Soil Test: Too Much Phosph, Zero Nitrogen (too much compost?)

15 years ago

Hello all,

I bought a little DIY soil test kit after having problems with one of my vegetable gardens. This one particular garden I tried to grow tomatoes, green beans, okra, and cucumbers. Cucumbers did well but everything else was stunted with gnarled leaves. The prior year this garden did awesome with peas, tomatoes, & okra.

The test results showed extremely high Phosphorous and non-existent nitrogen. Ph showed to be "Acceptable" and potash was "sufficient".

We raise rabbits and I compost all the rabbit manure and hay that falls through the cages. Then till it into the gardens. This particular garden is where I put the compost bins during the winter so needless to say it usually gets more compost than the other gardens. I'm wondering if maybe it received too much compost which I believe, from what I've read, would result in excessive phosphorous. I'm not sure why the nitrogen would show up as depleted? Maybe something is binding with the nitrogen making it unusable?

I would love to get this garden remedied for next year but am unsure how to approach this. Any help would be appreciated!

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Comments (3)

girlgroupgirl
15 years ago
Well rotted compost can be low in nitrogen. If you soil is great you can lay off the compost for a year or two and simply add some nitrogen in whatever form you like. If you need something quick, blood meal usually offers a very fast boost.
digdirt2
15 years ago
First, the DIY test kits are a waste of time and money. They are notorious for being inaccurate and mis-leading. So either get a pro test done from your local county AG office or don't do anything to your garden based on the DIY kit.

Second, most all garden soils will test normal to high in P as most all soils have plenty of it naturally - one reason why most new fertilizers are being sold P-free.

Third, most compost can't be your only source of nutrients, especially N, unless your soil also has a very active soil-food web, a good working micro-herd of bacteria to convert the compost to nutrients for the plants.

How much N your compost may have in it all depends on what the rabbits are fed and how long it is composted. N leaches and evaporates out of compost and soil very quickly - which is why it always tests low - so it may require regular additions of other N sources or at least of more quality compost several times during the season.

Too many who grow exclusively with compost make the mistake of assuming a 1x a year addition is sufficient for N. Unfortunately, given the fragile nature of N, it isn't.

But the place to start is with a REAL soil test.

Dave
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calliope
15 years ago
If you had problems with your crop this year, then do get your soil tested. Rabbit poo is quite high in nitrogen compared to some other manures. Yes, nitrogen can leach quickly, but manure based nitrogen is a slower release than non-organic sources and I don't understand why your soil should show depleted nitrogen, either. BTW, I use ONLY manure on my gardens from my chicken flock. I have not had to add any additional supplements other than compost. I do not have any problems with nutrient deficiencies.

You didn't elaborate when you spred manure in relation to when you plant your crops. Get a soil test done through your extension department. It's your first step and you really shouldn't do anything more to the soil until you find out the results.