scholarly journals A study of agrometeorological parameters for the Kharif maize at Anand (Gujarat)

MAUSAM ◽  
2022 ◽  
Vol 53 (2) ◽  
pp. 127-132
Author(s):  
P. G. THORAT
Keyword(s):  
Regression Models ◽  
Potential Evapotranspiration ◽  
Crop Coefficient ◽  
Maize Crop ◽  
Made In ◽  
Phenological Phases

A study was conducted on the behaviour of evaporation, evapotranspiration and potential evapotranspiration in different phenological phases, during the years 1989, 1990 and 1991 for Kharif Maize crop at Anand (Gujarat).  It has been noticed that evapotranspiration and potential evapotranspiration attained maximum values in grain phase.  In harvesting phase relative evapotranspiration and crop coefficient had lowest values.  The seasonal crop coefficient was obtained 0.84. An attempt has been made in this paper to develop the regression models to estimate potential evapotranspiration and relative evapotranspiration.

scholarly journals Maize Crop Coefficient Estimated from UAV-Measured Multispectral Vegetation Indices

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5250 ◽  
Author(s):  
Yu Zhang ◽  
Wenting Han ◽  
Xiaotao Niu ◽  
Guang Li
Keyword(s):  
Water Management ◽  
Deficit Irrigation ◽  
Regression Models ◽  
Vegetation Index ◽  
Measurement Data ◽  
Crop Coefficient ◽  
Maize Crop ◽  
Significant Difference ◽  
Farm Scale ◽  
Different Levels

The rapid, accurate, and real-time estimation of crop coefficients at the farm scale is one of the key prerequisites in precision agricultural water management. This study aimed to map the maize crop coefficient (Kc) with improved accuracy under different levels of deficit irrigation. The proposed method for estimating the Kc is based on multispectral images of high spatial resolution taken using an unmanned aerial vehicle (UAV). The analysis was performed on five experimental plots using Kc values measured from the daily soil water balance in Ordos, Inner Mongolia, China. To accurately estimate the Kc, the fraction of vegetation cover (fc) derived from the normalized difference vegetation index (NDVI) was used to compare with field measurements, and the stress coefficients (Ks) calculated from two vegetation index (VI) regression models were compared. The results showed that the NDVI values under different levels of deficit irrigation had no significant difference in the reproductive stage but changed significantly in the maturation stage, with a decrease of 0.09 with 72% water applied difference. The fc calculated from the NDVI had a high correlation with field measurement data, with a coefficient of determination (R2) of 0.93. The ratios of transformed chlorophyll absorption in reflectance index (TCARI) to renormalized difference vegetation index (RDVI) and TCARI to soil-adjusted vegetation index (SAVI) were used, respectively, to establish two types of Ks regression models to retrieve Kc. Compared to the TCARI/SAVI model, the TCARI/RDVI model under different levels of deficit irrigation had better correlation with Kc, with R2 and root-mean-square error (RMSE) values ranging from 0.68 to 0.80 and from 0.140 to 0.232, respectively. Compared to Kc calculated from on-site measurements, the Kc values retrieved from the VI regression models established in this study had greater ability to assess the field variability of soil and crops. Overall, use of the UAV-measured multispectral vegetation index approach could improve water management at the farm scale.

Computing Maize Crop Coefficients in the Port Harcourt area, Nigeria, using a Class a Pan Evaporimeter

1997 ◽  
Vol 26 (3) ◽  
pp. 185-189 ◽  
Author(s):  
J.M. Ayotamuno ◽  
A.J. Akor ◽  
S.C. Teme ◽  
E.W.U. Essiet ◽  
N.O. Isirimah ◽  
...  
Keyword(s):  
Potential Evapotranspiration ◽  
Crop Coefficient ◽  
Grain Filling ◽  
Maize Crop ◽  
Class A ◽  
Port Harcourt ◽  
The Mean ◽  
Crop Coefficients ◽  
Tropical Climates ◽  
Class A Pan

Farmers in hot tropical climates know the importance of irrigation, but for irrigation to be used effectively the water requirement of the crop must be known. This is computed as the product of the potential evapotranspiration (PET) and the crop coefficient (Kc). While the PET can easily be obtained through various methods, including pan evaporimeters, the Kc in the Port Harcourt area for maize and other crops was not known. The main objective of this research, therefore, was to obtain maize crop coefficients at different stages of growth using non-weighing water table lysimeters and a class A pan. The estimated mean maize evapotranspiration (ET) values for the establishment, vegetative, pollination, and grain-filling stages were 29,98,84 and 98 mm, respectively. Values ranging from 0.18 to 1.08 were calculated for the mean crop coefficients for 10-day periods.

scholarly journals Evapotranspiration and Dual Crop Coefficient of Maize Second Season Intercropped with Crotalaria

