Soil Science Commons^™

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 (1997-2023)

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 (1997-2023)

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 (1997-2023)

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 …

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

IGC Proceedings (1997-2023)

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 …

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

IGC Proceedings (1997-2023)

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).

Daytime Versus Nighttime Sprinkler Irrigation Of Two Urban Crops In A Semi-Arid Climate At High-Elevation, Samikshya Pyakurel

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nighttime irrigation scheduling is a longstanding water conservation approach to reduce evaporative losses in Utah's semi-arid, urban landscapes. However, residential demand now exceeds system capacity, and the efficiency of the practice has come under question. Therefore, the objectives of this study include: 1) quantify whether a water savings exists between day and night irrigation with a water balance and energy balance approach, and 2) analyze microclimate and crop quality effects to determine any changes to evaporative demand or plant stress by irrigation timing. In 2019, we established 12 field plots in North Logan, UT (41.77° N, -111.81° W, 1380 m …

Estimating Evapotranspiration And Analyzing Soil Moisture And Heat Flux Parameters At Taneum Creek, Central Washington, Edward Vlasenko

All Master's Theses

In the past two decades, stream restoration work, primarily in the form of wood emplacement, has been undertaken in the Taneum Creek watershed, resulting in increased channel-floodplain connectivity. One of the goals of stream restoration was to boost dry season groundwater storage in the shallow floodplain aquifer. However, any gains in groundwater due to increased connectivity may be nullified by increased evapotranspiration (ET) losses because of denser floodplain vegetation. Within the floodplain aquifer budget, ET is a major flow of water out of the system and is not well quantified.

In order to quantify ET, a monitoring site was established …

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 (1997-2023)

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

IGC Proceedings (1997-2023)

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 (1997-2023)

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 …

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 …

Partitioning Of Evapotranspiration In Four Grassland Ecosystems With A Two Source Model, Zhongmin Hu, Guirui Yu, Xiaomin Sun

IGC Proceedings (1997-2023)

No abstract provided.

Water Use Efficiency And Evapotranspiration Of Hybrid Napier (Pennisetum Purpureum X P. Americanum) Under Semi-Arid Indian Region, J. B. Singh, Rajiv K. Agrawal, Pradeep Behari

IGC Proceedings (1997-2023)

Napier bajra hybrid (Pennisetum glaucum x P. purpureum) is a highly valued for its abundant quality forage, round the year fodder availability, regenerative ability and suitability to silage and hay making. It yields upto 110-120 t/ha fresh fodder as sole crop. Though, it requires moist regimes for optimum growth, but it can withstand drought for a short spell and regenerate with rains. It contains 8.7-10.2 % crude protein, 28-30.5% crude fibre and 10-11.5 % ash on dry matter basis (Agrawal et al., 2001). The hybrid napier has wider adaptability and is grown all over the country, …

The Influence Of Geo-Morphological Landscape Patterns On Vegetation Characteristics In Tajikistan Grasslands, Mounir Louhaichi, Aziz Nubekov, Abdulla Madaminov, Barbara Rischkowsky

IGC Proceedings (1997-2023)

Grassland ecosystems are affected by a combination of physical and environmental factors, as well as by grazing and human induced activities. The primary objective of this study was to examine the influence of geo-morphological landscape patterns on vegetation characteristics in Tajikistan where two sites were selected. The vegetation sampling took place in spring and fall. Vegetation characteristics were assessed using the line intercept method for vegetation cover and species composition and quadrat sampling for biomass production. An ANOVA using replicated trials in complete block design was used to determine the relationship between aspect and vegetation characteristics. Treatments included location (site), …

County-Wide Assessment Of Irrigation Expansion On Air Temperature, Humidity And Evapotranspiration Rates In Nebraska, 1979-2015, Jozsef Szilagyi

Conservation and Survey Division

Total irrigated land area has been expanding in Nebraska over the last 40 years, propelling the state into a leading position within the US in terms of irrigated acreages. Typically, those counties which display the largest degree of irrigation development had a significant portion of their land area already irrigated in 1978. Large-scale irrigation in Nebraska affects its atmospheric environment. During the typical irrigation season of May to August, counties with the largest rate of irrigation expansion have cooled by about 0.2 – 0.3 °F per decade in the summer months of June, July and August, while counties with the …

Understanding The Food Water Nexus: Characterizing The Impact Of Climatological Anomalies On Agrosystems, Patrick M. Wurster Jr.

