Hi again

First, from your last post we can conclude that it shows that without much info, answering your question is difficult. Here's what can be found as regular medical info.
http://www.rnceus.com/ua/uaph.html

--Beginning of Quote--
A highly alkaline urine occurs in:

* Urinary tract obstruction
* Pyloric obstruction
* Salicylate intoxication
* Renal tubular acidosis
* Chronic renal failure
* Respiratory diseases that involve hyperventilation (blowing off carbon dioxide and the development of alkalosis)
--End of Quote--

Second, proteins come from vegetables, not only from meat and cheese. Ruminen (eg cows) don't eat meat.

Third Nitrogen does not only come from proteins.

NPN (Non-protein Nitrogen)
http://en.wikipedia.org/wiki/Non-protein_Nitrogen

--Beginning of quote--
Non-protein nitrogen (or NPN) is a term used in animal nutrition to refer collectively to components such as urea, biuret, and ammonia, which are not proteins but can be converted into proteins by microbia in the ruminant stomach. Due to their lower cost compared to plant and animal proteins their inclusion in a diet can result in economic gain, but at too high levels cause a Depression in growth and possible ammonia toxicity (microbes convert NPN to ammonia first before using that to make protein.) NPN can also be used to artificially raise crude protein values, which are measured based on nitrogen content, as protein is about 16% nitrogen, but, for example, urea is 47% nitrogen.
--End of quote--

Variation in nitrogen and NPN
http://www.fao.org/DOCREP/006/y5022e/y5022e03.htm

--Beginning of quote--
not all nitrogen in foods is found in proteins: it is also contained in variable quantities of other compounds, such as free amino acids, nucleotides, creatine and choline, where it is referred to as non-protein nitrogen (NPN). Only a small part of NPN is available for the synthesis of (non-essential) amino acids. Second, the nitrogen content of specific amino acids (as a percentage of weight) varies according to the molecular weight of the amino acid and the number of nitrogen atoms it contains (from one to four, depending on the amino acid in question).
--End of quote--

NPN and blood urea nitrogen (BUN) in ruminant and proportion of blood ammonia coming from true protein versus NPN
http://www.acresusa.com/toolbox/reprints/Brunetti_Protein.pdf

--Beginning of quote--
BUN: RUNAWAY ROGUE PROTEIN
Blood urea nitrogen (a.k.a. Blood ammonia, or serum urea nitrogen) is a significant problem in modern animal agriculture.
[...]
In Grass Productivity, Andre Voisin states that grass tetany (which is associated with magnesium deficiency) can be caused by an excess of ammonia dropping the blood’s content of magnesium as well as causing a poisoning of the bulbar respiratory center. Plants accumulate nitrates due to stress, such as drought. Plants produce more NPN (non-protein nitrogen) instead of true protein when there are excesses in soil minerals such as potassium and nitrogen, or deficiencies in minerals such as calcium, sulfur and boron. If the magnesium levels are excessive in the soil, for example, the plant would accumulate either additional nitrate and/or NPN. This same plant will most likely be deficient in magnesium, which is necessary to prevent grass tetany, even though the soil contains an excess.
[...]
Blood ammonia, being quite toxic, is quickly converted by the liver, which converts it to less toxic urea, which is then converted to uric acid via the kidney prior to excretion. The rumen schematic below illustrates the pathways of true protein and non-protein nitrogen through ruminants. As one can see, 60 percent of true protein degrades into ammonia in the rumen to feed rumen microbes, which in turn become microbial protein for the animal. Forty percent bypasses the rumen to be absorbed in the intestine. In contrast, 100 percent of the NPN in feeds degrades into rumen ammonia and, if it is not metabolized by rumen microbes, passes directly through the rumen wall, thus eventually becoming BUN. This phenomenon is a big reason why contemporary nutritionists want to know how much soluble versus bypass protein is in the ration. You need enough to feed the rumen microbes, but too much is not only a waste, it is also detrimental to production, reproduction and longevity.
--End of quote--

So, if NPN is a problem for ruminants why can't it be a problem for human vegetarians?

Waste Products of Protein Metabolism
http://www.carbsmart.com/pdigestion.html

--Beginning of quote
The destruction of proteins in the body gives rise to two classes of waste products: nitrogenous (ny-TRA-gin-us), those containing nitrogen, and non-nitrogenous (non-ny-TRA-gin-us), those that don't contain nitrogen. The non-nitrogenous types of waste products are carbon dioxide and water. Nitrogenous waste products only relate to proteins since only proteins contain nitrogen.

The nitrogenous waste products are known as urea (yur-RE-ah), uric acid (yur-ick acid), creatinine (cree-AT-tin-neen), and hippuric acid (hip-PURE-ick acid). Urea is the major nitrogenous waste product, making up some 80% of it. Urea is formed in the liver, and is excreted by the kidneys in the urine along with the other types of protein waste products.
--End of quote--

And last, being less familiar with alkalosis than acidosis I will stop here because I am short of other explanation. But I have the feeling that the alkalosis is related with some liver/renal problems or stomach problems.

However I would suggest you again to post at the AskMoreless pH balance forum. At the moment, with my limited knowledge, this is simply the best advice I can give you. If you ever post there, be precise about the symptoms you have, not just about alkaline urine. Also describe the typical diet you are following.

NB You can observe by yourself that only both refreshed and I replied to your post and that we both suggested the Ask Moreless forum and that we both had 2 “disagree” votes. I don't care about those votes. But those who voted “disagree” did not suggest you any alternative answers. All these facts makes me believe that you will unlikely receive any other answer in this forum.

Now the rest is up to you.

Good luck and Cheers