Agricultural Irrigation - Science topic

Dear Researcher

You can take help from my article " pollution in irrigation water and farmers satisfaction", available at researchGate.

Thanks Glicherie Caraivan

A great question, just in case you've not already seen it, FAO 56, Allen et al, 'Crop evapotranspiration - Guidelines for computing crop water requirements - FAO Irrigation and drainage paper 56', is worth looking at as it includes details of key environmental drivers and the use of crop coefficients.

Soil moisture sensors can be applied to avoid over watering and poor WUE as well as under watering leading to plant stress - specific moisture levels will be dependent on crop and soil type.

Moisture meter tests: This uses a specialized device called a moisture meter to determine the (%MC ) percentage moisture content of the material.

The pin meters use electrical resistance to measure the presence of water.

The less resistance there is to the electrical current, the more moisture there is in the plant matter.

I should also have given you the attached..

Water productivity (WP) and Water use efficiency (WUE) are mostly used interchangeably. However, this is a significant difference between the two. This book and journal (https://books.google.de/books?hl=en&lr=&id=L-hw0eRvpD4C&oi=fnd&pg=PA27&dq=water+use+efficiency&ots=1GmT8JsaNl&sig=5wGWfP7Kz3V1cLisgcbJjSmMGTo&redir_esc=y#v=onepage&q=water%20use%20efficiency&f=false and https://ageconsearch.umn.edu/record/208411/files/H046807.pdf) provide more clarity on WP and WUE.

I would say that WP is a subset of WUE. WUE is a concept that is mostly use to quantify water use - economics, energy, agriculture etc. WP is mostly an irrigated agriculture concept which is defined as the mass marketable value of crop (dry yield most times) per unit of water use to produce the crop (Transpiration, but Actual evapotranspiration is mostly use).

The journal below should help as well to provide more clarity.

Noha Abdelwarth The FAO's Land and Water Division developed the ETo calculator. FAO-standard reference evapotranspiration (ETo) is one of its primary functions. The ETo calculator uses the Penman-Monteith equation to estimate ETo from meteorological data.

According to the potential capacity of the lands and considering product ecology requirements and rely on the agronomy management requirements and considerations Ley-Farming cropping pattern is better than the mono-culturing.

Tomchilatib sug'orish orqali suv tuproqning qaysi qatlamigacha yetib boradi?

Hello Prof.Sean,

Check on this website

Biofilms are a recurrent problem in any nutrient rich circulating system. Other than periodically disinfection of the system with high pressure vapor (if its built with a suitable material) and using high power UV light or giving it a time residence within an ozone bubbling tank at some point of the recirculation system to lower the amount of CFUs, I can think only of another approach that is more alternative and not mainstream,

as it has been since long known that bacterial loads can be reduced with by adding some so called “colloidal“ silver ion solutions to the nutritive solution, I have seen excellent results of this in postharvest duration of flowers when used as a pulse dip before packing and also when used at the water in the flowerpot, chrysanthemum can last pristine for two months instead of two weeks with this treatment, without changing the water on the flowerpot at all.

That is okay, you can also try this website

Hi Dong, In a greenhouse having nearly zero wind speed, movement of air by convection takes over. Leaves are warmed by photons. The air in contact with the leaves warms and then expands and becomes more bouyant than the air above it. It therefore "floats" upward, vertically along with water vapor and is replaced by cooler air from above it. That process sustains some evapotranspiration even with zero wind speed. ET is all about energy. The energy inside a greenhouse that comes from solar radiation must be consumed by some other process that is represented by G, H or ET. FAO56 and ASCE literature therefore recommend that a lower limit of 0.5 m/s is used for the wind term in the PM equation to approximate the bouyant, convective transport and mixing of air under very low wind conditions. Rick Allen

