DES MOINES, Iowa (AP) – Topsoil in more than half of Iowa’s fields still needs more rain to reach adequate levels.  The U.S. Department of Agriculture says in Monday’s weekly report that topsoil in 54 percent of Iowa’s field rated very short or short of adequate moisture. The east-central part of the state was the driest, with 78 percent of the topsoil moisture rated short to very short.  The USDA says 68 percent of the corn crop, which is silking in most parts of the state, is in good or excellent condition.   The soybean crop is rated 63 percent good to excellent.   The USDA report says 98 percent of the state’s oat crop has headed, which is nearly three weeks ahead of normal progression.