scholarly journals Estimating Nitrogen and Chlorophyll Status of Romaine Lettuce Using SPAD and at LEAF Readings

2019 ◽  
Vol 47 (3) ◽  
Author(s):  
Rodrigo Omar MENDOZA-TAFOLLA ◽  
Porfirio JUAREZ-LOPEZ ◽  
Ronald-Ernesto ONTIVEROS-CAPURATA ◽  
Manuel SANDOVAL-VILLA ◽  
Iran ALIA-TEJACAL ◽  
...  
Keyword(s):  
Linear Correlation ◽  
Crop Production ◽  
Chlorophyll Concentration ◽  
Production Cycle ◽  
Digital Object Identifier ◽  
Romaine Lettuce ◽  
Fresh Matter ◽  
Nitrogen Levels ◽  
N Concentration

Nitrogen (N) is an essential nutrient for plant growth and development and is especially important in the production of high quality leafy green vegetables. In this experiment, leaf N concentration, chlorophyll concentration (Chl) and weight above fresh matter (AFM) of romaine lettuce (Lactuca sativa L. var. longifolia) were estimated by correlations between in situ SPAD and atLEAF readings. Lettuce was grown in high tunnels during 42 days and was irrigated at five nitrogen levels: 0, 4, 8, 12 and 16 mEq·L-1 of NO3-, based on the Steiner nutrient solution. The N concentration, Chl concentration and AFM were determined in the laboratory, while SPAD and atLEAF readings were measured in situ weekly. SPAD readings had high, positive and significant linear correlations with N (R2 = 0.90), Chl (R2 = 0.97) and AFM (R2 = 0.98); atLEAF readings had a similar linear correlation with N (R2 = 0.91), Chl (R2 = 0.92) and AFM (R2 = 0.97). Besides, SPAD and atLEAF readings had high, positive, and significant linear correlation (R2 = 0.96). Thus, SPAD and atLEAF meters can be used to non-destructively and accurately estimate the N status of lettuce, in a reliable and quick manner during the crop production cycle. In addition, atLEAF is currently more affordable than SPAD.   ********* In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 3, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue. *********

Evaluation of Zeolite-based Soilless Root Media for Potted Chrysanthemum Production

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 465e-465
Author(s):  
Janet L. Carlino ◽  
Kimberly A. Williams ◽  
Earl R. Allen
Keyword(s):  
Crop Production ◽  
Dry Mass ◽  
Nutrient Leaching ◽  
Fresh Mass ◽  
Production Cycle ◽  
Control Medium ◽  
Fertilizer Rate ◽  
Innovative Technologies ◽  
Root Media ◽  
Soluble Fertilizer

Chrysanthemum growth and nutrient leaching of three clinoptilolite-based root media, which were formulated and provided by Boulder Innovative Technologies, Inc. and ZeoponiX, Inc., were compared to the performance of control plants grown in Sunshine Mix #2 (3 peat: 1 perlite, v/v). The control received 210 mg·L–1 N from an 18N–4P–15K soluble fertilizer at each irrigation. The experimental zeolite-based medium NZ, which contained untreated zeolite and received the same soluble fertilizer as the control, leached lower concentrations of NH4-N, K, and PO4-P for most of the production cycle compared to the control. Medium EZ1 was formulated to provide N, P, and K as fertilizer nutrients and produced plants similar to the control based on ratings, height, width, and dry mass, but not fresh mass, at harvest when the fertilizer rate was half of that applied to the control, 105 mg·L–1 N. Medium EZ2, which did not receive P or K from soluble fertilizer, produced plants similar to the control based on rating, height, and dry mass, but not width or fresh mass, with soluble fertilizer input reduced to only N. Tissue N, P, and K concentrations of plants grown in media EZ1 and EZ2 were lower than those of control plants. With further refinements, these zeolite-based products show promise for decreasing nutrient leaching during crop production and allowing for application of lower rates of soluble fertilizers.