The IntErO model

The IntErO model (Spalevic, 2011, www.af.ac.me/Spalevic/IntErO; free to download) uses the Erosion Potential Method (Gavrilovic, 1972) in its algorithm background. The IntErO, an upgrading of the River Basins (Spalevic, 1999; www.af.ac.me/Spalevic/River; free to download) and the Surface and Distance Measuring (Spalevic, 1999) programs, is simple in handling and can be used to calculate a large number of data with the processing of 22 input parameters, returning, after the processing, 26 result parameters (Coefficient of the river basin form, A; Coefficient of the watershed development, m; Average river basin width, B; (A)symmetry of the river basin, a; Density of the river network of the basin, G; Coefficient of the river basin tortuousness, K; Average river basin altitude, Hsr; Average elevation difference of the river basin, D; Average river basin decline, Isr; The height of the local erosion base of the river basin, Hleb; Coefficient of the erosion energy of the river basin’s relief, Er; Coefficient of the region’s permeability, S1; Coefficient of the vegetation cover, S2; Analytical presentation of the water retention in inflow, W; Energetic potential of water flow during torrent rains, 2×gDF^½; Maximal outflow from the river basin, Qmax; Temperature coefficient of the region, T; Coefficient of the river basin erosion, Z; Production of erosion material in the river basin, Wyear; Coefficient of the deposit retention, Ru; Real soil losses, Gsp; Real soil losses per km2. The model considers six factors related to lithology (rocks permeability by percentage: fp, permeable; fpp, semipermeable; fo, low permeability) and soil type (erodibility coefficient, Y), topographic and relief data (I coefficient), monthly mean and annual precipitation (P coefficient), temperatures annual averages (t coefficient), land cover data (X coefficient), the state of erosion patterns, and development of the watercourse network (Φ coefficient). The IntErO model can be characterized as semi-quantitative because it is based on a combination of descriptive and quantitative procedures. Compared to other semi-quantitative methods, this is the most quantitative because it uses descriptive evaluation for three parameters only: soil erodibility, soil protection, and the extent of erosion in the catchment.

More information and application you may find in some of the following publications:

Spalevic, V.; Barovic, G.; Vujacic, D.; Curovic, M.; Behzadfar, M.; Djurovic, N.; Dudic, B.; Billi, P. The Impact of Land Use Changes on Soil Erosion in the River Basin of Miocki Potok, Montenegro. Water 2020, 12, 2973.

Chalise, D.; Kumar, L.; Spalevic, V.; Skataric, G. Estimation of Sediment Yield and Maximum Outflow Using the IntErO Model in the Sarada River Basin of Nepal. Water 2019, 11, 952.

Tavares, A.S.; Spalevic, V.; Avanzi, J.C.; Nogueira, D.A.; Silva, M.L.N.; Mincato, R.L. Modeling of water erosion by the erosion potential method in a pilot subbasin in southern Minas Gerais. Semin. Ciências Agrárias 2019, 40, 555–572.

Ouallali, A.; Aassoumi, H.; Moukhchane, M.; Moumou, A.; Houssni, M.; Spalevic, V.; Keesstra, S. Sediment mobilization study on Cretaceous, Tertiary and Quaternary lithological formations of an external Rif catchment, Morocco. Hydrol. Sci. J. 2020, 65, 1568–1582.

Hazbavi, Z.; Azizi, E.; Sharifi, Z.; Alaei, N.; Mostafazadeh, R.; Behzadfar, M.; Spalevic, V. Comprehensive estimation of erosion and sediment components using IntErO model in the KoozehTopraghi Watershed, Ardabil Province. Environ. Eros. Res. J. 2020, 10, 92–110.

Behzadfar, M.; Tazioli, A.; Vukleic-Shutoska, M.; Simunic, I.; Spalevic, V. Calculation of Sediment yield in the S1-1 watershed, Shirindareh watershed, Iran. Agric. For. 2014, 60, 207–216.

In order to support the idea of using the model for watershed management planning it is recommended to perform model validation and verification. To validate the sediment yield calculations, you may use some bathymetric measurements in the reservoirs on the studied river/s; calculating the accumulation of sediment in some time intervals. In order to determine the quantities of deposited sediment, you need to arrange (or to use previous / ongoing) survey of the bottom of the riverbed, performed with professional hydrographic equipment. We used for example GPS rover, which provides measurement accuracy of 10 mm horizontally, and 20 mm vertically, and a Trimble R6 base with an internal radio modem, while the depth in the accumulation was measured with a single-frequency portable echo sounder Oda Hydrotrac which provides measurement accuracy of 1 cm. The equipment is installed on a boat that is structurally adapted for the mentioned type of such research work. After the field recording, we developed a digital terrain model of the bottom of the accumulation. From the digital terrain model, transverse profiles are drawn whose position is defined by coordinates.

Spalevic, V. Impact of Land Use on Runoff and Soil Erosion in Polimlje. Ph.D. Thesis, Faculty of Agriculture, University of Belgrade, Belgrade, Serbia, 2011; pp. 1–260.

