The present investigation entitled "Effect of (Magnet B) of calcium phosphonate - boron in growing lettuce (Lactuca sativa.L), Great Lakes 659 range, in the Province of Lamas" The objective was to assess the effects on crop yields of lettuce (Lactuca sativa L.) with application of 4 doses of calcium phosphonate - boron in the Province of Lamas. The present research was conducted from August to October 2012, the block design was completely randomized, with 5 treatments and 4 blocks . The results we obtained indicate that all the variables studied had a direct relationship with performance. The T3 (0.75 1 I ha-1) treatment reached the highest average with Kg.ha 33,368,8-1 in which performance and statistically surpassed others, followed by other treatments T2 (0.5 Kg I ha) T4 (1.0 Kg I ha) T1 (0.25 Kg I ha) and TO .All treatments yielded indices B I C above zero being the T3 (0.75 Kg.ha Ma...