Irrigation management strategies for corn to conserve water

Presented at the Central Plains irrigation conference on February 17-18, 2004 in Kearney Nebraska.Includes bibliographical references

Evaluating Reflected GPS Signal as a Potential Tool for Cotton Irrigation Scheduling

Accurate soil moisture content measurements are vital to precision irrigation management. Remote sensing using the microwave spectrum (such as GPS signals) has been used for measuring large area soil moisture contents. In our previous work, we estimated surface soil moisture contents for bare soil using a GPS Delay Mapping Receiver (DMR) developed by NASA. However, the effect of vegetation was not considered in these studies. Hence the objectives of this study were to: 1) investigate the feasibility of using DMR to determine soil moisture content in cotton production fields; 2) evaluate the attenuation effect of vegetation (cotton) on reflected GPS signal. Field experiments were conducted during the 2013 and 2014 growing seasons in South Carolina. GPS antennas were mounted at three heights (1.6, 2.7, and 4.2 m) over cotton fields to measure reflected GPS signals (DMR readings). DMR readings, soil core samples, and plant measurements were collected about once a week and attenuation effect of plant canopy was calculated. Results showed that DMR was able to detect soil moisture changes within one week after precipitation events that were larger than 25 mm per day. However, the DMR readings were poorly correlated with soil volumetric water content during dry periods. Attenuation effect of plant canopy was not significant. For irrigation purpose, the results suggested that the sensitivity of reflected GPS signals to soil moisture changes needed to be further studied before this technology could be utilized for irrigation scheduling in cotton production. Refinement of this technology will expand the use of advanced remote sensing technology for site-specific and timely irrigation scheduling. This would eliminate the need to install moisture sensors in production fields, which can interfere with farming operations and increase production costs

EC01-797 Filtration and Maintenance: Considerations for Subsurface Drip Irrigation (SDI)

When using Subsurface Drip Irrigation (SDI) systems, it is important to prevent clogging problems before they occur. The best prevention plan includes an effective filtration and water treatment strategy. Depending on the water source and its quality, various combinations of sand separation, filtration and chemical treatments may be required and are discussed here in this extension circular

An Online Tool for Estimating Evapotranspiration and Irrigation Requirements of Crops in South Carolina

In recent years, there has been an increased interest in South Carolina regarding the amount of water used by different consumers, especially agricultural producers. This interest has sparked conversations among different stakeholders, including the media, policy makers, producers, scientists, and the general public, regarding the current state and future of water resources in the state. Central to these discussions, from the agricultural sector perspective, is the question of how much water producers really need to grow crops. The objective of this study was, therefore, to develop an online tool to use local South Carolina historic weather data to estimate daily and seasonal crop evapotranspiration and irrigation requirements for different crops. The overall goal was for the new tool to assist farmers and other stakeholders to better plan irrigation water allocations and management. Therefore, an interactive online tool called ETcCalc was created to address this objective. ETcCalc, which is freely available online (http://sccropwater.com), was developed using historic weather data; therefore, it is suitable as an irrigation planning tool rather than a real-time irrigation scheduling tool

Subsurface drip irrigation in Nebraska

Presented at the Central Plains irrigation conference on February 17-18, 2004 in Kearney Nebraska.Includes bibliographical references

EC06-783 Watermark Granular Matrix Sensor to Measure Soil Matric Potential for Irrigation Management

Extension Circular 06-783 discusses Watermark Granular Matrix Sensor to Measure Soil Matric Potential for Irrigation Management

EC05-776 Advantages and Disadvantages of Subsurface Drip Irrigation

Extension Circular 05-776: Advantages and Disadvantages of Substrate Drip Irrigation. This circular contains information about substrate drip irrigation including expected energy savings, potential yield increases, investment cost, and installation information

Principles and Operational Characteristics of Watermark Granular Matrix Sensor to Measure Soil Water Status and Its Practical Applications for Irrigation Management in Various Soil Textures

Technology implementation in agricultural water management can significantly enhance crop water productivity and result in soil, water, and energy conservation. Over the years a number of newer and cost-effective technologies/tools have been developed to measure soil water status. Deciding which technique should be used depends on the purpose of the measurements, soil and crop conditions, desired accuracy, cost and durability of the sensor, ease of operation and interpretation of the data, and other factors. This Extension Circular defines soil matric potential and describes principles and operational characteristics of one of the electrical resistance-type soil moisture sensors for irrigation management. It describes proper installation, maintenance, data downloading, interpretation, and use in irrigation management decisions. Examples show how soil matric potential can be used for irrigation management in various soil textures. The information, data, and recommendations made in this publication are based on long-term field research conducted by the first author at the UNL South Central Agricultural Laboratory, Clay Center, Neb., and other locations in Nebraska. Water in the soil influences plant growth and yield along with many other variables and management operations, including performance of tillage operations, planting, nutrient uptake, soil temperature, and field hydrologic components (runoff, deep percolation, drainage). Measurement of soil water status (soil water content or soil water potential) is essential in agriculture for research and development and for routine onfarm monitoring of a current crop\u27s status in terms of water stress so informed decisions about irrigation management can be made. Accurate determination of soil water status is a fundamental element of agricultural water management, and a fundamental component in studies related to soil water movement, crop water stress, evapotranspiration, hydrologic and crop modeling, and other agricultural practices. Irrigation management requires knowledge of when and how much water to apply to optimize crop production. Too much or frequent irrigations may cause anaerobic soil conditions and promote undesirable chemical and biological reactions in the soil, which can substantially reduce yield quantity and quality, and waste water resources. Conversely, too light or infrequent irrigation applications may cause drought conditions which also may reduce crop yield quantity and quality. Irrigation management requires the quantitative knowledge of when and how much water to apply to optimize crop production, which also requires utilizing technology for soil water status measurements. Effective irrigation management requires that soil water status be accurately monitored over time in representative locations in the field. For optimum yield, soil water in the crop root zone must be maintained between desirable upper and lower limits of plant available water. Proper irrigation management will help prevent economic losses caused by over- or under-irrigation; leaching of nutrients, pesticides, and other chemicals into the groundwater and other water bodies; and wasting water and resources. This publication discusses one of the newer electrical resistance methods to quantify soil water status through measurement of soil matric potential, and its practical applications in irrigation management

G05-1579 Using Modified Atmometers (ET\u3csub\u3egage\u3c/sub\u3e®) for Irrigation Management

This NebGuide describes the atmometer (evapotranspiration gage) and explains how it can be used for irrigation scheduling. Examlpes are provided to show how information collected with an atmometer can be used to estimate crop water use for corn and soybean