scholarly journals Assessment of Soybean Evapotranspiration and Controlled Water Stress Using Traditional and Converted Evapotranspirometers

Atmosphere ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 830
Author(s):  
Angela Anda ◽  
Brigitta Simon ◽  
Gabor Soos ◽  
Jaime A. Teixeira da Silva ◽  
Zsuzsanna Farkas ◽  
...  

Evapotranspiration (ETR), reference evapotranspiration (ET0), and seasonal ETR totals were determined for soybean over two growing seasons, at Keszthely, Hungary, using traditionally operated and converted evapotranspirometers. The study aimed to document the plant–water response of two soybean varieties (Sinara: Sin; Sigalia: Sig) which have different water demands. Three water supply treatments were tested: unlimited (WW) watering, 50% of crop water requirement (RO), and rainfed (P). Reconstructed evapotranspirometers allowed crop water deprivation to be simulated under field conditions. ETR sums were higher during the cooler 2017 than in the warmer 2018, calling attention to the importance of being informed about more detailed meteorological variables other than monthly (seasonal) means. In addition to variation in daily mean air temperatures (Ta), maximum Ta played a key role in determining ETR under naturally occurring extreme weather conditions in 2018. Irrespective of the variety, daily mean ETR was on average 65–75% greater than in the water-stress treatment. Unexpectedly, water stress-tolerant Sin used slightly more water than Sig, which was bred for standard weather conditions. Measured mean ETR was as much as 10% higher than derived ET0 rates, causing crop coefficient to exceed 1.0 during flowering. Careful selection of the soybean variety when practicing water-saving management may lead to more efficient variety improvement in a breeding program. It may also be important for soybean producers and farmers to adopt the best variety, aiming to decrease the use of irrigation water to increase seed yield.

Author(s):  
W. James Grichar ◽  
Peter A. Dotray ◽  
Todd Baughman

Aims: To determine peanut response and weed control following the use of carfentrazone plus pyroxasulfone (C + P). Study Design:  Randomized complete block design with 3-4 reps depending on location. Place and Duration of Study: Studies were conducted during the 2015 and 2016 growing seasons in south Texas near Yoakum (29.276o N, 97.123o W), the High Plains of Texas near Lamesa (32.769o N, 101.977o W) or Brownfield (33.104o N, 102.161o W), and southwestern Oklahoma near Ft. Cobb (35.091o N, 98.275o W). Methodology: Plots were infested with naturally occurring weed populations. Pendimethalin was applied either preplant incorporated (PPI) or preemergence (PRE). Early postemergence (EPOST) applications varied according to weather conditions and peanut growth at each location. Postemergence (POST) treatments were applied 26 to 58 days after planting. Weed control and peanut stunting were visually estimated on a scale of 0 to 100 (0 indicating no control or plant death and 100 indicating complete control or plant death). Results: Peanut stunting with C + P was only noted at the High Plains and Oklahoma locations in 2015 but not 2016. Urochloa texana (Buckl.) control with C + P (PRE) varied from 75 to 93%. POST applications provided inconsistent control.  Amaranthus palmeri S. Wats. control with C + P (PRE) was at least 78% season-long while POST applications were inconsistent (24 to 100%).  Pendimethalin plus C + P controlled Cucumis melo L. var. Dudaim Naud. at least 80% late-season. Ipomoea hederacea Jacq. control was excellent season-long (> 80%) in 2015 but poor (< 60%) in 2016.  Reduced peanut yields were noted with C + P in Oklahoma in 2015 to excessive season-long injury.    Conclusion: The premix of C + P has potential for use in peanut especially for control of many small-seeded annual broadleaf weeds that continue to plague many peanut growers across the southwest.  For effective broad-spectrum annual weed control season-long, the addition of pendimethalin to PRE applications will be required.


Water ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 38 ◽  
Author(s):  
Juan Ramírez-Cuesta ◽  
José Mirás-Avalos ◽  
José Rubio-Asensio ◽  
Diego Intrigliolo

Advances in information and communication technologies facilitate the application of complex models for optimizing agricultural water management. This paper presents an easy-to-use tool for determining crop water demands using the dual crop coefficient approach and remote sensing imagery. The model was developed using Python as a programming language and integrated into an ArcGIS (geographic information system) toolbox. Inputs consist of images from satellites Landsat 7 and 8, and Sentinel 2A, along with data for defining crop, weather, soil type, and irrigation system. The tool produces a spatial distribution map of the crop evapotranspiration estimates, assuming no water stress, which allows quantifying the water demand and its variability within an agricultural field with a spatial resolution of either 10 m (for Sentinel) or 30 m (for Landsat). The model was validated by comparing the estimated basal crop coefficients (Kcb) of lettuce and peach during an irrigation season with those tabulated as a reference for these crops. Good agreements between Kcb derived from both methods were obtained with a root mean squared error ranging from 0.01 to 0.02 for both crops, although certain underestimations were observed resulting from the uneven crop development in the field (percent bias of −4.74% and −1.80% for lettuce and peach, respectively). The developed tool can be incorporated into commercial decision support systems for irrigation scheduling and other applications that account for the water balance in agro-ecosystems. This tool is freely available upon request to the corresponding author.


