ABSTRACT The objective was to evaluate the effect of different irrigation systems and harvest frequencies on the cultivation of cactus pear. The study was conducted in the semi-arid region, in the municipality of Russas, CE, Brazil. The experiment was a split plot randomized block design, with four replications. Plots were represented by irrigation systems (surface drip, microsprinkler, Micro Spray Jet, and conventional sprinkler) and subplots by harvest frequencies (6, 9, 12, and 18 months). Cactus pear biomass production characteristics were evaluated. Most of the productive characteristics evaluated were influenced by harvest frequency and irrigation system. The harvest frequency of 12 months combined with conventional sprinkler system resulted in a total dry biomass production of 16,400 kg ha−1. The conventional sprinkler system showed the highest number of second-order cladodes (4.9 cladodes plant−1). The conventional sprinkler and Micro Spray Jet systems showed the highest values for various structural characteristics. For water use efficiency (WUE), the highest value was found at the frequency of six months (8.46 kg ha−1 mm−1). Regarding the effects of irrigation system on WUE, the highest values were observed with the conventional sprinkler system (8.20 kg ha−1 mm−1). The harvest frequency of 12 months combined with the conventional sprinkler system presents better results in the evaluated productive characteristics, mainly the cactus pear production by area.

This study evaluated the biomass flow of massai grass in regrowth subjected to different nitrogen levels (control - no fertilization; 400; 800; and 1200 N kg ha-1year-1) and under rotational stocking with sheep, in a completely randomized design with repeated measures over time. The leaf elongation rate increased with increasing nitrogen levels (N) and the fourth grazing cycle presented a lower value compared with the others. The stem elongation rate responded linearly with increasing levels of N, but it was not influenced by grazing cycles. The senescence rate of leaves remaining before grazing and after grazing were not influenced by the nitrogen fertilization or amended with successive grazing cycles. The phyllochron was influenced only by the nitrogen fertilization, with a decreasing linear response with nitrogen levels. Quadratic response was observed for the average length of leaves with increasing N levels and the grazing cycle 4 presented the lowest value for this variable. For each kilogram N ha-1 year-1, increases of 0.161 and 0.1604 kg ha-1 day-1 were verified in the herbage growth and accumulation rates, respectively. Nitrogen fertilization favors the biomass flow of massai grass, promoting an expressive increase in the production and accumulation of forage.

The objective was to evaluate the effect of salinity of irrigation water and different cutting ages on the biomass components of Echinochloa pyramidalis. Seedlings were planted in plastic pots (volume of 8 L) with sandy-textured Quartzarenic Neosol, under greenhouse conditions. The design was completely randomized in split plots with salinity levels (0.75, 2.0, 4.0, 6.0 and 8.0 dS m-1) in the main plot, and cutting ages (21, 28, 35, 42 and 49 days) in the subplots, with five replicates. After the standardization cut, the dry masses of total forage, dead forage, live forage, green leaf blade, green stem and ratios of live material/dead material and leaf/stem were determined. There was no interaction between the factors studied. Salinity decreased the dry masses of total forage, green leaf blade and green stem. Salinity had no effect on the dry masses of dead forage or ratios of live material/dead material and leaf/stem. Salinity changed the partitioning of dry matter, reducing the percentage of stems, and increasing the percentage of leaves in the dry mass of total forage. The advance in the cutting age caused increases in the dry masses of total forage, dead forage, live forage, green stem and green leaf blade. From the cutting age of 28 days, dead forage dry mass had a very sharp increase. The increase in stem dry mass rose from the 35th day. The extension of the cutting age promoted a decline in the live material/dead material and leaf/stem ratios. The cut of Echinochloa pyramidalis at 21 days, when it presents the best leaf/stem ratio is recommended.

This study evaluated intake and apparent digestibility of the nutrients in the diet of Morada Nova sheep that received diets containing increasing levels of juazeiro hay in substitution of Tifton 85 bermudagrass hay (0, 33, 67 and 100%). Sixteen non castrated male sheep, weighing an average of 26.75 kg, were used, placed in individual metabolic cages and distributed in a completely randomized block design with four treatments and four replications. Intakes of dry matter, organic matter, crude protein, ether extract, neutral detergent fiber, total carbohydrates, fibrous carbohydrates and non-fibrous carbohydrates and total digestible nutrients were not influenced by the addition of juazeiro hay to the diets, with mean values of 1,042.78 and 595.59 g/day of dry matter and neutral detergent fiber intake, respectively. Linear reduction was observed for digestibility of the dry matter, organic matter, neutral detergent fiber and fibrous carbohydrates. Quadratic reduction was observed for the acid detergent fiber digestibility coefficient. The digestibility coefficients of the crude protein, ether extract, total carbohydrates and fibrous carbohydrates were not significant. The nitrogen balance was not influenced and was positive for all the treatments. The inclusion of juazeiro hay did not influence nutrient intake or nitrogen balance, but reduced the digestibility coefficient of some diet components.