Uma grande variedade de produtos tóxicos é emitida durante o processo de tratamento do couro nos curtumes que usam o cromo III para obter o couro wet blue. O resíduo sólido (raspas e aparas) contém cerca de 3 % de Cr III, que representa um sério problema ambiental e não tem, atualmente, destino adequado. O resíduo de couro após extração de Cr (colágeno) foi utilizado como fonte nitrogenada para o capim-elefante (Pennisetum purpureum Schum cv. Napier), em um Latossolo Vermelho-Amarelo, aplicando-se quatro doses do colágeno (4, 8, 16 e 32 t ha-1) e três tratamentos adicionais (testemunha; adubação com N mineral e resíduo de couro wet blue- sem a extração do Cr). O colágeno é uma boa fonte nitrogenada alternativa para crescimento do capim-elefante até a dose de 16 t ha-1. O resíduo de couro wet blue não disponibilizou N durante o cultivo de capim-elefante. Isso mostra que a extração do Cr utilizando-se o ácido fosfórico é fundamental para uso do rejeito de couro como fonte nitrogenada na agricultura. A aplicação do colágeno supriu a necessidade de N para plantas de capim-elefante, semelhantemente à adubação com N mineral.

Large amounts of solid wastes are produced in tanneries, which use chromium (III) to obtain wet blue leather hides. The solid residues (leather scraps and strips) contain around 3 % chromium (III), which represent a serious environmental problem and, presently, have no adequate destination. The leather waste after chromium extraction (collagen) was used as a nitrogen source for elephantgrass- Pennisetum purpureum Schum cv. Napier. Four doses of collagen (4, 8, 16, and 32 t ha-1) and three additional treatments (control; mineral fertilizer N; and wet blue leather residue without Cr extraction) were used. Collagen as alternative nitrogen source has a positive effect on elephantgrass growth at rates up to 16 t ha-1. Little N became available to elephantgrass plants after application of wet blue leather residues. These results show that the phosphoric acid extraction of chromium is necessary if leather waste is to be used as a nitrogen source in agriculture. The application of collagen supplied the N need of elephantgrass plants, similarly to mineral N fertilization.

Parasitoid Hymenoptera collected in a soybean plantation (Glycine max (L.)) Merril (Fabaceae) at the municipal district of Nuporanga, SP, Brazil. Parasitoid Hymenoptera were collected by using Moericke trap placed in a soybean plantation (Glycine max (L.) Merril) (Fabaceae) of the variety Conquista, during the period of March 24th to April 7th, 2000. A total of 4,969 specimens of parasitoids, belonging to seven superfamilies and 15 families, were collected. Scelionidae, Encyrtidae, Aphelinidae and Trichogrammatidae were the most common families, being responsible for 41.66%, 19.42%, 11.19% and 7.35% of the total number of parasitoids collected, respectively. Other eleven families showed the relative frequency lower than 5%.