The effect of renovation of long-term temperate grassland on N2O emissions and N leaching from contrasting soils.

Renovation of long-term grassland is associated with a peak in soil organic N mineralisation which, coupled with diminished plant N uptake can lead to large gaseous and leaching N losses. This study reports on the effect of ploughing and subsequent N fertilisation on the N2O emissions and DON/NO3(-) leaching, and evaluates the impact of ploughing technique on the magnitude and profile of N losses. This study was carried out on isolated grassland lysimeters of three Irish soils representing contrasting drainage properties (well-drained Clonakilty, moderately-drained Elton and poorly-drained Rathangan). Lysimeters were manually ploughed simulating conventional (CT) and minimum tillage (MT) as two treatments. Renovation of grassland increased N2O flux to a maximum of 0.9kgN2O-Nha(-1) from poorly-drained soil over four days after treatment. Although there was no difference between CT and MT in the post-ploughing period, the treatment influenced subsequent N2O after fertiliser applications. Fertilisation remained the major driver of N losses therefore reducing fertilisation rate post-planting to account for N mineralised through grassland renovation could reduce the losses in medium to longer term. Leaching was a significant loss pathway, with the cumulative drainage volume and N leached highly influenced by soil type. Overall, the total N losses (N2O+N leached) were lowest from poorly and moderately draining soil and highest for the well draining soil, reflecting the dominance of leaching on total N losses and the paramount importance of soil properties.

[Umbilical vein varix thrombosis]. / Thrombose d'un anévrysme de la veine ombilicale.

Umbilical vein varix is a rare entity, which can lead to in utero fetal death. We report the case of a women diagnosed with umbilical vein varix on the 31st week of amenorrhea. A close follow-up and the early diagnosis of umbilical vein thrombosis have allowed the patient to give birth to a healthy newborn on the 34th week of amenorrhea. Improved ultrasound imaging as well as systematic study of fetal annexes lead to an early diagnosis of umbilical vein abnormalities. This allows a close follow-up and an early diagnosis of fetal life-threatening complications.