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

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

Agronomy ◽

10.3390/agronomy11020249 ◽

2021 ◽

Vol 11 (2) ◽

pp. 249

Author(s):

Emmanuel Frossard ◽

Frank Liebisch ◽

Valérie Kouamé Hgaza ◽

Delwendé Innocent Kiba ◽

Norbert Kirchgessner ◽

...

Keyword(s):

Management Practices ◽

Leaf Surface ◽

Plant Traits ◽

Soil Surface ◽

Shoot Biomass ◽

N Content ◽

Total Leaf ◽

Image Pixels ◽

Leaf N Content ◽

Yield Formation

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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Growth, Development, and Seed Biology of Feather Fingergrass (Chloris virgata) in Southern Australia

Weed Science ◽

10.1017/wsc.2016.33 ◽

2017 ◽

Vol 65 (3) ◽

pp. 413-425 ◽

Cited By ~ 6

Author(s):

The D. Ngo ◽

Peter Boutsalis ◽

Christopher Preston ◽

Gurjeet Gill

Keyword(s):

Seedling Emergence ◽

Soil Surface ◽

Summer Rainfall ◽

Management Program ◽

Field Conditions ◽

Shoot Biomass ◽

Base Temperature ◽

Weed Species ◽

Seed Biology ◽

Growth Development

Feather fingergrass is a major weed in agricultural systems in northern Australia and has now spread to southern Australia. To better understand the biology of this emerging weed species, its growth, development, and seed biology were examined. Under field conditions in South Australia, seedlings that emerged after summer rainfall events required 1,200 growing degree days from emergence to mature seed production and produced 700 g m−2shoot biomass. Plants produced up to 1,000 seeds panicle−1and more than 40,000 seeds plant−1, with seed weight ranging from 0.36 to 0.46 mg. Harvested seeds were dormant for a period of about 2 mo and required 5 mo of after-ripening to reach 50% germination. Freshly harvested seed could be released from dormancy by pretreatment with 564 mM sodium hypochlorite for 30 min. Light significantly increased germination. Seed could germinate over a wide temperature range (10 to 40 C), with maximum germination at 15 to 25 C. At 20 to 25 C, 50% germination was reached within 2.7 to 3.3 d, and the predicted base temperature to germinate was 2.1 to 3.0 C. The osmotic potential and NaCl concentration required to inhibit germination by 50% were −0.16 to −0.20 MPa and 90 to 124 mM, respectively. Seedling emergence was highest (76%) for seeds present on soil surface and was significantly reduced by burial at 1 (57%), 2 (49%), and 5 cm (9%). Under field conditions, seeds buried in the soil persisted longer than those left on the soil surface, and low spring–summer rainfall increased seed persistence. This study provides important information on growth, development, and seed biology of feather fingergrass that will contribute to the development of a more effective management program for this weed species in Australia.

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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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Response of winter wheat to prolonged waterlogging under outdoor conditions

The Journal of Agricultural Science ◽

10.1017/s0021859600036881 ◽

1981 ◽

Vol 97 (3) ◽

pp. 557-568 ◽

Cited By ~ 53

Author(s):

R. K. Belford

Keyword(s):

Winter Wheat ◽

Water Table ◽

Stem Elongation ◽

Soil Surface ◽

Root Production ◽

Or Efficiency ◽

Plant Nitrogen ◽

Stages Of Growth ◽

Nodal Root ◽

Waterlogging Treatment

SUMMARYThe response of winter wheat cv. Maris Huntsman to waterlogging was studied in two experiments in soil columns outdoors. Winter waterlogging treatments increased nodal root production and the proportion of aerenchyma within roots, but caused chlorosis and premature senescence of leaves, and decreased tillering. For all treatments, grain losses were much less than expected from the extent of tiller loss in winter; losses after single waterlogging events ranged from 2% (after 47 days with the water-table at 5 cm) to 16% (after 80 days with the water-table at the soil surface). Yield losses after three waterloggings at the seedling, tillering and stem elongation stages of growth were additive, and totalled 19%. In many treatments, grain loss was associated with lighter individual grain weights, suggesting that the size of the root system or efficiency of water and nutrient uptake by roots at the later stages of growth may have been less after earlier waterlogging. The importance of nitrogen fertilizer in maintaining a satisfactory plant nitrogen status was shown when nitrogen was with held before a 3-week waterlogging treatment during stem elongation; tiller and floret survival was subsequently greatly restricted and grain yields decreased 22% below those of plants waterlogged at the same stage of growth but supplied with nitrogen.