Nitrogen form, time and rate of application, and nitrification inhibitor effects on crop production

2014 ◽  
Vol 94 (2) ◽  
pp. 425-432 ◽  
Author(s):  
R. E. Karamanos ◽  
K. Hanson ◽  
F. C. Stevenson
Keyword(s):  
Crop Production ◽  
Protein Concentration ◽  
Wheat Yield ◽  
Nitrification Inhibitor ◽  
N Fertilizer ◽  
Nitrogen Form ◽  
Anhydrous Ammonia ◽  
N Concentration ◽  
Fertilizer Rates ◽  
Better Than

Karamanos, R., Hanson, K. and Stevenson, F. C. 2014. Nitrogen form, time and rate of application, and nitrification inhibitor effects on crop production. Can. J. Plant Sci. 94: 425–432. Nitrogen management options for anhydrous ammonia (NH3) and urea were compared in a barley–wheat–canola–wheat cropping sequence (2007–2010) at Watrous and Lake Lenore, SK. The treatment design included a factorial arrangement of N fertilizer form (NH3versus urea), nitrification inhibitor application, time of N application (mid-September, mid- to late October, and spring) and four N fertilizer rates (0, 40, 80 and 120 kg ha−1). Anhydrous ammonia applications at 40 kg N ha−1in 2008 (fall) and in 2010 (all times of application) resulted in wheat yield reductions relative to the same applications for urea. For wheat years, yield was reduced for both fall versus spring N fertilizer applications, when no nitrification inhibitor was applied and the inclusion of nitrification inhibitor maintained wheat yield at similar levels across all times of N fertilizer applications, regardless of form. Protein concentration was approximately 2 g kg−1greater with urea compared with NH3at both sites in 2008 and only at Watrous in 2010. Also, early versus late fall N fertilizer applications consistently increased N concentration of grain only for the 40 and/or 80 kg N ha−1rates. Effects of nitrification inhibitor on N concentration were not frequent and appeared to be minimal. Urea had greater agronomic efficiency (AE) than NH3at the lower N fertilizer rates. The nitrification inhibitor had a positive effect on wheat AE only for early fall N fertilizer applications. It can be concluded that for maximum yields NH3or urea will be suitable if applied at rates of 80 kg N ha−1and greater. If N fertilizer is applied at 40 kg N ha−1, especially in fall without inhibitor, urea is better. In terms of protein concentration for wheat, urea seemed to better than NH3and fall was better than spring application.

scholarly journals Annual cycles of chlorophyll-<i>a</i>, non-algal suspended particulate matter, and turbidity observed from space and in-situ in coastal waters

Ocean Science ◽  
2011 ◽  
Vol 7 (5) ◽  
pp. 705-732 ◽  
Author(s):  
F. Gohin
Keyword(s):  
Particulate Matter ◽  
Continental Shelf ◽  
Mediterranean Sea ◽  
North Sea ◽  
Suspended Particulate Matter ◽  
Chlorophyll Concentration ◽  
Statistical Characteristics ◽  
Monitoring Networks ◽  
Suspended Particulate

Abstract. Sea surface temperature, chlorophyll, and turbidity are three variables of the coastal environment commonly measured by monitoring networks. The observation networks are often based on coastal stations, which do not provide a sufficient coverage to validate the model outputs or to be used in assimilation over the continental shelf. Conversely, the products derived from satellite reflectance generally show a decreasing quality shoreward, and an assessment of the limitation of these data is required. The annual cycle, mean, and percentile 90 of the chlorophyll concentration derived from MERIS/ESA and MODIS/NASA data processed with a dedicated algorithm have been compared to in-situ observations at twenty-six selected stations from the Mediterranean Sea to the North Sea. Keeping in mind the validation, the forcing, or the assimilation in hydrological, sediment-transport, or ecological models, the non-algal Suspended Particulate Matter (SPM) is also a parameter which is expected from the satellite imagery. However, the monitoring networks measure essentially the turbidity and a consistency between chlorophyll, representative of the phytoplankton biomass, non-algal SPM, and turbidity is required. In this study, we derive the satellite turbidity from chlorophyll and non-algal SPM with a common formula applied to in-situ or satellite observations. The distribution of the satellite-derived turbidity exhibits the same main statistical characteristics as those measured in-situ, which satisfies the first condition to monitor the long-term changes or the large-scale spatial variation over the continental shelf and along the shore. For the first time, climatologies of turbidity, so useful for mapping the environment of the benthic habitats, are proposed from space on areas as different as the southern North Sea or the western Mediterranean Sea, with validation at coastal stations.

