Digital Commons Network^™

Seasonal Water Use And Productivity Of Lucerne-Grass Pastures, B A. Mckensize, R J. Lucas, P Gyamtsho

IGC Proceedings (1993-2023)

A. long-term grazing experiment at Lincoln University examined the yield and water use efficiency (WUE) of pure lucerne (Medicago saliva L.), luceme plus Grasslands Matua prairie grass (Bromus wildenowii Kunth.) and lucerne plus Grasslands Maru phalaris (Phalaris aqualica L.). Pure lucerne, lucerne-phalaris and lucerne­prairie yielded 12.7, 11.6 and 10.4 t DM/ha/year. Production from deep soils was 16% greater than from shallow soils. Over a 6 month growth cycle from 29 Sept 88 until 16 May 89 total evapotranspiration did not vary between pasture types and mean water use was 378 mm. Water use was 10% higher on …

A Comparative Analysis Of Openet For Evaluating Evapotranspiration In California Almond Orchards, Kyle Knipper, Martha Anderson, Nicholas Bambach, Forrest Melton, Zac Ellis, Yun Yang, John Volk, Andrew J. Mcelrone, William Kustas, Matthew Roby, Will Carrara, Sebastian Castro, Ayse Kilic, Joshua B. Fisher, Anderson Ruhoff, Gabriel B. Senay, Charles Morton, Sebastian Saa, Richard G. Allen

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The almond industry in California faces water management challenges that are being exacerbated by droughts, climate change, and groundwater sustainability legislation. The Tree-crop Remote sensing of Evapotranspiration eXperiment (T-REX) aims to explore opportunities to improve precision irrigation management for woody perennial cropping systems. Almond orchards in the California Central Valley were equipped with eddy covariance flux measurements to evaluate satellite remote sensing-based evapotranspiration (RSET) models. OpenET provides high-resolution (30-m spatial and daily temporal) RSET data, synthesizing decades of research for practical water management. This study provides an evaluation of OpenET performance at six almond sites covering a large range in …

The Influence Of Range Condition On The Hydrological Characteristics In A Semi-Arid Rangeland, H A. Snyman

IGC Proceedings (1993-2023)

Herbage production, water-use efficiency (i.e. above-ground phytomass production per unit of evapotranspiration), surface runoff, deep percolation, soil loss and soil organic matter content were determined on rangeland in three different ecological conditions, viz. poor, moderate and good, for 20 years. Hydraulic non-floating lysimeters were used to determine evapotranspiration (Et), soil evaporation (E) and deep percolation. Runoff and soil loss were recorded on runoff plots. Above-ground phytomass production, water-use efficiency, deep percolation and soil organic matter content decreased (P<0.01) when plant cover was reduced or range and soil condition declined. The dense plant cover of veld in good condition provides a situation in which surface runoff and soil loss rates are lower (P<0.01) than that from veld in poor condition.

Effects Of Climate Change On Grassland Production In Switzerland, J Fuhrer, M Riedo

IGC Proceedings (1993-2023)

A mechanistic model for productive grassland was used to simulate annual dry matter yield in relation to fluxes of C, N, and water, and to test the sensitivity to climate change and to elevated [CO2] (2xCO2). Local weather scenarios were derived from the results of two General Circulation Models (GCM) by statistical down-scaling. Annual yield increased by a maximum of 10% without 2xCO2 effects, by 1-16% in response to 2xCO2, and by 6-24% with the combination of climate change and 2xCO2. Decreased evapotranspiration and increased water use efficiency in response to 2xCO2 were partially offset by climate change. The simulations …

Water Use Efficiency In Chilean And Argentine Humid Temperate Grass-Legume Pastures, H G. Landi, M H. Wade, V Garcia De Cortazar, D E. Dalla Valle

IGC Proceedings (1993-2023)

