Effect of urea addition on chemist composition and in vitro dry matter digestibility of Brachiaria humidicola (Rendle) Schweick hay harvesd at different cutting ages

With the purpose of evaluating the effect of the urea addition of the hay of Brachiaria humidicola at differents cutting ages on dry matter (MS), ash and nitrogen content (N) and digestibility in vitro of the dry matter (DIVMS) a research was carried out under tropical dry forest conditions at Perija region in Venezuela. The desing used was a completely randomized with a split plot arragement and three repetitions. In the main plots were located the five strip of the cutting ages (30, 44, 58, 72 and 86 days) for the hay production, using one hectare with Brachiaria humidicola with an effective area of 102 m2 for each cutting ages strip. The chopped hay was placed in plastic bags and it was added 0, 3 and 6% of urea diluted with 40% of water in relation to the dry weight of the hay. It was stored for 28 days at ambient temperature. Samples from hay were taken for MS content, ash and N and DIVMS. The results show a effect of the urea adddition (P<0.0001) on the variables, with increasing of N from 1.2 to 2.9% and DIVMS from 65.1 to 70.8%; the MS and ash content decresing from 93.8 to 69.6% and from 6.2 to 5.7%, respectively. Showed an effect of the cutting age (P<0.005) on the variables, with decreasing in the ash content (from 7.4 to 5.3%), N content (from 2.1 to 1.6%), and DIVMS (from 71.0 to 64.8%) from 30 to 86 days, respectively. The DIVMS was affected (P<0.005) by the interaction cutting age x urea treatments, with the valor more high of 74.2% at 30 days of cutting age with 3% of urea

Dinámica de crecimiento en plantas de añil dulce ( Indigofera hirsuta L.)

A greenhouse trial was conducted to analyze the growth dynamics of sweet indigo ( Indigofera hirsuta L.). Five plants grown in 20 kg-polyethylene bags were harvested at each of the ages after sowing of 10, 17, 24, 31, 38, 45, 52, 59, 66, 73, 80, 87, 94, 101 and 115 d and separated into leaf (L), stems (S), petioles (P), and root (R) fractions. The experimental design was completely randomized. The total mass of dry matter (DM) did not begin to show significant differences (P < 0.05) as a function of time until after the 80-d harvest. Mean values observed for the respective days of age were: 0.005, 0.006, 0.008, 0.008, 0.048, 0.069, 0.311, 0.591, 0.966, 1.840, 4.696, 7.512, 12.606, 24.044 and 108.734 g DM/plant. All four fractions of the plants grew very slowly during the first 31 d, but thereafter accelerated their growth, especially L and P fractions until the final harvest at 115 d.Se realizó un ensayo en umbráculo para analizar la dinámica de crecimiento del añil dulce ( Indigofera hirsuta L.). Se cosecharon cinco plantas que crecieron en bolsas de polietileno de 20 kg, a cada una de las edades después de la siembra de 10, 17, 24, 31, 38, 45, 52, 59, 66, 73, 80, 87, 94, 101 y 115 d, las cuales se seccionaron en las fracciones hojas (H), tallos (T), pecíolos (P) y raíz (R). El diseño experimental fue totalmente al azar. La masa de materia seca (MS) total no empezó a mostrar diferencias significativas (P < 0.05) en función del tiempo hasta después de la cosecha de 80 d. Las medias observadas a las respectivas edades fueron de 0.005, 0.006, 0.008, 0.008, 0.048, 0.069, 0.311, 0.591, 0.966, 1.840, 4.696, 7.512, 12.606, 24.044, y 108.734 g MS/planta. Todas las cuatro fracciones de las plantas crecieron muy lentamente durante los primeros 31 d, para luego acelerar su crecimiento, destacándose las fracciones H y P hasta la última cosecha a los 115 d