2020 ◽  
Vol 25 ◽  
pp. 02005
Author(s):  
Valentina Gorina ◽  
Vadim Korzin ◽  
Nikita Saplev ◽  
Ekaterina Melkozerova

The aim of the work is a comprehensive assessment of the genetic resources of apricot in the Nikitsky Botanical Garden, determination of the main directions of breeding and the selection of appreciable genotypes for further most effective breeding use for creating competitive varieties, and their introduction into production. Based on the conducted studies, it was revealed that the main directions of apricot breeding at the modern level is to determine the possibility of effective targeted selection of parental pairs for creating varieties with high commercial qualities of fruits, high-yielding, resistant to abiotic and biotic stress factors, adapted to intensive cultivation technologies. It has been determined that the Zard variety, up to the second generation, transmits to its offspring late flowering and small fruiting size. The most promising apricot genotypes for cultivation in areas with unstable weather conditions in Southern Russia have been identified: Boyarin, Yaltinec, 84-951, 89-653, 99-396, 8316, 10841, 84-941, they are characterized by large or medium-sized fruits, good taste (tasting score 4.1-4.7 points, on a 5-point scale) and attractive appearance, late or mid-late flowering of plants. For breeding for late flowering is of interest: Zapozdalyj, Ozornik, 84-383, 84-895, 8319, 84-875; weak susceptibility to fungal pathogens: clasterosporium and moniliosis 84-919, 84-880, 84-383, 84-915, 84-875, 84-909, 84-803, 84-769, 84-803, 89-545, 10841; drought resistance: Krokus, Yaltinec, 87-2, 84-651, 84-942, 84-988, 84-639, 89-359, 89-526, 89-166 и 89-169. Against the background of dry growing seasons, the yield of the selected breeding forms was at the level of the control variety and higher (2.6-3.9 points).


2021 ◽  
pp. 93-97
Author(s):  
N. N. Dubenok ◽  
D. V. Yalansky ◽  
Yu. A. Mazhaysky ◽  
O. V. Chernikova ◽  
Yu. N. Dubrova

Relevance. The most important element of the operational regime of irrigation is the correct (timely) appointment and timing of irrigation, taking into account the biological characteristics of crops, weather conditions and the mechanical composition of the soil.Methods. In this work, the results of the calculation of the irrigation regime of the hay-pasture grass mixture for the growing season april-october 2016-2018 were presented, on the basis of which the values of the water consumption of the crop, the average values of bioclimatic and biothermal coefficients in relation to sod-podzolic loamy soils in the northeastern zones of the Republic of Belarus. The calculations were carried out by the water balance method, as well as by the method of maximum daily air temperatures.Results. As a result of calculating bioclimatic and biothermal coefficients and values of water consumption for the growing seasons. It was found that their highest values in all years of research were recorded in the variant with a pre-irrigation humidity level of 80% of the lowest moisture capacity, while their lowest values were observed in the variant with natural humidification. At the same time, as a result of calculations, it was established that the highest values of bioclimatic coefficients corresponding to the variant 80% of HB took the following values: 0.88; 0.72 and 0.66, the smallest are 0.71; 0.64 and 0.50, and the largest values of the biothermal coefficients were: 0.13; 0.15 and 0.15, the smallest are 0.09; 0.13 and 0.10, respectively, for the growing seasons. The largest values of water consumption, calculated by the water balance method, corresponding to the option 80% of the HB took the following values: 423.0; 462.0 and 440.0 mm, the smallest in this case were: 334.0; 404.0; and 331.0 mm, and the highest values of water consumption, calculated by the method of maximum daily temperatures were: 439.4; 420.0 and 432.2, while the smallest were equal: 318.7, 396.4 and 325.7 mm, respectively, for the growing seasons. 


