|Seed and Planting - 71
SEEDLING GROWTH STIMULATED
Stands were established faster when a test chemical was applied to rice seed preplant. Although seedling growth was stimulated to a highly significant degree, the end result was not improved yield at least in the preliminary work.
IMPROVED STANDS SEEM CERTAIN
Work continues on best conditions: high-density seeds, greater oxygen supply at the seed, higher water temperatures, and optimum seedbed conditions. Progress is excellent toward minimizing the high risk in stand establishment by arriving at ideal management factors and pest control.
þ "ALKALI DISEASE"
This major nutrient disorder of rice is now definitely known to be cured by zinc fertilization. Zinc can be added in various ways:
1) Zinc deficiency can be corrected on most soils with 2 to 8 lb of actual zinc per acre, but growers should apply 8 to 16 lb to be certain of enough. The compounds used, in order of effectiveness, are: ligno sulfonates, zinc sulfate, and zinc oxide. Soil zinc levels below 0.5 part per million need correction. Soil is tested by extraction with DTPA. The zinc need not be incorporated in the soil; in fact, incorporation is inferior to surface application if minimal rates are used.
2) Superior carriers of zinc for rice are nitrogen fertilizers, which are physiologically acid in the soil. Ammonium sulfate and ammonium chloride are superior to urea, which is better than calcium cyanimid, a physiologically alkaline fertilizer. Don't use phosphate as a zinc carrier: it may tie up the zinc.
3) Treating rice seed with up to 2 lb of zinc per 100 lb of seed and appropriate sticker corrects zinc deficiency under most soil and water conditions