Furrow Fields Research Articles

Bedform evolution along a submarine canyon in the South China Sea: New insights from an autonomous underwater vehicle survey

ABSTRACTTraditional mapping of bedforms in submarine canyons relied on vessel‐mounted and towed sensors, but their fine‐scale geomorphology and shallow structure requires higher resolution datasets. This study utilizes a high‐resolution dataset obtained from an autonomous underwater vehicle, combined with seismic reflection profiles and sediment cores, to analyse bedform sets within a 25.6 km long submarine canyon (canyon C14) in the northern South China Sea. A train of crescent‐shaped axial steps, indicative of cyclic steps formed by supercritical turbidity currents, is imaged along the canyon. Axial steps in the upper course show erosional truncations and sub‐horizontal reflectors on the lee and stoss sides, respectively, pointing to erosional–depositional cyclic steps formed by confined flows with high erosional capacity. This is facilitated by canyon narrowness and steeper axial gradient. After a transition segment, the lower course widens, with a gentler axial gradient, resulting in increased asymmetry and wavelength of axial steps. Backset bed deposits on the stoss sides of these steps indicate depositional cyclic steps with higher aggradation. Sediment filling, almost padding each cyclic step associated scour suggests the reworking of previously formed bedforms by gravity flows fed by destabilization processes on the canyon sidewalls and upstream lee faces and, possibly, by shelf‐edge and uppermost slope spillover into the canyon. At the lowermost course, cyclic steps transition to a furrow field, likely associated with flow velocity reduction facilitated by canyon floor widening and a further decrease in slope gradient. Flow braiding and re‐convergence, related to the erosion of fine‐grained deposits within the canyon floor, should have played a role to produce furrows under supercritical conditions. This work enhances our understanding of the detailed morphology and shallow relief configuration of bedforms in deep‐water submarine canyons, providing insights into their causative processes and evolution.

Erosion Modelling Indicates a Decrease in Erosion Susceptibility of Historic Ridge and Furrow Fields Near Albershausen, Southern Germany

Ridge and furrow fields are land-use-related surface structures that are widespread in Europe and represent a geomorphological key signature of the Anthropocene. Previous research has identified various reasons for the intentional and unintentional formation of these structures, such as the use of a mouldboard plough, soil improvement and drainage. We used GIS-based quantitative erosion modelling according to the Universal Soil Loss Equation (USLE) to calculate the erosion susceptibility of a selected study area in Southern Germany. We compared the calculated erosion susceptibility for two scenarios: (1) the present topography with ridges and furrows and (2) the smoothed topography without ridges and furrows. The ridges and furrows for the studied site reduce the erosion susceptibility by more than 50% compared to the smoothed surface. Thus, for the first time, we were able to identify lower soil erosion susceptibility as one of the possible causes for the formation of ridge and furrow fields. Finally, our communication paper points to future perspectives of quantitative analyses of historical soil erosion.

Deepwater sedimentary bedforms in a mobile substrate terrain: Examples from the central Gulf of Mexico Basin

We have used high-resolution geophysical data to investigate depositional and erosional bedforms in two geomorphologic provinces of the deepwater central Gulf of Mexico Basin: (1) the Mad Dog and Atlantis areas in the Sigsbee Escarpment region and (2) the Holstein minibasin within the salt canopy in the slope. Multibeam bathymetry indicates that the seafloor relief in the study areas is highly irregular because it is influenced by the dynamic behavior of underlying salt bodies resulting in the development of diverse bathymetric features. Side-scan images reveal erosional furrows of different morphologies at the base of the Sigsbee Escarpment that are oriented subparallel to the escarpment. Wide and sinuous furrows overlie mass transport deposits (MTDs), whereas, in other areas along strike, narrow rectilinear furrows are found beneath MTDs. The furrow fields in the Sigsbee Escarpment are located within a large series of erosional features that are linked to the action of westward flowing bottom currents associated with topographic Rossby waves that manage to rework sediments at water depths up to 2000 m. The interaction between the bottom current flow and the seafloor is likely influenced by the MTD’s irregular top surface relief and lateral changes in the escarpment’s morphology resulting in the development of complex sinuous furrow morphologies. North of the escarpment, subbottom profiles indicate a series of buried sediment waves found in the southern rim of the Holstein minibasin. Sediment wave morphometry indicates wavelengths ranging from 116 to 339 m and wave heights between approximately 0.8 and 2.4 m. Sediment waves were likely formed by turbidity currents as they exited the minibasin. The vertical change in topographic relief from the minibasin to the salt high led to variations in flow thickness and flow velocity of turbidity currents passing over the minibasin’s open rim. Consequently, these changes in flow regime led to the formation of sediment waves.

