In calcareous alkaline soils P leaching is not the problem. But when pH increases to > 8.5 and above, more soluble sodium phosphate is formed that get leached. In our studies during reclamation of a saline-sodic soil using gypsum @ 100 % soil Gypsum Requirement (Schoonover method) following rice-wheat rotation and saline-sodic tube well irrigation water, there was an increase in available P. It was concluded that at least one third P application (recommended for that region) could be saved.

some papers are attached.

Dear Annangi,

see for example

http://www.publish.csiro.au/paper/AR9610409

http://www.css.cornell.edu/faculty/lehmann/publ/Lehmann%20et%20al.,%202003,%20Leaching%20CABI%20book.pdf

Regards, C.J.

Dear Annangi,

The dynamics of phosphorus in aquatic systems is complex and has been

studied by many workers. Phosphorus is a key nutrient in pond fertilization,

so its dynamics is of practical value to pond managers. Inorganic phosphate

added to fish ponds in fertilizers is removed from the water primarily by

phytoplankton, bacteria, and sediment. 

Regards..

Thank you very much Drs. Ghafoor, Stigter andTepe for your good responses.I also thank you for the good references attached.From the literature it appears that in most of the soils P is retained in soil because of precipitation and sorption reactions .However as revealed in the attached literature and also in some other published works it it appears that substantial losses of P can occur in sandy soils,organic soils,sodic soils and in  dissolved organic P form.It is also possible that in highly fertilized soils the soils get saturated with respect  to P and soil solution P increases and is subjected to leaching.But the main problem is that the information is not consolidated properly in those conditions mentioned so the real magnitude of P leaching is not known/authenticated.

Dear Annangi,

Please also find the attached file whether answer your question.

Best.

Article Sediment Quality in Arkansas Bait Minnow Ponds

I agree with what has been raised by others. In a nutrient balance work we did across scales ( attached)  loss of P through leaching  was small compared to N and K. The reason is already discussed very well.... but it should be also underlined that level of saturation of the exchange complex is important. In this relation there are arguments of P availability in soil solution by increasing the P stock of soil . The principle is just to saturate the exchange complex so that P will be available to the plant or released to soil solution.  The more P flows from exchange complex to soil solution the more likely it can be washed to  below root zone, particularly if the plant can not use it for different reason. Thanks for sharing this

There has been very throughout investigations in the 1970s in Germany which came all to the same conclusion: the loss of P by leaching is some sort of a "background noise", says more or less independent on the management of the top soil and amounts to < 0.5 kg/ha*y. Considering all the other errors of the P balance (uptake/remove, spatial variability etc.) this value is negligible or carried on as a minor constant. Sorry, one of the key works again in German (THE LANGUAGE OF SCIENCE! (it was)) "Hoffmann, W.: Phosphor-und Stickstoffzufuhr aus der Landwirtschaft in die Ostsee, insbesondere durch die Schwebstoffe der Gewässer. Wasser und Abwasser in Forschung und Praxis Bd. 16, Erich Schmidt Verlag Bielefeld, 1979. 108 S., 33 Tab., 16 Abb., kartoniert, DM29,–". I was working in this project myself as a young student!

Remarkable is, however, that in the years later suddenly researchers lamenting again about big losses, mostly conclusions drawn from single experiments under extreme conditions: meanwhile the general opinion on P utilization (mostly due to the work of Armi Kaila in Finland!) went away from the old "1 quarter = "angles share" 75% doctrine) towards a complete utilization over infinite time, says fertilization equals removal by crops, unless there are no significant non avoidable losses (like gaseous one with N). There may be P  losses from agroecosystems, especially through erosion, but those are in the majority of cases avoidable through prober tillage techniques, green cover etc.. Each % you could attribute to losses is one more % for  fertilizer sales ! I spoke to you at another place of "bias free" information: watch the source where the information is coming from and you become aware of the bias!

In North American conditions the loss of Phosphorus is mainly a function of soil erosion losses. Despite the strides in conventional no till agriculture the losses are still generally greater than the Universal soil loss value.

Green cover is the best approach to drastically curving those losses in a tilled system where rainfall is sufficient for this cropping.

 In terms of Phosphorus the use of acidified sources curtail the value of having rock phosphate as a micronutrient source. United States Geological Survey Miscellaneous publication 1228 puts the excess soluble Nitrogen in the Chesapeake Bay as 59% from synthetic fertilizer mostly from maize production 34% from the raw manure use also for maize production. When legumes are optimized in mixed rotation there is no need for synthetic Nitrogen in the rotation.

The use of cover legumes for Nitrogen needs eliminates the largest portion and the composting of manures would drastically reduce the secondary. When composted manures are returned to the field the issues with all these issues are ameliorated.

The mixed agriculture system which controls erosion and returns manures into fields as composts avoids the eutrophication issues and creates an ability to counteract greenhouse gas as soil organic natter is conclusively improved. In areas of soil acidity the use of rock phosphate in the composting process would be sufficient to optimize the Phosphorus for all crops. In the diversified production system the mycorrhizae greatly reduces the level of Phosphorus needed in the source resource. 