Effect of heavy metals on the leaf disc ferricyanide reduction in cucumber

2009 ◽  
Vol 57 (3) ◽  
pp. 307-320
Author(s):  
G. Rabnecz ◽  
G. Záray ◽  
L. Lévai ◽  
F. Fodor
Keyword(s):  
Heavy Metals ◽  
Nutrient Solution ◽  
Chlorophyll Concentration ◽  
Leaf Disc ◽  
Transport Systems ◽  
Ferricyanide Reduction ◽  
Plasma Membrane Electron Transport ◽  
Significant Linear Correlation ◽  
Drastic Effect

The effect of heavy metals on the leaf plasma membrane electron transport systems was investigated in connection with the tissue Fe concentration in Fe-sufficient and Fe-deficient cucumber leaves. Ten M μPb in the nutrient solution inhibited leaf ferricyanide reduction by 20–26%, whereas 10 M μCd had a more drastic effect, with 80–83% inhibition. Ferricyanide reduction decreased by 14% when 1 mM Pb was applied in situ by vacuum infiltration into control leaf discs, whereas it decreased by 40% when 0.1 mM Cd was applied. Ferricyanide reduction was completely inhibited by 1 mM Cd. The ferricyanide reduction values were correlated with the heavy metal, Fe and chlorophyll concentrations in the leaves. A significant linear correlation was only found with the chlorophyll concentration. The data suggest that there are also direct effects on membranebound reductases, but these are of less significance. Using differentially Fe-deficient plants (grown with 0 to 300 nM Fe in the nutrient solution), a chlorophyll concentration of 0.9–1.0 mg g −1 fresh weight was estimated as the threshold for achieving the ferricyanide reduction levels found in the controls.

Cropping frequency, wheat classes and flexible rotations: Effects on production, nitrogen economy, and water use in a Brown Chernozem

2003 ◽  
Vol 83 (4) ◽  
pp. 667-680 ◽  
Author(s):  
R. P. Zentner ◽  
C. A. Campbell ◽  
F. Selles ◽  
B. G. McConkey ◽  
P. G. Jefferson ◽  
...  
Keyword(s):  
Soil Water ◽  
Water Use ◽  
Harvest Index ◽  
Crop Production ◽  
Water Control ◽  
Mineral N ◽  
Nitrogen Yield ◽  
Cropping Frequency ◽  
N Yield ◽  
N Concentration

Producers in the semiarid Canadian prairies rely on frequent summerfallowing (F) to conserve water, control weed infestations, and maximize soil mineral N reserves, but this practice often results in soil degradation. A crop rotation experiment was initiated in 1987 on a medium-textured, Orthic Brown Chernozem at Swift Current, Saskatchewan, to determine the most ideal cropping frequency for wheat in this region and whether a fixed rotation such as fallow-wheat (Triticum aestivum L.) - wheat (F-W-W) or F-W-W-W would be more effective than flexible rotations in which fallowing is decided each spring based on criteria such as available soil water (if water), or the need to control perennial weed infestations (if weeds). The study also compared the production of traditional Canada Western Red Spring (CWRS) wheat class with the newer higher-yielding (Hy), Canada Prairie Spring (CPS) wheat class. We analyzed results of six rotations over the first 12 yr of the study. The rotations included F-W-W, F-W-W-W, F-Hy-Hy, Continuous wheat (Cont W), Cont W (if weeds), and Cont W (if water). Reduced tillage management was used and stubble was cut tall to enhance snowtrap. Fertilizer N was applied based on soil tests and fertilizer P was applied based on the general recommendations for the region. Over the 1988–1999 period, weather conditions were generally favourable and yields were above average for this region. Canada Prairie Spring wheat outyielded CWRS by 32% when grown on fallow and by 17% when grown on stubble; however, straw yields of the two wheat classes were similar on fallow and CPS was 11% less than CWRS on stubble. Harvest index (HI) averaged 44% for CPS and 37% for CWRS wheat. Water use efficiency for CWRS wheat grown on fallow averaged 7.2 kg ha-1 mm-1 and for CPS 9.4; when grown on stubble the respective values were 6.3 and 7.5 kg ha-1 mm-1. Grain N concentration for CWRS was slightly higher for wheat grown on fallow (25.7 g kg-1) than on stubble (24.5 g kg-1), but was similar for CPS wheat on grown on fallow and stubble (21.9 g kg-1). Straw N concentration averaged 3.8 g kg-1 for CWRS and 4.4 g kg-1 for CPS. Nitrogen yield for grain from CPS was 9% greater than from CWRS when grown on fallow, but there was no effect of wheat class when grown on stubble. Nitrogen yield of CPS straw was 15% greater than for CWRS when grown on fallow, but on stubble N yield was generally not affected by wheat class. Nitrogen harvest index (NHI) averaged about 80% for both wheat classes, whether grown on fallow or stubble. On a rotation basis, grain produced with F-W-W was 1502 kg ha-1 yr-1. The F-W-W-W and Cont W (if weeds) rotations produced 9% more grain than F-W-W, while Cont W (if water) produced 24% more, F-Hy-Hy produced 26% more, and Cont W produced 30% more than F-W-W. Nitrogen production in the grain, straw and aboveground plant material was lowest in F-W-W, highest in Cont W, and intermediate for other rotations. Although the economic and soil quality assessments have yet to be completed, a preliminary conclusion based on crop production characteristics alone suggests that a flexible cropping system in which available soil water in spring is used as the determining criterion is superior to a fixed F-W-W or F-W-W-W rotation. Key words: Yield, N concentration, N yield, water deficit, wheat classes, regressions

scholarly journals Effects of Increasing Nitrogen Content on Process Stability and Reactor Performance in Anaerobic Digestion