Assessment of straight and meandering furrow irrigation strategies under different inflow rates

This paper reports the effect of straight furrow (SF) and meandering furrow (MF) irrigation strategies, as well as inflow rate, on infiltration and hydraulic parameters including advance time, recession time, and runoff hydrograph. The performance of SF and MF irrigation in terms of runoff ratio, deep percolation, and application efficiency was evaluated in 6 furrow fields at Shahid Bahonar University of Kerman, Iran. The required data were collected from the farm, consisting of free drainage furrows with length 70 m, top width 0.8 m, depth 0.25 m, and slope 0.2%. The advance and recession times were significantly longer in MF than SF irrigation. The infiltration was estimated by Lewis-Kostiakov equation. The infiltration coefficients were calculated: The values of k were higher and of a were lower in MF furrows than in SF furrows. The average runoff ratio and application efficiency for the SF irrigation events were 50.53% and 49.07%, respectively, while those of the MF irrigation events were 7.04% and 52.94%, respectively. Based on the results, the velocity of water advance in MF irrigation is decreased and, thus, the runoff, erosion losses, mass of fertilizer lost and surface water contamination were reduced. Using a lower inflow rate and appropriate irrigation time leads to better management outcomes in irrigation systems.

Bottom currents, submarine mass failures and halokinesis at the toe of the Sigsbee Escarpment (Gulf of Mexico): Contrasting regimes during lowstand and highstand conditions?

In this study we explore the role of sediment supply, halokinesis and deep ocean circulation in promoting margin instability. The analysis was carried out on multibeam and high-resolution seismic data that allowed the imaging of mass failure deposits and current-driven depositional features along a portion of the lower continental slope and upper continental rise of the Sigsbee Escarpment (Gulf of Mexico). Different styles of deposition have been recognised during sea level lowstand (LST) and highstand (HST) conditions, due to alternating bottom current activity and salt tectonics. Lowstands are characterized by a reduced intensity of the Loop Current, as underlined by the lack of current-driven erosional features. On the contrary, highstands show a strengthened Loop Current that generates a fast bottom current circulation, as suggested by the presence of extensive furrow fields on the modern sea floor and on the Marine Isotope Stage 5e palaeo-sea floor horizon. Increased sediment load combined with changes in the intensity of deep water circulation are also responsible for the instability of the Sigsbee Escarpment, triggering mass failure phenomena with distinct morphology, size, location and timing of emplacement. Type 1 mass transport complexes (MTCs) form on the upper continental rise during sea level fall, and are genetically linked to the growth of deep water sediment drifts. Type 2 MTCs develop during sea level lowstands and originate along the slope of the Sigsbee Escarpment, triggered by oversteepening generated by halokinesis. Type 3 MTCs form during sea level rise to highstand conditions and mostly consist of debris flow deposits, generated in the lower portions of the Sigsbee Escarpment and then accumulated in the upper continental rise.

Stereovision-Based Guidance Line Detection Method for Auto-guidance system on Furrow Irrigated Fields

Furrow irrigation, which is conducted by creating parallel channels along the field length, is a cultivation method widely used for growing row crops such as hot pepper, garlic, soybean and tree crops. These artificially structured parallel channels, commonly referred to as ridge-furrow, can provide guidance to autonomous tractors with its characteristic of undulating surface. This study reports the development of a stereovision-based guidance line detection system applicable to ridge-furrow cropping fields. The algorithm implemented in the detection system consisted of two different phases, i.e., splitting depth images into two parts (ridge and furrow) and extracting a guidance line from the split images. Through the image binarization method based on a distance transform and image segmentation method, the depth image was divided into two regions of ridge and furrow and the boundary points of each region were then detected. The second phase extracted a guidance line from the detected boundary points based on linear regression. The guidance lines detected by the developed algorithm were compared with those manually labelled, and the results were RMSEs of 0.02 m and 0.63 degree in lateral deviation and heading angle, respectively. Further, the stereo camera was installed on a tractor and field tests were proceeded on a straight and regularly spaced ridge and furrow field. As a result, the RMSE of lateral deviation measured by a RTK-GPS was 1.37 cm at 3 km/s.

