Crop Coefficients Specific to Multiple Phenological Stages for Evapotranspiration-based Irrigation Management of Onion and Spinach

Weighing lysimeters are used to measure crop water use during the growing season. By relating the water use of a specific crop to a well-watered reference crop such as grass, crop coefficients (KC) can be developed to assist in predicting crop needs using meteorological data available from weather stations. This research was conducted to determine growth stage-specific KC and crop water use for onions (Allium cepa L.) and spinach (Spinacia oleracea L.) grown under south Texas conditions. Seven lysimeters, consisting of undisturbed 1.5 × 2.0 × 2.2-m deep soil monoliths, comprise the Texas AgriLife Research–Uvalde lysimeter facility. Six lysimeters, weighing ≈14 Mg, have been placed each in the middle of a 1-ha field beneath a linear low-energy precision application irrigation system. A seventh lysimeter was established to measure reference grass reference evapotranspiration. Daily water use for onion and spinach was measured at 5-min intervals. Crop water requirements, KC determination, and comparison with existing Food and Agricultural Organization (FAO) KC values were determined over a 2-year period for each crop. The KC values determined over the growing seasons varied from 0.2 to 1.3 for onion and 0.2 to 1.5 for spinach with some of the values in agreement with those from FAO. It is assumed that the application of growth stage-specific KC will assist in irrigation management and provide precise water applications for a region of interest.

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Determination of Crop Coefficients (Kc) and Water Use of Spinach and Onion

HortScience ◽

10.21273/hortsci.40.4.1095c ◽

2005 ◽

Vol 40 (4) ◽

pp. 1095C-1095

Author(s):

Giovanni Piccinni ◽

Daniel I. Leskovar ◽

Thomas Marek

Keyword(s):

Water Use ◽

Irrigation System ◽

Meteorological Data ◽

Irrigation Management ◽

Edwards Aquifer ◽

Daily Water ◽

Subsurface Drip ◽

Crop Coefficients ◽

Extension Center

Lysimeters are used to measure real-time water use during the growing season. By relating the water use of a specific crop to a well-watered reference crop, such as alfalfa or grass, crop coefficients (Kc) can be developed to assist in predicting accurate crop needs using available meteorological data. Reference evapotranspiration can be obtained from several weather networks; however, without crop coefficients for specific crops, this information is only useful for grass. Three weighing lysimeters, consisting of undisturbed 1.5 m × 2.0 m area by 2.2-m depth cores of soil, comprise the Texas A&M Research and Extension Center–Uvalde lysimeter facility. Two lysimeters, weighing around 15,000 kg, have been placed beneath a linear LEPA irrigation system and used in field production. A third lysimeter measures reference ET values (ETo) and is located in a grassed area near the field lysimeters irrigated by subsurface drip irrigation system. Spinach was grown in one of the two crop lysimeters while onion was grown in the second lysimeter. Daily water use was measured on 5-min intervals. Results show the possibility of saving ≈61 to 74 million m3 of water per year in the irrigated farms of the Edwards aquifer region if proper irrigation management techniques are implemented in conjunction with the newly developed crop coefficients. Crop water requirements, Kc determination, and comparison to existing FAO Kc values will be discussed.

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Crop Simulation and Crop Evapotranspiration for Irrigation Management of Spinach

HortScience ◽

10.21273/hortsci.41.4.971b ◽

2006 ◽

Vol 41 (4) ◽

pp. 971B-971

Author(s):

Giovanni Piccinni ◽

Thomas Gerik ◽

Evelyn Steglich ◽

Daniel Leskovar ◽

Jonghan Ko ◽

...

Keyword(s):

