http://www.ipni.net/ en-us http://www.ipni.net/ Lotus Domino webmaster@ipni.net webmaster@ipni.net http://www.ipni.net/ipniweb/portal.nsf/0/02AB679B6294C2A44825763E0051024COver application of nitrogen (N) and phosphorus (P), and insufficient supply of potassium (K) are considered primary reasons for restriction of yield improvement in North China Plain. Optimized nutrient management practices that are based on soil ...Sun, 27 Sep 2009 08:00:00 GMT http://www.ipni.net/ipniweb/portal.nsf/0/5A25CE566A6E38974825763D004A5349This region, which includes Hebei, Henan, Shanxi, and Shandong provinces, plus Beijing and Tianjin, is the production base not only for grain crops, but also for vegetables. The region is densely populated. It has high fertilizer consumption, but in ...Sat, 26 Sep 2009 08:00:00 GMT