2019 ◽  
Vol 11 (21) ◽  
pp. 2519 ◽  
Author(s):  
Jiandong Tang ◽  
Wenting Han ◽  
Liyuan Zhang

As the key principle of precision farming, variation of actual crop evapotranspiration (ET) within the field serves as the basis for crop management. Although the estimation of evapotranspiration has achieved great progress through the combination of different remote sensing data and the FAO-56 crop coefficient (Kc) method, lack of the accurate crop water stress coefficient (Ks) at different space–time scales still hinder its operational application to farmer practices. This work aims to explore the potential of multispectral images taken from unmanned aerial vehicles (UAVs) for estimating the temporal and spatial variability of Ks under the water stress condition and mapping the variability of field maize ET combined with the FAO-56 Kc model. To search for an optimal estimation method, the performance of several models was compared including models based on Ks either derived from the crop water stress index (CWSI) or calculated by the canopy temperature ratio (Tc ratio), and combined with the basal crop coefficient (Kcb) based on the normalized difference vegetation index (NDVI). Compared with the Ks derived from the Tc ratio, the CWSI-based Ks responded well to water stress and had strong applicability and convenience. The results of the comparison show that ET derived from the Ks-CWSI had a higher correlation with the modified FAO-56 method, with an R2 = 0.81, root mean square error (RMSE) = 0.95 mm/d, and d = 0.94. In contrast, ET derived from the Ks-Tc ratio had a relatively lower correlation with an R2 = 0.68 and RMSE = 1.25 mm/d. To obtain the evapotranspiration status of the whole maize field and formulate reasonable irrigation schedules, the CWSI obtained by a handheld infrared thermometer was inverted by the renormalized difference vegetation index (RDVI) and the transformed chlorophyll absorption in reflectance index (TCARI). Then, the whole map of Ks can be derived from the VIs by the relationship between CWSI and Ks and can be taken as the basic input for ET estimation at the field scale. The final ET results based on multispectral UAV interpolation measurements can well reflect the crop ET status under different irrigation levels, and greatly help to improve irrigation scheduling through more precise management of deficit irrigation.


2016 ◽  
Author(s):  
Helene Hoffmann ◽  
Rasmus Jensen ◽  
Anton Thomsen ◽  
Hector Nieto ◽  
Jesper Rasmussen ◽  
...  

Abstract. This study investigates whether a Water Deficit Index (WDI) based on imagery from Unmanned Aerial Vehicles (UAVs) can provide accurate crop water stress maps at different growth stages of barley and in differing weather situations. Data from both the early and the late growing season are included to investigate whether the WDI index has the unique potential to be applicable both when the land surface is partly composed of bare soil and when crops on the land surface are senescing. The WDI index differs from the more commonly applied Crop Water Stress Index (CWSI) in that it uses both a spectral vegetation index (VI), to determine the degree of surface greenness, and the composite land surface temperature (LST) (not solely canopy temperature). Lightweight thermal and RGB (Red-Green-Blue) cameras were mounted on a UAV on three occasions during the growing season, 2014, and provided composite LST and color images, respectively. From the LST, maps of surface-air temperature differences were computed. From the color images, the Normalized Green-Red Difference Index (NGRDI), constituting the indicator of surface greenness, was computed. Advantages of the WDI as an irrigation map, as compared with simpler maps of the surface-air temperature difference, are discussed, and the suitability of the NGRDI index is assessed. Final WDI maps had a spatial resolution of 0.25 m. It was found that the UAV-based WDI index determines accurate crop water status. Further, the WDI index is especially valuable in the late growing season because at this stage the remote sensing data represent crop water availability to a greater extent than they do in the early growing season, and because the WDI index accounts for areas of ripe crops that no longer have the same need of irrigation. WDI maps can potentially serve as water stress maps, showing the farmer where irrigation is needed to ensure healthy growing plants, during entire growing seasons.


2020 ◽  
Vol 62 ◽  
pp. 122-133
Author(s):  
R. R. Salimova ◽  
Z. A. Avdeeva ◽  
E. V. Aminova

The article presents data from field and laboratory studies on the productivity and drought tolerance of strawberry varieties in the Pre-Urals (on the example of the Orenburg region). The purpose of the research is a comparative study of the drought resistance of introduced strawberry varieties and the selection of the most productive and valuable for breeding. The Orenburg region belongs to the zone of insufficient moisture a characteristic feature of its climate is aridity. High air temperatures and lack of moisture are a stressor, leading to a partial loss of yield. During the research period (2017-2019), weather conditions were typical for the zone, which allowed us to assess the adaptive capacity of the varieties. In laboratory conditions, a study of the water regime in 12 varieties of strawberries was carried out. The obtained results revealed the nature of the reactions of strawberry plants to changes in environmental conditions depending on the characteristics of the genotype and made it possible to identify the varieties most adapted to local soil and climatic conditions. Data on productivity and its components of strawberry varieties distinguished by resistance to drought are presented. Among the varieties of early ripening in terms of productivity, the following stood out: Darenka, Studencheskaya, Rosinka (more than 200 g/bush). The productivity of the control variety Orlets was less than 200 g. Among the varieties of medium and late ripening by productivity (more than 300 g from the bush) stood out: Anastasia, Bereginya; more than 200 g from the bush yielded varieties: Polka, Urozhaynaya TSGL, Fireworks, Tsariсa. The average productivity (150-200 g per Bush) was in the control variety Zenga Zengana. In years with adverse factors, there was a decrease in the yield. As the initial forms for use in breeding for drought resistance, productive varieties are recommended: Anastasia, Bereginya, Darenka, Polka, Rosinka, Studentskaya, Urozhaynaya TSGL, Fireworks, Tsarina.


