scholarly journals Analysis of dynamics for 15 vegetation indices based on Sentinel-2A image data for the test sites of winter wheat crop different on the state from each other within the forest-steep zone in Ukraine

2018 ◽  
pp. 32-39
Author(s):  
Galina Zholobak ◽  
Oksana Sybirtseva ◽  
Mariana Vakolyuk ◽  
Inna Romanciuc
Keyword(s):  
Winter Wheat ◽  
Vegetation Indices ◽  
Image Data ◽  
Early Summer ◽  
Wheat Crop ◽  
Winter Wheat Cultivars ◽  
Winter Wheat Crop ◽  
Analysis Of Dynamics ◽  
Sentinel 2A ◽  
Reflecting Surface

Dynamics of 15 vegetation indices estimated from the Sentinel-2A images within two test sites with the area of 1 ha for the production crops of two winter wheat cultivars (Bohdana and Skagen) are analyzed for winter dormancy and spring-early summer in 2016. The decrease of total nitrogen content in dry matter of the plant organs, which are formed the reflecting surface of the vegetation cover from the booting stage to milk one is consistent with the behavior of the Green NDVI (740, 560) for the both test sites of winter wheat cover. Dynamics of the other 14 indices have been analyzed under the conditions of the deterioration of phytosanitary situation for the winter wheat crop of Bohdana cultivar.

scholarly journals Winter wheat crop water consumption and its effect on yields in southern Romania, in the very dry 2019-2020 agricultural year

2021 ◽  
Vol 49 (2) ◽  
pp. 12309
Author(s):  
Mihai BERCA ◽  
Valentina-Ofelia ROBESCU ◽  
Roxana HOROIAS
Keyword(s):  
Winter Wheat ◽  
Water Consumption ◽  
Soil Depth ◽  
Vegetation Period ◽  
Early Summer ◽  
Wheat Crop ◽  
Soil Drought ◽  
Crop Water ◽  
Winter Wheat Crop ◽  
Crop Water Consumption

Researches on winter wheat in the south part of Romanian Plain during the dry years 2019 and 2020 have been focused on the crop water consumption issue in excessive conditions of air and soil drought. The wheat crop water consumption in the research sites (Calarasi and Teleorman counties), for the entire vegetation period, autumn – spring – summer, is between 1000 and 1050 m3 of water for each ton of wheat produced. Only in the spring-summer period, the wheat extracts a quantity of about 5960 m3 ha-1, i.e. 851 m3 t-1. The useful water reserve is normally located at about 1500 m3/ha-1, at a soil depth of 0-150 cm. In the spring of 2020, it has been below 400 m3 ha-1, so that at the beginning of May the soil moisture had almost reached the wilting coefficient (WC). Wheat plants have been able to survive the thermal and water shock of late spring - early summer, due to enhanced thermal alternation between air and soil. For a period of about 34 days, this alternation brought the plants 1-1.5 mm water, i.e. approximately 442 m3 ha-1, which allowed the prolongation of the plant’s agony until the rains of the second half of May. Yields have been, depending on the variety, between 1500 and 3000 kg ha-1, in average, covering only 60% of the crop costs. Other measures to save water in the soil have also been proposed in the paper.

scholarly journals Influence of Soil Background on Spectral Reflectance of Winter Wheat Crop Canopy

2019 ◽  
Vol 11 (16) ◽  
pp. 1932 ◽  
Author(s):  
Elena Prudnikova ◽  
Igor Savin ◽  
Gretelerika Vindeker ◽  
Praskovia Grubina ◽  
Ekaterina Shishkonakova ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Soil Type ◽  
Spectral Reflectance ◽  
Vegetation Index ◽  
Vegetation Indices ◽  
Soil Surface ◽  
Wheat Crop ◽  
Crop Canopy ◽  
Winter Wheat Crop ◽  
Type Factor

