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| What is the net of nutrient import to and nutrient export from the farm?
Is water being used efficiently (all seasons) to supply the crop with the nutrients needed and prevent leaching?
Is it about managing water or managing nutrients?
After 30-70 yrs of no-tillage pasture and a good portion of those years with annual ryegrass and a lot of 'other stuff' growing including native plants similar in funtion to current 'cover crops', soil P status was 2.5-5 ppm in 2004, K was mid to high 200s when I took over the ranch. So is it just no-tillage and a bunch of mixed plant species and then 'boom' we have high soil fertility and soil funtion? No...not IMO not all soils/areas....the soil physics, chemistry, and biology and the grazing system/land use practice and the water cycle all have to play together to recycle nutrients properly! Misuse water then misuse nutrients! Inherently low or high fertility soils both cycle nutrients if managed properly, but that doesn't mean that each will cycle at a rate conducive of requirement for each plant to be grown nor to replenish annual crop removal....that doesn't mean the system won't 'leak' either (eg soil retrictions to root growth)!
The best way IMO to build soybean P K status is using pre-digested grain/crop/forage/cover crop residue (eg import and spread a manure source/s) then use cover crops (plural) to recycle the surplus nutrients and use the surplus water efficiently! Manure OM can stimulate the soil biology and MAY make some unavailable nutrients more available, but manure alone may be too slow to improve deep soil physics and chemistry before soil nutrient losses occur....one may need a mixed source Ca program to compliment the nutrient/water system at sub topsoil depths. | |
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Cover crops to increase P & K
