Soil testing is the best way to determine lentil’s fertility requirements and is recommended before every lentil crop.
As well as determining the amounts of nutrients required, soil testing allows producers to screen fields for excessive nitrogen (N) content. Too much soil N reduces yield by encouraging rank plant growth and delaying maturity. Because lentil can fix up to 75 per cent of its own needed N, fertilizer N is rarely required. If called for, N should never be seed-placed. Instead, applications before seeding (or side-banding where there is separation of the seed and N band) are recommended.
Lentil is moderately tolerant to seed-placed phosphate. Up to 15 lb. of P2O5 per acre may be safely applied with the seed. If greater amounts of phosphorus are needed, side-banding during seeding is the best way. The closer phosphorus can be placed to the seed without damaging it, the greater the pop-up effect (quicker seedling emergence) and the greater the seedling vigor. Banding of phosphorus prior to seeding can be done, but is less efficient in supplying needed phosphorus to the lentil crop.
Potassium & Sulphur
Potassium (K) and sulphur (S) are usually adequately supplied by most soil types. The same holds true for micro-nutrients: namely boron (B), chlorine (Cl), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo) and zinc (Zn). If deficiencies are a concern, soil testing is especially recommended. Test soil to a depth of 24 inches to determine if sulphur fertilizer is required.