Legacy of medieval ridge and furrow cultivation on soil organic carbon distribution and stocks in forests

Land management history can influence soil organic carbon (SOC) stocks over centuries. In this study, the impact of medieval ridge and furrow cropland management on SOC in forests was assessed. Continuous clockwise ploughing in rectangular fields moved topsoil from the outer part of strip-shaped fields towards the centre, thus forming a corrugated microtopography with peripheral furrows and central ridges. This tillage technique led to the burial of former topsoil under the ridges.The effect of this human-created microtopography and the centuries old topsoil burial on forest SOC spatial distribution and stocks was investigated. Five sites with ridge and furrow field strips under deciduous forests on soils of differing texture in Germany were sampled, with three orthogonal transects of the field strips and a defined reference position where neither net soil removal nor accumulation occurred. Reforestation took place between the 17th and 19th century.At 0 to 10cm depth, average SOC content was 28±3gkg−1 at ridges, 37±3gkg−1 at reference positions and 47±5gkg−1 at furrows. SOC stocks were 7±5% lower at ridges and 8±4% higher at furrows than at reference positions. Enhanced C input at furrows through leaf litter accumulation was indicated by higher SOC content in the free light fraction at furrows (10±5gkg−1) than at ridges (6±3gkg−1), higher specific SOC mineralisation (37±4μgCO2-Cg−1 SOC at furrows and 31±3μgCO2-Cg−1 SOC at ridges) and wider C/N ratio at furrows (18±1) compared with ridges (17±1).Buried topsoil under ridges (20 to 33–52cm depth) did not contain significantly less SOC than corresponding samples at furrows and reference positions. However, SOC content was 0.4 to 0.9gkg−1 higher at ridges than at reference positions, indicating long-term preservation of former topsoil SOC by burial under ridges, although enhanced SOC stocks at ridges due to carbon burial could not be significantly confirmed for all sites. It can be concluded that preserved microtopography over centuries and ancient topsoil burial, a legacy of medieval ridge and furrow cultivation, still influences forest SOC spatial distribution and stocks.

The reshaping of the South West Adriatic Margin by cascading of dense shelf waters

The South West Adriatic Margin (SAM) includes a steep and morphologically complex continental slope stretching about 600km from the Pelagosa sill to the Otranto strait. The margin is clearly dissected by submarine slides, active fault systems (e.g.: the Gondola deformation belt), numerous shallowly incised and relatively straight canyons located south of Bari Canyon, and a variety of large-scale erosional and depositional features. This area is seasonally impacted by dense shelf water forming in the North Adriatic through wind-forced winter cooling, moving south along the western side of the basin, and cascading across the South Adriatic slope.The area has been investigated through multibeam surveys integrated by high-resolution seismic stratigraphic data resolving glacial and post-glacial deposits. This paper gives a detailed and comprehensive description of the SAM seafloor morphology to document how the process of dense shelf water cascading concurs to a thorough “restyling” of the submarine landscape by interacting with the pre-existing and markedly differentiated morphologies and sediment distribution. We focus on depositional and erosional features such as: giant sediment drifts down to 1200m water depth, muddy and sandy sediment waves, comet marks against pre-existing slide blocks, furrow fields against steep slopes, large scours at the shelf edge and large erosional moats adjacent to major morphological barriers. The analysis of the bedform orientation and spatial distribution indicates that the downslope-cascading bottom-currents (dominantly directed to the SE) encounter a straight upper slope, oriented north south in the north and progressively more east west proceeding to the south; as the slope orientation becomes more E–W it also appears more dissected by small-scale canyons, active during glacial times. In the latter area, therefore, the dense shelf waters follow a slope-parallel direction almost perpendicular to the pre-existing slope canyons. As a consequence, erosional furrows develop perpendicular to the canyon flanks and some of the canyon heads become disconnected from the main canyon downslope.

Sediment Transport Model for a Surface Irrigation System

Controlling irrigation-induced soil erosion is one of the important issues of irrigation management and surface water impairment. Irrigation models are useful in managing the irrigation and the associated ill effects on agricultural environment. In this paper, a physically based surface irrigation model was developed to predict sediment transport in irrigated furrows by integrating an irrigation hydraulic model with a quasi-steady state sediment transport model to predict sediment load in furrow irrigation. The irrigation hydraulic model simulates flow in a furrow irrigation system using the analytically solved zero-inertial overland flow equations and 1D-Green-Ampt, 2D-Fok, and Kostiakov-Lewis infiltration equations. Performance of the sediment transport model was evaluated for bare and cropped furrow fields. The results indicated that the sediment transport model can predict the initial sediment rate adequately, but the simulated sediment rate was less accurate for the later part of the irrigation event. Sensitivity analysis of the parameters of the sediment module showed that the soil erodibility coefficient was the most influential parameter for determining sediment load in furrow irrigation. The developed modeling tool can be used as a water management tool for mitigating sediment loss from the surface irrigated fields.