In the Rodale Institute Farming Systems Trial of more than 34 years the increase of soil organic matter to over 5% optimizes the productive capacity while the 33,000 lysimeter readings show the problems with Nitrogen and Phosphorus losses are ameliorated simultaneously. 

In the diverse areas around the world the more systems and long term approaches need to focused on as the single factor short term approaches is part and parcel of the problems at hand. 

Thank you Drs Tepe,Amare ,Schnug,Barbara and Hepperly. for excellent information provided.From the comments and other information I believe that there is no need for much fear of leaching losses of P in normal soils especially under good management as pointed out by Drs Schnug and Hepperly.In the past I have seen some papers on P leaching from soils in countries like Netherlands ,UK,and USA  under high P fertilization.When P adsorption or anion exchange sites are saturated under high intensity cropping and P fertilizer use,solution P can increase and is subjected to leaching losses..The figures can be low as pointed out by Dr.Schnug and Dr.(Ms)Barbara.Is the any consolidated information on P leaching from intensively cultivated and fertilized  areas?Even heavy inputs of organic manures may also accumulate P in soil and facilitate leaching of P from soil.

Dr. Rao! High P accumulation i soils does only under rare circumstances (mostly preferential flow) correlate with P leaching! As I said before: watch for biases!

Its always different with loss by erosion, especially through what we call "light particle erosion", see attached file!

Light particle erosion is a  new topic to me.Interesting presentation and worth reading .Dr.Schnug,thank you for your comments and attaching interesting presentation material.

The answer to this question is context-dependant.  If the focus is on commerical value of added phosphorus from fertilisers etc, then yes, the leaching losses are negligible.  But if the context is impact on water quality, then P leaching losses can indeed be 'considerable'.  Numerous factors are important, such as land use type and intensity, soil P buffering, but connectivity is key.  See this recent paper by McDowell et al for just one example - DOI: 10.1111/1752-1688.12337

Problem is, Murray, that the amount of P loss through leaching is more or less independent from the management system of the soil, its what I called earlier just background noise, says that (under normal and usual conditions) here is no efficient way to reduce leaching loss by changing management practice! This is certainly completely different with P losses through surface run-off!

The type and amount of applied fertilizer are the major factors influencing         

long term P losses and gains from sandy soils under leaching conditions. In the field, environmental conditions (Weaver et al. 1987), plant uptake and the top dressing (rather than incorporation) of fertilizers would also affect the extent of P losses. Changes in acid-extractable P reflected the long-term gains and losses of P from sandy soils.

 Dr.Ravikumar ,you have raised a good point regarding use of soil tests to diagnose the critical limits of P(environmental) beyond which P losses can occur This approach is valid for P losses through erosion also.It is a point to ponder that even good management can not make much difference in P losses by leaching as mentioned by Dr.Schnug .I have yet to go through the paper suggested by Dr.Murra to get more details.

Ewald, you are right, which means that a completely different approach is needed to tackle phosphorus movement via subsurface flow, whether natural, or more typically where environmental problems may ensue, via man-made drainage systems.  I believe I'm right in saying that in most tile-drained areas in the UK, the drainage water (eventually) flows directly into river systems.  What is needed are mitigation methods to address the P content of drainage water before it enters rivers and streams, such as diverting it into constructed wetlands, or there are various drainage ditch management methods that could be employed.  A good review covering this topic was published by King et al in 2014 - doi:10.2134/jeq2014.04.0163.  The real difficulty is getting farmers to adopt such methods when there is little or no economic reason for them personally to take on such costs.

After the application of phosphatic fertilizers in soil it takes longer time to dissolve with soil water, and sometimes phosphate may generally make complex with metallic substances (Fe, Al, Zn etc.) in soil those have limited chance for leaching loss. Ultimately this leaching loss is negligible compare to other fertilizers. However, phosphate leaching losses in soil may be considerable.

Phosphates are not easily leached but most P losses are related to erosion.

To get more efficient use of organic P the use of compost would be recommendable as it gives longer term soil improvements.

Raw manures when incorporaated into the soil and not used exorbitantly are good agricultural practices.

The issues with raw manures are largely eliminated through composting and the long term benefits are also combined with better environmental and health responses.

Rates need to controlled in both conventional and organic production fields.

The use of mycorrhizae can greatly reduce responses to P fertilizers which are the most expensive nutrient in conventional fertilizers.

The leaching losses of phosphate depends on the nature of soils and the presence of humus. For the adsorption of phosphate to clay particles (Illite, Kaolin, Montmorillonite) it depends on the pH (better adsorption at higher pH) and the presence of cations (Ca better than K). The presence or organic substances (humus) increases the retention of phosphate in the soil.

According to the literature review and due to the nature of structure and function of phosphorous cycle in soil in various ecosystems and when the vital activities of some organisms is endangered due to its fluctuations, it should be considered a series suitable management decisions to prevent diminish of that. In fact, the balancing/equilibrium building of this macro element/ion as a conventional approach is proposed in soil science. Among that, the pH of soil is decisive role that should be considered.