Nutrition, productivity and soil chemical properties in an apple orchard under weed management

Weed management in orchard may affect apple tree nutritional status and yield, N flow and other soil chemical properties. This study evaluated apple tree nutritional status and yield, N flow in soil and soil chemical properties in an apple orchard under different weed managements. The experiment was started in October 2011 in an apple orchard established in 2008, on 80 plants submitted to the following treatments: no weed management, weed desiccation in rows, weed mowing in rows and weed mowing in rows and interrows. In 2011/2012, 2012/2013, and 2013/2014 crop seasons, stem diameter, number of fruits per plant and yield were measured, and nutrient leaf concentrations were quantified. In 2012/2013 and 2013/2014 crop seasons, soil samples were collected from 0 to 0.20 m layers, in order to quantify NH4 ?–N and NO3 -–N. In September 2013, 24 months after beginning of the experiment, stratified soil samples were collected in the 0–0.025, 0.025–0.05, 0.05–0.10, 0.10–0.15, 0.15–0.20 and 0.20–0.40 m layers. Soil total organic carbon, pH, available P and exchangeable K, Ca, and Mg were measured. The weed management methods did not affect apple tree yield and growth and they had a small effect on nutrient concentrations in leaves and in soil. Row and inter-row weed management had little or no effect on competition with apple trees for water and nutrients. The weed management can be dispensed during the production cycle, reducing soil erosion, N losses and the use of herbicide

A study of multi-jet events at the CERN p̄p collider and a search for double parton scattering

A study of events containing at least four high transverse momentum jets and a search for double parton scattering (DPS) have been performed using data collected with the UA2 detector at the CERN p̄p Collider (√s=630 GeV). The results are in good agreement with leading order QCD calculations. A value of σDPS<0.82 nb at 95% confidence level (CL) is obtained for the DPS cross section