Accounting for temporal inflow variation in the inverse solution for infiltration in surface irrigation   总被引：1，自引：0，他引：1  

M. H. Gillies  R. J. Smith  S. R. Raine 《Irrigation Science》2007,25(2):87-97

A simple modification of the volume balance equation of the IPARM model is presented to facilitate the use of variable inflow. Traditional approaches for estimating infiltration from advance and/or runoff have merely considered the constant or step inflow case. Whenever this assumption is violated, significant uncertainty is introduced into the estimated infiltration parameters. Evaluation of the procedure with a number of data sets has demonstrated significant improvements in the estimates of infiltration parameters. Furthermore, the technique has shown that a portion of the apparent variability in estimated soil intake rates between furrows in the same field is a consequence of the constant inflow assumption. Accounting for the variable inflow to estimate infiltration functions, both standardised the shape of the infiltration curve and reduced the magnitude of the variation between curves. The proposed technique remains restricted by limitations similar to that of other volume balance models but offers greater performance under typical inflow variations often experienced in practice.  相似文献   

“WaterMan”: an on-farm water management game with heuristic capabilities     

Mohammed Z. Shaban  Gary P. Merkley 《Irrigation Science》2016,34(6):483-499

A modern computer-based simulation tool (WaterMan) in the form of a game for on-farm water management was developed for application in training events for farmers, students, and irrigators. The WaterMan game utilizes an interactive framework, thereby allowing the user to develop scenarios and test alternatives in a convenient, risk-free environment. It includes a comprehensive soil water and salt balance calculation algorithm. It also employs heuristic capabilities for modeling all of the important aspects of on-farm water management, and to provide quantitative performance evaluations and practical water management advice to the trainees. Random events (both favorable and unfavorable) and different strategic decisions are included in the game for more realism and to provide an appropriate level of challenge according to player performance. Thus, the ability to anticipate the player skill level, and to reply with random events appropriate to the anticipated level, is provided by the heuristic capabilities used in the software. These heuristic features were developed based on a combination of two artificial intelligence approaches: (1) a pattern recognition approach and (2) reinforcement learning based on a Markov decision processes approach, specifically the Q-learning method. These two approaches were combined in a new way to account for the difference in the effect of actions taken by the player and action taken by the system in the game world. The reward function for the Q-learning method was modified to reflect the suggested classification of the WaterMan game as what is referred to as a partially competitive and partially cooperative game.  相似文献   

Water productivity: science and practice—introduction     

A. H. Kassam  D. Molden  E. Fereres  J. Doorenbos 《Irrigation Science》2007,25(3):185-188

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Water uses and productivity of irrigation systems     

A. J. Clemmens  D. J. Molden 《Irrigation Science》2007,25(3):247-261

Reducing overall water diversions for agriculture, while maintaining or increasing production to keep up with increasing world population, has been and will continue to be a challenge. Yet there is not good agreement regarding the programs needed to improve the productivity of agricultural water use, nor what increases are feasible. It is recognized that field irrigation is inherently nonuniform. So also is the distribution of water to users and water delivery service nonuniform. Here, we suggest that crop-scale irrigation uniformity can be examined at a project scale by understanding how field, farm and project irrigation systems contribute to nonuniformity. We also discuss the interrelation between project scale uniformity and the relative irrigation water supply, and their combined impact on project productivity. We provide an example which relates internal measures of project performance (e.g., water distribution operations) and external measures of project performance (e.g., project-wise water productivity).  相似文献   

Solute movement in an intact soil core under different ponding heights     

F. Tonguç  H. Merdun 《Eurasian Soil Science》2009,42(13):1497-1503

Contaminant transport to groundwater systems through the unsaturated zone follows, in most cases, preferential pathways. The understanding and assessment of this preferential flow mechanism is important to the prevention and solution of resulting problems. A column study was carried out where a NaCl-tracer solution (33 to 37 mmohs/cm of conductivity) was passed through an intact soil core under saturated conditions and three different ponding heights ranging from 5 to 30 mm. Outflow rates varied from 13 to 103 ml/min during the three tests performed. A subsequent dye tracing and slicing of the soil column was performed. Electrical conductivity measurements assessed indirectly the chloride content of the water outflow. Breakthrough curves (BTCs) showed short threshold times (less than 20% pore volume time) and asymmetry with respect to the point defined by C/Co = 0.5 and pore volume time. The BTCs successfully represent the flow measurements through the soil column, this fact is supported by the subsequent horizontal slicing (5 cm thick) of the intact core.  相似文献   

Comparison of the results of soil profiles’ diagnostics performed in three classification systems     

M. I. Gerasimova  N. B. Khitrov 《Eurasian Soil Science》2012,45(12):1087-1094

Three soil classification systems—the World Reference Base for Soil Resources (WRB), Soil Taxonomy, and the recent Russian system—were used for the identification of 17 soil profiles in southwestern Poland; all the systems put emphasis on the soil properties as diagnostic criteria. Different soils developed on glaciofluvial plains, loessic uplands, and in the Sudetes Mountains were classified. The best correlation between the classification decisions in the different systems was obtained for the most widespread soils owing to the similarity of the diagnostic criteria, which were essentially close although not coinciding. The most prominent divergence between the systems in both the names and the taxonomic categories of the soils was found for the polygenetic soils and for the soils developing from the lithologically discontinuous parent materials. It was also found that the diagnostic elements differ in terms of their taxonomic importance among the classification systems.  相似文献   

