Limits to nitrogen fertilizer on grassland.

The effect of N fertilizer on seasonal response of predominantly Lolium perenne grassland, sward quality and productivity, herbage nitrate content and soil mineral N was studied in cutting trials lasting 1-6 years. At an assumed marginal profitability of 7.5 kg DM/kg N applied, the av. opt. annual N application on sand and clay soils was 420 kg/ha. At this rate, herbage nitrate content did not exceed 0.75% NO3 and accumulation of soil mineral N was minimal. At annual N rates exceeding 500 kg/ha sward quality deteriorated and productivity decreased the following year. (Abstract retrieved from CAB Abstracts by CABI’s permission

Grassland productivity as affected by intensity of nitrogen fertilization in preceding years.

2 sown grasslands on a sandy and clay soil and an old permanent grassland on a clay soil comprising mostly perennial ryegrass were given up to 1120 kg N/ha annually and cut at various stages of development. Productivity decreased with increasing N application in the pretreatment yr, and was accompanied by a decrease in pasture quality. Annual applications of 400-480 kg N/ha gave a good balance between DM yield and sward quality. These results indicated that 1-yr field trials do not allow general conclusions as to long-term effects. (Abstract retrieved from CAB Abstracts by CABI’s permission

Landbouwkundige waarde van verschillende stikstofmeststoffen

Aan de orde komen: keuze van stikstofmeststoffen aan de hand van de voornaamste oorzaken van het verschil in werking, stikstofmeststoffen bij bouw- en grasland op diverse grondsoorten en onderzoek elders in Europ

Cholinergic imbalance in the multiple sclerosis hippocampus

Hippocampal pathology was shown to be extensive in multiple sclerosis (MS) and is associated with memory impairment. In this post-mortem study, we investigated hippocampal tissue from MS and Alzheimer's disease (AD) patients and compared these to non-neurological controls. By means of biochemical assessment, (immuno)histochemistry and western blot analyses, we detected substantial alterations in the cholinergic neurotransmitter system in the MS hippocampus, which were different from those in AD hippocampus. In MS hippocampus, activity and protein expression of choline acetyltransferase (ChAT), the acetylcholine synthesizing enzyme, was decreased, while the activity and protein expression of acetylcholinesterase (AChE), the acetylcholine degrading enzyme, was found to be unaltered. In contrast, in AD hippocampus both ChAT and AChE enzyme activity and protein expression was decreased. Our findings reveal an MS-specific cholinergic imbalance in the hippocampus, which may be instrumental in terms of future treatment options for memory problems in this diseas

Verkenning van grootschalige grondgebonden landbouwbedrijven in 2016

In dit onderzoek wordt inzicht gegeven in de financierbaarheid van een verdergaande schaalvergroting op de huidige grote grondgebonden landbouwbedrijven tot 2016. Ten aanzien van de verwachte schaalvergroting is aangesloten bij de LNV-visie 'Kiezen voor Landbouw' uit 2005. Met behulp van bedrijfseconomische rekenmodellen is voor een aantal representatieve voorbeeldbedrijven in de akkerbouw en melkveehouderij de liquiditeitsontwikkeling bij een drietal groeitempo's doorgerekend. Daarnaast heeft een gevoeligheidsanalyse plaatsgevonden voor kernvariabelen als rente en aflossingsduu

Changes in quantity of mineral nitrogen in three grassland soils as affected by intensity of nitrogen fertilization

Changes in quantity of soil mineral nitrogen down to a depth of 1 m in cloverfree grassland were monitored within one growing season and over successive growing seasons. Accumulation of mineral nitrogen in the soil occurred on permanent grassland with split application of nitrogen totalling more than 400 kg N ha-1 yr-1 and on young grassland, sown after arable crops, with applications of more than 480 kg N ha-1 yr-1. The relationship between the rate of nitrogen application minus nitrogen uptake, and accumulation of mineral nitrogen in the upper 50 cm of soil during each growing season is described