Spalevic, V.; Dlabac, A.; Spalevic, B.; Fustic, B.; Popovic, V. Application of computer—Graphic methods in the research of runoff and intensity of ground erosion—I program “River basins”. Agric. For. 2000, 46, 19–36.

Spalevic, V. Application of Computer-Graphic Methods in the Studies of Draining Out and Intensities of Ground Erosion in the Berane Valley. Master’s Thesis, Faculty of Agriculture of the University of Belgrade, Belgrade, Serbia, 1999; 135p.

Gavrilovic, S. Engineering of Torrential Flows and Erosion; Izgradnja: Beograd, Serbia, 1972; 272p.

You can find some info in below links:

https://www.headwallphotonics.com/hyperspectral-sensors

https://www.specim.fi/

Irrigation regime is irrigation scheduling

Example :Days of irrigation varied from 14 days interval in Summer, 18 days interval in Spring , 19 days interval in Autumn and 25 days interval in Winter seasons Sujit Kumar Biswas

Hello sir

Simply take meteorological data ( i.e. Tmax, T min, RH, wind speed, and solar radiation) of your region . and use CROPWAT (developed by FAO ) to estimate ET0, CROPWAT has in-built options to select the ET0 calculation equations based on the availability of meteorological data.

Crop water stress index- What you are mentioning is based on canopy temperature or deficit irrigation by stopping irrigation

There are several approaches, by which you do. It may be based on soil moisture based ( Up to Wilting point), 2) deficit irrigation based on actual ETc ( 50 %, 60 % etc) . Kindly clarify on this. One of the paper on CWSI I am enclosing for reference.

Dear Mr Zaheer,

I worked on this topic 5 years ago and there was a huge debit about how magnetic field effects on the physical and chemical properties of treated water. Based on some lab experiments have been done, I found out that the EC of the treated water increases and also its ability to dissolve the suspension material increases as well. Depending on the relevant literature, polarity of water molecules increases when they pass through the magnetic filed by re-organize the molecules; thus EC of water increases. See the attachment for some Figures.

Zeyad

pl read groud wter well hydrology by Todd or johnson water wells

See Grid Cell Processing on p. 10-4 of the HEC-GeoHMS User's Manual: https://www.hec.usace.army.mil/software/hec-geohms/documentation/HEC-GeoHMS_Users_Manual_10.1.pdf

see my profile to get the publication related to the calibration.

The saturation and maximum water holding capacity are different levels of soil water content.  The saturation capacity is the level of water content when the soil is saturated and all pores are filled with water (in compact soil, few air often remains trapped in the soil). At saturation, some water is under the effect of gravity more than under attraction to soil particles. This amount of water is known as gravitational or free water.

After drainage of free water, the level of soil water content is the field capacity, which known also as the maximum water holding capacity. The field capacity is the best level of soil water content as there is much water available to roots of plants and a sufficient amount of air for respiration. As the water is lost from the soil by evaporation or absorption of roots, more air will replace water and the soil became more dry.

Saturation capacity %= field capacity % + Free water %

Soluble calcium can be added to soil that will reduced water SAR and increasing water EC and will prevent formation of sodium bicarbonate.

definitely dripping irrigation is the most suitable option.

Dear respected M.R. Yadav,

The best practical way of measuring the infiltration rate is by using a double ring infiltrometer. You can also check this link:

https://www.researchgate.net/publication/325091235_Soil_Porosity_and_Water_Infiltration_as_Influenced_by_Tillage_Practices_on_Federal_University_of_Agriculture_Abeokuta_Ogun_State_Nigeria_Soil.

Best regards

Kifilideen

Hi Daniel,

Water in the root zone may be measured by sampling and oven-drying the soil before and after every shower of rain. The increase in soil moisture, plus evapotranspiration loss (ETa) from the time the rain starts until the soil is sampled, is the amount of effective rainfall. After heavy rainfall evapotranspiration can be assumed to be at the potential rate during the short period from cessation of rainfall until the sampling time. This can be taken as 0.4 to 0.8 times the evaporation value of the Class A Pan

The method takes into account the soil and the crop characteristics. The determination is simple and accurate but it may involve errors due to soil variation; the sampling errors may range from 5 to 40 percent. The method is also laborious and time consuming. The use of neutron probes reduces the drudgery of periodic soil sampling, but these are costly methods for routine purposes and also subject to sampling errors

Best Regards.