At two sites in Argentina and Chile five levels of water input were applied to four sown pastures of varying ages during spring and summer. The pastures consisted principally of C3 grasses and legumes, some of which were sown such as Lolium perenne, Trifolium repens, Dactylis glomerata. Dry matter (DM) production was measured and related to the estimated total evapotranspiration (ET): responses were both highly linear. Both responses to ET and absolute yields were higher at the Argentinian than at the Chilean site: respectively 10.7 and 15.2 kg DM/mm water evapotranspired. Nevertheless the calculated indices of sensitivity (Ky) of Doorenbos …

Mechanistic Modelling Of Grassland Energy Balance, G D. Buchan, B Main, B A. Mckenzie

IGC Proceedings (1993-2023)

No abstract provided.

Palatability Of Alfalfa (Medicago Sativa L.) And Orchard Grass (Dactylis Glomerata L.) Silages, R. D. Améndola-Massiotti, J. A. Burgueño, M. Concepción, L. Cruz

IGC Proceedings (1993-2023)

The objective was to compare palatability with different methodologies for characterizing silages at Chapingo Autonomous University, México. Eight silages were used resulting from an experiment which evaluated effects of cutting time (08:00 and 14:00), time of wilting (0, 1 and 2 h) and use of lactic bacteria inoculant on properties of alfalfa (Medicago sativa L.) and orchard grass (Dactylis glomerata L.) silages. Organoleptic properties (odor, color, texture, moisture) were assessed by trained observers, using as categories: excellent, good, fair and poor. Dry matter content, CO₂ rate of production and pH were also measured. For the evaluation of …

Deficit Irrigation Of Pastures, Matt Yost, Clara Anderson, Niel Allen, Burdette Barker, Melanie Heaton, Justin Wyatt Clawson, Earl Creech

All Current Publications

Deficit irrigation is any irrigation level that does not meet the crop’s full evapotranspiration (ET) demand, meaning evaporation from plant and soil surface and transpiration through plant growth. This strategy is often a last resort for optimizing water use as opposed to those that will not limit production. However, deficit irrigation is often necessary in parts of Utah due to drought or inadequate water supplies. This was especially true in 2021–2022 due to record droughts. Deficit irrigation strategies for pastures have been developed, but they have yet to be compared and evaluated in Utah. This fact sheet summarizes 6 years …

Evapotranspiration Of Rewetted And Drained Fen Soils With Grass – Long Term Lysimeter Studies, M. Pesch, J. Hoysagk, F. Eulenstein, A. Behrendt

IGC Proceedings (1993-2023)

In the context of reducing greenhouse gas (GHG) emissions to combat climate change, rewetting of peatlands is of particular importance. High groundwater levels covering organic matter in the soil prevent its oxidation to CO₂. The amount of water needed to allow the rewetting of peatlands can be determined in lysimeter studies.

The evapotranspiration in fens depends essentially on the groundwater table, the vegetation (transpirational active biomass) and the saturation deficit of the atmosphere. After rewetting, these factors can lead to an evapotranspiration of 1000 l m^-2 a^-1 and even 2000 l m^-2 a^-1 in …

Evaluation Of Evapotranspiration Estimates Using An Existing Hybrid Machine Learning Model In A Natural And A Managed Dryland Site, Katya Esquivel Herrera

Open Access Theses & Dissertations

Evapotranspiration (ET) is a critical component of the hydrologic cycle, encompassing both evaporative water loss from surfaces and transpiration through plant stomata. The environmental factors influencing ET include water and energy availability, atmospheric capacity for water uptake, and various meteorological variables. ET serves as a unique climate variable linking water, energy, and carbon cycles. In agroecosystems, accurate ET quantification is vital for optimizing water use efficiency, irrigation management, and crop yield. Traditional methods for ET estimation involve direct measurements and indirect models, with both presenting limitations.