Water ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3306
Author(s):  
Angela Anda ◽  
Brigitta Simon-Gáspár ◽  
Gábor Soós

A field experiment was conducted with soybean to observe evapotranspiration (ET) and crop water stress index (CWSI) with three watering levels at Keszthely, Hungary, during the growing seasons 2017–2020. The three different watering levels were rainfed, unlimited, and water stress in flowering. Traditional and converted evapotranspirometers documented water stress levels in two soybean varieties (Sinara, Sigalia), with differing water demands. ET totals with no significant differences between varieties varied from 291.9 to 694.9 mm in dry, and from 205.5 to 615.6 mm in wet seasons. Theoretical CWSI, CWSIt was computed using the method of Jackson. One of the seasons, the wet 2020 had to be excluded from the CWSIt analysis because of uncertain canopy temperature, Tc data. Seasonal mean CWSIt and Tc were inversely related to water use efficiency. An unsupervised Kohonen self-organizing map (K-SOM) was developed to predict the CWSI, CWSIp based on easily accessible meteorological variables and Tc. In the prediction, the CWSIp of three watering levels and two varieties covered a wide range of index values. The results suggest that CWSIp modelling with the minimum amount of input data provided opportunity for reliable CWSIp predictions in every water treatment (R2 = 0.935–0.953; RMSE = 0.033–0.068 mm, MAE = 0.026–0.158, NSE = 0.336–0.901, SI = 0.095–0.182) that could be useful in water stress management of soybean. However, highly variable weather conditions in the mild continental climate of Hungary might limit the potential of CWSI application. The results in the study suggest that a less than 450 mm seasonal precipitation caused yield reduction. Therefore, a 100–160 mm additional water use could be recommended during the dry growing seasons of the country. The 150 year-long local meteorological data indicated that 6 growing seasons out of 10 are short of precipitation in rainfed soybean.


Author(s):  
Roy McCormick ◽  
Konni Biegert ◽  
Josef Streif

Physiological storage disorders continue to cause sizable economic losses in a range of commercially important pomefruit cultivars. Given similar storage regimes, the incidence and severity of browning disorders in the apple cultivar &lsquo;Braeburn&rsquo; can vary in different years in a way that can be explained by the interaction of preharvest seasonal and orchard factors. Over a three-year period (2016 to 2019) at the Kompetenzzentrum Obstbau-Bodensee (KOB) in Southwest Germany a range of orchard and storage treatments were conducted for: air temperature during cell division for three weeks post petalfall or during four weeks preharvest, calcium orchard sprays, crop load and harvest timings. Following controlled atmosphere (CA) storage, the disorder incidence for internal browning and cavity formation varied markedly over the three different growing seasons. Crop load treatments strongly influenced the expression of browning disorders in all years. Differences in air temperatures (△ +/- 2 &deg;C compared to ambient) during the cell division period showed little effect on browning incidence. Warm night temperatures (&gt;10 &deg;C) prior to harvest can reduce internal browning in &lsquo;Braeburn&rsquo; apples during CA storage and shelf-life.


2020 ◽  
Vol 12 (4) ◽  
pp. 348-352
Author(s):  
S. Malchev ◽  
S. Savchovska

Abstract. The periods with continuous freezing air temperatures reported during the spring of 2020 (13 incidents) affected a wide range of local and introduced sweet cherry cultivars in the region of Plovdiv. They vary from -0.6°C on March 02 to -4.9°C on March 16-17. The duration of influence of the lowest temperatures is 6 and 12 hours between March 16 and 17. The inspection of fruit buds and flowers was conducted twice (on March 26 and April 08) at different phenological stages after continuous waves of cold weather conditions alternated with high temperatures. During the phenological phase ‘bud burst’ (tight cluster or BBCH 55) some of the flowers in the buds did not develop further making the damage hardly detectable. The most damaged are hybrid El.28-21 (95.00%), ‘Van’ (91.89%) and ‘Bing’ (89.41%) and from the next group ‘Lapins’ (85.98%) and ‘Rosita’ (83.33%). A larger intermediate group form ‘Kossara’ (81.67%), ‘Rozalina’ (76.00%), ‘Sunburst’ (75.00%), ‘Bigarreau Burlat’ (69.11%) and ‘Kuklenska belitza’ (66.67%). Candidate-cultivar El.17-90 ‘Asparuh’ has the lowest frost damage values of 55.00% and El.17-37 ‘Tzvetina’ with damage of 50.60%.


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