Graduate Student Theses, Dissertations, & Professional Papers

Climate variability at global and regional scales is escalating with increased atmospheric carbon and is expected to magnify the intensity and duration of meteorological extremes, especially droughts. From the many environmental stresses that diminish crop production (e.g., soil salinity, frost, soil erosion) drought is one of the most prevalent. This study focuses on the sensitivity of three key crops produced in the northwestern United States to climatological anomalies, while controlling for attribution using anomalies in price. The study differs from similar studies in that we focus on variability in production which captures both yield (tonnes/ha) and cropping area (ha), as …

Basic Meteorological Data Derived 30-Year Normas (1981-2010) Of Actual Evapotranspiration Rates In Nebraska, Usa, Jozsef Szilagyi

Conservation and Survey Division

No abstract provided.

Linking Montane Soil Moisture Measurements To Evapotranspiration Using Inverse Numerical Modeling, Ling Lv

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Evapotranspiration (ET) and soil moisture play important roles in annual water delivered from snowpack to reservoirs, lakes and streams. Indeed, ET and soil moisture are key factors dictating the performance of the regional climate models in the intermountain west (IMW) of the USA. Water resources management and climate modeling require accurate prediction of ET and areal soil moisture for reliable estimates of ongoing and future water needs. This research has examined ways to estimate ET from four common vegetation types in the IMW (aspen, conifer, grass and sage) using local soil moisture measurements from an advanced instrumentation network located in …

Calibration And Use Of A Combination Atmometer To Estimate Evapotranspiration And Monitor Soil Moisture Storage On Farmland Catchments In Western Australia, K J. Bligh

Resource management technical reports

The readily-operated combination method of estimating evapotranspiration was applied using simple atmometers, calibrated against absolute evapotranspiration. While 76.6 per cent of the variance of estimates was accounted for by the regression in the first season under wheat, no significant results were achieved in a further four seasons. Combined data for two seasons under legume pastures enabled 30.1 per cent of the variance of estimates to be accounted for.

Modelling Direct Episodic Recharge In The Western Australian Wheatbelt, F Lewis, Cooperative Research Centre For Catchment Hydrology (Australia)

Resource management technical reports

In agricultural regions of Western Australia, salinity is spreading. This is because the area taken up by groundwater discharge is increasing as a result of increased groundwater recharge following the replacement of native vegetation systems by annual crops and pasture species. Attempts to reduce groundwater recharge are now being made as it is hoped that this will decrease the rate of land salinisation. At several sites, average recharge rates have been estimated to be from 2% to 13% of the average annu ter hydrographs from the agricultural regions indicate that at some sites recharge does not occur as small amounts …

Improving Irrigation Scheduling And Water Use Efficiency In Cotton, Derrick M. Oosterhuis

Technical Reports

Cotton (Gossypium hirsutum L) is an important crop in the southern United States. The crop is grown in both irrigated and rainfed situations and is seldom free from periods of water shortages at some stage during the season. In recent years the need for consistency in yields and a stable cash flow has resulted in a rapid expansion in the number of irrigated acres of cotton in the Mississippi Delta. Irrigation research has, however, not kept pace with this expansion. This project represents a start at meeting this urgent need. The influence of weather patterns necessitates that these studies be …

Report On The Application Of An Evapotranspiration Equation To The Waca Dome, P R. Scott

Resource management technical reports

No abstract provided.

A Formula To Express Evapotranspiration As A Function Of Soil Moisture And Evaporative Demands Of The Atmosphere, Aldo L. Norero

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A mathematical expression was developed and tested which describes the relation between evapotranspiration and soil moisture. A general premise of this mathematical model is that the evapotranspiration-soil moisture relationship is determined by interaction of climatic, soil and plant factors. The basic model is

dETa/dYs = -ke[1-(ET_a/ET_mx)]

in which ET_a is the actual evapotranspiration, Ψ_s is the total soil water potential, k is a proportionality coefficient, ∈ is the soil moisture extraction capacity of the atmosphere , and ET_mx is the evapotranspiration that would occur from a particular crop-soil unit when soil moisture was …

The Influence Of Advective Energy On Evapotranspiration, Mahmoud Abdel Aziz

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Evaporation and transpiration from the soil and plant, respectively, have received increasing attention from those who work with water supply, irrigation, and drainage.

The Influence Of Soil Moisture Suction And Evaporative Demand On Actual Evapotranspiration And Yield Of Alfalfa, Bozorg Bahrani

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Evapotranspiration has been defined as the combination of evaporation of water from the soil surface and transpiration of water by vegetation. If the ground is well covered by plants, most of the water is lost by transpiration of water directly from the plant tissue, rather than by evaporation of water directly from the soil surface. The term consumptive use is synonymous with evapotranspiration.