Evaluation of Image-Based Phenotyping Methods for Measuring Water Yam (Dioscorea alata L.) Growth and Nitrogen Nutritional Status under Greenhouse and Field Conditions

New management practices must be developed to improve yam productivity. By allowing non-destructive analyses of important plant traits, image-based phenotyping techniques could help developing such practices. Our objective was to determine the potential of image-based phenotyping methods to assess traits relevant for tuber yield formation in yam grown in the glasshouse and in the field. We took plant and leaf pictures with consumer cameras. We used the numbers of image pixels to derive the shoot biomass and the total leaf surface and calculated the ‘triangular greenness index’ (TGI) which is an indicator of the leaf chlorophyll content. Under glasshouse conditions, the number of pixels obtained from nadir view (view from the top) was positively correlated to shoot biomass, and total leaf surface, while the TGI was negatively correlated to the SPAD values and nitrogen (N) content of diagnostic leaves. Pictures taken from nadir view in the field showed an increase in soil surface cover and a decrease in TGI with time. TGI was negatively correlated to SPAD values measured on diagnostic leaves but was not correlated to leaf N content. In conclusion, these phenotyping techniques deliver relevant results but need to be further developed and validated for application in yam.

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Evaluation of Image-Based Phenotyping Methods for Measuring Water Yam (Dioscorea alata L.) Growth and Nitrogen Nutritional Status under Greenhouse and Field Conditions

10.20944/preprints202012.0542.v1 ◽

2020 ◽

Author(s):

Emmanuel Frossard ◽

Frank Liebisch ◽

Valérie Kouamé Hgaza ◽

Delwendé Innocent Kiba ◽

Norbert Kirchgessner ◽

...

Keyword(s):

Nutritional Status ◽

Management Practices ◽

Leaf Surface ◽

Plant Traits ◽

Soil Surface ◽

Field Conditions ◽

Shoot Biomass ◽

N Content ◽

Plant Nitrogen ◽

Total Leaf

Management practices must be developed to improve yam production sustainability. Image-based phenotyping techniques could help developing such practices based on non-destructive analyses of important plant traits. Our objective was to determine the potential of image-based phenotyping methods to assess traits relevant for tuber yield formation in yam grown in glasshouse and field. We took plant and leaf pictures with consumer cameras. We used the numbers of image pixels to derive the shoot biomass and the total leaf surface and calculated the ‘triangular greenness index’ (TGI) which is an indicator of the plant nitrogen (N) nutritional status. Under glasshouse conditions, the number of pixels obtained from nadir view (image taken top down) was positively correlated to the shoot biomass, and the total leaf surface, while the TGI was negatively correlated to the N content of diagnostic leaves. Under field conditions, pictures taken from the nadir view showed an increase in soil surface cover and a decrease in TGI with time. TGI was negatively correlated to SPAD measured on specific leaves but was not correlated to the N content of these leaves. In conclusion, these phenotyping techniques deliver relevant results but need to be further developed and validated for application in yam.

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The Performances of Hyperspectral Sensors for Proximal Sensing of Nitrogen Levels in Wheat

Sensors ◽

10.3390/s20164550 ◽

2020 ◽

Vol 20 (16) ◽

pp. 4550

Author(s):

Huajian Liu ◽

Brooke Bruning ◽

Trevor Garnett ◽

Bettina Berger

Keyword(s):

Hyperspectral Imaging ◽

High Throughput ◽

Management Practices ◽

Leaf Tissue ◽

Plant Phenotyping ◽

Proximal Sensing ◽

N Content ◽

Hyperspectral Sensors ◽

Wheat Leaves ◽

Non Destructive

The accurate and high throughput quantification of nitrogen (N) content in wheat using non-destructive methods is an important step towards identifying wheat lines with high nitrogen use efficiency and informing agronomic management practices. Among various plant phenotyping methods, hyperspectral sensing has shown promise in providing accurate measurements in a fast and non-destructive manner. Past applications have utilised non-imaging instruments, such as spectrometers, while more recent approaches have expanded to hyperspectral cameras operating in different wavelength ranges and at various spectral resolutions. However, despite the success of previous hyperspectral applications, some important research questions regarding hyperspectral sensors with different wavelength centres and bandwidths remain unanswered, limiting wide application of this technology. This study evaluated the capability of hyperspectral imaging and non-imaging sensors to estimate N content in wheat leaves by comparing three hyperspectral cameras and a non-imaging spectrometer. This study answered the following questions: (1) How do hyperspectral sensors with different system setups perform when conducting proximal sensing of N in wheat leaves and what aspects have to be considered for optimal results? (2) What types of photonic detectors are most sensitive to N in wheat leaves? (3) How do the spectral resolutions of different instruments affect N measurement in wheat leaves? (4) What are the key-wavelengths with the highest correlation to N in wheat? Our study demonstrated that hyperspectral imaging systems with satisfactory system setups can be used to conduct proximal sensing of N content in wheat with sufficient accuracy. The proposed approach could reduce the need for chemical analysis of leaf tissue and lead to high-throughput estimation of N in wheat. The methodologies here could also be validated on other plants with different characteristics. The results can provide a reference for users wishing to measure N content at either plant- or leaf-scales using hyperspectral sensors.