Please have a look at enclosed PDF..

Hello Praveen,

First, you need time-series data (preferably remotely sensed images) to observe trends in LULC.

A good starting point in deciding the suitable image spatial resolution is to consider the landscape structure in terms of composition and spatial configuration.

And depending on the extent of your study area you may consider satellite or aerial images.

I assume you are familiar with your study area and have a fair idea about the rate of LULC changes. This will be vital in deciding the temporal resolution of the images (e.g seasonal, yearly, decadal etc.).

You can then apply supervised image classification methods and make area estimates of different LULC types (see FAO's OpenForis tool for area estimation) and analyze trends in LULC.

At the crop level, you may extract and test suitability of spectral (e.g. NDVI, EVI, spectral bands, tasseled cap variables etc.), textural (Homogeneity, entropy, variance etc.) and phenological (e.g. mean NDVI) variables from the remotely sensed images to characterize different crop types.

Select the most suitable variables and apply image differencing and thresholding methods.

Hope you find these useful.

Best regards,

Kwame

Hi dear Rouhallah,

Thanks a lot aziz.

Hope to see you soon

Friendly Yours

Behzad

Hope this site may be useful to you.

Look for http://www.zohrabsamani.com/research_material/files/Hargreaves-samani.pdf

less evapotranspiration & less weed

Pl. go through this link:

You may found there a key formula to compute GW net rechage component for Indian scenario, although Paper from Dr. C P Kumar (first comment in trailing text) would be really helpful and well explained.

You will have to work out the the available water content of the soil (AWC) , and accordingly , you will have to impose treatments based on depletion of 10%, 20% , 30% , 40% etc  of AWC, keeping in mind the daily evaporation rate, to cover both wet and dry soil moisture level . these levels could finally be cross verified either through gravimetric soil moisture content or using moisture sensors , including neutron moisture probe... 

SALTMED Model provides such information.

Water use efficiency (WUE) and water productivity (WP) are two different terms. However, they seem to cause some confusion only among agronomists.The Water Productivity term plays a crucial role in modern agriculture which aims toincrease yield production per unit of water used, both under rainfed and irrigated conditions.  The recent literature shows that what previously was wrongly defined as Water Use Efficiency has been renamed in “Water Productivity” in the early 1980’s. The key principles for improving water productivity at field, farm and basin level, which apply regardless of whether the crop is grown under rainfed or irrigated conditions, are: (i) increase the marketable yield of the crop for each unit of water transpired by it; (ii) reduce all outflows (e.g. drainage, seepage and percolation), including evaporative outflows other than the crop stomatal transpiration; and (iii) increase the effective use of rainfall, stored water, and water of marginal quality...Some PDFs enclosed for better understanding on the issue...

Many thanks Kassahum and Alex!! 

What engineering techniques can be applied to prevent flooding in plains?

Hi, attached my article which we developed a simple model. check the article and if you need a help let me know.

Dear Zafar Hashmi

You may can read the question  again and the answer above. Surly the Idea very clear.

Regards.

Jalal

Were you able to find any data?

I have observed flows for furrow irrigation ranging from 0.3L/s to above 10 L/s per furrow for broadacre crops. The ideal flowrate is influenced by many factors including the field length.    For example in Australia for cotton grown on heavy clay soil with a 1000m field length we commonly recommend a flowrate of 5 to 6 L/s per furrow (furrows on 2m spacing)

Malcolm

 شكرا لك على النصائح المفيدة

Dear Anurang

It depends on many factor and the soil is one factor only. I recommend you to read articles:

