Nitrate leaching and residual soil nitrogen supply following outdoor pig farming

Effect of poplar trees on nitrogen and water balance in outdoor pig production – A case study in Denmark

“…Measurements of soil mineral N (0-50 cm) during autumn after sow occupation showed comparable values in the zones with trees and the zones with grass-clover (Jakobsen et al, 2018). Given the correlation between autumn soil mineral N and potential nitrate leaching that some studies found (e.g., Williams et al, 2005), the poplars probably took up soil nitrate effectively: 5-7 Mg DM ha −1 poplar biomass with N content of 10 mg g −1 DM (3 and 7 mg N g DM for stem and braches, respectively), as approximated from Georgiadis et al (2017), equates to 50-70 kg N ha −1 taken up by the poplars. While future studies may accurately measure N uptake by poplars and grass-clover in organic pig farms, the results support the hypothesis 1-2 4-3 6-5 7-8 10-9 11-12 14-13 mean Number of poplar trees (count) Paddock number NAT AT 1-2 4-3 6-5 7-8 10-9 11-12 14-13 mean that nitrate leaching is lower in areas with trees compared to grassclover, due to a higher N uptake by the trees prior to and during the leaching season.…”

“…Another relevant factor for decreasing nitrate leaching is vegetation cover. Williams et al (2005) reported about 50% lower leaching from paddocks with grass (137 kg N ha −1 ) compared to stubble (235 kg N ha −1 ) on outdoor pig farms in the UK. Grasses are efficient in N uptake due to their fast regrowth after grazing and already developed root system.…”

Potential loss of nutrients from different rearing strategies for fattening pigs on pasture

“…However, it seems likely that extra energy would be required for maintenance and locomotion. Another and probably more realistic option to reduce the nutrient surplus is by increasing the area to which the pigs have access, because reduced stocking rates will lead to reduced N leaching losses (Williams et al. , 2005).…”

“…The environmental impact of outdoor pig production is to a large extent related to the nutrient content in the supplementary feed for the pigs and the stocking density because it has proved difficult to obtain optimal utilization of the nutrients deposited during grazing (Zihlmann et al. , 1997; Williams et al. , 2000, 2005; Eriksen & Kristensen, 2001).…”

Editorial

“…Highlights of his early work included research on the physical properties of horticultural composts (Bragg & Chambers, 1988), alternatives to the use of peat in growing media (Bragg, 1990) and assessing the extent of soil water erosion in lowland England and Wales (Chambers et al, 1992(Chambers et al, , 2000aSkinner & Chambers, 1996;Chambers & Garwood, 2000), before he moved on to investigate the nutrient value of manures (Smith & Chambers, 1993;Nicholson et al, 1996Nicholson et al, , 1999Nicholson et al, , 2003Nicholson et al, , 2013Smith et al, 1998;Chambers et al, 1999Chambers et al, , 2000bChadwick et al, 2000;Sagoo et al, 2007;Shepherd & Chambers, 2007). He also assessed the environmental impacts of a range of organic materials recycled to agricultural land in terms of nutrient losses to water (Catt et al, 1998;Smith et al, 1998;Dampney et al, 2000;Hodgkinson et al, 2002;Williams et al, 2005), ammonia volatilization (Pain et al, 1998;Misselbrook et al, 2000Misselbrook et al, , 2005Nicholson et al, 2004a), nitrous oxide emissions (Cardenas et al, 2010) and pathogen behaviour (Nicholson et al, 2004b. His other research interests included heavy metals in manures and biosolids (Chaudri et al, 1999(Chaudri et al, , 2000(Chaudri et al, , 2001(Chaudri et al, , 2007(Chaudri et al, , 2008Georgieva et al, 2002;…”