Alfalfa (Medicago sativa L.) forage nutritional value and yield at different cattle manure doses

The present study was carried out at the Comarca Lagunera Region, Coahuila, Mexico, with the objective of assessing both nutritional value and yield of three varieties of alfalfa at three different doses of fertilization with cattle manure, with subsurface drip irrigation. N, P, K, Ca and Mg content in plant tissue was used as indicator of nutrient withdrawal. The following varieties were evaluated: CUF 101, Sandor and Altaverde. Five different cattle manure treatments were applied: 0, 40, 80, 120 and 160 t ha(-1). Control was fertilized with a chemical fertilizer at 30 to 100 kg ha(-1) for N and P, respectively. Significant differences were found in dry matter between treatments but not between varieties. The greater yields were found in the March, April and June cuts in the 80, 120 and 160 t manure treatments, yielding more than 4 t ha(-1). No significant differences were found in forage nutritional value variables (crude protein, acid detergent fiber, neutral detergent fiber and energy) between either varieties or treatments. With reference to mineral nutrient withdrawal, the greater values were found from the 5(th) to the 8(th) cut, approximately 160 kg ha(-1) N, 12 - 14 kg ha(-1) P and 125 kg ha(-1) K.