Alternate Wetting and Drying (AWD) is a water-saving technology that lowland (paddy) rice farmers can apply to reduce their water use in irrigated fields. In AWD, irrigation water is applied to flood the field a certain number of days after the disappearance of ponded water. Hence, the field is alternately flooded and non-flooded. The number of days of non-flooded soil in AWD between irrigations can vary from 1 day to more than 10 days depending on the soil type. To implement alternate wetting and drying (AWD) method of rice field flooding, you will need a tube of 40cm length and a measuring tape to measure water depth. The field water tube can be made from a plastic pipe or bamboo. Cut this material to a 30cm length with a diameter of 10-15 cm to easily see the water level inside the tube Drill the bottom 15cm of the tube with holes on all sides; these holes should be about 0.5cm each and 2cm away from one another. Placing the Tube Place the tube in a readily accessible part of the field, close to the bund (not less than 1m away) for easy monitoring. The location should be representative of the average water depth in the field (i.e. it should not be in a high spot or a low spot). Bury the tube up till 20cm depth so that half of its length remains on the surface remove the soil inside the tube so that the bottom of the tube can be seen. Ensure that the level of water inside the tube is the same as the level of water on the field. Practicing Alternate Wetting and Drying (AWD) Apply nitrogen fertilizer preferably on the dry soil just before flooding. From one week before to one week after flowering, ponded water should always be kept at 5 cm depth above soil level to avoid water stress which could result to potentially severe yield loss. After flowering, during grain filling and ripening, the water level can drop again to 15 cm below the surface before flooding (Safe AWD). In Safe AWD, water savings may be up to 15-25 percent with no yield penalty. The depth of water can be allowed to drop from 15cm to 20 or even 25cm below the soil surface. Training and extension materials on AWD are included in curricula of agricultural colleges, universities and extension certification schemes. Users and benefits of AWD technology Water savings may be up to 15-25 percent with no yield penalty. AWD promotes good root anchorage, thus reduction in plant lodging problems. In pump irrigation systems, it reduces pumping costs and fuel consumption and an increased income of US$67-97 per hectare. AWD reduces 30-70 per cent of methane emissions depending on the combination of water usage and management of rice stubble. It also promotes higher zinc availability in soil and grains by enabling periodic aeration of the soil, which releases zinc from insoluble forms and makes it available for plant uptake.

I think, you need to prepare wilcox diagram to identify the suitability of water quality for irrigation. you can use AquaChem software to prepare wilcox diagram.

Prof. Achour, Your insight has given me some idea on why in majority of the hydroponic fodder system they use sprinkler system instead of drip or other system of irrigation. Certainly a drought resistant genes can create many possibilities and the food we produce is not only consumed by humans but also by domestic animals.

I would like to have your some wisdom in this regard. I live in a place where humidity used to vary from 50-80 % depending upon season. As you have mentioned that stomata opens in high humid condition and for that we found that majority of the hydroponic fodder production is done with sprinkler system. Can you suggest some other techniques by which I can increase the chambers' humidity.

Regards,

Kapil

Dear kadir,

There are some studies i share to you, that may be useful

Dear Parameshwar,

Different types of agricultural practices and systems affect the soil biota in different ways and the response may be either positive or negative depending on which part of the soil the biota, e.g. fungal or bacterial, is affected. For example, organisms which are sensitive to pH will be affected by the addition of lime; the bacterial: fungal ratio will be affected by the addition of fertilizers and manures which alter the C:N ratio as will the effects of tillage. Tilling the soil will reduce the number of fungal hyphens, because soil aggregates, which are held together by these hyphens, are broken down.

The consequences of agricultural practices on soil biota may be direct and far reaching. Organisms which are of benefit to agriculture and which may be affected include those responsible for

1.       Organic matter decomposition and soil aggregation;

2.       Breakdown of toxic compounds both metabolic by-products of organisms and agrochemicals;

Agricultural practices that use high amounts of external-inputs, such as inorganic fertilizers, pesticides, and other amendments, can overcome specific soil constraints to crop production. These practices have led to considerable increases in overall food production in Europe, Asia and the Americas. However, especially in the most intensively managed systems, this has resulted in continuous environmental degradation, particularly of soil, vegetation and water resources, such as in the state of Haryana in India.

 Any misuse of high external inputs for crop production has far reaching effects, which include:

1.       Deterioration of soil quality and reduction in agricultural productivity due to nutrient depletion, organic matter losses, erosion and compaction.

2.       Pollution of soil and water through the over use of fertilizers and the improper use and disposal of animal wastes

3.       Increased incidence of human and ecosystem health problems due to the indiscriminate use of pesticides and chemical fertilizers

4.       Loss of biodiversity due to the use of reduced number of species being cultivated for commercial purposes

5.       Loss of adaptability traits when species that grow under specific local environmental conditions become extinct

6.       Loss of beneficial crop-associated biodiversity that provides ecosystem services such as pollination, nutrient cycling and regulation of pest and disease outbreaks

7.       Soil salinisation, depletion of freshwater resources and reduction of water quality due to unsustainable irrigation practices throughout the world

8.       Disturbance of soil physicochemical and biological processes as a result of intensive tillage and slash and burning.