2020 ◽  
pp. 142-157
Author(s):  
Diego Fernando Daniel ◽  
Rivanildo Dallacort ◽  
João Danilo Barbieri ◽  
Marco Antônio Camillo de Carvalho ◽  
Santino Seabra Júnior ◽  
...  
Keyword(s):  
Developmental Stages ◽  
Crop Coefficient ◽  
The State ◽  
State University ◽  
Crop Evapotranspiration ◽  
Maize Crop ◽  
Evaporation Coefficient ◽  
Mato Grosso ◽  
Weight Variation ◽  
Phenological Phases

The objective of this work was to determine the dual coefficient of culture (Kc) of maize in monoculture and intercropping systems, as well as to evaluate the influence of intercropping on evapotranspiration and productive characteristics of maize second season. The experiment was carried out in the experimental field of the State University of Mato Grosso - UNEMAT in 2018, with three treatments: T1 - maize monoculture; T2 - Crotalaria monoculture and T3 - maize + Crotalaria. The crop evapotranspiration (ETc) of maize, Crotalaria, and maize + Crotalaria intercropping was determined daily by weight variation of weighing lysimeters, converted into mm day-1. The methodology used was that of dual Kc - FAO 56, dividing the crop coefficient (Kc), in soil evaporation coefficient (Ke), determined in microlysimeters, and basal crop coefficient (Kcb), determined in weighing lysimeters. The phenological phases of the maize crop were observed to determine the coefficients in the different developmental stages, being the Kc, Kcb, Ke in the phases: Initial (I), Development (II), Intermediate (III) and Final (IV). The accumulated culture evapotranspiration was 312.00; 436.16 and 422.38 mm and daily averages of 2.86; 4.00- and 3.88-mm d-1, respectively for monoculture maize, for Crotalaria and for intercropping. The Kc values for each phase of maize development in intercropping with crotalaria were: I (1.46); II (1.48); III (1.59) and IV (0.94). For maize monoculture, dual Kc values were: I (1.24), II (1.30), III (1.00) and IV (1.11) and for Crotalaria monoculture were: I (1.77), II (1.59), III (1.56) and IV (1.05).

scholarly journals INQUIRY INTO VERTICAL MOVEMENTS OF THE EARTH‘S CRUST BASED ON SAMPLES FROM EASTERN LITHUANIA

2014 ◽  
Vol 40 (2) ◽  
pp. 58-67
Author(s):  
Ruta Puziene ◽  
Asta Anikeniene ◽  
Gitana Karsokiene
Keyword(s):  
Regression Models ◽  
Earth’S Crust ◽  
Movement Velocity ◽  
Correlation Matrices ◽  
Vertical Movements ◽  
Statistical Correlations ◽  
Horizontal Gradients ◽  
The Earth ◽  
Earth's Crust ◽  
Made In

In the research of vertical movements of the earth’s crust, examination of statistical correlations between the measured vertical movements of the earth’s crust and territorial geo-indexes is accomplished with the help of mathematical statistical analysis. Availability of the precise repeated levelling measuring data coupled with the preferred research methodology offer a chance to determine and predict recent vertical movements of the earth’s crust. For the inquiry into recent vertical movements of the earth’s crust, a Lithuanian class I vertical network levelling polygon was used. Drawing on measurements made in the polygon, vertical velocities of earth’s crust movements were calculated along the following levelling lines. For determining the relations shared by vertical movements of the earth’s crust and territorial geo-parameters, the following territory-defining parameters are accepted. Examination of the special qualities of relations shared by vertical movements of the earth’s crust and geo-parameters in the territory under research contributed to the computation of correlation matrices. Regression models are worked out taking into consideration only particular territory-defining geo-parameters, i.e. only those parameters which exhibit the following correlation coefficient value of the vertical earth’s crust movement velocity: r ≥ 0.50. A forecast of the velocities pertaining to vertical movements of the earth’s crust in the territory under examination was made with the application of regression models. Further in the process of this research, a map was compiled specifying the velocities of vertical movements of the earth’s crust in the territory. In the eastern part of this territory, the earth’s crust rises at a rate of up to 3 mm/year; while in the western part of it, the earth crust lowers at a rate of up to –1.5 mm/year. In order to pinpoint territories characterised by temperate and regular rising/lowering or intensive rising/lowering, a map of horizontal gradients of recent vertical earth crust movements in the territory enclosed by levelling polygon was compiled.

scholarly journals STATISTICAL EQUATIONS OF MAIZE CROP COEFFICIENT (Kc)

2020 ◽  
Vol 34 (1) ◽  
pp. 87-102
Author(s):  
S.A.A. El-Raires, ◽  
T.A Aboul Defan, ◽  
A. Sh .A. Osman,
Keyword(s):  
Crop Coefficient ◽  
Maize Crop

scholarly journals Spatio-temporal variability of biophysical parameters of irrigated maize using orbital remote sensing

