Cereal Nitrogen Use Efficiency in Sub Saharan Africa

Cereal production in Sub Saharan Africa (SSA) is inadequate for supporting population nutritional demands. Nutrient mining of nitrogen (N) has taken place in all areas where cereals are produced in SSA. This review reports on the nitrogen use efficiency (NUE) of Sub Saharan Africa cereal grain production. For SSA, NUE's exceed 100%. In light of the low N application rates, high NUE's speak to a much bigger and potentially damaging situation for cereal production in SSA. Limited supplies of N, the continual rise in prices and elevated economic risk of N fertilization, combined with existing low yield levels of cereal production reiterates the importance of NUE in SSA and the importance of aiding this region in overcoming its dysfunctional agriculture production systems. High NUE's for SSA are a direct result of applying so little fertilizer N, at the ultimate expense of mining an already depleted soil resource.     

Pharmacokinetics and Effects of Alkalization after Intravenous Administration of Eltenac in Horses

Eltenac (ELT) [4-(2,6-dichlorophenyl)amino-3-thiophene] is a non-steroidal anti-inflammatory drug (NSAID) that was developed for veterinary use in horses and cattle. The pharmacokinetics of ELT was evaluated in horses at 0.5 mg/kg body weight (BW) after single IV injection after 5 days of repeated IV administration and after a single IV injection in horses previously subjected to 250 mg/kg BW of sodium bicarbonate (NaHCO₃) as an alkalization treatment. The aim was to determine whether blood and subsequent urinary alkalization could modify the pharmacokinetics of ELT. Drug quantification was performed with serum and urine using high performance liquid chromatography with UV-visible detection. The results were also integrated with cyclo-oxygenase-inhibition literature data to review the dosage scheme of ELT in horses. After a single intravenous administration, ELT was characterized by rapid distribution (mean t½_λ1 = 0.18 ± 0.07 hour) and a short elimination half-life (mean t½_λ2 = 2.9 ± 0.68 hour). The volume of distribution was small (V_dss = 253.51 ± 47.55 mL/kg), which is likely because of the high percentage of drug protein binding (approximately 97%). The AUC_0-∞ and Cl_B were 6.92 ± 0.84 h*μg/mL and 73.2 ± 10 mL/h/kg, respectively. Repeated administration did not cause either accumulation or modification of the pharmacokinetic profile. The in vitro effective concentrations were maintained for a 6-hour period. The alkalization procedure appeared to accelerate drug elimination, as ELT was quantifiable only for 6 hours; however, the drug clearance was not significantly modified. Thus, the administration of alkaline compounds to accelerate the elimination of ELT is not completely confirmed.     

Adjusting P-K Fertilization and Liming Strategies to Enhance Yield of Cherry Tomato Plants Grown on an Oxisol

ABSTRACT

Although cherry-tomato is becoming more popular in the last years, there are no specific recommendations for P and K fertilization or liming strategies for this specific variety. Our aim was to assess rates of P and K and liming strategies in order to improve the yield of cherry-tomato grown on an Oxisol with a limited P-availability. Two pot experiments were developed. In the first-one, a two-factor factorial design was developed with 4 P (first-factor) and 4 K rates (second-factor), being these rates the 0%, 50%, 100%, and 200% of the recommended fertilization for tomato in South-Brazil. In the second experiment, the soil pH (4.3) was adjusted to 5.5, 6.0, and 6.5 with limestone. Soil P-availability, plant growth, diameter, number of fruits and cherry tomato yields were increased with the P addition, while a non-significant effect was observed after adding K. The highest yield was produced with 50% of the suggested amount of P for tomato in comparison with the non-fertilized plants (yield increase of 674%), while higher P rates (100% and 200%) produced a lower yield increase. The significant effect of soil liming was observed on increase of the flower bunches number when the soil pH was amended to 6.5. Cherry-tomato requirements seem to be different from the recommended for other varieties. Our results indicate that higher yields were achieved with a lower amount of chemical inputs than the recommended for tomato in general, stressing the importance of P for tomato cherry production over the other factors assessed here.