Tillage, monoculture, pesticide use, erosion and soil contamination or pollution generally have negative effects on most soil organisms, reducing the soil's capacity to maintain its function. This has numerous facets including decreased soil organic matter content, loss of soil structure, loss of soil through wind and water erosion, development of acidic, saline and sodic soils, and soil contamination with pesticide residues and heavy metals .On the other hand, the application of organic wastes, moderate use of mineral fertilisers, crop rotations, irrigation in dry and drainage in wet areas generally have positive impacts on soil organism densities, diversity and activity. 

Regards,

Prem Baboo

Hi Gerhard,

Some starting points:

Good luck,

Jack

I agree with all friends that answered you and I am not going to repeat them. I like to write some exact costs that have validity in Iran.  I hope this information be helpful:

Investment:

Set sprinkler systems with portable sprinklers and buried PE lines     3600 $ per ha

Center pivot sprinkler system     2600 $ per ha

Drip irrigation systems     3500 $ per ha 

Subsurface drip irrigation    6100 $ per ha

I canonly add another link to a road side effect in NZ https://researcharchive.lincoln.ac.nz/bitstream/handle/10182/820/aeru_rr_156.pdf?sequence=1, For all kind of claim it seems advisable to run in situ tests by using upwind and downwind positions

I would recommend you to use DRAINMOD provided that you have daily weather data and soil and irrigation data for the specific site.

In the webpage of AquaCrop (http://www.fao.org/nr/water/aquacrop.html) you could download the new version of AquaCrop (v.5) and the AquaCrop-GIS tool described in Lorite et al. (2013) and published in Computers and Electronics in Agriculture. Thank you!!

Dear Noha , you have a genuine issue to investigate . I am enclosing some our PDFs fro further reference of yours. Hope , they will be of some use for your work.

Renjith , similar type of  question we debated at length raised by Dr Nazir on ReseacrhGate . Probably , we take advantage very useful discussion already there .

Maybe you can have an exchange with professor Basso and to see it its model could help you to bettere understand quat happens.

Have a look at the model here.

We had some experience in the south of italy with farmers adpatation to high salinity level of river water and how to manage overtime the problems of salt accumulation

hi

these article may help u

Dear Md. Nurul Kadir,

Thank you for your interesting question, I hope I am able to give you some help with my response below...

As you (& Aleksandra) suggest, determining ET is part of the solution however, this will tell you only what the (approximate) total amount of water the crop is using, which is not necessarily (nor usually) the amount of this water that is supplied by irrigation alone.  The amount of water used by an irrigated crop can be made up from a number of sources, the major ones are likely to be irrigation water, effective rainfall (as per Aleksandra answer above) +/- a contribution from groundwater (I'll call this "effective groundwater" from now on although this is not a accepted term).  Therefore, in the simplest terms, working out how much of the crop water use is supplied from irrigation (your unknown) can approximately be determined from the following equation:

While determining crop ET and effective rainfall is (relatively) simple, determining the 'effective groundwater' can be more difficult, especially if you have a shallow watertable.

There are plenty of good references about determining 'effective rainfall' and the one quoted by Aleksandra above is a good place to start.

When determining 'effective groundwater', the first thing to do is determine what the average depth to the watertable is below your crop.  If you have a deep watertable (more than 2 to 3 meters below the rootzone of your crop), then it is likely that the contribution from groundwater will be very low, and it can reasonably be considered to be zero in the above equation (send me a note if you need a reference for this).

If however, you have a shallow watertable (less than 2 to 3 meters below the rootzone of your crop) below your crop then determining the 'effective groundwater' can be much more difficult and will likely depend on a large number of factors (the relative contribution of each will also vary widely from place to place).  These factors may include the actual watertable depth, its variation through the growing season, the soil type (composition, grain size, texture etc) the groundwater chemistry (especially salinity and sodicity), the type of crop grown and a number of others.

If you do have a shallow watertable under the crop you are working with, and would like some more information/references about the factors I have described in the above paragraph, please let me know (or you may be interested in reading some of my listed publications, which (in part) deal with this topic).

I hope my response has been of some help to you (although I realise it only expands a little on the excellent answer already given by Aleksandra).

Best wishes,

Alister

Dear Mostafa

You can visit this link:

Also you can read these papers.

