scholarly journals Nitrogen Requirements of Fresh-market Tomatoes on Hairy Vetch and Black Polyethylene Mulch

HortScience ◽  
1997 ◽  
Vol 32 (2) ◽  
pp. 217-221 ◽  
Author(s):  
Aref A. Abdul-Baki ◽  
John R. Teasdale ◽  
Ronald F. Korcak
Keyword(s):  
Above Ground Biomass ◽  
Fertilizer N ◽  
Hairy Vetch ◽  
Fresh Market ◽  
N Content ◽  
Ground Biomass ◽  
Leaf N Content ◽  
N Rates ◽  
Polyethylene Mulch ◽  
Leaf N

A 3-year experiment was conducted to determine the optimum fertilizer N requirements of fresh-market tomato (Lycopersicon esculentum Mill.) `Sunbeam' grown on a hairy vetch (Vicia villosa Roth.) or black polyethylene mulch. In 1993 and 1994, four rates of fertilizer N (0, 56, 112, and 168 kg·ha-1) as water-soluble NH4NO3 were applied in 14 equal applications through the trickle irrigation system starting 1 week after planting. Four additional rates (224, 280, 336, and 392 kg·ha-1) were applied in 1995 to assess the plant response to supra-optimal levels of N. Hairy vetch produced 3.3–4.5 t·ha-1 of above-ground biomass and a total N content of 126–169 kg·ha-1 in the above-ground biomass. Leaf N content at 7 weeks after transplanting of tomatoes correlated positively with yield from black polyethylene but did not correlate with yield from the hairy vetch plots where leaf N content was optimal at all N rates. Predicted tomato yields were higher for the hairy vetch than for the black polyethylene treatment at all applied N rates in all years. Tomatoes grown in black polyethylene required N at 130 to 144 kg·ha-1 to achieve yields equivalent to those grown following unfertilized hairy vetch. Tomato yield increased in response to applied N in both mulches in all 3 years; optimum N rates of 89 and 190 kg·ha-1 in hairy vetch and black polyethylene, respectively, were predicted by a linear plateau model, and 124 and 295 kg·ha-1 by a quadratic plateau model. The linear plateau model is recommended because it would allow less N to become available for runoff and leaching.

scholarly journals Spad index for diagnosis of nitrogen status in ‘Esmeralda’ peach

2021 ◽  
Vol 43 (1) ◽  
Author(s):  
Jorge Atílio Benati ◽  
Gilberto Nava ◽  
Newton Alex Mayer
Keyword(s):  
Block Design ◽  
Middle Part ◽  
Full Bloom ◽  
N Content ◽  
Randomized Block Design ◽  
Positive Linear Correlation ◽  
Leaf N Content ◽  
N Rates ◽  
Spad Readings ◽  
Leaf N

Abstract The objective of this research was to evaluate the technical feasibility of SPAD index in the diagnosis of N status in ‘Esmeralda’ peach. The field trial, with five N rates applied to the soil (0, 40, 80, 120 and 160 kg ha-1 of N as urea form) was conducted in a randomized block design with four replications. During the years 2014, 2015, 2016 and 2017, SPAD readings were carried out with a Minolta SPAD-502 chlorophyll meter, in the leaf middle part, in 40 leaves per plot. The leaf N content determination was performed in CHN-S Elemental Analyzer. SPAD index and leaf N content increased in a linear way in response to increasing N rates applied in soil. There was a positive linear correlation between SPAD index and N concentration in leaves (0.652; 0.756; 0.762 and 0.767, p<0.05). SPAD index can be used for nutritional N diagnosis purpose in peach when readings are taken between the 13th and 15th weeks after full bloom. In the range between 39 and 49, the SPAD index indicates the leaf N content is included in “normal” class (33 – 45 g kg-1) of agronomic interpretation for the States of Rio Grande do Sul and Santa Catarina, Brazil.

scholarly journals Sweetpotato Growth and Nitrogen Content Following Nitrogen Application and Inoculation with Azospirillum

HortScience ◽  
1990 ◽  
Vol 25 (7) ◽  
pp. 758-759 ◽  
Author(s):  
Desmond G. Mortley ◽  
Walter A. Hill
Keyword(s):  
Root Growth ◽  
Nitrogen Content ◽  
Ipomoea Batatas ◽  
Storage Root ◽  
Nitrogen Application ◽  
Fertilizer N ◽  
Marketable Yield ◽  
N Content ◽  
N Rates ◽  
Leaf N

