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Since the opening of the website a number of questions about soil problems, reclamation,
drainage systems, irrigation, land and water management, and statistics have reached me.
Sometimes I was unable to provide an adequate answer.
However, there were questions I could categorize and answer collectively through generalized
texts that were made for the occasion.
Twelve of the categories are dealt with below in PDF documents that can be viewed and saved
on your computer provided you have got an Acrobat Reader installed.
More papers can be found on the articles page. Other publications may follow in due course. |
Software
Articles
Reports |
The following 16 questions were frequently asked:
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1 - What is waterlogging? (This is probably the most frequently asked question}
2 - What are saline and salty soils, how do they originate, where are they found, what is their problem, how can the problem be solved?
3 - What are alkali, alkaline sodic and acid sulphate (sulfate) soils (cat clays), how do they originate, where are they found, what is their problem, how can the problem be solved?
4 - What kind of drainage systems are applicable under what conditions?
5 - How can I calculate drainage discharge needs and irrigation/leaching requirements for salinity control using water and salt balances without resorting to simulation models like SaltMod and SahysMod?
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6 - What is the development of river salinity in downstream direction when, in arid and semi-arid regions, the salty river water is used for irrigation of agricultural land and the drainage flow and effluent are returned to the river, and what are the effects on soil salinity and how can eventual problems of salty soils be tackled?
8 - How can hydraulic conductivity (permeability) of the soil be measured and determined?
9 - Drain spacing equations for horizontal tile/pipe drains are well known. Can subsurface drainage also be done by (tube)wells and how can the required spacing be calculated?
10 - What is the optimimum depth of the water table and how can we develop suitable drainage criteria to design a subsurface drainage system
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11 - What are the principles of linear regression analysis (used in the SegReg program, see Software page) and how are confidence statements and intervals determined. What is breakpoint (break point), threshold, and coefficient of explanation (determination)?
12 - What are the principles of cumulative frequency analysis and (discontinuous) probability distributions (used in the CumFreq program, see Software page), and what to do if there is a discontinuity? What is return period and how reliable is it?
13 - The SegReg model (see Software page) provides confidence intervals of the break-point in segmented linear regression analysis to test its statistical significance. Is it necessary to additionally perform an analysis of variance (ANOVA) and F-test and how is this done?
14 - What envelope materials (filters, wraps) are used for pipe drains?
15 - What is tidal irrigation and how does it work?
16 - How is the river and surface water pollution tackled in The Netherlands?
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| For more papers proceed to the articles page or else return to the home page. |