen-P (r(2)=0.68, P<0.001) and exchangeable K (r(2)=0.86, P<0.001) were correlated with the nutrient budgets. Soil C concentrations increased from 10.0gkg(-1) (1995) to between 11.1-14.6gkg(-1) (2016), with the greaTest accumulation under slurry applications (P<0.05, equalling 17-47% retention of slurry-C inputs). Relative yield responses of spring barley were associated with early season cold stress, but the model was not applicable to other crops. Increases of ANR in response to long-term phosphorus (P) applications were not significant.ConclusionsBalanced fertilisation is an effective way to maintain nutrient availability, and to ensure high and stable crop productivity and efficient use of nutrients. Direct C inputs from animal slurry are a major driver for increases of Soil C concentrations.
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long term fertilisation strategies and form affect nutrient budgets and Soil Test Values Soil carbon retention and crop yield resilience
Plant and Soil, 2019Co-Authors: Frederik Van Der Bom, Jakob Magid, Lars Stoumann JensenAbstract:The aim of this study was to evaluate the effects of long-term mineral and organic fertilisation on crop performance and Soil fertility. The Long-Term Nutrient Depletion Trial (Denmark) was used to analyse changes in concentrations of Olsen-P, exchangeable potassium (K) and Soil carbon (C). Yield responses (2010–2016) were evaluated making use of an early-season temperature model, fertilisation practices were evaluated by nutrient budgets, and nitrogen use efficiency by calculation of apparent recovery (ANR) in subplots receiving mineral N. Olsen-P (r2 = 0.68, P < 0.001) and exchangeable K (r2 = 0.86, P < 0.001) were correlated with the nutrient budgets. Soil C concentrations increased from 10.0 g kg−1 (1995) to between 11.1–14.6 g kg−1 (2016), with the greaTest accumulation under slurry applications (P < 0.05, equalling 17–47% retention of slurry-C inputs). Relative yield responses of spring barley were associated with early season cold stress, but the model was not applicable to other crops. Increases of ANR in response to long-term phosphorus (P) applications were not significant. Balanced fertilisation is an effective way to maintain nutrient availability, and to ensure high and stable crop productivity and efficient use of nutrients. Direct C inputs from animal slurry are a major driver for increases of Soil C concentrations.
R Natesan - One of the best experts on this subject based on the ideXlab platform.
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integrated fertilizer prescriptions for beetroot through inductive cum targeted yield model on an alfisol
Communications in Soil Science and Plant Analysis, 2011Co-Authors: R Santhi, A Bhaskaran, R NatesanAbstract:Field experiments were conducted on a Typic Haplustalf Soil of Tamil Nadu by adopting the inductive cum targeted yield model, and fertilizer requirements were quantified for beetroot based on Soil Test and yield target. The basic parameters [nutrient requirement (NR) and contributions of nutrients from Soil (Cs), fertilizer (Cf), and vermicompost (Cvermi)] were computed from the field experimental data. Using these basic parameters, we developed fertilizer prescription equations under the integrated plant nutrition system (IPNS), and nomograms were formulated for the desired yield target of beetroot for a range of Soil Test Values. The quantity of fertilizers that could be contributed by vermicompost at 5 t ha−1 was evaluated as 40, 21, and 30 kg nitrogen (N), phosphorus pentoxide (P2O5), and potassium oxide (K2O), respectively, when applied along with the NPK fertilizers as per Soil Test and desired yield target.