Recent years have witnessed the integration of remote sensing and machine learning (ML) algorithms …

Evapotranspiration And Precipitation Data For Calculating Irrigation Requirements In Utah, Shital Poudyal, Anju Chaudhary

All Current Publications

Reference evapotranspiration (ETo) and precipitation data are essential for developing water budgets and calculating irrigation water requirements. However, it is crucial that the data used for such purposes are recent and easily accessible to stakeholders. In this fact sheet, we calculated average reference evapotranspiration and precipitation data for multiple locations in Utah, USA. To accomplish this, we collected the data from the Utah Climate Center and compiled it to show an average of 20 years of data by month in an easily digestible format. We compiled data for 69 locations in Utah, making it easy to find one close to …

Evapotranspiration In Urban And Agricultural Systems With Interacting Irrigation And Nitrogen Fertilizer Treatments, Samantha R. Shumate

Theses and Dissertations

Nitrogen (N) fertilizer and irrigation are important inputs for all managed plant species, especially in arid and semi-arid climates. The interaction between N management and irrigation can lead to more sustainable practices. This is true for both agricultural and urban environments. Precision nutrient management has been widely adopted by producers in recent decades, and water conservation has become an important goal for turfgrass managers. In urban systems, our goal was to evaluate Kentucky bluegrass (Poa pratensis L.) to determine response to three N fertilizer rates and three irrigation rates in all possible combinations. The main and interacting treatment effects were …

Effect Of Timing And Intensity Of Drought On Perennial Ryegrass Seed Yield, R. J. Martin, R. N. Gillespie, S. Maley

IGC Proceedings (1993-2023)

Perennial ryegrass seed worth about $50 million is produced annually in Canterbury, New Zealand (Rowarth 1998). Ryegrass seed production in New Zealand is often affected by drought, reducing both seed number and seed size (Rolston et al., 1994). Irrigation management recommendations are not currently available for farmers growing ryegrass seed crops. To quantify the effect of water stress on perennial ryegrass seed yield, we carried out an experiment in a rainshelter where rainfall was excluded from experimental plots otherwise exposed to normal weather (Martin et al., 1990).

Using Machine Learning And Distributed Hydrologic Modeling To Predict Soil Texture, Surface Soil Moisture And Evapotranspiration In Jornada Experimental Range, Southwestern U.S., Jorge Andres Mayo

Open Access Theses & Dissertations

In water-limited ecosystems, detailed knowledge of the soil, vegetation, and atmosphere interactions is critical to understand the processes that control the partitioning of energy, water fluxes, and biogeochemical cycles within the critical zone. This Master's thesis is divided into two main contributing sections. The first, is on the use of machine learning to reconstruct missing soil type information, and the second, on the calibration and validation of a physically-based distributed hydrological model to estimate soil moisture and evapotranspiration within the Jornada Experimental Range of the U.S. in southern New Mexico. For the first contribution, three explainable, shallow machine-learning techniques are …

Peer Review Of Teaching: Et Theory, Deficit Irrigation And Consumptive Use, Derek M. Heeren, Saleh Taghvaeian

Department of Biological Systems Engineering: Conference Presentations and White Papers

A BSE Peer Review of Teaching was carried out for a graduate level course on Advanced Irrigation Management. This course has been offered for several years; each time improvements are made, but there is always a need for additional improvement. In particular, ET theory, deficit irrigation, and consumptive use are topics that the students struggle to grasp. These topics involve a relatively high level of math for an MS-level (800-level) Agricultural Systems Technology course, and the available materials on these topics either were not well developed or were not a good fit for this class. The primary objective was to …

Evapotranspiration And Energy Balance Of Irrigated Urban Turfgrass, Matthew D. Miksch

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Water usage for irrigation is a big consumer of water resources in urban areas in Utah and other parts of the Intermountain Region of the Western United States. As populations continue to increase in these states, it is important to understand how much water is being used by urban landscapes in order to plan and manage future water resources. Evapotranspiration (ET), or the amount of water leaving a surface over a certain timeframe due to both transpiration from plants and evaporation from the soil, is a key variable in understanding how much water urban landscapes are really using to grow …

