Increased CO2 emission and organic matter decomposition by leaf-cutting ant nests in a coastal environment

Leaf-cutting ants perform a vital role in the cycling of carbon and nutrients in tropical ecosystems. Nests have high levels of organic matter and refuse dumps host up to two times more soil micro-organisms than non-nest soil. The increased levels of organic matter in the soil of nests, however, can affect CO₂ emissions from soil and alter the balance of atmospheric CO₂. We aimed at assessing the effect of nests of the leaf-cutting ant Acromyrmex balzani on CO₂ emissions in a coastal area of Northeast Brazil. Results show that A. balzani nests emitted up to four times more CO₂ than the surrounding soil and emissions were positively correlated with soil moisture and soil organic matter (SOM) content. In addition, field experiments demonstrated that refuse material has a lower residence time than the leaf material brought to the colonies. Despite the high density of nests and high content of SOM compared to adjacent control soil, CO₂ emissions by A. balzani nests represent only 0.3% of the total CO₂ efflux by the studied ecosystem. Although these effluxes account for a relative small portion of the total soil CO₂ emission, they are still important for the understanding of C balance, especially when one considers the thousands of tons of CO₂ emitted each day, across entire Neotropical regions where leaf-cutting ants occur.     

Critical periods of weed control in naturally green colored cotton BRS Verde

Cotton with naturally colored fiber is increasing as a commercial crop due specially to its textile processing with reduced environmental impact, as dying is not necessary. The critical period of weed control and the weed community were studied in a field with the naturally green colored fiber cv. BRS Verde cultivated in Missão Velha, Brazil. Without weed control during all the cycle, a reduction of 82.9% in yield was observed. The critical period of weed control was between 31 and 74 days after emergence for a reduction of 5% in yield. The weed community was composed of 21 species, with higher relative importance and dominance of monocotyledonous species. The beginning of the critical period was found to be more influential on yield than the ending. Thus, defining the right moment to start weed control can be more important to yield than determining the moment to cease it.     

Searching for bioactive compounds from Solanaceae: lethal and sublethal toxicity to Spodoptera frugiperda and untargeted metabolomics approaches

Journal of Pest Science - The fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), is a major pest of maize crops and others row crops on the American continent, and this...     

Distribution of the equilibrium moisture content in four hardwoods below fiber saturation point with magnetic resonance microimaging

Wood Science and Technology - The distribution of liquid and bound water in wood samples under equilibrium moisture contents (EMC) below fiber saturation point (FSP) was assessed by magnetic...     

Reactive natural phosphate enriched with filter cake enhances soil P content and noni seedlings growth*

One of the major challenges in crop production is increase efficiency of non-renewable P sources, or replace them with renewable sources. The objective of this study is to evaluate the effects of phosphorus (P) fertilization using reactive natural phosphate, filter cake, peat and biofertilizer on soil P content, foliar P content and growth of noni seedlings. The treatments were: control (without P fertilization); phosphorus; filter cake; phosphorus?+?filter cake; phosphorus?+?filter cake?+?peat; and phosphorus?+?filter cake?+?peat?+?biofertilizer. All treatments were replicated four times and arranged in a completely randomized design. The treatments phosphorus?+?filter cake; phosphorus?+ filter cake?+?peat; and phosphorus?+?filter cake?+?peat?+?biofertilizer increased phosphorus content in soil and in leaf, and the growth of noni seedlings. Our results indicates that natural reactive phosphate enriched with filter cake can be used as phosphate fertilizer on noni seedlings cultivation.     

Creep feeding effects on male Nellore calves influencing behavior and performance of their dams

The objective of the present study was to evaluate the effect of different schemes of calves’ supplementation in a creep feeding system, on the behavior of Bos indicus calves and dams, and also the influence of the calves’ supplementation on dams’ performance. Forty-eight Nellore male calves (147 ± 7 kg body weight and 3 months of age) in the suckling phase and their dams (476 ± 9 kg and 6 years of age) were studied in a completely randomized design. The experiment was divided into two periods of 71 days. The treatments were 5- and 10-g supplement dry matter (DM)/kg BW day offered in periods 1 and 2, respectively (5S/10S); 10- and 5-g supplement DM/kg BW day offered in periods 1 and 2, respectively (10S/5S); 7.5-g supplement DM/kg BW day in both periods 1 and 2 (7.5S); and mineral mix ad libitum in both periods 1 and 2 (MM). No differences (P < 0.05) in body condition score (BCS), final body weight (FBW), and average daily gain (ADG) were found in dams’ performance. Calves from MM treatment spent more time (P < 0.05) grazing than the supplemented calves from 5S/10S and 10S/5S treatments, in the first period. No difference in suckling time was found between the treatments (P > 0.05) in the first evaluated period. Calves from 10S/5S treatment spent more time suckling and less time eating supplements (P < 0.05) than 5S/10S treatment animals, in the second evaluated period. Dams of MM treatment’s calves had more idle time and lower grazing time when compared with the mothers of calves from 5S/10S and 10S/5S treatments. It was concluded that different schedules of Nellore calves’ supplementation on pasture do not affect their mothers’ performance, and supplementation decreases the grazing time of calves in the suckling phase.     

Acuaroid nematodes in the common kestrel (Falco tinnunculus) in the south of Spain

The prevalence, intensity and abundance of acuaroid nematodes were determined in the common kestrel (Falco tinnunculus) in Andalusia, Spain. Acuaroid nematodes were present in 26/41 (63.4%) of birds examined. The most common species belonged to the genus Synhimantus subgenus Synhimantus (56%): S. (S.) laticeps (36.5%), S. (S.) robertdollfusi (24.3%) and a single specimen of a third, unknown, Synhimantus (S.) spp., unlike any other described previously (2.4%). Other species identified were Synhimantus (Dispharynx) spp. (2.4%), S. (D.) nasuta (4.8%), Desportesius spinulatus (9.7%) and Skrjabinoclava spp. (2.4%). This is the first record of these three species in F. tinnunculus, but the latter two are considered to be accidental parasites in birds of prey.