Dr Nazir , your question is very thought provoking ,since very meagre  work has been done to address salinity tolerance using saline irrigation water in soils of varying textures . And , if you talk of drainage vis-a-vis salt balance under  saline irrigation , it becomes still a very cumbersome job. While talking the salinity tolerance of different crops using saline irrigation , we also need to define the extent of yield reduction , is 25%, 50% or 1005 yield reduction ?. And accordingly , such thresholds are given . We can also define such tolerance in terms of germination of seeds as well. Again , these limits will be quite different  as per crop . For example seed spices ( Cumins , Dill, Fennel, Fenugreek etc) can tolerate much higher EC of saline water ( Up to EC of 12-18 dS/m saline water   and soil EC of  5-7 dS/m) , on the other hand potato or spinach will wilt ( Up to 3-4 dS/m saline  water  and soil EC of 1.0-2.0 dS/m) . Onions can tolerate soil EC upto 4.5dS/m, potato upto 6.2dS/m , while cabbage  only upto 1.80 dS/m , considering the 50% yield reduction  as maximum limit of investigation.    Likewise Valencia yield is reported to  decrease by 8-13% per dS/m increase in salinity of the soil beyond threshold value of 1.4 dS/m. Grape is another perennial fruit crop , which can tolerate soil EC upto 5.5 dS/m (  EC of water as  8-10 dS/m) on a black clay soil  .

Generally speaking, growth rate of plants' roots response reversly to the amount of the irrigated water. For example, plants irrigated with least amount of water will have the longest growth of roots and vise versa. The logical explanation of such observation that in case of water deficiency the plant is forced to elongate it's roots growth seeking for water. However, in the case of water availability the plant would has adequate access to water & no need to enhance the growth rate of the roots.

Thank you Dr. Hani for the attached interesting references .Among the possible causes of seedling  toxicity due to urea application,biuret, ammonium/ammonia and nitrite ,the excess ammonium in plant cells and the nitrite derived from   ammonium appears to be the cause of the ill affects of urea or any ammonium containing fertilizer, when ammonium accumulation is more than nitrification in soil.When ammoniuum ions get converted into nitrate quickly ,possibly the bad affect may not manifest. However it  is often heard from farmers that the proximity of high concentration  of urea to seed may cause the toxicity to seedlings.So in effect ,the excess ammonium in soil during germination may be the causitive factor for seedling injury.

Dear KS, your question is very pertinent but I doubt , sprinkler irrigation will be handy under such circumstances where water scarcity is a pivotal issue, since sprinkler  irrigation is  a type of rainfall -like pressurised irrigation  . In-line drip irrigation probably holds far  more promise than sprinkler irrigation . Sprinkler irrigation consumes  more water than drip irrigation . however , with some of the developments in sprinkler irrigation like whirligig sprinkler , gun sprinkler, perforated pipes etc., it has shown some good promise . Provision of real time  pulsing as per diurnal variation in  temperature, VRT , sprinkler irrigation has attained some real utility in field. Despite all these developments , issues relating  droplet ballistics  are still un-resolved. Find below some PDFs , hope , they will be of some further use .

For WQI calculation you can visit the link 

FAO Irrigation and Drainage Paper No. 56

Crop Evapotranspiration

(guidelines for computing crop water requirements)

Maybe can help you ... 

Hi Amir Reza

In Isfahan Mr Jalili has accomplished an economic research on water use for all consumptions.

He determined how much the costumer can pay for water uses satisfactory.

His Ph.D thesis defence  is this summer.

I've just started working on  integrated water resources management with considering economic, social and environmental aspect and so on.

Hi Mahdi,

I worked quite extensively in treated wastewater reuse in agriculture.

The chemical and biological quality of regenerated wastewater for use in irrigation it will depend on the tertiary treatment. Generally regenerated wastewater contains dissolved nitrogen and phosphorus with are valuable fertilizers, that minimizing inputs of these fertilizers into the crops.

It is no recommendable use this type of water horticulture crops such us lettuce, spinach and so on. But it is perfectly fine to use in crops that need to process before to human consumption or even better in biomass crops. I know a several number of projects using this types of water in golf lawns.

some of the projects I have involved, they recovered the drainage water to avoid contamination of other surface or groundwaters

However, I have involved in other projects using regenerated wastewater to recharge groundwater aquifers. But in these cases wastewater receive special treatments and it has to pass a chemical and biological standards

We calculate contribution of essential macro nutrients supplied by irrigation water, according to water concentration and irrigation volume.