Irrigation Zone Delineation And Management With A Field-Scale Variable Rate Irrigation System In Winter Wheat, Elisa A. Flint, Bryan G. Hopkins, Jeffery D. Svedin, Ruth Kerry, Matthew J. Heaton, Ryan R. Jensen, Colin S. Campbell, Matt Yost, Neil C. Hansen

Plants, Soils, and Climate Faculty Publications

Understanding spatial and temporal dynamics of soil water within fields is critical for effective variable rate irrigation (VRI) management. The objectives of this study were to develop VRI zones, manage irrigation rates within VRI zones, and examine temporal differences in soil volumetric water content (VWC) from irrigation events via soil sensors across zones. Five irrigation zones were delineated after two years (2016 and 2017) of yield and evapotranspiration (ET) data collection. Soil sensors were placed within each zone to give real time data of VWC values and assist in irrigation decisions within a 23 ha field of winter wheat ( …

Alfalfa Water Productivity And Yield Gaps In The U.S. Central Great Plains, Kaylin P. Fink, Patricio Grassini, Alexandre Rocateli, Leonardo M. Bastos, Jude Kastens, Luke P. Ryan, Xiaomao Lin, Andres Patrignani, Romulo P. Lollato

Department of Agronomy and Horticulture: Faculty Publications

Context: Yield gap (Yg) analyses using farmer-reported yield and management data have been performed for a number of annual grain crops, but it lacks for perennial forages. The U.S. accounts for 21 % of the global alfalfa production with a large rainfed area located in the central Great Plains, serving as an interesting case-study for Yg in perennial forages. Most existing alfalfa Yg analyses quantified the magnitude of the Yg but failed to identify associated management practices to reduce it. Challenging this analysis, a systematic benchmark for alfalfa water productivity [WP, kg dry matter per mm evapotranspiration (ETc)] that …

Changes In The Invasion Rate Of Prosopis Juliflora And Its Impact On Depletion Of Groundwater In The Northern Part Of The United Arab Emirates, Fares M. Howari, Manish Sharma, Yousef Nazzal, Ali El-Keblawy, Shajrat Mir, Cijo M. Xavier, Imen Ben Salem, Ahmed A. Al-Taani, Fatima Alaydaroos

All Works

Prosopis species were introduced to the United Arab Emirates (UAE) region for desert greening. However, the species now pose a great threat to the native plant diversity. This study used high-resolution satellite imagery (1990–2019) to understand the history and current distribution of Prosopis species and their impact on fresh groundwater. The results show that the Prosopis invasion in the study area reached its maximum expansion rate in 2019 and covered an area of about 16 km2 compared to 0.2 km2 in 1990. The areas near Sharjah Airport, Umm Fannan, and Al Talla, located at a lower elevation of the sand …

Increasing Precipitation Decreases Water Use Efficiency Of Alfalfa (Medicago Sativa L.) In A Semiarid Region, H. Ni, H. K. Chu, X. F. Lai, J. Q. Deng, Yuying Shen

IGC Proceedings (1993-2023)

Alfalfa (Medicago sativa L.) plays an important role within the integrated farming systems in Northwestern Loess Plateau of China, because of its traits on a high productivity, prolonged growing season, and excellent nutritive value. However, water use efficiency (WUE) is a crucial indicator for forage production under different water conditions in the semiarid regions. To explore the responses of alfalfa growth and water use to precipitation variability, we set precipitation shelters to manipulate precipitation scenario as 30% precipitation increased (P+30), normal precipitation (CK), and 30% precipitation decreased (P-30) with the measurement of dry matter yield and soil water content. …

Water Use Characteristics Of Weeds: A Global Review, Best Practices, And Future Directions, Mandeep Singh, Meetpal Singh Kukal, Suat Irmak, Amit J. Jhala

