Influence of AmiSorb on coastal bermudagrass growth and nutrient uptake

Carp ra mid (copoly-[(3-carboxypropionamide)(2-carboxymethylacetamide)]) is being marketed as a nutrient absorption enhancer under the trade name AmiSorb, No published research is available on the response of a perennial forage to AmiSorb, Two studies using AmiSorb were conducted on 'Coastal' bermudagrass [Cynodon dactylon (L,) Pers,] in northeast Texas. For 2 yr commercial fertilizer (200 N-50 P2O5-150 K2O/acre) and broiler titter (6 tons/acre) were applied with and without 2 qt of AmiSorb/acre, When AmiSorb was applied to commercial fertilizer, forage production was increased in two of the nine harvests over the 2 yr, However, AmiSorb did not increase annual yield with commercial fertilizer or broiler litter. Nor did AmiSorb have a consistent influence on N, P, K, Ca, and Mg concentration in the forage or uptake, or P, K, Ca, and Mg residual soil levels at the end of the growing seasons. A second study conducted for 1 yr examined AmiSorb rate and time of application when it was sprayed directly on the grass sod, Coastal bermudagrass responded positively to 2 qt/acre applied 1 May (300 lb dry matter [DM]/acre) and to an additional 0.5 qt/acre applied after the first harvest (500 to 700 Ib DM/acre) when 2 or 4 qt AmiSorb were applied 1 May. However, as in the first study, AmiSorb did not increase total forage production for the year. Results from this study with a perennial forage crop do not support the claim that AmiSorb increases DM production or nutrient uptake.