The influence of soil steaming on some properties of the soil and on the growth and heading of winter glasshouse lettuce. II. The reaction of the crop.

Soil steaming increased fresh and dry weights and N and Mn contents of the plants. Leaching the steamed soil caused a further increase in Mn content but decreased yields and N content. The addition of straw to the steamed soil did not affect growth or N content but it reduced the Mn content. Plants grown on steamed soil had darker coloured leaves and a greater incidence of leaf margin necrosis and bad heading than plants grown on unsteamed soil. See also Sous Fertil. 33 [1230]. (Abstract retrieved from CAB Abstracts by CABI’s permission

Very high applications of nitrogen fertilizer on grassland and residual effects in the following season

At very high nitrogen applications (480 and more kg N ha-1 yr-1) in field trials on all-grass swards the amount of N applied exceeded the amount of N harvested. In the humid temperate climate of the Netherlands in the subsequent spring approximately 25, 40, and 50% of this excess nitrogen was recovered as accumulated mineral nitrogen in the 0-100 cm layer of sandy, clay and heavy clay soil, respectively. The effect of this excess nitrogen on growth during the subsequent season was measured through the increase in DM and N yield over a reference treatment. In this season all treatments received a uniform application (40 kg N ha-1 cut-1). Residual effects were absent on sandy soil but distinct on the clay soils. On the clay soils each accumulated kg soil mineral nitrogen produced 15 kg DM. Assuming a relatively small contribution of residual nitrogen carried over in stubble, roots and organic matter, the accumulated soil mineral nitrogen would seem to be as effective as applied fertilizer nitrogen

The seasonal response of grassland to nitrogen at different levels of nitrogen pretreatment

Verslag van een onderzoek naar de invloed op permanent grasland (zonder klaver, op kleigrond) van een gedeelde stikstofgift van verschillende niveaus en op verschillende tijdstippe