Comparative evaluation of actual evapotranspiration of capsicum inside and outside of naturally ventilated polyhouse

2020 ◽  
Vol 44 (04) ◽  
pp. 14-21
Keyword(s):  
Soil Moisture ◽  
Comparative Evaluation ◽  
Meteorological Parameters ◽  
Reference Evapotranspiration ◽  
Crop Coefficient ◽  
Weather Data ◽  
Crop Evapotranspiration ◽  
Reference Crop Evapotranspiration ◽  
The Relationship ◽  
Reference Crop

This study was conducted to study the relationship between capsicum crop evapotranspiration inside (ETCin) and crop evapotranspiration outside (ETCout) the naturally ventilated polyhouse (NVPH) using meteorological parameters. Polyhouse has a straightway impact on air temperature and relative humidity while it indirectly influences soil temperature and soil moisture inside the structure. Under this study, crop evapotranspiration was estimated by conventional method i.e., obtaining reference evapotranspiration from weather data recorded inside the polyhouse and multiplying it with crop coefficient values of capsicum crop. Reference crop evapotranspiration inside and outside the polyhouse found as 745.19 mm and 590.22 mm, respectively whereas capsicum crop evapotranspiration inside and outside the polyhouse was 868.40 mm and 694.16 mm, respectively. The results of the study revealed that the relationship between weekly ETCin and ETCout can be expressed mathematically as ETCin = 0.84 ETCout. This implies that, there was approximately 15 % lower crop evapotranspiration requirement for the capsicum crop inside the naturally ventilated polyhouse as compared to outside the polyhouse.

scholarly journals Characterization of a “New Greenhouse Model”: with and without insect proof-screen

2017 ◽  
Vol 11 ◽  
Author(s):  
Luigi Santonicola ◽  
Antonietta Napolitano ◽  
Francesco Castelluccio ◽  
Barbara Greco ◽  
Michele De Maio ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Dry Matter ◽  
Natural Ventilation ◽  
Crop Evapotranspiration ◽  
Fresh Matter ◽  
Area Index ◽  
Reference Crop Evapotranspiration ◽  
Plant Parts ◽  
Reference Crop

In the " Natural ventilation greenhouse", patented new greenhouse model which maximizes the natural ventilation and allows stable installation of the anti-insect proof-screen. The effects of the presence or absence of the anti-insect proof-screen are compared on different parameters of the soil (moisture, pH, EC (Electrical Conductivity), nitrates), of greenhouse environment (irradiance, Hargreaves-Samani ETo (reference crop evapotranspiration)) and of plant (fresh matter, dry matter, Leaf Area Index (LAI)). The presence of the insect proofscreen reduces the water needs of tomato, in fact soil moisture, water delivered and ETo are significantly lower compared to the greenhouse without an insect proof-screen, also it reduces the EC and nitrates in the soil. It improves LAI, doubles the amount of fresh matter of plant parts and triples the fresh matter of the productive part with respect to the greenhouse without anti-insect proof-screen.

scholarly journals Performance evaluation of solar radiation equations for estimating reference evapotranspiration (ETo) in a humid tropical environment

2019 ◽  
Vol 42 (1) ◽  
pp. 124-135
Author(s):  
Emeka Ndulue ◽  
Ikenna Onyekwelu ◽  
Kingsley Nnaemeka Ogbu ◽  
Vintus Ogwo
Keyword(s):  
Solar Radiation ◽  
Reference Evapotranspiration ◽  
Meteorological Data ◽  
Accurate Estimate ◽  
Tropical Environment ◽  
Crop Evapotranspiration ◽  
Reference Crop Evapotranspiration ◽  
Field Crops ◽  
Essential Input ◽  
Reference Crop