Kg N / ha= NO3- x Vr x 22.6 x F / 10⁵

where NO3-= water nitrate concentration (mg/L)

Vr= irrigation volume

22.6 % N in nitrate molecule

F: efficiency factor between 0.6 - 0.9

Kg MgO / ha = xMg2+ x Vr x 1.66  x F1 x F2 /10⁵

where MgO-= water magnessium concentration (mg/L)

Vr= irrigation volume

1.66 % Mg in MgO

F1: irrigation efficiency factor between 0.6 - 0.9

F2: Mg insolubilization factor, values between 0.4 and 0.6

Dear Stigter, 

thanks for this thesis it will help me 

You can try biological nutrient removal technique through Integrated Fixed-Film Activated Sludge (IFAS) process.

Good question.  You might assume that the mass of the fresh plant is (say) 90% water.  Since the mass of water in the soil is usually very much greater than that in the plants, a small uncertainty in plant mass will cause very little uncertainty in soil water.  Validation of this approach requires serial estimates of plant mass. 

1) fill a bare soil area with excess water inducing drainage.

2) cover the wet soil with a plastic cover

3) wait about 2-3 days

4) collect a soil sample

5) weigh moist soil, dry in a oven at 105°C till to constant; weigh (after about 24 hours) and weigh the dry soil.

6) Calculate moisture at field capacity

Contact irrigation department they will guide you. If you become member of Hydrological Data User Group, Nashik it will more better

Energy is required n every action. It's form may change. You should consider, potential energy, kinetic energy, electrical or mechanical energy, solar energy, human energy and energy from any other source. Keep in mind that energy can neither be created nor be destroyed so while accounting energy please avoid double accounting.

Dear

Provided that all soil characteristics are same and ofcourse the ''geographical location'' should also be same as climatic factors play major role in water consumption:

I will say, in both cases if the ''water availability is not defficient'' the amount of fertilizer for a ''given plant'' would be same. Within the case of irrigated land you can mix water and fertilizer to apply at a time taking into account backwater in the sprayer is avoided.

Hope it will give you hint

-Don't forget a good soil drainage (good design is in question)

-Soil exploitation and remidiation by halophytics plant culture

-Try to keep an any saline soil of an average humidity, to reduce an eventual damage

The key to reducing evaporation is to reduce exposure of wet soil to the atmosphere.  The two factors to consider are the amount of wet soil surface which is exposed, and the duration of exposure.

The amount of wet soil surface exposed can be manipulated by mulching and shading, or by reducing the amount of the soil surface which is wet during irrigation. So for example drip irrigation wets only a small portion of the soil surface, but sprinklers wet the whole surface. Subsurface drip can result in little or no wet surface soil.

Duration of exposure of wet soil to the atmosphere is tied in with the frequency of irrigation.  Frequent small irrigation events result in a higher exposure of wet surface soil than fewer deep irrigation events applying the same amount of water in total.  Thus fewer, larger irrigation events are preferable to reduce evaporative losses

There is a trade-off, however, with drip irrigation, which wets less of the soil surface, therefore reducing exposure, but stores less water in the soil and therefore requires more frequent irrigation, increasing the duration of exposure.

This also brings us to the second part of your question, minimizing drainage. The rootzone of a crop can only hold a certain amount of water before drainage occurs, and applying significantly more than this "water holding capacity" will result in unnecessary loss of water.

Matching the depth of irrigation events to the water holding capacity of the rootzone, plus a small amount for leaching salt (often around 10% of the applied volume) is the key to efficient irrigation.  In shallow soils or drip irrigated situations, this may mean that more frequent irrigation events are required, which then increases exposure to evaporation, taking us back to the previous discussion.

In summary, there is no magic bullet to saving water, the key is careful management based on knowledge of the system (soil type, rootzone depth, irrigation system characteristics) you are working with, to try to reach a middle ground where the various water losses are minimized as much as possible.

Pasquale

this is a very good question, considering the fact that the environmental impact is both positive and negative, both on the long term (lifecycle) and in the short term (seasonal).

I am sure you must have seen the report from the World Bank Cost Recovery and Water Pricing for Irrigation and Drainage Projects

It also studies cost recovery within the limits of having the ability to pay.

the case studies in the Annexures may help with your question.

thank you

FC