2021 ◽  
Vol 42 (4) ◽  
pp. 2181-2202
Author(s):  
Taiara Souza Costa ◽  
◽  
Robson Argolo dos Santos ◽  
Rosângela Leal Santos ◽  
Roberto Filgueiras ◽  
...  
Keyword(s):  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Crop Coefficient ◽  
Coefficient Of Determination ◽  
Landsat 8 ◽  
Crop Evapotranspiration ◽  
Biophysical Parameters ◽  
Planting Dates ◽  
Maize Crop ◽  
Spatio Temporal

This study proposes to estimate the actual crop evapotranspiration, using the SAFER model, as well as calculate the crop coefficient (Kc) as a function of the normalized difference vegetation index (NDVI) and determine the biomass of an irrigated maize crop using images from the Operational Land Imager (OLI) and Thermal Infrared (TIRS) sensors of the Landsat-8 satellite. Pivots 21 to 26 of a commercial farm located in the municipalities of Bom Jesus da Lapa and Serra do Ramalho, west of Bahia State, Brazil, were selected. Sowing dates for each pivot were arranged as North and South or East and West, with cultivation starting firstly in one of the orientations and subsequently in the other. The relationship between NDVI and the Kc values obtained in the FAO-56 report (KcFAO) revealed a high coefficient of determination (R2 = 0.7921), showing that the variance of KcFAO can be explained by NDVI in the maize crop. Considering the center pivots with different planting dates, the crop evapotranspiration (ETc) pixel values ranged from 0.0 to 6.0 mm d-1 during the phenological cycle. The highest values were found at 199 days of the year (DOY), corresponding to around 100 days after sowing (DAS). The lowest BIO values occur at 135 DOY, at around 20 DAS. There is a relationship between ETc and BIO, where the DOY with the highest BIO are equivalent to the days with the highest ETc values. In addition to this relationship, BIO is strongly influenced by soil water availability.

scholarly journals Evaluation of Climate Change Impacts on Cotton Yield using Cropsyst and Regression Models

2018 ◽  
Vol 8 ◽  
pp. 1433-1451 ◽  
Author(s):  
Pantazis Georgiou ◽  
Panagiota Koukouli
Keyword(s):  
Climate Change ◽  
Regression Models ◽  
General Circulation ◽  
Management Practices ◽  
Potential Evapotranspiration ◽  
Circulation Model ◽  
Planting Date ◽  
Climate Variables ◽  
Cotton Yield ◽  
Cotton Production

The regional as well as the international crop production is expected to be influenced by climate change. This study describes an assessment of simulated potential cotton yield using CropSyst, a cropping systems simulation model, in Northern Greece. CropSyst was used under the General Circulation Model CGCM3.1/T63 of the climate change scenario SRES B1 for time periods of climate change 2020-2050 and 2070-2100 for two planting dates. Additionally, an appraisal of the relationship between climate variables, potential evapotranspiration and cotton yield was done based on regression models. Multiple linear regression models based on climate variables and potential evapotranspiration could be used as a simple tool for the prediction of crop yield changes in response to climate change in the future. The CropSyst simulation under SRES B1, resulted in an increase by 6% for the period 2020-2050 and a decrease by about 15% in cotton yield for 2070-2100. For the earlier planting date a higher increase and a slighter reduction was observed in cotton yield for 2020-2050 and 2070-2100, respectively. The results indicate that alteration of crop management practices, such as changing the planting date could be used as potential adaptation measures to address the impacts of climate change on cotton production.

THE WATER RELATIONS AND IRRIGATION REQUIREMENTS OF PASSION FRUIT (PASSIFLORA EDULIS SIMS): A REVIEW

2013 ◽  
Vol 49 (4) ◽  
pp. 585-596 ◽  
Author(s):  
M. K. V. CARR
Keyword(s):  
Water Stress ◽  
Water Relations ◽  
Potential Evapotranspiration ◽  
Crop Coefficient ◽  
Heavy Rain ◽  
Passion Fruit ◽  
Flower Bud ◽  
Leaf Production ◽  
Passiflora Edulis ◽  
Bud Initiation

SUMMARYIt is generally accepted that the two forms of Passiflora edulis, the golden and the purple, originated on the edges of tropical rainforests in Brazil. Extensive hybridisation has since taken place between these two forms and their hybrids. The passion fruit (a vine) is now grown throughout the tropics and subtropics. A limited amount of basic, fundamental research has been published on the water relations of passion fruit. Leaf production and expansion are both sensitive to water deficits, while water stress reduces leaf and floral bud initiation. A single axillary flower bud forms at each leaf node of new growth along with a tendril. Flower bud development and fruit set are less sensitive to water stress than leaf initiation. Heavy rain during pollination prevents fertilization. Unevenness in crop distribution during the year is possibly linked to water stress and temperature variation. Potential evapotranspiration rates in Brazil varied between 3.5 mm d−1 and 5.8 mm d−1. The value for the crop coefficient increases from about 0.6 during apical vegetative growth up to about 1.25 during flowering and fruiting. Water productivities still need to be determined. Micro-sprinklers and drip are the most effective ways of applying irrigation water with precision to passion fruit. Opportunities exist for international cooperation in research projects of mutual interest on passion fruit water relations.

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