Emergence of six crap species treated with sewage sludge, non-composted and composted, of waste water depuration plant

Previous tests designed to study the influence of both composted and non-composted sewage sludge on the germination of several crops established the convenience of complementing these with observations made during the emergence phase, in order to evaluate the effect of the sewage sludge on different growth parameters. An emergence test was conducted in pots under greenhouse conditions Tomato (Lycopersicon esculentum Mill.), spinach (Spinacia oleracea L.), lentil (Lens esculenta Moench), maize (Zea mays L.), wheat (Triticum aestivum L.), and rye-grass (Lolium perenne L.), were the experimental species. The objective was to evaluate two treatments, composted and non-composted sewage sludge applied in rates 0, 40 and 80 t ha-1. The variables studied were the number of emerging seedlings (PE), stem length (LT), and root length (LR). The substrate used was a 50 % mixture of sand and peat with its respective type of sewage sludge and rate. Each crop responded differently in terms of PE, LT and LR. Regarding the tomato, the principal factors (type of sewage sludge and rate) and their interaction were significant in terms of PE, LT, and LR. As for rye-grass, the type and rate of sewage sludge only had a significant effect on LT; whereas with wheat, lentils, spinach, and maize, only the effect of rate was significant. Regarding rye-grass, spinach, and wheat the type of sewage sludge and the rate had a significant effect on the variable LR; but when studying the lentil, only the rate was significant. In conclusion, this experiment indicates that LT and LR are respectively the best variables to evaluate the influence of treatments with different types and rates of sewage sludge. In general, the 40 t ha-1 treatment rate with composted sewage sludge responded best to the three variables evaluated.