The spectral reflectance of crop canopy is a spectral mixture, which includes soil background as one of the components. However, as soil is characterized by substantial spatial variability and temporal dynamics, its contribution to the spectral reflectance of crops will also vary. The aim of the research was to determine the impact of soil background on spectral reflectance of crop canopy in visible and near-infrared parts of the spectrum at different stages of crop development and how the soil type factor and the dynamics of soil surface affect vegetation indices calculated for crop assessment. The study was conducted on three test plots with winter wheat located in the Tula region of Russia and occupied by three contrasting types of soil. During field trips, information was collected on the spectral reflectance of winter wheat crop canopy, winter wheat leaves, weeds and open soil surface for three phenological phases (tillering, shooting stage, milky ripeness). The assessment of the soil contribution to the spectral reflectance of winter wheat crop canopy was based on a linear spectral mixture model constructed from field data. This showed that the soil background effect is most pronounced in the regions of 350–500 nm and 620–690 nm. In the shooting stage, the contribution of the soil prevails in the 620–690 nm range of the spectrum and the phase of milky ripeness in the region of 350–500 nm. The minimum contribution at all stages of winter wheat development was observed at wavelengths longer than 750 nm. The degree of soil influence varies with soil type. Analysis of variance showed that normalized difference vegetation index (NDVI) was least affected by soil type factor, the influence of which was about 30%–50%, depending on the stage of winter wheat development. The influence of soil type on soil-adjusted vegetation index (SAVI) and enhanced vegetation index (EVI2) was approximately equal and varied from 60% (shooting phase) to 80% (tillering phase). According to the discriminant analysis, the ability of vegetation indices calculated for winter wheat crop canopy to distinguish between winter wheat crops growing on different soil types changed from the classification accuracy of 94.1% (EVI2) in the tillering stage to 75% (EVI2 and SAVI) in the shooting stage to 82.6% in the milky ripeness stage (EVI2, SAVI, NDVI). The range of the sensitivity of the vegetation indices to the soil background depended on soil type. The indices showed the greatest sensitivity on gray forest soil when the wheat was in the phase of milky ripeness, and on leached chernozem when the wheat was in the tillering phase. The observed patterns can be used to develop vegetation indices, invariant to second-type soil variations caused by soil type factor, which can be applied for the remote assessment of the state of winter wheat crops.

scholarly journals Crop Water Content of Winter Wheat Revealed with Sentinel-1 and Sentinel-2 Imagery

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 4013 ◽  
Author(s):  
Dong Han ◽  
Shuaibing Liu ◽  
Ying Du ◽  
Xinrui Xie ◽  
Lingling Fan ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Water Content ◽  
Vegetation Indices ◽  
Spectral Feature ◽  
Wheat Crop ◽  
Crop Water ◽  
Inversion Model ◽  
Model Based ◽  
Winter Wheat Crop ◽  
Sentinel 2

This study aims to efficiently estimate the crop water content of winter wheat using high spatial and temporal resolution satellite-based imagery. Synthetic-aperture radar (SAR) data collected by the Sentinel-1 satellite and optical imagery from the Sentinel-2 satellite was used to create inversion models for winter wheat crop water content, respectively. In the Sentinel-1 approach, several enhanced radar indices were constructed by Sentinel-1 backscatter coefficient of imagery, and selected the one that was most sensitive to soil water content as the input parameter of a water cloud model. Finally, a water content inversion model for winter wheat crop was established. In the Sentinel-2 approach, the gray relational analysis was used for several optical vegetation indices constructed by Sentinel-2 spectral feature of imagery, and three vegetation indices were selected for multiple linear regression modeling to retrieve the wheat crop water content. 58 ground samples were utilized in modeling and verification. The water content inversion model based on Sentinel-2 optical images exhibited higher verification accuracy (R = 0.632, RMSE = 0.021 and nRMSE = 19.65%) than the inversion model based on Sentinel-1 SAR (R = 0.433, RMSE = 0.026 and nRMSE = 21.24%). This study provides a reference for estimating the water content of wheat crops using data from the Sentinel series of satellites.

scholarly journals Analysis and comparison of vegetation indices of winter wheat crop areas, calculated on the basis of Sentinel-2 and fieldspec spectroradiometer data

2017 ◽  
pp. 37-46 ◽  
Author(s):  
Vadim Lyalko ◽  
Oleksii Sakhatsky ◽  
Galina Zholobak ◽  
Oksana Sybirtseva ◽  
Stanislav Dugin ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Vegetation Indices ◽  
Correlation Coefficients ◽  
Wheat Crop ◽  
Growth Stages ◽  
Double Ratio ◽  
Winter Wheat Crop ◽  
Chlorophyll Index ◽  
Spectral Channels ◽  
Sentinel 2

Ten vegetation indices (VIs) were analyzed, which were calculated simultaneously based on Sentine-l2 data and on results of ground spectrometric survey by ASD FieldSpec® 3FR for the identically geographical sites of the production crops of winter wheat of two cultivars Bohdana and Skagen. The values of the most studied VIs on Sentinel-2 satellite data are similar by quantity to the same indices, calculated on the narrow spectral channels of ASD FieldSpec® 3FR, except for DRICI (Double ratio index for chlorophyll index) and СІ green (ratio green chlorophyll index), the satellite values of which are much lower than those received by spectroradiometer. It was shown that the differences of VIs received by Sentinel-2 and ASD FieldSpec® 3FR depend on the growth stages of winter wheat: during vegetation season the correlation coefficients between them increase for crop areas of both studied cultivars.