Development of a Muskingum- Cunge routing model for design of furrow irrigation

Surface irrigation projects which accounts for almost all of the irrigated land areas of the world has been studied extensively by many investigators and their performance was found to be lower than expected. Many of these projects are built and operated without adequate technical input, with consequent low uniformity and efficiency of water application. However, irrigators are still faced with significant challenges in making both design and operation of surface irrigation systems more efficient. In this study a mathematical design approach for furrow irrigation was developed as spreadsheet model to simulate all hydraulic phases of water movement as aid to design and to evaluate the performance of furrow irrigation. The irrigation model simulates the hydraulics of furrow irrigation at the field scale. The principle role of the model is the evaluation of alternative field layouts (field length and slope) and management practices (water application rates and cut-off times). Input data requirements for the simulation component include field length, slope, infiltration characteristics (or advance data), target application depth, water application rate, Manning’s resistance and furrow geometry. A series of simple relations were presented for estimating the advance, recession, and performance of surface irrigation systems. The approach uses continuity to compute the advance time to field end and half the distance to field end. The irrigation methods differ slightly in how the surface volume is computed. Initially a surface shape factor is used to compute storage volume during advance phase; however, estimation of this storage volume was corrected during storage, depletion and recession phases by utilizing Muskingum-Cunge routing method. The subsurface volume calculations use a modified Kostiakov equation that includes both an initial sink term and a constant final infiltration rate. Recession calculations differ for each method. With sloping methods, adjustments to a straight line recession curve make recession estimates more reasonable. It is shown that the procedure can produce reasonable predictions of design performance over a range of conditions. Model verification was made by its comparison with FAO-surface-model, and zero-inertia model using data from furrow fields of Kenana Sugar Scheme-Sudan.

Pesticide Leaching from Agricultural Fields with Ridges and Furrows

In the evaluation of the risk of pesticide leaching to groundwater, the soil surface is usually assumed to be level, although important crops like potato are grown on ridges. A fraction of the water from rainfall and sprinkler irrigation may flow along the soil surface from the ridges to the furrows, thus bringing about an extra load of water and pesticide on the furrow soil. A survey of the literature reveals that surface-runoff from ridges to furrows is a well-known phenomenon but that hardly any data are available on the quantities of water and pesticide involved. On the basis of a field experiment with additional sprinkler irrigation, computer simulations were carried out with the Pesticide Emission Assessment at Regional and Local scales model for separate ridge and furrow systems in a humic sandy potato field. Breakthrough curves of bromide ion (as a tracer for water flow) and carbofuran (as example pesticide) were calculated for 1-m depth in the field. Bromide ion leached comparatively fast from the furrow system, while leaching from the ridge system was slower showing a maximum concentration of about half of that for the furrow system. Carbofuran breakthrough from the furrow system began about a month after application and increased steadily to substantial concentrations. Because the transport time of carbofuran in the ridge soil was much longer, no breakthrough occurred in the growing season. The maximum concentration of carbofuran leaching from the ridge–furrow field was computed to be a factor of six times as high as that computed for the corresponding level field. The study shows that the risk of leaching of pesticides via the furrow soil can be substantially higher than that via the corresponding level field soil.

LiDAR‐derived Local Relief Models – a new tool for archaeological prospection

AbstractLocal relief models (LRM) are proposed as a new tool for archaeological prospection. A data processing approach is presented which produces LRM from LiDAR‐derived high‐resolution digital elevation models (DEMs). The LRM represents local, small‐scale elevation differences after removing the large‐scale landscape forms from the data. The LRM greatly enhances the visibility of small‐scale, shallow topographic features irrespective of the illumination angle and allows their relative elevations as well as their volumes to be measured directly. This makes the LRM an improved basis for spatially extensive archaeological prospection over a wide range of landscapes. The LRM raster map of local positive and negative relief variations can be used for the mapping and prospection of archaeological features such as burial mounds, linear and circular earthworks, sunken roads, agricultural terraces, ridge and furrow fields, kiln podia and mining/quarrying sites. This approach is currently being used in a project aimed at the complete archaeological mapping and prospection of the state Baden‐Württemberg (Germany), covering an area of 35 751 km2. The goal of the project is the verification and extension of the existing archaeological data base. An object‐based local relief vector layer is produced as a by‐product; however, due to the common amalgamation of natural and anthropogenic features this cannot be used efficiently for archaeological prospection at present. Copyright © 2010 John Wiley & Sons, Ltd.

