scholarly journals Microclimate Characteristics and Evapotranspiration Estimates of Cucumber Plants in a Newly Developed Sunken Solar Greenhouse

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2275
Author(s):  
Haijun Liu ◽  
Congyan Yin ◽  
Xiaodong Hu ◽  
Josef Tanny ◽  
Xiaopei Tang
Keyword(s):  
North China ◽  
Crop Coefficient ◽  
Soil Surface ◽  
Fruit Production ◽  
Daily Maximum ◽  
Crop Evapotranspiration ◽  
Cucumber Fruit ◽  
Solar Greenhouse ◽  
New Type ◽  
Reference Crop

In north China, vegetables are always cultivated in conventional solar greenhouses (SG), however, these structures cannot be used during most of the winter due to extremely low temperatures. In this study, a new type of a solar greenhouse named sunken solar greenhouse (SSG), where the inside soil surface is lowered 1–2 m below outside and the back wall is 5–8 m width at the bottom and 1.5–2 m on top, was investigated. Inside climatic variables were recorded and compared with those outside during seven cucumber cultivation seasons. Crop evapotranspiration (ETc) was estimated using the Penman–Monteith method. Results show that inside solar radiation was reduced by approximately 40%, however days with a daily maximum inside temperature higher than 20 °C accounted for 80–90% of the days during the winter, which greatly enhanced cucumber fruit production compared to common SGs. The reference crop evapotranspiration (ETo) inside the SSG was reduced by 27% compared to outside. The estimated ETc was generally lower than 4 mm day−1, which resulted in a basal crop coefficient of 0.83. In conclusion, the SSG is environmental-friendly, preferable for winter vegetable cultivation in north China, and can be useful for other regions of the world with cold winter conditions.

scholarly journals Selecting Essential Factors for Predicting Reference Crop Evapotranspiration Through Tree-based Machine Learning and Bayesian Optimisation

2021 ◽  
Author(s):  
Long Zhao ◽  
Xinbo Zhao ◽  
Yi Shi ◽  
Yuhang Wang ◽  
Ningbo Cui ◽  
...  
Keyword(s):  
Machine Learning ◽  
North China ◽  
Machine Learning Algorithms ◽  
Influential Factor ◽  
Superior Performance ◽  
Gradient Boosting ◽  
Crop Evapotranspiration ◽  
Reference Crop Evapotranspiration ◽  
Extreme Gradient Boosting ◽  
Reference Crop

Abstract Reference crop evapotranspiration (ETO) is a basic component of the hydrological cycle, and its estimation is critical for agricultural water resource management and scheduling. In this study, three tree-based machine learning algorithms (random forest [RF], gradient boosting decision tree [GBDT], and extreme gradient boosting [XGBoost]) were adopted to determine the essential factors for ETO prediction. The tree-based models were optimised using the Bayesian optimisation (BO) algorithm, and they were compared with three standalone models in terms of daily ETO and monthly mean ETO estimation in North China, with different input combinations of essential variables. The results indicated that solar radiation (Rs) and air temperature (Ts), including the maximum, minimum, and average temperature, in daily ETO were the key parameters affecting model prediction accuracy. Rs was the most influential factor in the monthly average ETO model, followed by Ts. Both relative humidity (RH) and wind speed at 2 m (U2) had little impact on ETO prediction at different scales, although their importance differed. Compared with the GBDT and RF models, the XGBoost model exhibited the highest performance for daily ETO and monthly mean ETO estimation. The hybrid tree-based models with the BO algorithm outperformed the standalone tree-based models. Overall, compared with other inputs, the model with three inputs (Rs, Ts, and RH/U2) had the highest accuracy. The BO-XGBoost model exhibited superior performance in terms of the global performance index (GPI) for daily ETO and monthly mean ETO prediction and it is recommended as a more accurate model predicting daily ETO and monthly mean ETO in North China or areas with a similar climate.

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 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.

Sign in / Sign up

Export Citation Format

Share Document