The influence of Azospirillum inoculation on sweetpotato Ipomoea batatas (L.) Lam.] was evaluated in combination with fertilizer N rates of 0, 40, and 80 kg·ha-1. Plants were inoculated with 5 ml of the inoculant at 2, 4, and 6 weeks after transplanting. Inoculation increased total and marketable yield by 12% and 17%, respectively, in 1984 and 5% and 22%, respectively in 1985. Higher storage root yields were accompanied by lower foliage yields, which suggested the inoculant may enhance storage root growth at the expense of foliage growth on soils with low to moderate N levels (40 to 80 kg·ha-1). Storage root N (1984 and 1985) and leaf N (1985) were higher for 40 kg N/ha with inoculation than with inoculation alone (treatments 4 vs. 2), which suggested that Azospirillum plus fertilizer N increased the N content of the plants.

scholarly journals Use of an Active Canopy Sensor and SPAD Chlorophyll Meter to Quantify Geranium Nitrogen Status

HortScience ◽  
2012 ◽  
Vol 47 (1) ◽  
pp. 45-50 ◽  
Author(s):  
Yun-wen Wang ◽  
Bruce L. Dunn ◽  
Daryl B. Arnall ◽  
Pei-sheng Mao
Keyword(s):  
Green Leaf ◽  
Fertilizer Treatment ◽  
N Content ◽  
Chlorophyll Meter ◽  
N Concentration ◽  
Flower Traits ◽  
Leaf N Content ◽  
N Rates ◽  
N Status ◽  
Leaf N

This research was conducted to investigate the potentials of normalized difference vegetation index (NDVI), a Soil-Plant Analyses Development (SPAD) chlorophyll meter, and leaf nitrogen (N) concentration [% dry matter (DM)] for rapid determination of N status in potted geraniums (Pelargonium ×hortorum). Two F1 cultivars were chosen to represent a dark-green leaf cultivar, Horizon Deep Red, and a light-green leaf cultivar, Horizon Tangerine, and were grown in a soilless culture system. All standard 6-inch (15.24-cm) pots filled with a medium received an initial top-dress application of 5 g controlled-release fertilizer (15N–9P–12K), then plants were supplemented with additional N in the form of urea at 0, 50, 100, or 200 mg·L−1 N every few days to produce plants ranging from N-deficient to N-sufficient. The NDVI readings of individual plants from a NDVI pocket sensor developed by Oklahoma State University were collected weekly until the flowering stage. Data on flower traits, including number of pedicels (NOP), number of full umbels per pot (NOFU), total number of flowers per pot (TNF), number of flowers per pedicel (NOF), and inflorescences diameter (IFD), were collected 3 months after initial fertilizer treatment. After measuring flower traits, pedicels were removed from each pot, and SPAD value, NDVI, and leaf N concentration (g·kg−1 DM) were measured simultaneously. Cultivar and N rate significantly affected all but two flower and one N status parameters studied. The coefficient of determination R2 showed that NOP, NOFU, and TNF traits were more related to the N rates and the status parameters studied for ‘Horizon Tangerine’ than for ‘Horizon Deep Red’. For the latter cultivar, NOP and TNF traits were highly related to NDVI and SPAD values than N rates and leaf N content parameters. Correlation analysis indicated that the NDVI readings (R2 = 0.848 and 0.917) and SPAD values (R2 = 0.861 and 0.950) were significantly related to leaf N content (g·kg−1 DM) between cultivars. However, sensitivity of the NDVI and chlorophyll values to N application rate in geranium was slightly less than leaf N content. Strong correlations (R2 = 0.974 and 0.979, respectively) between NDVI and SPAD values were found within cultivars. The results demonstrated NDVI and SPAD values can be used to estimate N status in geranium. Because the pocket NDVI sensor will be cheaper than the SPAD unit, it has an advantage in determining N content in potted ornamentals.

scholarly journals A novel approach for nitrogen diagnosis of wheat canopies digital images by mobile phones based on histogram

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xin Qi ◽  
Yanan Zhao ◽  
Yufang Huang ◽  
Yang Wang ◽  
Wei Qin ◽  
...  
Keyword(s):  
Neural Network ◽  
Mobile Phones ◽  
Mean Value ◽  
Wheat Cultivars ◽  
N Content ◽  
Color Parameters ◽  
The Neural Network ◽  
The Mean ◽  
Leaf N Content ◽  
Leaf N