scholarly journals Comparison of Proximal and Remote Sensing for the Diagnosis of Crop Status in Site-Specific Crop Management

Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 19
Author(s):  
Jiří Mezera ◽  
Vojtěch Lukas ◽  
Igor Horniaček ◽  
Vladimír Smutný ◽  
Jakub Elbl
Keyword(s):  
Remote Sensing ◽  
Winter Wheat ◽  
Vegetation Indices ◽  
Wheat Yield ◽  
Nitrogen Fertilizers ◽  
Wheat Crop ◽  
Significant Difference ◽  
Winter Wheat Crop ◽  
The Individual ◽  
Sentinel 2

The presented paper deals with the issue of selecting a suitable system for monitoring the winter wheat crop in order to determine its condition as a basis for variable applications of nitrogen fertilizers. In a four-year (2017–2020) field experiment, 1400 ha of winter wheat crop were monitored using the ISARIA on-the-go system and remote sensing using Sentinel-2 multispectral satellite images. The results of spectral measurements of ISARIA vegetation indices (IRMI, IBI) were statistically compared with the values of selected vegetation indices obtained from Sentinel-2 (EVI, GNDVI, NDMI, NDRE, NDVI and NRERI) in order to determine potential hips. Positive correlations were found between the vegetation indices determined by the ISARIA system and indices obtained by multispectral images from Sentinel-2 satellites. The correlations were medium to strong (r = 0.51–0.89). Therefore, it can be stated that both technologies were able to capture a similar trend in the development of vegetation. Furthermore, the influence of climatic conditions on the vegetation indices was analyzed in individual years of the experiment. The values of vegetation indices show significant differences between the individual years. The results of vegetation indices obtained by the analysis of spectral images from Sentinel-2 satellites varied the most. The values of winter wheat yield varied between the individual years. Yield was the highest in 2017 (7.83 t/ha), while the lowest was recorded in 2020 (6.96 t/ha). There was no statistically significant difference between 2018 (7.27 t/ha) and 2019 (7.44 t/ha).

scholarly journals Weed Control and Winter Wheat Crop Yield With the Application of Herbicides, Nitrogen Fertilizers, and Their Mixtures With Humic Growth Regulators

2021 ◽  
Vol 74 ◽  
Author(s):  
Irina Korotkova ◽  
Mykola Marenych ◽  
Volodymyr Hanhur ◽  
Oksana Laslo ◽  
Oksana Chetveryk ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Ammonium Nitrate ◽  
Weed Control ◽  
Block Design ◽  
Nitrogen Fertilizers ◽  
Wheat Crop ◽  
Yield Increase ◽  
Physiologically Active Substances ◽  
Winter Wheat Cultivars ◽  
Winter Wheat Crop

Abstract The aim of the present study was to determine the efficacy of the application of mixtures containing various combinations of humic substances, with herbicides and nitrogen fertilizers, in weed control and optimizing the plant nutrition system. We also aimed to evaluate the influence of these substances on winter wheat productivity. Five Ukrainian winter wheat cultivars (‘Kryzhynka,’ ‘Smuhlyanka,’ ‘Slavna,’ ‘Kubus,’ and ‘Mulan’) were sown in a randomized complete block design, with three replications, in the years 2014–2019. The analysis of the effect of the compositions containing herbicides, with various physiologically active substances, in a mixture with humic preparations (Humifield, 4R Foliar concentrate) was performed by counting weeds per square meter in each experimental plot. The best performance in weed control, including perennial species, was obtained from using a mixture of Grodil Maxi herbicide with the humic preparation, Humifield. The crop treatment of this mixture resulted in a 23.6% reduction in weeds, compared to the treatment with the Grodil Maxi herbicide only. At the same time, the complex application of a number of herbicides in a mixture with the humic preparation, 4R Foliar concentrate led to the opposite effect. Various applications of mixtures of humates (4R Foliar concentrate, 5R SoilBoost) with nitrogen fertilizers (ammonium nitrate; carbamide-ammonium mixture) to optimize the winter wheat nutritional system and yield increases have been studied. The highest yield increase of 20%–22% was harvested in the plots treated with 5R SoilBoost and 4R Foliar concentrate plus ammonium nitrate. In addition, the efficacy of wheat crop foliar feeding with mixtures of humates, plus a carbamide-ammonia mixture, in different phases of vegetation has been established. A yield increase of 10.0%–21.4% resulting from the use of such compositions was obtained.

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