@INPROCEEDINGS {VAN DER HEIDE: 1985, title = {Nitrogen management in multiple cropping systems}, author = {van der Heide, J. and Van der Kruijs, A. C. M. B. and Kang, B. and Vlek, P. L. G. }, booktitle = {Nitrogen Management in Farming Systems in Humid and Subhumid Tropics}, year = {1985}, pages = {291--306}, note = {Proceedings Symposium on Nitrogen Management in Farming Systems in Humid and Subhumid Tropics, Held at the international institute of Tropical Agriculture, Ibadan, Nigeria, 23-26 October 1984; edited by B.T. Kang and J. van der Heide. Haren, The Netherlands, IITA and Institute for Soil fertility(IB)}, }