Department of Agronomy and Horticulture: Faculty Publications

Weeds usually penalize crop yields by competing for resources, such as water, light, nutrients, and space. Most of the studies on the crop-weed competition domain are limited to assessing crop-yield losses due to weed pressure and other crop-weed interactions, overlooking the significant uptake of soil-water by weeds that exacerbates global water constraints and threatens the productivity and profitability. The objective of this review was to synthesize globally available quantitative data on weed water use (WU) sourced from 23 peer-reviewed publications (filtered from 233 publications via a multi-step protocol of inclusion criteria) with experimental investigations across space (3 continents), time (1927–2018), …

Deficit Irrigation Strategies For Subsurface Drip-Irrigated Alfalfa, F. R. Lamm, R. Reyes-Esteves, K. R. Harmoney

Kansas Agricultural Experiment Station Research Reports

This subsurface drip-irrigated study was conducted from 2020 to 2021 at the Kansas State University Northwest Research-Extension Center near Colby, KS, to evaluate five deficit irrigation strategies for alfalfa. All strategies were irrigated similarly (100% of Evapotranspiration (ET) minus Rain) through the first seasonal cutting. Following the first cutting, treatments were 1) Irrigate to replace 85% ET minus Rain; 2) Irrigate to replace 50% ET minus Rain between Cutting 2 and 3, then 85% ET-Rain; 3) Irrigate to replace 50% ET minus Rain between Cutting 2 and 4, then 85% ET-Rain; 4) Irrigate to replace 70% ET minus Rain between …

Water-Use Efficiency And Infiltration Under Different Rangeland Conditions And Cultivation In A Semi-Arid Climate Of South Africa, Hennie A. Snyman

IGC Proceedings (1993-2023)

The objective of this study was to determine the impact of rangeland in different botanical composition classes (good, moderate and poor), on water-use efficiency (WUE: crude protein produced per unit of evapotranspiration) and soilwater content. The same measurements were also made on an undisturbed bare soil surface and soil cultivated twice per annum. Evapotranspiration was determined by quantifying the soil-water balance equation with the aid of runoff plots and soil-water content measurements done by a neutron hydroprobe. Water-use efficiency declined significantly (P ≤ 0.01) with rangeland degradation. Rangeland in good condition averaged a WUE of 0.28 kg crude protein ha …

Exploring Water Use And Production Dynamics Of Indigenous Protected Sikumi Forest In South Western Zimbabwe, O. Gwate

IGC Proceedings (1993-2023)

Monitoring changes in carbon and water vapour fluxes over a landscape helps in understanding ecosystem functioning and improves vegetation management. To understand potential shifts in ecosystem functioning, MoDerate Resolution Imaging Spectroradiometer (MODIS) evapotranspiration (ET), net photosynthesis, gross primary production and net primary production data were explored in Sikumi forest dominated by three species clusters (Teak forest woodland, Miombo woodland and savannah, and Vachellia). Measures of ecosystem stability including water use efficiency (WUE), rainfall use efficiency (RUE), evaporative index, and carbon use efficiency (CUE) were assessed for trends and step changes together with rainfall and evapotranspiration data. Miombo woodland and …

Nitrogen And Rainfall Effects On Crop Growth—Experimental Results And Scenario Analyses, Saadi Sattar Shahadha, Ole O. Wendroth, Dianyuan Ding

Plant and Soil Sciences Faculty Publications

Nitrogen (N) fertilization is critical for crop growth; however, its effect on crop growth and evapotranspiration (ETc) behaviors under different amounts of rainfall is not well understood. As such, there is a need for studying the impact of nitrogen application rates and rainfall amounts on crop growth and ETc components. Agricultural system models help to fill this knowledge gap, e.g., the Root Zone Water Quality Model (RZWQM2), which integrates crop growth-related processes. The objective of this study is to investigate the effect of the nitrogen application rate on crop growth, soil water dynamics, and ETc behavior under different rainfall amounts …

