1. Centre for Nuclear Energy in Agriculture (CENA/USP)Univ. of São PauloCaixa Postal 9613416‐903PiracicabaSPBrazil
2. Brazilian Agricultural Research Corporation (EMBRAPA)51020‐240RecifePEBrazil
3. Dep. of AgroecologyAarhus Univ.Blichers Allé 208830TjeleDenmark
4. Institute of Bio‐ and Geosciences (IBG‐3), AgrosphereForschungszentrum Jülich52425JülichGermany