José Francisco da Silva

Recovery of drippers clogged by use of water high in iron content

A study was carried out (Reciclean) to evaluate the efficiency of using the phosphoric acid, sodium hypochlorite, a commercial product and mechanical impact for cleaning the drippers in which the clogging was due to the presence of high iron content in water. The experiment was set up in the Vista Alegre Farm, located in Jaboticatubas County - Minas Gerais State. A drip irrigation system was adopted for the accomplishment of the tests. Eight treatments were tested, of which, seven with application of chemical products and one with mechanical impact. In accomplishing the chemical treatments, the phosphoric acid was used at pH 2 and 3, sodium hypochlorite at 100, 50 and 25 mg L-1 chlorine and Reciclean at 50 and 25 mg L-1. According to the results, the following conclusions were drawn: the treatment using the phosphoric acid at pH 2 provided the best results, when evaluating the improvement of uniformity in the irrigation system, since it showed the highest increase in the values of uniformity coefficients (CUD and CUC); however, it is an expensive treatment. The treatment with 25 mg L-1 chlorine presented the best benefit/cost relation, since it showed to be the cheapest besides being the second best in improving the uniformity of the irrigation system. The mechanical impact is a good alternative to recover the drip irrigation systems, principally under organic farming.

Digestibilidade aparente dos nutrientes de rações contendo diferentes fontes de fibra e níveis de amido com coelhos em crescimento

ABSTRACT - The objective of the present study was to evaluate the nutrients apparent digestibilities in growing rabbits fed dietswith different starch levels (22 or 32% on average) by high or low inclusion of corn grain and different fiber sources (alfalfa hay or soybeanhulls), in 2x2 factorial outline. The diets were pelleted and supplied to 64 New Zealand White rabbits (16 replicates per treat ment), weanedat 34 days, housed individually in metabolism cages and allotted to a complete randomized design. Significant effects were not observedfor the interaction between the starch levels and the fiber sources. The best digestibility was observed with high starch diets (73.56%DM,74.30%OM, 71.51%CP, 63.89%GE, 95.08% starch, 45.87%NDF, 37.78%ADF, 55.57% hemicellulose, 39.86%cellulose), except forlipid fraction. On the other hand, the best digestibility of nutrients was observed with the diets containing with soybean hull s (72.37%DM,73.06%OM, 69.10%CP, 61.74%GE, 76.84%EE, 95.10% starch, 47.00%NDF, 38.42%ADF, 55.51% hemicellulose, 42.42% cellulose).These results suggest that diets with high starch levels or soybean hulls can be used efficiently by rabbits, maintaining the n utritionalrecommendations.Key Words: alfalfa hay, corn grain, digestibility, nutrition, rabbits, soybean hulls

Desempenho e características de carcaça de coelhos alimentados com rações contendo diferentes níveis de amido e fontes de fibra

The objective of the present study were evaluated the performance, quantitative and qualitative characteristics of the carcass in growing rabbits feeding with diets contents different starch levels (22 or 32% on average) by high or low inclusion of corn grain and different fiber sources (alfalfa hay or soybean hulls), in 2x2 factorial design. The experimental diets were pellets and fed ad libitum during 40 days to 40 rabbits weaned at 35 days, housed individually and assigned to a complete randomized design. Significant effects were not observed for the interaction between the fiber sources and the starch levels to the parameters evaluated in this study. Higher feed intake was observed with diets contents alfalfa hay (91.27 g/d), but the weight gain and food conversion were significant affected by the dietary treatments (30,18 g/d and 2.94 general average, respectively). The carcass yield, protein level, protein and energy efficiency in the carcass showed giher values for the diets with high starch levels (50.20, 62.36, 56.38 and 30.04%, respectively). Diets with high starch level or with soybean hulls resulted in better indexes of food conversion and characteristics of the carcass, reflex of a better nutrients utilization efficiency.

Tolerância de três cultivares de cebola ao Ioxynil e Oxyfluorfen em semeadura direta

To estimate the tolerance of three onion (Allium cepa L.) cultivars (Baia Periforme Super Precoce, Granex Ouro and Texas Grano 502 PRR), cultivated under direct drilled system, to Ioxynil and Oxyfluorfen, and the efficiency of these herbicides in weed control a trial was installed in Vicosa, State of Minas Gerais, Brazil. Three rates of each herbicide (0.125, 0.250, 0.372 kg/ha and 0.096, 0.192, 0.288 kg/ha) were applied 27 days after drilling, in a nested factorial design with four replications. Ioxynil was more selective than Oxyfluorfen, specially at higher rates. The lowest rate of Ioxynil did not provide effective control of most weeds present. Baia Periforme Super Precoce cultivar was more tolerant in relation to Texas Grano 502 PRR. The susceptibility of Texas Grano 502 PRR to Oxyfluorfen was expressed by significant decreases in final onion plant population and bulb yield.