Working Document Series Open Access Minjingu phosphate rock extractability by white lupin and chickpea in Njoro and Kiambu sub-counties, Kenya J.J. Lelei · R. O. Onwonga · J.P. Ouma Declining phosphorus (P) fertility is a major production constraint in Kiambu and Njoro subCounties of Kenya. Use of Minjingu phosphate rock (MPR) to rebuild soil capital P is limited by its insolubility in water. Field experiments were co… RUF-33952 2014 CC BY 4.0 11 Aug 2015