6.4.1 Improving nutrient use efï¬ciency A key factor is to improve the eï¬ciency of nutrient use. By far the largest amount of our net phosphate is consumed in agriculture (see 6.1). A more eï¬cient use of agricultural phosphate is needed. Options for a better balance of inputs and outputs are given in section 6.2. The objective of the Fertilisers Act is to introduce equilibrium in phosphate input and output in the agricultural sector by 2015. The amount of phosphate application will depend on the actual soil P status and the focus is to balance the input and output of the soil balance (i.e. the maintenance of fertilisation). This will lead to improved eï¬ciency in nutrient use. In order to avoid using phosphate ores from geological deposits, phosphate should ideally be recycled from a renewable source (e.g. manure, compost, bone meal, biochar, ashes etc.). Substantial phosphate losses occur during the transportation, processing and preparation of food. It is estimated that 30 to 40% of the food produced in the Netherlands is wasted during production, transportation and storage (LNV, 200941). Moreover, 11-13% of the food purchased by consumers is estimated to be wasted (LNV, 2009). 53 41 6.4.2 Improving fertiliser efï¬ciency 1. Regular fertilisers When fertilising, a substantial amount of P2O5 is not available for plants due to instantaneous adsorption and a slower co-precipitation with soil compounds. Placing phosphate in planting rows, in planting holes, or side-application will improve the eï¬ciency of phosphate fertilisers (Smit et al., 201042, Ehlert & De Willigen, 200243). We could learn from the way plants and symbiotic fungi use chelating agents to keep phosphate available. Further research is needed to evaluate the feasibility of this. LNV, 2009. Bijlage Nota Duurzaam voedsel. Naar een duurzame consumptie en productie van ons voedsel. Ministerie van Landbouw, Natuur en Voedselkwaliteit, Den Haag, 29 juni 2009. 42 Smit, A.L, A.A. Pronk & P. de Willigen, 2010. Placement of Phosphate Leads to a More Eï¬cient Use of a Finite Resource Proc. 4th IS on Ecol. Fert. Strat. Field Veg. Prod., Ed.: R.U. Larsen, Acta Hort. 852, ISHS 2010. Ehlert, P.A.I., C.A.Ph. van Wijk & P. de Willigen, 2002. Fosfaatbehoefte van vollegrondsgroentegewassen, 3. Rijenbemesting. Praktijkonderzoek Plant & Omgeving B.V., Lelystad, PPO-projectrapportnr. 1125232. Richards, I.I. and A E Johnston, 2001. The eï¬ectiveness of diï¬erent precipitated phosphates as sources of phosphorus for plants. Report on work undertaken for CEEP1, EFMA (European Fertiliser Manufacturers Association), Anglian Water UK, Thames Water UK and Berlin Wasser Betriebe. 2. New fertilisers Struvite has proven agronomic qualities (Richards & Johnston, 200144). Pure struvite is similar to conventional phosphate fertilisers such as triple superphosphate. But the raw materials used to produce struvite and the production method used will aï¬ect the availability of phosphate from struvite. Rapid release characteristics are required if the product is intended for the Dutch market. However, slow release characteristics are favourable for phosphate ï¬xating soils such as oxisols in Brazil or Central Africa, where the slow release of phosphate improves P-availability for plants. Several measures can be taken to improve the availability of P from struvite. One option is dehydration (and sterilisation) at 110 C, whereby the struvite loses 5 of its 6 bound water molecules, after 43 44 Pagina 62
Pagina 64Scoor meer met een webshop in uw sportbladen. Velen gingen u voor en publiceerden uitgaven online.
458 Lees publicatie 159Home