Understanding Water And Energy Fluxes In The Amazonia: Lessons From An Observation-Model Intercomparison, Natalia Restrepo-Coupe, Loren P. Albert, Marcos Longo, Ian Baker, Naomi M. Levine, Lina M. Mercado, Alessandro C. Da Araujo, Bradley O. Christoffersen, Marcos H. Costa, David R. Fitzjarrald

Biology Faculty Publications and Presentations

Tropical forests are an important part of global water and energy cycles, but the mechanisms that drive seasonality of their land-atmosphere exchanges have proven challenging to capture in models. Here, we (1) report the seasonality of fluxes of latent heat (LE), sensible heat (H), and outgoing short and longwave radiation at four diverse tropical forest sites across Amazonia—along the equator from the Caxiuanã and Tapajós National Forests in the eastern Amazon to a forest near Manaus, and from the equatorial zone to the southern forest in Reserva Jaru; (2) investigate how vegetation and climate influence these fluxes; and …

Day Versus Night Irrigation Loss From Sprinkler Irrigation Of Urban Crops, Samikshya Pyakurel

Student Research Symposium

Nighttime irrigation is a widespread strategy to conserve water, as it reduces wind drift and evaporation loss (WDEL). However, daytime sprinkler irrigation may also conserve water by lowering the temperature and increasing the humidity of crop microclimates, thereby reducing evapotranspiration (ET). Therefore, the objectives of this study include: 1) quantify whether a water savings exists between day and night irrigation with a water balance approach, 2) analyze the microclimate effects by irrigation timing to determine any changes to WDEL and evaporative demand, and 3) assess the quality and yield response of two urban crops. In 2019-21, we established 12 field …

Spatiotemporal Analysis Of Variability In Soil Volumetric Water Content And Spatial Statistical Methods For Management Zone Delineation For Variable Rate Irrigation, Isak Lars Larsen

Theses and Dissertations

Irrigated agriculture is the largest user of freshwater in a world experiencing increased water scarcity and water demands. Variable rate irrigation (VRI) aims to use water efficiently in crop production, resulting in good yields and water conservation. With VRI, the grower is able to employ custom irrigation rates for different parts of a field. Adoption of VRI has been limited due to the complexity of matching irrigation to spatiotemporal crop water needs and the cost/benefit economics of VRI equipment. The goal of this study was to quantify spatiotemporal variability of VWC in a field that has uniform soil type and …

The Role Of Aerodynamic Resistance In Thermal Remote Sensing-Based Evapotranspiration Models, Ivonne Trebs, Kaniska Mallick, Nishan Bhattarai, Mauro Sulis, Jamie Cleverly, William Woodgate, Richard Silberstein, Nina Hinko-Najera, Jason Beringer, Wayne S. Meyer, Zhongbo Su, Gilles Boulet

Research outputs 2014 to 2021

Aerodynamic resistance (hereafter ra) is a preeminent variable in evapotranspiration (ET) modelling. The accurate quantification of ra plays a pivotal role in determining the performance and consistency of thermal remote sensing-based surface energy balance (SEB) models for estimating ET at local to regional scales. Atmospheric stability links ra with land surface temperature (LST) and the representation of their interactions in the SEB models determines the accuracy of ET estimates. The present study investigates the influence of ra and its relation to LST uncertainties on the performance of three structurally different SEB models. It used data from nine Australian OzFlux eddy …

Midwestern U.S. Diurnal Temperature Range: Spatial And Temporal Trends From 1900-2018, Kelly Ann Swaney

Graduate Research Theses & Dissertations

In the Corn Belt region of the United States, the twentieth century saw many land use changes as the land had been converted from the natural landscape to cropland. As the twentieth century progressed, numerous advancements occurred to increase the crop acreage, crop density, and amount of irrigated land. All of these changes contributed to higher rates of evapotranspiration, which put more moisture into the low levels of the atmosphere. This additional moisture played a role in changing the radiative fluxes and, as a result, the surface temperature. The Diurnal Temperature Range (DTR) is examined across the 1900 to 2018 …