potassium guidelines for field crops in new york - Purdue Agriculture

Potassium Guidelines for Field Crops in New York. Second Release. June 12, 2003.This set of equations implies that if the soil test K level is higher than 150% of the “A”value of a specific soil management group, the potassium requirement becomes zero. Ifthe soil test K level between 100 and 150% of the “A” value, the potassium requirementis 20 lbs per acre K 2 O. At low soil K levels, a maximum K 2 O recommendation rate is set(Table 3). For crop establishment and topdressing potassium, manure can be used tosupply the entire requirement. Appendix Table B shows the K recommendations for eachof these crops by Cornell Morgan soil test K level. The recommendations in this Table Bare rounded to the nearest 5 lbs.5.2 SoybeansThe K recommendations for soybeans are soil management group and soil testspecific as outlined in Table 4.Table 4: Potassium recommendations (lbs K 2 O/acre) for soybeans.CNAL Morgan extractable KSoil Management Grouplbs K/acre I, II III IV, V, VI269 0 0 05.3 Established stands of alfalfa, alfalfa grass, and alfalfa birdsfoot trefoilThe potassium recommendations for established stands of alfalfa (ALT), alfalfagrass (AGT) and alfalfa birdsfoot trefoil (ABT) are derived using the followingequations:Soil management group I:K recommendation (lbs K 2 O/acre) = [{(ypa * 40) – SoilTestK} / 0.6] – 120[8]Soil management group II:K recommendation (lbs K 2 O/acre) = [{(ypa * 40) – SoilTestK} / 0.6] – 100[9]16