þ STOP NITROGEN WASTE

Practically all the nitrogen can be kept in the rice field by preventing water outflow for 5-7 days after ammonium fertilizer is broadcast in the water. Nitrogen waste is thereby minimized, and so is contamination of the outflow. (RM4)

þ CALCIUM PEROXIDE IMPROVES STANDS

Rice stands were improved by coating rice seed with calcium peroxide prior to planting. The chemical serves as an oxygen extender and germination aid. With the increasing cost of rice seed, such use (at about 20 lb per 100 lb of seed) is economically sound as a safeguard against poor stands. (RB1)

þ FLOODED VS. UNFLOODED

Under unflooded conditions (unlike flooded), fine soil aggregation and puddling promoted vegetative growth and increased yields. Flooded rice absorbed more phosphorus, iron, and silicon, and less potassium, magnesium, and zinc, than did unflooded rice. (RB1)

þ PHOSPHORUS DEFICIENCY CAUSE

Alternating flooded and drained soils showed that phosphorus becomes immobilized when the soil becomes aerated, accompanied by a reversion of the iron complex to a ferric iron form. Such immobilization of phosphorus on gel surfaces containing ferric oxyhydroxide is the cause of phosphorus deficiency in crops following rice. (RB1)

þ STRAW INCORPORATION EFFECTS ON RICE FERTILIZATION

Soil incorporation of straw does not interfere with nitrogen nutrition of the rice plant or require changes in fertilization to provide nitrogen for decomposition of the straw. That's the indication of three years of investigation in two locations. (RM7) (See also the next item: Straw incorporation vs. stem rot.)