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

Scientific Reports ◽

10.1038/s41598-021-92431-5 ◽

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.

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

Journal of Forestry Research ◽

10.1007/s11676-021-01308-w ◽

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.

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Trace Metal Distribution and Mobility in Soils after Silvicultural Thinning and Burning

Journal of Agricultural Science ◽

10.5539/jas.v9n5p83 ◽

2017 ◽

Vol 9 (5) ◽

pp. 83

Author(s):

Ngowari Jaja ◽

Monday Mbila ◽

Yong Wang

Keyword(s):

Trace Metal ◽

Management Practices ◽

Soil Depth ◽

Anthropogenic Activities ◽

Block Design ◽

Forest Health ◽

Soil Surface ◽

Parent Material ◽

Design Experiment ◽

Randomized Block Design

Silvicultural thinning and burning are common management practices that are widely used to address ecosystem problems such as tree stocking and general forest health. However, high-severity fire has variable effects on soils, resulting in damages which are directly or indirectly reflected on the trace metal chemistry of the soil. This study was conducted to evaluate the trace metal variation at the Bankhead National Forest in Northern Alabama following the silvicultural thinning and burning. The experimental site had treatments consisting of two burning patterns and three levels of thinning as part of an overall treatment of three burning patterns and three levels of thinning applied to nine treatment plots to fit a completely randomized block design experiment. Four treatments sites were used for this study and samples were collected from soil profile pits excavated at representative plots within each treatment. The samples were analyzed for trace metals-As, Cu, Ni, Zn and Pb-using Perkin Elmer 2100 ICP-OES. Post treatment samples indicated that the trace metal concentrations generally decreased with soil depth. Copper, Ni, and Zn at the Pre-burn site gradually increased with depth to a maximum concentration at about 50 cm below the soil surface. Arsenic in the surface horizons increased by 156% in the burn-only sites, 54% in the thin-only treatment, 30% for the burn and thin treatments. Such differences were unlikely due to differences in the geochemistry of the parent material, but likely due to anthropogenic activities and possibly the forest management practices in question.

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THE ROLE OF FLAG LEAVES AND AWNS IN THE FORMATION OF WINTER WHEAT PRODUCTIVITY (REVIEW)

Grain Economy of Russia ◽

10.31367/2079-8725-2018-58-4-32-34 ◽

2018 ◽

pp. 32-34 ◽

Cited By ~ 1

Author(s):

S. N. Gromova ◽

P. I. Kostylev

Keyword(s):

Winter Wheat ◽

Leaf Surface ◽

Wheat Yield ◽

Complex Trait ◽

Genetic System ◽

Flag Leaves ◽

Grain Productivity ◽

Agricultural Yield ◽

Yield Formation

The article presents the results of the conducted analysis of research works about the effect of size of flag leaves and awns on winter wheat productivity. The genetic potential of the variety, which can be realized on the basis of its biologic characteristics largely influences on its productivity. Productivity is a complex trait that is controlled by a complex genetic system closely connected with many factors of environment. The size and duration of assimilation surface are the most important components of biologic and agricultural yield of wheat. Many researchers showed that the amount and duration of photosynthesis by leaf surface are the main factors limiting productivity in the definite conditions of growing, and the size of leaf surface correlates with grain productivity. Photosynthetic parts of winter wheat include not only leaves, but also stems, heads, awns, etc. The conducted analysis of the literature showed that there is no consensus on the effect of flag leaves on wheat yield formation. Therefore it’s necessary to fulfill the study and evaluation of the part of flag leaves and awns in the formation of winter soft wheat productivity in the Rostov region.

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Study on Physiological Parameters and Economics of Rice Cultivation under Different Establishment Methods and Water Management Practices

Current Journal of Applied Science and Technology ◽

10.9734/cjast/2020/v39i2030816 ◽

2020 ◽

pp. 123-131

Author(s):

S. Selvakumar ◽

S. Sakthivel ◽

Akihiko Kamoshita ◽

R. Babu ◽

S. Thiyageshwari ◽

...

Keyword(s):

Water Management ◽

Field Experiment ◽

Water Level ◽

Water Scarcity ◽

Tamil Nadu ◽

Management Practices ◽

Irrigation Management ◽

Management Strategies ◽

Soil Surface ◽

Physiological Parameters

A field experiment was conducted at Tamil Nadu Agricultural University, Agricultural College and Research Institute, Madurai, Tamil Nadu, India, during summer 2019 to study about the changes in physiological parameters of rice under various establishment and water management strategies and to find out the suitable method of rice establishment and irrigation management practices for tank irrigated command areas during water scarcity situation. Field experiment comprised of four establishment methods in combination with four irrigation management strategies. Medium duration fine grain rice variety TKM 13 was used for the study. Results of the study revealed that machine transplanting under unpuddled soil combined with irrigation after formation of hairline crack recorded improved physiological parameters and yield. It was on par with machine transplanting under unpuddled soil combined with irrigation when water level reaches 5 cm below soil surface. Higher gross return, net return and B:C ratio were observed with machine transplanting under unpuddled soil combined with irrigation after formation of hairline crack. This was followed by machine transplanting under unpuddled soil combined with irrigation when water level reaches 5 cm below soil. Hence, the result of study concluded that machine transplanting under unpuddled soil combined with irrigation when water level reaches 5 cm below soil surface can be recommended as the suitable technology for the farmers of tank irrigated command area to get higher return with minimum use of resources under water scarcity situation.