AbstractThe accurate and nondestructive assessment of leaf nitrogen (N) is very important for N management in winter wheat fields. Mobile phones are now being used as an additional N diagnostic tool. To overcome the drawbacks of traditional digital camera diagnostic methods, a histogram-based method was proposed and compared with the traditional methods. Here, the field N level of six different wheat cultivars was assessed to obtain canopy images, leaf N content, and yield. The stability and accuracy of the index histogram and index mean value of the canopy images in different wheat cultivars were compared based on their correlation with leaf N and yield, following which the best diagnosis and prediction model was selected using the neural network model. The results showed that N application significantly affected the leaf N content and yield of wheat, as well as the hue of the canopy images and plant coverage. Compared with the mean value of the canopy image color parameters, the histogram could reflect both the crop coverage and the overall color information. The histogram thus had a high linear correlation with leaf N content and yield and a relatively stable correlation across different growth stages. Peak b of the histogram changed with the increase in leaf N content during the reviving stage of wheat. The histogram of the canopy image color parameters had a good correlation with leaf N content and yield. Through the neural network training and estimation model, the root mean square error (RMSE) and the mean absolute percentage error (MAPE) of the estimated and measured values of leaf N content and yield were smaller for the index histogram (0.465, 9.65%, and 465.12, 5.5% respectively) than the index mean value of the canopy images (0.526, 12.53% and 593.52, 7.83% respectively), suggesting a good fit for the index histogram image color and robustness in estimating N content and yield. Hence, the use of the histogram model with a smartphone has great potential application in N diagnosis and prediction for wheat and other cereal crops.

scholarly journals Effects of ontogenetic stage and leaf age on leaf functional traits and the relationships between traits in Pinus koraiensis

2021 ◽  
Author(s):  
Meng Ji ◽  
Guangze Jin ◽  
Zhili Liu
Keyword(s):  
Significant Positive Correlation ◽  
Leaf Age ◽  
Leaf Traits ◽  
Ontogenetic Stage ◽  
Pinus Koraiensis ◽  
Mature Trees ◽  
N Content ◽  
Ontogenetic Stages ◽  
Leaf N Content ◽  
Leaf N

AbstractInvestigating the effects of ontogenetic stage and leaf age on leaf traits is important for understanding the utilization and distribution of resources in the process of plant growth. However, few studies have been conducted to show how traits and trait-trait relationships change across a range of ontogenetic stage and leaf age for evergreen coniferous species. We divided 67 Pinus koraiensis Sieb. et Zucc. of various sizes (0.3–100 cm diameter at breast height, DBH) into four ontogenetic stages, i.e., young trees, middle-aged trees, mature trees and over-mature trees, and measured the leaf mass per area (LMA), leaf dry matter content (LDMC), and mass-based leaf nitrogen content (N) and phosphorus content (P) of each leaf age group for each sampled tree. One-way analysis of variance (ANOVA) was used to describe the variation in leaf traits by ontogenetic stage and leaf age. The standardized major axis method was used to explore the effects of ontogenetic stage and leaf age on trait-trait relationships. We found that LMA and LDMC increased significantly and N and P decreased significantly with increases in the ontogenetic stage and leaf age. Most trait-trait relationships were consistent with the leaf economic spectrum (LES) at a global scale. Among them, leaf N content and LDMC showed a significant negative correlation, leaf N and P contents showed a significant positive correlation, and the absolute value of the slopes of the trait-trait relationships showed a gradually increasing trend with an increasing ontogenetic stage. LMA and LDMC showed a significant positive correlation, and the slopes of the trait-trait relationships showed a gradually decreasing trend with leaf age. Additionally, there were no significant relationships between leaf N content and LMA in most groups, which is contrary to the expectation of the LES. Overall, in the early ontogenetic stages and leaf ages, the leaf traits tend to be related to a "low investment-quick returns" resource strategy. In contrast, in the late ontogenetic stages and leaf ages, they tend to be related to a "high investment-slow returns" resource strategy. Our results reflect the optimal allocation of resources in Pinus koraiensis according to its functional needs during tree and leaf ontogeny.

scholarly journals Variation of nitric oxide emission potential in plants: a possible link to leaf N content and net photosynthetic activity

2014 ◽  
Vol 8 (3) ◽  
pp. 313-320 ◽  
Author(s):  
Juan Chen ◽  
Chao Wang ◽  
Fei-Hua Wu ◽  
Wen-Hua Wang ◽  
Ting-Wu Liu ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Photosynthetic Activity ◽  
N Content ◽  
Nitric Oxide Emission ◽  
Leaf N Content ◽  
Leaf N

scholarly journals Dissection of hyperspectral reflectance to estimate nitrogen and chlorophyll contents in tea leaves based on machine learning algorithms

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hiroto Yamashita ◽  
Rei Sonobe ◽  
Yuhei Hirono ◽  
Akio Morita ◽  
Takashi Ikka
Keyword(s):  
Machine Learning ◽  
Learning Algorithms ◽  
Visible Region ◽  
Machine Learning Algorithms ◽  
Hyperspectral Reflectance ◽  
N Content ◽  
Green Leaves ◽  
Leaf N Content ◽  
N Status ◽  
Leaf N

