- Location
- Yorkshire dales
Farmers need to realise that there is a massive p+k requirement difference in ' maintaining ' when soil levels are adequate , compared to ' buid up ' when they are low. Build up is a very long term investment of adding more than you take out , at the right time. 1 index of p equates to 350 units and 1 index of k equates to 500 units. I did a trial on a 10 acre 3 cut silage field, pH 6.7 p index 3 , k index 3. Same total N on all field, but put slurry and bagged mop 30 units on half. Weighed and measured fresh cut grass . 12.5 tons /acre 1 st cut compared to 9.25tons/acre. And rb209 would tell you that you didnt need the extra potash at k3. 2nd cut same benefits although total yield lower on all field. Potash uptake by growing plants is higher than offtake.