The effect of Ferralsol mineralogy on the distribution of organic C across aggregate size fractions under native vegetation and no‐tillage agriculture

No‐tillage management can increase soil surface layer organic C (OC) levels compared with conventional tillage. The mechanisms underlying this increase in highly weathered tropical soils, such as Ferralsols, are not well established. The objective of this study was therefore to evaluate the influence of mineralogy on aggregation and the apportionment of OC across aggregate size fractions in a Brazilian Ferralsol under native vegetation (NV) and no‐tillage management for 10 (NT10) or 20 (NT20) yrs. Under native vegetation, soil OC generally increased with increasing aggregate size while, in response to changing management, soil OC increased in the order NT10 (8.8 g/kg) < NT20 (12.7 g/kg) < NV (19.1 g/kg). There were no significant differences in the mineralogy of the clay size fractions among the three treatments, with the notable exception of the CBD‐extractable Fe oxide fraction (Fe_CBD). The Fe_CBD fraction comprises various pedogenic Fe(hydr)oxides and increased from NT10 (33.9 g/kg) to NT20 (64.2 g/kg). The OC/Fe_CBD mass ratio within aggregates increased in the order NT10 <  NT20 <  NV while R² values for OC and Fe_CBD occurrence follow this same trend, with the NT10 soil showing a weaker correlation (R² = 0.178) compared with the NV soil (R² = 0.533). We propose that formation of organo‐Fe(III) oxide associations is promoted with implementation of NT management and the consequent reduction in macroaggregate turnover. The development of the OC‐Fe(III) oxide associations and their evolution over time within aggregates to more thermodynamically stable entities will strongly influence the long‐term preservation of soil OC.     

Congenital atresia of the parotid salivary duct in a 7-month-old quarter horse colt

A 7-month-old Quarter Horse colt was examined because it had had a tortuous, distended vessel on the side of its head since birth. An abnormality of the parotid salivary duct was suspected on the basis of location and course of the vessel. Atresia of the duct near the parotid papilla was diagnosed by use of contrast sialography. Surgical transpositioning was attempted, but failed because of stricture formation. Chemical ablation of the salivary gland has been used to treat traumatic rupture of the duct. It proved to be an effective and practical method of resolving the problem in this case. Cosmetic outcome was excellent, and functional problems associated with loss of the gland were not observed.     

Dystocia attributable to a fetal monster resembling schistosomus reflexus in a donkey

A schistosomus reflexus fetal monster was removed from a jenny via cesarean section. This type of anomaly is seen principally in ruminants and swine. Only 3 cases have been reported in Equidae.     

Rapid microbial stabilization of unconsolidated sediment against wind erosion and dust generation

Purpose  

Mineral dust pollution is a concern for human health due to the reaction of mineral particles in the organism and their role as pathogen carriers. Human activity generates unconsolidated sediments that become a dust source. This study investigates the effect of microbial growth on dust stabilization through aggregation in order to help alleviate this problem.