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EFFECT OF CANOPY AND INCORPORATION ON METRIBUZIN PERSISTENCE IN SOILS

Canadian Journal of Soil Science ◽

10.4141/cjss89-072 ◽

1989 ◽

Vol 69 (3) ◽

pp. 711-714 ◽

Cited By ~ 6

Author(s):

K. I. N. JENSEN ◽

E. R. KIMBALL ◽

J. A. IVANY

Keyword(s):

Key Words ◽

Half Life ◽

Field Tests ◽

Soil Surface ◽

Bare Soil ◽

Field Conditions ◽

Row Width ◽

Sampling Zone

The half-life of metribuzin applied to a bare soil surface was calculated to be 3–7 d over four field tests. An artificial cover erected after application or a shallow incorporation increased the half-life of metribuzin approximately 2.5- to 3-fold. Leaching out of the 0- to 5-cm-deep sampling zone could not account for loss of metribuzin. It was concluded that metribuzin persistence may be affected by volatility and/or photodecomposition losses under field conditions, especially shortly after application. Key words: Metribuzin half-life, volatility, photodecomposition, row width

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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 method for recalibration of thoron concentration reading of RAD7 and obtaining the thoron exhalation rate from soil surface

Nuclear Technology and Radiation Protection ◽

10.2298/ntrp1301092t ◽

2013 ◽

Vol 28 (1) ◽

pp. 92-96 ◽

Cited By ~ 1

Author(s):

Yanliang Tan ◽

Detao Xiao

Keyword(s):

Flow Rate ◽

South China ◽

Soil Surface ◽

Field Conditions ◽

Radon Exhalation Rate ◽

Exhalation Rate ◽

Air Flow Rate ◽

Rapid Decay ◽

The University ◽

Chamber Technique

Thoron exhalation rate can be obtained through the combination of the ?accumulation chamber? technique and RAD7. Thoron?s rapid decay causes the intake path and the air flow rate to become important factors in calibration. In field conditions, since the flow rate of the internal pump in RAD7 will change as the voltage of the battery decreases, the big drying tube is more suitable for a long measurement than the small drying tube. We developed the method for recalibration of the thoron concentration reading of RAD7 based on the calibration factor for 222Rn, and obtained the thoron exhalation rate from soil surface near by the Radon Laboratory of the University of South China. This method can be applied to develop and improve instruments for measuring the radon exhalation rate.

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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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Weed Mapping in Vineyards Using RGB-D Perception

Engineering Proceedings ◽

10.3390/engproc2021009030 ◽

2021 ◽

Vol 9 (1) ◽

pp. 30

Author(s):

Dimitrios Kateris ◽

Damianos Kalaitzidis ◽

Vasileios Moysiadis ◽

Aristotelis C. Tagarakis ◽

Dionysis Bochtis

Keyword(s):

Weed Management ◽

Management Practices ◽

Field Conditions ◽

Yield Losses ◽

Weed Mapping ◽

Significant Yield ◽

Different Levels

Weed management is one of the major challenges in viticulture, as long as weeds can cause significant yield losses and severe competition to the cultivations. In this direction, the development of an automated procedure for weed monitoring will provide useful data for understanding their management practices. In this work, a new image-based technique was developed in order to provide maps based on weeds’ height at the inter-row path of the vineyards. The developed algorithms were tested in many datasets from vineyards with different levels of weed development. The results show that the proposed technique gives promising results in various field conditions.

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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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