How big an issue do you think nutrient stratification is in no till?

[SilliamWhale]

The recent Potash Development newsletter pushes it as an issue based on USA no till data. Half of all soil nutrients are concentrated in the top 1-2". Advice is therefore to sample to 15cm depth so that you get a proper picture of the nutrient status further down. But I wonder if rainfall makes a difference as well as cover crops

Any views?

 

[Will Blackburn]

Its the natural way, shallow roots collect nutrients, deep roots anchor and collect water. They are less likely to leach from the top inches than the full profile. Sampling at 15cm would be good for nutrient sales?

 

[Simon C]

I had the same thought about three years ago so got Plumbo to do two tests to compare 0 to 2 inches with 2 to 5 inches in the same field, it would have been in no-till for about 6 years. Pretty much the same all the way down

 

[matttargett4]

Not sure about nutrient stratification but sure about nasty stratification, have some plant sap test results from this yr from maize fields all treated with the same cow slurry but some ploughed one direct drilled, ploughed shows normal nutrient uptake, dd has lots of chloride and copper upsetting the uptake of ca and mg if I remeber correctly, appears to me this is more of an issue than actual maki ng the mechanics of the system work. Cover crop has also been completely removed by the grass weed spray from june, 4 " cultivation on other land has stopped this happening.

Just shows concentrations rather than absolutes are important

 

[Andrew K]

Surely the worm population would be constantly recycling said nutrients through the profile?

 

[bactosoil]

I had the same thought about three years ago so got Plumbo to do two tests to compare 0 to 2 inches with 2 to 5 inches in the same field, it would have been in no-till for about 6 years. Pretty much the same all the way down

Bacterial and fungal densitys are very different zonally within the top 100-150mm layer and play their part in nutrient availability accordingly