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Sugar cane straw left in the field during harvest: decomposition dynamics and composition changes

Soil Research ◽

10.1071/sr16310 ◽

2017 ◽

Vol 55 (8) ◽

pp. 758 ◽

Cited By ~ 11

Author(s):

José G. de A. Sousa ◽

Maurício R. Cherubin ◽

Carlos E. P. Cerri ◽

Carlos C. Cerri ◽

Brigitte J. Feigl

Keyword(s):

Sugar Cane ◽

Management Practices ◽

Soil Surface ◽

Straw Decomposition ◽

N Losses ◽

No Removal ◽

Bioenergy Production ◽

Starting Point ◽

Decomposition Dynamics ◽

Straw Incorporation

The understanding of sugar cane straw decomposition dynamics is essential for defining a sustainable rate of straw removal for bioenergy production without jeopardising soil functioning and other ecosystem services. Thus, we conducted a field study in south-east Brazil over 360 days to evaluate sugar cane straw decomposition and changes in its composition as affected by increasing initial straw amounts and management practices. The sugar cane straw amounts tested were: (1) 3.5 Mg ha–1 (i.e. 75% removal); (2) 7.0 Mg ha–1 (i.e. 50% removal); (3) 14.0 Mg ha–1 (i.e. no removal); and (4) 21.0 Mg ha–1 (i.e. no removal plus 50% of the extra straw left on the field). In addition, two management practices were studied for the reference straw amount (14 Mg ha–1), namely straw incorporation into the soil and irrigation with vinasse. The findings showed that dry mass (DM) loss increased logarithmically as a function of the initial amount left on the soil surface. An exponential curve efficiently described straw DM and C losses, in which more readily decomposable compounds are preferably consumed, leaving compounds that are more recalcitrant in the late stages of decomposition. After 1 year of decomposition, net straw C and N losses reached approximately 70% and 23% respectively for the highest initial straw amounts. Straw incorporation in the soil significantly accelerated the decomposition process (i.e. 86% DM loss after 1 year) compared with maintenance of straw on the soil surface (65% DM loss after 1 year), whereas irrigation with vinasse had little effect on decomposition (60% DM loss after 1 year). We conclude that straw decomposition data are an essential starting point for a better understanding of the environmental effects caused by straw removal and other management practices in sugar cane fields. This information can be used in models and integrated assessments towards a more sustainable sugar cane straw management for bioenergy production.

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Nutrient Release Pattern and Greenhouse-Grown Swiss Chard Response to Biochar Inoculated with Vermicast

International Journal of Agronomy ◽

10.1155/2020/7852187 ◽

2020 ◽

Vol 2020 ◽

pp. 1-9

Author(s):

Lord Abbey ◽

Jinsheng Cai ◽

Lokanadha R. Gunupuru ◽

Mercy Ijenyo ◽

Ebenezer O. Esan ◽

...

Keyword(s):

Plant Growth ◽

Growth Response ◽

Leaf Surface ◽

Nutrient Release ◽

Principal Component ◽

Fresh Weight ◽

Total Leaf Area ◽

Total Leaf ◽

Swiss Chard ◽

Leaf Surface Area

A study was performed to assess nutrient release from biochar inoculated with solid vermicast (SVB), vermicast tea (VTB), deionized water (DWB), uninoculated biochar (Bioc), and Promix-BX (Pro-BX). The growth response of Swiss chard (Beta vulgaris subsp. vulgaris) cv. Rhubarb chard was also assessed. Comparatively, nutrients were released slowly from treatments SVB and VTB compared to the other treatments. The rate of nutrient release determined by total dissolved solids and electric conductivity from the Pro-BX was the highest. The trend for the plant growth components, total leaf surface area and leaf fresh weight at first harvest, was Pro-BX > Bioc > DWB = SVB > VTB. The only treatment that increased total leaf area and leaf fresh weight at the second harvest by approximately 1.02- and 1.88-fold was VTB. Leaf fresh weight was significantly reduced by approximately 0.33-fold for DWB, 0.28-fold for Bioc, and 0.70-fold for Pro-BX but was not altered by SVB at the second harvest as compared to the first harvest. A 2-dimensional principal component analysis (PCA) biplot confirmed that treatment Pro-BX increased plant growth components at the first harvest only. The locations of SVB and VTB on the PCA biplot confirmed their efficacies, which led to increases in the plant growth components at the second harvest. Overall, the VTB adsorbed more nutrients onto its surface that were slowly released to enhance the Swiss chard cv. Rhubarb chard plant growth at the second harvest. Further studies should consider microbial activities.

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