If you were looking at soil you'd not seen before (eg in someone else's garden, or in the wild) what would be the indicators of fertility that you would look for?
What would you be looking for? I was hoping this thread would generate some specific knowledges on how to assess soil fertility.
I guess it would not be helpful to say "use your intuition" but it is important to feel whether you like the soil. Chocolate cake texture often indicates good soil but not all good soils look/feel like chocolate cake. Smell and taste are good indicators - sour soil smells and tastes sour and good soils smell perhaps like a forest floor. Sticky soils needs work but perhaps has potential due to colloids. If the soil is sandy in texture you can be assured of good drainage if that is a requirement for you and access to constant water is not a problem. What plants (weeds) are growing in it? By and large if you think it is good soil then it probably is.
YOu can also look at the surrounding plants such as fruit trees to see if they are healthy or showing signs of mineral lackages (my word). I've got a book out of the library called Tropical Fruit and Nut crops Vol 2 which shows pictures of nutrient disorders. Perhaps there is something similar for your area. For drainage, you can do a test of digging a hole filling it with water and seeing how long it takes to drain.
If there's no natural or introduced mulch, I generally assume the fertility's low. While the 'feel' of native soil varies, you should be able to get your hand right into a well-fed, healthy soil. (In NZ anyway, I claim no overseas knowledge!)
A handful of soil could tell you if there is a reasonable mix of ingredients, sand, clay and organic matter. If it's obviously got too much sand or clay, or you can't see much organic matter, you would automatically assume that it's got problems. If you dropped that handful (or two) of soil into a clear glass one-litre jar, filled it 3/4 full of water and shook it, you could watch it settle out and estimate the amount of sand, clay and organic matter. Small pebbles would hit the bottom first, then the sand would settle down. The clay might take a few days to form its layer (really fine stuff might not at all), and organic matter would tend to float at the top. There is a place near me that keeps its 'topsoil' damp so it looks nice and dark. When you've bought it and it starts to dry out, you see that it's just about straight sand. Looking at the kinds of plants that grow there can be an indication, but where I live, the weeds seem to thrive in a wide varieties of soil when I look them up individually. The trees and shrubs might be a better indication of pH range and nutrient content of the soil. If you see nutrient deficiencies, and have memorized what all the nutrient deficiencies look like, that would give you a better idea. But some deficiencies closely resemble others. And if you're not up on all of the, you could easily get it wrong. But really, the best you can do is just get a rough estimate. Without a lab doing some work for you, most of it is just a guess. Sue
I once heard that a good indicator of the soils health is to put something dead on it and see how long it lasts.
PP, you just made me snort my coffee and have a choking fit. Now my workmates are SURE I'm nuts (the blue hair apparently wasn't a tipoff).