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1139 ◽  
Author(s):  
Ievgeniia Morozova ◽  
Nadiia Nikulina ◽  
Hans Oechsner ◽  
Johannes Krümpel ◽  
Andreas Lemmer
Keyword(s):  
Anaerobic Digestion ◽  
Conversion Efficiency ◽  
Stable Process ◽  
Process Stability ◽  
Reactor Performance ◽  
High Nitrogen ◽  
Fresh Matter ◽  
Feeding Regime ◽  
N Concentration ◽  
Feeding Regimes

The aim of this study was to analyse the effect of different nitrogen increase rates in feedstock on the process stability and conversion efficiency in anaerobic digestion (AD). The research was conducted in continuously stirred tank reactors (CSTR), initially filled with two different inocula: inocula #1 with low and #2 with high nitrogen (N) concentrations. Three N feeding regimes were investigated: the “0-increase” feeding regime with a constant N amount in feeding and the regimes “0.25-increase” and “0.5-increase” where the N concentrations in feedstock were raised by 0.25 and 0.5 g·kg−1, respectively, related to fresh matter (FM) every second week. The N concentration inside the reactors increased according to the feeding regimes. The levels of inhibition (Inhibition) in specific methane yields (SMY), related to the conversion efficiency of the substrates, were quantified. At the N concentration in digestate of 10.82 ± 0.52 g·kg−1 FM measured in the reactors with inoculum #2 and “0.5-increase” feeding regime, the level of inhibition was equal to 38.99% ± 14.99%. The results show that high nitrogen increase rates in feeding regime are negatively related to the efficiency of the AD process, even if low volatile fatty acid (VFA) concentrations indicate a stable process.

EFFECTS OF TOPSOIL LOSS AND INTENSIVE CROPPING ON SOIL PROPERTIES RELATED TO THE CROP PRODUCTION POTENTIAL OF A PODZOLIC GREY LUVISOL

1984 ◽  
Vol 64 (4) ◽  
pp. 533-543 ◽  
Author(s):  
J. M. SADLER
Keyword(s):  
Crop Production ◽  
Storage Capacity ◽  
Potato Production ◽  
Production Potential ◽  
Water Storage Capacity ◽  
Nitrogen Levels ◽  
Ap Horizon ◽  
Intensive Cropping ◽  
Mineralizable Nitrogen ◽  
Intact Soil

A 5-yr field study was conducted at Charlottetown, Prince Edward Island to determine the effect of losses of topsoil and organic matter likely to accrue from intensive potato production on the crop production potential of a loam to fine sandy loam Podzolic Grey Luvisol representative of major soil types used for potato production on P.E.I. The top 7.5 or 15 cm of the original 20-cm-thick Ap horizon was removed from strips on either side of a control (intact soil) strip. These strips were cropped under a 5-yr potato-barley rotation. Soil-loss treatments reduced the organic carbon content of the new 20-cm-thick Ap horizons formed by tillage by 9.4 and 37%, respectively, from 51.3 tonnes (ha∙20 cm)−1 in the original Ap horizon. Similarly, mineralizable nitrogen levels were reduced initially by 21 and 64%, respectively, compared with the intact soil. During the subsequent 2 yr, mineralizable nitrogen levels in the Ap horizons of the intact and minus 7.5-cm strips fell by 35%. Soil-loss treatments had no effect on Ap horizon texture, porosity, or bulk density. However, losses of topsoil reduced the soil’s capacity to store plant-available water (33 kPa – 1500 kPa) within the rooting zone above a Bt, horizon (bulk density 1.67 tonnes∙m−3) by 1.3 and 3.4 cm of water, respectively, from 9.8 cm for the intact soil. Rainfall patterns on P.E.I. suggest that such reductions in water storage capacity may reduce the soil’s crop production potential in 2 out of 5 yr. Key words: Topsoil loss, intensive cropping, Luvisol, organic carbon, mineralizable nitrogen, water storage capacity

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