A walk down the Cap de Creus canyon, Northwestern Mediterranean Sea: Recent processes inferred from morphology and sediment bedforms

The Cap de Creus canyon, northwestern Mediterranean Sea, belongs to a complex network of submarine canyons cutting the western Gulf of Lion continental shelf and opening into the larger Sète canyon. Swath bathymetry data, MAK-1M deep-towed side-scan sonar imagery and 5 kHz high resolution seismic reflection profiles show striking morphologies in the Cap de Creus canyon floor and walls. As a consequence of the canyon head and the upper reach severe incision, the continental shelf dramatically narrows in front of the Creus Cape promontory. The upper canyon has a flat-bottomed thalweg incised in a mega-scale sediment furrow field displaying hyperbolic seismic facies. The tens of kilometres long linear furrows extend also over the middle canyon down to 1400 m of water depth. The furrows on either side of the canyon are not parallel but oblique and display varying degrees of excavation. Mid-channel sediment bars are locally present in the thalweg, which is made of sandy lag deposits, as revealed by its acoustic response and verified by sediment samples. The middle canyon is linear and steep, with an up to 700 m high southern wall, contrasting with the sinuous, smooth lower canyon, which is controlled by flowage of the underlying Messinian evaporites. Large sections of the canyon are affected by sediment instability processes. The lower Cap de Creus canyon hangs up to 260 m over its distalmost reach and the Sète canyon through a narrow, less than 1 km wide, gorge. Numerous scours up to 10 m deep suggesting bed load transport occupy the lower Sète canyon immediately downstream of the Cap de Creus canyon mouth. The data set provides the first complete very-high resolution imaging of a submarine canyon from its upper part down to its distalmost reach. The observations evidence a wide set of erosion, transport and deposition processes along the Cap de Creus canyon, including sediment entrapment at the canyon head, furrow-generating dense water cascading through the southern wall, along-channel currents strong enough to excavate specific sections of the channel floor and bed load sediment transport as demonstrated by the presence of mega-ripples, crescent scours and grooves in the lower canyon.

Short-distance variability in slope bed-forms along the Southwestern Adriatic Margin (Central Mediterranean)

The slope of SW Adriatic Margin (SAM) is impinged today by two bottom-water masses, of thermohaline origin, that interact constructively along a preferred path: the Levantine Intermediate Water (LIW), generated in the eastern Mediterranean through intense evaporation and flowing along the contour, and the North Adriatic Dense Water (NAdDW), formed on the shallow north Adriatic and cascading episodically off the shelf. These two southward-flowing bottom-water masses impact the upper slope, which is characterized by an irregular physiographic setting, and together create the bottom-current deposits (e.g. fine-grained contourite drifts and sediment waves) and related erosional features (e.g. furrows, scours, comet marks). This study is focussed on a small open-slope area of the SAM (ca. 35 × 25 km), where high-resolution seismic data allow observe elongated contour-parallel scours, widespread erosion surfaces (accompanied by wide crescent-shape scours and furrow fields) and giant comet-marks spatially associated and genetically linked along a common current path. Further downslope, and away from this highly energetic current path, a field of sediment waves migrates upcurrent and shows bifurcated crests. In some cases the downcurrent limbs of the sediment waves display a well-defined erosional character on seismic profiles and furrows on side scan sonar mosaics. All bottom-current features observed are in equilibrium with the present day oceanographic regime, as documented by the available current-metre data. Moreover, sediment cores suggest that the sediment waves are actively migrating during the present interglacial, possibly implying that bottom waters formation was enhanced after the shallow Adriatic shelf was drowned during the late-Quaternary eustatic rise. The SAM slope represents, therefore, an ideal site to improve our understanding of the depositional impact of bottom currents along the Mediterranean margins and may provide useful hints on the activity of bottom currents elsewhere on the Mediterranean margins.

