00357    a2200109   4500082001600000100001800016245010800034260005300142300001500195650001800210650001900228  a631.41bCOO  aCooke, G. W.   aThe role and importance of potassium in the agricultural systems of the humid tropics bthe way forward  aBernbInternational Potash Institutec1986g1986  a39p.c21cm  aSoil sciences  aSoil chemistry