Before the lab report, the spade: infiltration and compaction in a degraded pasture
Physics and biology come before chemistry — which is why I would not start the diagnosis of a degraded pasture in the laboratory.
Translated from the Portuguese original, which is the version the author wrote. Read it in Portuguese.
If I had only one afternoon in a degraded pasture, my first step would not be to take soil samples to the laboratory. It would be to pick up a spade and measure water infiltration and compaction.
The reason is simple: I start with water. It is the measurement made in situ, and it is the starting point of any recovery.
Water is the immediate fuel. Before knowing whether the soil needs lime or NPK, I need to know whether the rain goes in or runs off across the surface, carrying away what is left of the organic matter. A degraded soil is usually sealed and compacted.
The answer comes straight away. Within a few hours, using an infiltration ring test — or even a tin with the bottom cut out — and measuring soil resistance with an impact penetrometer, or simply feeling it through the spade, I find out how well structured the ground is without waiting weeks for a laboratory report.
And that tells me where recovery has to begin: if water does not go in, no seed germinates and no fertilizer works. Soil physics comes before soil chemistry. From that diagnosis I know whether the first step is mechanical decompaction, a deep-rooted green manure, or an adjustment to grazing management.
Before asking what the soil chemistry is missing, I need to know whether the soil is “alive” enough to hold water. In a degraded pasture, compaction builds an impermeable shield. If rainwater runs off instead of soaking in, no investment in fertilizer or seed pays for itself. Fixing infiltration is the key that unlocks the land's capacity to recover.