Abstract Solar radiation (Rs) is an essential input for estimating reference crop evapotranspiration, ETo. An accurate estimate of ETo is the first step involved in determining water demand of field crops. The objective of this study was to assess the accuracy of fifteen empirical solar radiations (Rs) models and determine its effects on ETo estimates for three sites in humid tropical environment (Abakaliki, Nsukka, and Awka). Meteorological data from the archives of NASA (from 1983 to 2005) was used to derive empirical constants (calibration) for the different models at each location while data from 2006 to 2015 was used for validation. The results showed an overall improvement when comparing measured Rs with Rs determined using original constants and Rs using the new constants. After calibration, the Swartman–Ogunlade (R2 = 0.97) and Chen 2 models (RMSE = 0.665 MJ∙m−2∙day−1) performed best while Chen 1 (R2 = 0.66) and Bristow–Campbell models (RMSE = 1.58 MJ∙m−2∙day−1) performed least in estimating Rs in Abakaliki. At the Nsukka station, Swartman–Ogunlade (R2 = 0.96) and Adeala models (RMSE = 0.785 MJ∙m−2∙day−1) performed best while Hargreaves–Samani (R2 = 0.64) and Chen 1 models (RMSE = 1.96 MJ∙m−2∙day−1) performed least in estimating Rs. Chen 2 (R2 = 0.98) and Swartman–Ogunlade models (RMSE = 0.43 MJ∙m−2∙day−1) performed best while Hargreaves–Samani (R2 = 0.68) and Chen 1 models (RMSE = 1.64 MJ∙m−2∙day−1) performed least in estimating Rs in Awka. For estimating ETo, Adeala (R2 =0.98) and Swartman–Ogunlade models (RMSE = 0.064 MJ∙m−2∙day−1) performed best at the Awka station and Swartman–Ogunlade (R2 = 0.98) and Chen 2 models (RMSE = 0.43 MJ∙m−2∙day−1) performed best at Abakaliki while Angstrom–Prescott–Page (R2 = 0.96) and El-Sebaii models (RMSE = 0.0908 mm∙day−1) performed best at the Nsukka station.

scholarly journals An assessment of the water requirements of a mountain pasture sward in the Polish Western Carpathians

2011 ◽  
Vol 15 (1) ◽  
pp. 193-208 ◽  
Author(s):  
Antoni Kuźniar ◽  
Stanisław Twardy ◽  
Agnieszka Kowalczyk ◽  
Marek Kostuch
Keyword(s):  
Surface Resistance ◽  
Meteorological Data ◽  
Crop Coefficient ◽  
Western Carpathians ◽  
Crop Evapotranspiration ◽  
Water Requirements ◽  
Reference Crop Evapotranspiration ◽  
Mountain Pasture ◽  
Weather Stations ◽  
Reference Crop

An assessment of the water requirements of a mountain pasture sward in the Polish Western Carpathians The water requirements of the pasture sward using the Penman-Monteith method (FAO-56), which is seldom applied in Poland, was assessed. The reference crop evapotranspiration ETo from a hypothetical grass crop with an assumed crop height of 0.12 m, a fixed surface resistance of 70 s·m-1 and an albedo of 0.23, was used. These assumptions are similar under conditions of ruminant grazing. ETo was computed by using meteorological data from 43 weather stations. The crop evapotranspiration ETc is the product of ETo, and single crop coefficient Kc. The differences between precipitation and ETo and ETc (climatic water balances) were determined for mountain pastures. The results were summarised form of a table and maps of isohyets and isolines elaborated by applying the Geographic Information System techniques (Arc View 9) with the data interpolated by the geostatic method (Kriging).

scholarly journals Evapotranspiration and crop coefficient of basil determined by weighing lysimeters

2019 ◽  
Vol 37 (4) ◽  
pp. 373-378
Author(s):  
Izabela P Martins ◽  
Rogério T de Faria ◽  
Luiz F Palaretti ◽  
Miquéias G dos Santos ◽  
João Alberto Fischer Filho
Keyword(s):  
Crop Coefficient ◽  
Human Consumption ◽  
Crop Evapotranspiration ◽  
Area Index ◽  
Reference Crop Evapotranspiration ◽  
Daily Evapotranspiration ◽  
Cover Ratio ◽  
Crop Coefficients ◽  
Reference Crop ◽  
Monteith Equation

ABSTRACT The basil (Ocimum basilicum) crop is of great importance for trading as fresh or dried condiment for human consumption and essential oil for pharmaceutical and cosmetic industries. Water excesses and deficits can affect biomass production of plants, making it necessary to use the correct amount of water for each crop. Considering that determinations of water consumption and cultivation coefficients for medicinal plants are scarce, the aim of this study was determining evapotranspiration and crop coefficients of basil using lysimeters. The crop evapotranspiration was determined by weighing lysimeters for the replacements of 100, 75 and 50% of the maximum daily evapotranspiration. The reference crop evapotranspiration was estimated by the Penman-Monteith equation. Crop evapotranspiration for the 49 day cycle was 471, 352 and 236 mm, and daily rates ranged from 4.8 to 9.4; 4 to 8.1 and 3.7 to 7.4 mm/day, for the replacements of 100, 75 and 50% of the maximum daily evapotranspiration. Crop coefficients varied from 1.5 to 2.8 and were related to the days after transplanting, leaf area index, cover ratio and cumulative degrees-day.

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