Abstract Nondestructive techniques for estimating nitrogen (N) status are essential tools for optimizing N fertilization input and reducing the environmental impact of agricultural N management, especially in green tea cultivation, which is notably problematic. Previously, hyperspectral indices for chlorophyll (Chl) estimation, namely a green peak and red edge in the visible region, have been identified and used for N estimation because leaf N content closely related to Chl content in green leaves. Herein, datasets of N and Chl contents, and visible and near-infrared hyperspectral reflectance, derived from green leaves under various N nutrient conditions and albino yellow leaves were obtained. A regression model was then constructed using several machine learning algorithms and preprocessing techniques. Machine learning algorithms achieved high-performance models for N and Chl content, ensuring an accuracy threshold of 1.4 or 2.0 based on the ratio of performance to deviation values. Data-based sensitivity analysis through integration of the green and yellow leaves datasets identified clear differences in reflectance to estimate N and Chl contents, especially at 1325–1575 nm, suggesting an N content-specific region. These findings will enable the nondestructive estimation of leaf N content in tea plants and contribute advanced indices for nondestructive tracking of N status in crops.

Concentration of N, P and K in leaves, straw and grain of wheat and barley as influenced by N and P fertilizers under semi-arid conditions

1980 ◽  
Vol 94 (3) ◽  
pp. 551-556 ◽  
Author(s):  
P. I. Orphanos ◽  
V. D. Krentos
Keyword(s):  
Durum Wheat ◽  
Fertilizer N ◽  
Wheat Grain ◽  
N Content ◽  
Arid Conditions ◽  
P Content ◽  
N Rates ◽  
Semi Arid ◽  
P Fertilizers

SummaryThe N, P and K contents of leaves, straw and grain of the durum wheat Kyperounda, the aestivum wheat Pitic 62 and Athenais barley under semi-arid conditions (150–400 mm) as influenced by N and P fertilizers are reported (N rates: 0–105 kg/ha; P rates: 0–26 kg/ha).Fertilizer N increased linearly the N content of the leaves, straw and grain as well as the K content of leaves and straw, but slightly reduced P content of the grain. Straw K content was increased relatively more in Athenais barley. Such increases of N and K content occurred beyond the N rates giving maximum grain and sheaf yields. Increased K content of the straw resulting from fertilizer N is wasteful where the straw is removed, and accelerates depletion of soil K. Durum wheat grain containing more than 2–8% N showed less than 6% yellow berry (mealy grains) but at lower N contents yellow berry could be high or low depending on location.Fertilizer P did not significantly influence the P content of any of the components analysed even though it increased grain and straw yields, particularly in the drier years.

Variability in physiological responses of Venezuelan cacao to drought

2020 ◽  
Vol 56 (3) ◽  
pp. 407-421 ◽  
Author(s):  
Wilmer Tezara ◽  
Gabriela Pereyra ◽  
Eleinis Ávila-Lovera ◽  
Ana Herrera
Keyword(s):  
Chlorophyll Content ◽  
Water Use ◽  
Isotopic Ratio ◽  
Water Status ◽  
Common Garden ◽  
Photochemical Activity ◽  
Total Soluble Protein ◽  
N Content ◽  
Leaf N Content ◽  
Leaf N

AbstractIn order to assess the response of cocoa trees to drought, changes in water status, gas exchange, leaf carbon isotopic ratio (δ13C), photochemical activity, and leaf N and chlorophyll content during the rainy and dry season were measured in 31 Venezuelan cocoa clones (17 Trinitarios, 6 Criollos, and 8 Modern Criollos) grown in a common garden. Drought caused a 40% decrease in water potential (ψ) in all but the Modern Criollos, and a reduction in net photosynthetic rate (A) and stomatal conductance (gs) without an increase in instantaneous water use efficiency (WUE) in 93% of clones, and an increase in δ13C (long-term WUE) in 74% of clones; these responses suggest differences in tolerance to drought among clones. A positive correlation between A and both gs and leaf N content was found for all genotypes. Leaf N content, chlorophyll content, and photochemical activity were reduced during drought, suggesting that metabolism was also inhibited. The best performance during drought was shown by Modern Criollos with the highest WUE, while five Trinitario clones seemed to be less sensitive to drought, since neither chlorophyll, N, total soluble protein concentration, nor gs changed with drought, indicating that those Trinitario clones, with lower A, have a conservative water use. Modern Criollos showed no reductions in either ψ or gs; A remained unchanged, as did WUE, which was the highest, suggesting that these clones would be more successful in environments with low water availability. Our results indicate large variation in physiological response to drought over a range of parameters, suggesting possible differences in tolerance among clones.

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