Effect of improved cultural practices on crop yield and soil salinity under relatively saline groundwater applications

The salinity in the root zone increases with the application of relatively saline groundwater. Therefore, a limited water supply coupled with high pumping cost and salinity hazards, makes it more important than ever that irrigation water be used efficiently and judiciously. In the present study, farmer's practices of irrigation application methods (Field 1) were compared with the water saving techniques (Field 2) for crop yield and salinization for two years with maize–wheat–dhanicha cropping pattern. For maize crop, regular furrow method of irrigation was used in Field 1 and alternate furrow method of irrigation was used in Field 2. For wheat experiments, basin irrigation method of water application was compared with bed and furrow method. For dhanicha, basin irrigation was applied in both the fields. The results showed that about 36% water was saved by applying irrigation water in alternate furrows in each season without compromising the maize crop yield. The salt accumulation in root zone in alternate furrow field was less than that in regular furrow field. The salinity level near the surface increased substantially in both the fields. The water saving in wheat crop under bed and furrow was 9–12% in both seasons. The salinization process in both fields during wheat crop was almost same except redistribution of salts throughout the root zone in basin field of wheat. The salinity developed in root zone during two major growing seasons was leached in monsoon.

Agre og miler ved Filsø

Agre og miler ved Filsø

PREPLANT IRRIGATION IN THE CENTRAL AND SOUTHERN HIGH PLAINS - A REVIEW

ABSTRACT Preplant irrigation has been widely practiced in the semi-arid High Plains since the early expansion of pump irrigation from the Ogallala Aquifer in the late 1930s. As groundwater storage continues to decline, the common practice of heavy water application to fully wet the root zone of graded furrow fields prior to planting is being questioned. Under some conditions, preplant irrigation is an essential practice for timely stand establishment and high yields. However, in many situations, the large application depths required for surface irrigation result in inefficient soil water storage and low yield response. With center pivot sprinkler systems, smaller and more precise preplant irrigation application amounts are possible resulting in more efficient preseason storage. We conclude that the benefits of preplant irrigation are likely to be greatest (1) when the soil profile is dry before planting; (2) when seasonal irrigations are not applied to drought-tolerant crops or are reduced in amount; (3) when early planting limits soil wetting by precipitation by the desired date; and (4) when preplant irrigation plus seasonal precipitation on deep, high water storage soils can result in moderately high irrigated yields without seasonal irrigation. The benefits are likely to be low (1) when soil profiles are moderately wet at time of irrigation; (2) when planting dates are flexible and can follow precipitation events for stand establishment; and (3) when seasonal irrigation provides adequate water to meet plant requirements. As groundwater decline continues and precipitation becomes more important for supplying crop water requirements, the use of preplant irrigation as an irrigation water management practice will likely decline in importance in the High Plains.

Yield and Water Use Efficiency of Grain Sorghum in a Limited Irrigation‐Dryland Farming System1

AbstractA Limited Irrigation‐Dryland (LID) farming system for the conjunctive use of rainfall and limited irrigation of graded furrows was developed and field tested. The unique feature of the LID system is that it actually adjusts, during the crop growing season, the amount of land irrigated since more land can be irrigated during above‐average rainfall years with a limited amount of irrigation water than during below‐average years. The design used a limited water supply to irrigate a larger area than could be conventionally irrigated. A graded furrow field, 600 m long on a 0.3 to 0.4% slope was divided into three water management sections. The upper half of the field was managed as “fully irrigated.” The next one‐fourth was managed as a “tailwater runoff” section that utilized furrow runoff from the fully irrigated section. The lower one‐fourth was managed as a “dryland” section capable of utilizing runoff from either rainfall or irrigation on the wetter sections. The system was field tested for 3 years with grain sorghum (Sorghum bicolor (L.) Moench) on a Pullman clay loam (fine, mixed, thermic family of Torretic Paleustolls). Seasonal rainfall values were 224 mm in 1979, 103 mm in 1980, and 424 mm in 1981 as compared to the average of about 250 mm. The LID system was successful in increasing the utilization efficiency of irrigation water. Irrigation water added to a field can be transpired, evaporated, percolated, lost as runoff, or left stored in the soil after harvest. The LID system tended to reduce all losses other than transpiration. When 125 mm or 185 mm of irrigation water were added with the LID system, the evapotranspiration by grain sorghum was increased by an almost equal amount. This increased grain yield an average of 154 kg/ha for each 10 mm added irrigation, compared to 92 kg/ha for each 10 mm under conventional irrigation practices.