Legume N Fixation & Mineral Cycle Math ?

[Stocker Steve]

Aggressive grazing experts recommend up to 50% legume in the mix, partially to increase N fixation for feeding the grass component.
Soil health experts are show casing the minerals provided each year by organic matter.
If you combine these two - - a 40% legume/4% OM pasture should be putting out about 145 to 180# N per acre per year. Sounds good to me.

The cautionary note that has been repeated a lot is that the grass/legume mix may be limited by P. I know I have some eroded hill sides and mined out remote fields, that are less than 10 on the Olsen scale. Do you see a lot of land that is P limited, or is something else the weak link in your system ?

 

[Ebenezer]

We have worn out cotton fields of the past century, the shift in the 50s was to pines, get the pines cut and the small amount of P left rides off on the logger's truck. Soil test and get results of 7, 12, ... pounds per acre. I could hope that in 10 years I could make the P come back up naturally with particular management while losing a lot of grazing potential for 10 years. Or I can put down broiler litter, unroll hay on those hill sides, put out lime to allow soils to begin to release natural but bound up P. I decided to fast track and also be keenly aware of soil health issues. It works.

I have no idea of OM% and do not need to know to feel good or bad. Focus on soil, prioritize legumes, grow complementary grasses and forbes and select livestock for environmental fit while managing for forage needs. It works and not having to buy spring and fall commercial fertilizer frees up a lot of money. It seems to get better each year.

 

[Stocker Steve]

We have worn out cotton fields of the past century, the shift in the 50s was to pines, get the pines cut and the small amount of P left rides off on the logger's truck. Soil test and get results of 7, 12, ...

More fields here are being worn out faster here with the reduction of small livestock operations. A few folks buy in turkey litter. Many mine as long as possible and then try to sign up for a FSA land retirement program.

I got one field up to an Olsen value of 39 ppm after bale grazing and cover cropping. Got a lot of fields to go...