Rapportage bemesting 2007 : deelrapport sector vollegrondsgroenteteelt : telen met toekomst

Dit is de rapportage bemesting van het praktijknetwerk Telen met toekomst voor de open teelten voor het jaar 2007. Dit rapport geeft het resultaat van de analyse van de bemesting van het vierde jaar van de kernbedrijven in Telen met toekomst, waarbij de resultaten getoetst worden tegen de gebruiksnormen 2008. Tevens wordt een beoordeling gegeven van ontwikkelingen in de toepassing van de Best Practices Bemesting

Strategies to increase nitrogen use efficiency and reduce nitrate leaching in vegetable production in the Netherlands

Environmental concern and legislation of fertilization requires strategies to increase nitrogen use efficiency and reduce nitrate leaching. Strategies can be fertilizer choice, timing of N availability and fertilizer placement. Rainfall in the experimental year 2007 was moderate and different strategies were therefore not seriously tested. However, for crops that allow regular fertilization, it is questionable whether special fertilizers can do better than calcium ammonium nitrate (CAN) when fertilizers are applied according to good practice (i.e., row application, side dressing and split applications). Specific application of small amounts of N near planted endive showed increased initial growth, even at high levels of soil mineral N, and was found to lead in one of two plantings to increased yield at harvest. Substitution of broadcast N before planting by a starter application close to the plants followed by side dressing maintains maximum production while leaching risk is reduced

The fate of nitrogen from crop residues of broccoli, leek and sugar beet

Environmental concern has lead to legislation on fertilization to reduce nutrient losses to the environment. Reducing N input may be inadequate for crops that have a high N content in their residues. Reducing N input will negatively affect yield, but the residues remain. Management of crop residues may then be a more effective strategy to reduce N losses, notably nitrate leaching. Two experiments were carried out in 2006-07 and 2007-08 to study all emission routes of N from crop residues of broccoli, leek and sugar beet, and to determine the contribution of N from the residues to nitrate in groundwater. Crop residues were surface applied or rototilled, and compared with a blank and application of fertilizer N. About 11 to 16% of the N-content was lost to the air. Total N-losses to the air as ammonia and through denitrification were little affected by tillage, but partitioning was. When residues were left on the soil surface, most N was lost as ammonia, when the residues were rototilled, most N was lost through denitrification. Year strongly affected N leaching from crop residues, and the fraction of N from crop residues that was leached was twice as high in 2006-07 than in 2007-08. Tillage increased N leaching from broccoli, but had little effect with leek or sugar beet. Between 20 and 60% of the N content of residues of leek and broccoli was leached. Removal of residues after harvest will therefore contribute to reduce N leaching. However, options for treatment and re-use of the residues need to be studied as well as the effects on nitrate leaching and gaseous losses to assess the effects of the system as a whol

Safety and Effectiveness of Struvite from Black Water and Urine as a Phosphorus Fertilizer

To ensure food supply, phosphorus must be recycled, for which an appealing method is using struvite fertilizer from human excreta. One struvite from black water and another from urine were assessed for safety under Dutch regulations, and for effectiveness as P fertilizer in a maize field experiment and a literature review. Both struvites contained 12% P, 12% Mg, 6% N, and 0.5-1.5% of several micronutrients. Struvites did not exceed Dutch regulations for heavy metals or pathogens, and based on literature, organic toxins should be far below regulatory limits. In this study and 18 others, struvite appears to have similar effectiveness to soluble fertilizer. Early in the season, 200 kg P2O5 ha-1 of black water struvite and soluble phosphorus improved maize performance (

Uit de mest- en mineralenprogramma's : Kwaliteit van grond- en oppervlaktewater in project Telen met toekomst, eerste fase

Aan de eerste fase van Telen met toekomst (2000-2003) deden ondernemers uit de akkerbouw, vollegrondsgroenteteelt, bloembollenteelt en boomteelt mee. Daarnaast was er voor iedere sector een onderzoeksbedrijf waar nieuwe systemen werden ontwikkeld en beproefd met verregaande maatregelen om nutriëntenemissies te reduceren. De bedrijven lagen verspreid over Nederland (zie kaartje) en veelal op zandgrond. Uitzondering is de akkerbouw in zuidwest Nederland met kleigrond. Binnen zandgrond zijn er nog verschillen zoals duinzandgrond bij de bloembollenteelt en dalgronden in noordoost Nederland. Bemesting en gewasopbrengst zijn geregistreerd in de projectjaren 2000 t/m 2003. De waterkwaliteit op de bedrijven is gemeten in de jaren 2002 t/m 200

Waterkwaliteit op open teelt bedrijven en de relatie met bodem- en bemestingsvariabelen : Resultaten van het project Telen met toekomst, 2000-2004

Het doel van het project is ondermeer om aanscherpingen in het nutriëntenbeleid voor een brede groep telers haalbaar te maken. In de periode 2000 tot en met 2003 hebben 34 praktijkbedrijven uit de akkerbouw, vollegrondsgroenteteelt, boomteelt en bollenteelt deelgenomen. Daarnaast was er voor iedere sector een onderzoeksbedrijf waarop nieuwe systemen onderzocht werden. De bedrijven lagen verspreid over Nederland en veelal op zandgrond. Uitzondering is de akkerbouw in zuidwest Nederland met kleigrond. Binnen zandgrond zijn er nog verschillen zoals duinzandgrond bij de bloembollenteelt en dalgronden in noordoost Nederlan

Stikstofbemesting in waspeen en schorseneer

Verslag van stikstofbemestingsproeven in waspeen op westelijk zand en late waspeen en schorseneer voor conserven op zuidoostelijke zandgrond, in het kader van Telers Mineraal Paraat