Varkenshouderij in niet-concentratiegebieden : op weg naar duurzaamheid

In opdracht van de vakgroepen varkenshouderij van de N LTO en WLTO is onderzoek uitgevoerd naar de voorwaarden om een duurzame varkenshouderij in de niet-concentratiegebieden mogelijk te maken. Met behulp van gegevens uit de CBS-Landbouwtelling, een analyse van de inhoud van Streek- en Bestemmingsplannen en de resultaten van een enquête onder varkenshouders is nagegaan op welke wijze gekomen kan worden tot: 1) een verantwoorde en duurzame afzet van de geproduceerde mest; 2) een optimale afstemming tussen opfokzeugen, zeugen en vleesvarkens in het gebied; 3) ontwikkelingsmogelijkheden voor individuele bedrijven. Hiervoor zijn oplossingsrichtingen aangegeven en worden beleidsaanbevelingen gedaa

Effect of DDGS manure on soil and plant: preliminary results of the greenhouse study

Non-Peer ReviewedThe use of dried distillers’ grains with solubles (DDGS) in feedlot cattle diets is increasing as the bio-ethanol industry expands. Manure derived from dried distiller’s grain with solubles (DDGS) fed cattle seem to have higher amounts of N and P than manure from regular grain fed cattle. This study investigates how DDGS manure affects soil fertility and nutrient uptake by barley grown in a controlled greenhouse environment. Both DDGS and regular manure were applied at 30, 60, 120 and 180 Mg ha-1 yr-1 to a sand soil. The results of the first 3 harvest cycles indicate that both types of manure resulted in similar increase in plant total P content. However, soil TP and available P concentrations in DDGS manure treatments were higher. Soil available in DDGS treatments was twice as much of that in regular manure. Increase in soil TN and available N contents was similar with both types of manure. Plant TN content did not seem to be influenced by manure application. This study indicates that the main concern with the use of DDGS manure is its high P solubility. However, no significant increase in soil available P was observed at a manure rate of 30 Mg ha-1 yr-1

Espécies crípticas em Pagamea coriacea sensu lato (Rubiaceae): evidências morfológicas, ecológicas e de comportamento reprodutivo em um contexto simpátrico

In this study we explore morphological and ecological variation in sympatric populations of Pagamea coriacea s.l. - a species complex from white-sand vegetation in the Amazon. A total of 147 trees were sampled and monitored at three nearby sites in Central Amazon, Brazil. Multivariate analyses of morphology indicated two distinct groups (A and B), which also differed in bark type, each containing subgroups associated with sexual dimorphism. However, a single hermaphroditic individual was observed within group B. As expected, all pistillate plants produced fruits, but 23% of the staminate plants of group B, and 5% of group A also produced fruits. This variation suggests that the sexual systems of both groups are between dioecy and gynodioecy. There was an overlap in flowering phases between the two groups, but the pattern of floral maturation differed. Ecologically, plants of group B were found in more shaded habitats and over sandstone bedrocks, while group A was prevalent in deeper sandy soils as canopy plants. The significances of morphological and environmental differences were tested by a multivariate analysis of variance, and a canonical discriminant analysis assessed the importance of variables. The coexistence in sympatry of two discrete morphological groups in the P. coriacea s.l., with different habitat preferences and reproductive behaviors, indicates they represent distinct species.O objetivo deste estudo foi testar se o complexo de espécies Pagamea coriacea inclui múltiplas espécies, usando evidências morfológicas, ecológicas e de comportamento reprodutivo. Um total de 147 árvores foram amostradas e monitoradas em três locais próximos na Amazônia Central, Brasil. Análises multivariadas de dados morfológicos indicaram dois grupos discretos (A e B), que coincidem com diferenças no tipo de casca, cada um por sua vez com subgrupos que representam dimorfismo sexual. Contudo, um indivíduo distintamente hermafrodita foi encontrado no grupo B. Todas as plantas pistiladas produziram frutos, mas também foram observados frutos para 23% das plantas estaminadas do grupo B, e para 5% das estaminadas do grupo A. Essa variação sugere que ambos grupos possuem um sistema sexual entre dioicia e ginodioicia. Houve sobreposição das fases de floração e frutificação entre os dois grupos, mas o padrão de maturação de flores foi diferente. Quanto ao hábitat, o grupo B predominou em situações de sombra e em solos arenosos rasos sobre lajes de pedra, enquanto o grupo A ocorreu em solos arenosos mais profundos e no dossel da vegetação. A coexistência de dois grupos morfológicos discretos no complexo P. coriacea s.l., com diferenças ecológicas e de comportamento reprodutivo, indica que correspondem a duas espécies distintas