Water Use ◽

Irrigation Water ◽

Crop Production ◽

Meteorological Data ◽

Irrigation Management ◽

Irrigation Scheduling ◽

South Texas ◽

Crop Evapotranspiration ◽

Crop Water ◽

Crop Water Use

Improving irrigation water management for crop production is becoming increasingly important in South Texas as the water supplies shrink and competition with urban centers in the region grows. Crop simulators and crop evapotranspiration (ET) are appealing methods for estimating crop water use and irrigation requirements because of the low investment in time and dollars required by on-site (in-field) measurement of soil and/or crop water status. We compared the effectiveness of the Crop.m.an/EPIC crop simulator and Crop-ET approaches estimating the crop water use for irrigation scheduling of spinach. In-ground weighing lysimeters were used to measure real-time spinach water use during the growing season. We related the water use of the spinach crop to a well-watered reference grass crop to determine crop coefficients (Kc) to assist in predicting accurate crop needs using available meteorological data. In addition, we ran several simulations of CropMan to evaluate the best management for growing spinach under limited water availability. Results show the possibility of saving about 61 to 74 million m3 of water per year in the 36,500 ha of irrigated farms of the Edwards aquifer region if proper irrigation management techniques are implemented in conjunction with the newly developed decision support systems. We discuss the implications of the use of these technologies for improving the effectiveness of irrigation and for reducing irrigation water requirements in South Texas.

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A simulation study on the effect of climate change on crop water use and chill unit accumulation

South African Journal of Science ◽

10.17159/sajs.2017/20160119 ◽

2017 ◽

Vol 113 (7/8) ◽

Author(s):

Abiodun A. Ogundeji ◽

Henry Jordaan

Keyword(s):

Climate Change ◽

Water Resources ◽

Water Use ◽

Irrigation System ◽

Future Climate ◽

Crop Water ◽

Crop Water Use ◽

Chill Unit ◽

The Future ◽

The Impact

Climate change and its impact on already scarce water resources are of global importance, but even more so for water scarce countries. Apart from the effect of climate change on water supply, the chill unit requirement of deciduous fruit crops is also expected to be affected. Although research on crop water use has been undertaken, researchers have not taken the future climate into consideration. They also have focused on increasing temperatures but failed to relate temperature to chill unit accumulation, especially in South Africa. With a view of helping farmers to adapt to climate change, in this study we provide information that will assist farmers in their decision-making process for adaptation and in the selection of appropriate cultivars of deciduous fruits. Crop water use and chill unit requirements are modelled for the present and future climate. Results show that, irrespective of the irrigation system employed, climate change has led to increases in crop water use. Water use with the drip irrigation system was lower than with sprinkler irrigation as a result of efficiency differences in the irrigation technologies. It was also confirmed that the accumulated chill units will decrease in the future as a consequence of climate change. In order to remain in production, farmers need to adapt to climate change stress by putting in place water resources and crop management plans. Thus, producers must be furnished with a variety of adaptation or management strategies to overcome the impact of climate change.

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Determining water use of sorghum from two-source energy balance and radiometric temperatures

Hydrology and Earth System Sciences ◽

10.5194/hess-15-3061-2011 ◽

2011 ◽

Vol 15 (10) ◽

pp. 3061-3070 ◽

Cited By ~ 21

Author(s):

J. M. Sánchez ◽

R. López-Urrea ◽

E. Rubio ◽

V. Caselles

Keyword(s):

Energy Balance ◽

Water Use ◽

Irrigation Management ◽

Crop Coefficient ◽

Balance Model ◽

Crop Water ◽

Phenological Stages ◽

Crop Water Use ◽

Promising Tool ◽

Experimental Campaign

Abstract. Estimates of surface actual evapotranspiration (ET) can assist in predicting crop water requirements. An alternative to the traditional crop-coefficient methods are the energy balance models. The objective of this research was to show how surface temperature observations can be used, together with a two-source energy balance model, to determine crop water use throughout the different phenological stages of a crop grown. Radiometric temperatures were collected in a sorghum (Sorghum bicolor) field as part of an experimental campaign carried out in Barrax, Spain, during the 2010 summer growing season. Performance of the Simplified Two-Source Energy Balance (STSEB) model was evaluated by comparison of estimated ET with values measured on a weighing lysimeter. Errors of ±0.14 mm h−1 and ±1.0 mm d−1 were obtained at hourly and daily scales, respectively. Total accumulated crop water use during the campaign was underestimated by 5%. It is then shown that thermal radiometry can provide precise crop water necessities and is a promising tool for irrigation management.