The content of microelements and iron in soils and plants in the basin of lake Kotokel’ in Western Transbaikalia     

S. B. Sosorova  A. B. Gyninova  M. G. Merkusheva  L. L. Ubugunov  L. N. Boloneva 《Eurasian Soil Science》2012,45(4):376-385

The content of microelements (Mn, Zn, Cu, Co, Ni, Cr, Pb, and Cd) and Fe is determined in the soils and plants of the Lake Kotokel’ basin. Their content in the soils is proved not to exceed the regional background and the existing MPC and APC. The content of Cd is revealed to exceed its clarke value for the world soils, which is related to the natural origin of this element. The concentrations of Mn, Co, and Pb are close to their clarke values, and those of Zn, Cu, Ni, and Cr are lower than their clarkes. The studied soils are specified by the maximal amount of the mobile forms of microelements. The profile distribution of the microelements differs depending on the genetic soil type. For Mn, Zn, and Cu, a significant biogenic accumulation is pronounced in the organic soil horizons. The content of microelements in the aboveground phytomass exceeds the maximal permissible levels for Mn, Co, Cr, and Fe. The intensity of the microelements absorption by the plants varies widely, being specified by the high coefficient of the biological adsorption (except for Fe). Mn, Zn, and Cu are accumulated in the plant phytomass the most intensely.  相似文献   

Special features of humus acids extraction from soils by sodium pyrophosphate solutions of different alkalinity     

L. G. Bakina  N. E. Orlova 《Eurasian Soil Science》2012,45(4):392-398

The regularities of extracting humus acids from soils of different types with solutions of sodium pyrophosphate at the equilibrium pH values of 5–13 were studied. The increase in the humus acids yield from the soils with the increasing alkalinity of the solution applied is directly related to the capability of acid functional groups (carboxyl and phenol hydroxyl) for dissociation at definite pH values. The regularities of the changes in the chemical nature and degree of humification of humus acids extracted from the soils related to the pH of the solution were revealed. A sodium pyrophosphate solution (pH 10) was suggested for extracting the humus acids most active in the given soil.  相似文献   

Role of active aluminum in the formation of water-stable macroaggregates     

Saiyed Md. Ibrahim  Yoshiaki Inoue  Haruo Shindo 《Soil Science and Plant Nutrition》2013,59(4):685-689

Soil structure is determined by the arrangement of particles in soil and the particles of sand, silt, and clay bind together into aggregates of various sizes by organic and inorganic materials. Structural stability which is the ability of the aggregates and pores to remain intact when subjected to stress, markedly affects crop production and soil erosion (Tisdall 1996). Since water, either directly as rainfall or as surface runoff is the main agent of aggregate breakdown, in the analyzes of stable soil aggregation, the term water-stable aggregation is generally used (Lynch and Bragg 1985). Water-stable aggregates have been divided into micro aggregates < 0.25 mm dia.) and macro aggregates (> 0.25 mm dia.) (Edwards and Bremner 1967; Tisdall and Oades 1982). Microaggregates show a relatively high stability against physical disruption (Edwards and Bremner 1967). On the other hand, macro aggregates are sensitive to soil management (Tisdall and Oades 1982).

There are many reports on the relationships between the aggregate stability and the soil physicochemical properties. For example, significant correlations were found between the aggregate stability and the amounts of organic C (Tisdall and Oades 1982), total N, and carbohydrates or the CEC (Chaney and Swift 1984). However, most of these studies were conducted in non-volcanic ash soils. Volcanic ash soils are widely distributed in Japan and are very important soils for crop production. The objective of this study was, therefore, to obtain more information on the relationship between the degree of macro aggregation and the soil physicochemical properties in non-volcanic and volcanic ash soils.  相似文献   

Contact angles at the water–air interface of hydrocarbon-contaminated soils and clay minerals     

O. A. Sofinskaya  A. V. Kosterin  E. A. Kosterina 《Eurasian Soil Science》2016,49(12):1375-1381

Contact angles at the water–air interface have been measured for triturated preparations of clays and soils in order to assess changes in their hydrophobic properties under the effect of oil hydrocarbons. Tasks have been to determine the dynamics of contact angle under soil wetting conditions and to reveal the effect of chemical removal of organic matter from soils on the hydrophilicity of preparations. The potentialities of static and dynamic drop tests for assessing the hydrophilic–hydrophobic properties of soils have been estimated. Clays (kaolinite, gumbrine, and argillite) have been investigated, as well as plow horizons of soils from the Republic of Tatarstan: heavy loamy leached chernozem, medium loamy dark gray forest soil, and light loamy soddy-calcareous soil. The soils have been contaminated with raw oil and kerosene at rates of 0.1–3 wt %. In the uncontaminated and contaminated chernozem, capillary water capacity has been maintained for 250 days. The contact angles have been found to depend on the degree of dispersion of powdered preparation, the main type of clay minerals in the soil, the presence and amount of oxidation-resistant soil organic matter, and the soil–water contact time. Characteristic parameters of mathematical models for drop behavior on triturated preparations have been calculated. Contamination with hydrocarbons has resulted in a reliable increase in the contact angles of soil preparations. The hydrophobization of soil surface in chernozem is more active than in soils poorer in organic matter. The complete restoration of the hydrophilic properties of soils after hydrocarbon contamination is due to the oxidation of easily oxidizable organic matter at the low content of humus, or to wetting during several months in the absence of the mazut fraction.  相似文献