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Effect of decision variables on yield and water productivity of onion under conventional furrow irrigation system in bako woreda, Ethiopia

International Journal of Agricultural Research Innovation and Technology ◽

10.3329/ijarit.v11i1.54471 ◽

2021 ◽

Vol 11 (1) ◽

pp. 92-100

Author(s):

G Genemo ◽

T Seyoum

Keyword(s):

Water Use Efficiency ◽

Water Use ◽

Flow Rate ◽

Irrigation System ◽

Water Productivity ◽

Furrow Irrigation ◽

Crop Water ◽

Crop Water Use ◽

Decision Variables ◽

Use Efficiency

Flow rate and furrow length are the main irrigation decision variables currently affecting yield and water productivity at farm level. Improper selection of these variables produces an over use of water and loss in crop production. The general objective was to investigate the effect of decision variables on yield and water productivity of onion under conventional furrow irrigation system, with specific objective to analyze the effect of flow rate, furrow length and their interaction on yield and water productivity of onion. The field experiment was laid out in randomized complete block design with factorial arrangement of three levels of flow rate (0.7, 0.98 and 1.3 L/S) and three levels of furrow length (25, 35 and 50 m) with three replications. Inflow out flow method was used to determine the infiltration characteristics of the soil and Irrigation depth was controlled by using 3-inch Parshall flume. The maximum non-erosive flow rate to the experimental site was fixed through design equation considering soil textural class and furrow bed slope. Effect of furrow length and flow rate on yield and water productivity of the onion were used for evaluation. Their analyses indicated that effect of furrow length and their interaction with flow rate on yield were not significant (p<0.05). However, the flow rate showed highly significant (p<0.01) effect on yield of onion. The ranges of mean yield gained from furrow length and flow rate were F1 (14.75 ton ha-1) to F3 (15.96 ton ha-1) and Q1 (13.59 ton ha-1) to Q3 (19.69 ton ha-1), respectively. The effect of furrow length on crop water use efficiency and field water use efficiency was not significant (p<0.05). However, the flow rate has showed highly significant (p<0.01) effect on crop water use efficiency and field water use efficiency. The range of mean crop water use efficiency and field water use efficiency from furrow length and flow rate were F1 (33.65 kg/ha/mm) to F3 (36.41 kg/ha/mm) and Q1 (30.99 kg/ha/mm) to Q3 (38.65kg/ha/mm) and F1 (2.06 kg/m3) to F3 (2.23 kg/m3) and Q1 (1.89 kg/m3) to Q3 (2.36 kg/m3), respectively. Therefore, it can be concluded that a furrow length of 50 m is suitable to use 1.3 L/S of flow rate for better onion yield and water productivity under similar soil type of study area. Int. J. Agril. Res. Innov. Tech. 11(1): 92-100, June 2021

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Water extraction by sugarcane on soils of the Ord Irrigation Area

Australian Journal of Experimental Agriculture ◽

10.1071/ea02043 ◽

2003 ◽

Vol 43 (5) ◽

pp. 487 ◽

Cited By ~ 5

Author(s):

G. M. Plunkett ◽

R. C. Muchow

Keyword(s):

Soil Water ◽

Water Use ◽

Best Practice ◽

Irrigation Management ◽

Water Extraction ◽

Soil Types ◽

Crop Water ◽

Wet Season ◽

Irrigation Area ◽

Crop Water Use

Sugarcane is a new commercial crop in the Ord River Irrigation Area and irrigation management strategies are required for profitable production with minimal environmental consequences such as rising ground water. Knowledge of soil water properties and sugarcane water requirements is a necessary prerequisite for best-practice irrigation. Accordingly, soil water measurements were taken to quantify the amount and depth pattern of water extraction by sugarcane on the Ivanhoe Plain in the Ord River Irrigation Area.The drained upper limit and crop lower limit of extraction were measured on 4 soil types. The amount of soil water available to the sugarcane plant varied between soil types, ranging from 226 to 167 mm in a 2.0 m profile. Sugarcane extracted water down to 1.8 m at the Central and Northern Ivanhoe sites, down to 1.6 m at the Southern Ivanhoe site, but only down to 1.0 m at the Aquitaine site. The pattern of water use over time was determined at 2�sites and showed higher crop water use before the wet season and much lower crop water use after the wet season. There was considerable reduction in the ratio of crop water use to Class A pan evaporation after the wet season. Lower irrigation frequency after the wet season on maturing crops will improve irrigation efficiency and reduce impacts on the environment.This knowledge of the different soil water properties of the 4 soil types can be used with crop growth models to develop recommendations for best-practice irrigation management of sugarcane across the Ord River Irrigation Area. These recommendations need to account for the high soil water extraction capability of sugarcane growing in this environment.

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