Studies on Surface Sowing in Grassland Establishment : I. Effects and applicability of wet methods of coating seeds

To improve the oversowing in grassland establishment that is thought to fit for difficult sites because of gravels, slopet, trees, labour shortages etc., the author studied the introduction of forage species with some coating materials and abhesives and compared germination of the pelleted seeds of various methods. Specially-made rotary type coating machine was also described. The results obtained are as follows: 1. Lime, infusorial earth, peat moss powder and bentonite were compared as coating material with 3% solution of methylcellulose as adhesive with seeds of hairy vetch and it was found that most of the materials except infusorial earth were excellent and gave good germination. Solutions of methyl cellulose 3%, gum arabic 13%, polyvinylalcohol 3%, Doharon, soil stabilizing agent, 5%, Bond 30%, algin 0.75% were compared as adhesives with infusorial soil as coating meterial. The combination of methylcellulose and gum arabic gave best result. Bond was also available for coating and ease of obtaining and there was no depression in germination of the pelleted seeds made of the industrial adhesive. 2. The mixture of coating materials with the rate of peat moss 30, lime 50, bentonite 9 with bond 30% solution was thought to be satisfactory and the possibility of mixing fertilizers into the coating materials with crimson clover seeds was studied. 1) Mixing ammonium sulphate as coating material into the mixture was injurious for seed germination even at 5% in weight. 2) Superphosphate did not reduce germination at 5% and mixing fused phosphate was safe up to 20% but it is not good for pelleting from its glassy characteristics. 3) Muriate of potash reduced germination when mixed at 5% into the mixture. 4) Germination was safe when the compound fertilizer (15-15-15) was added to the mixture up to 5%. 5) Dried fowldung can be mixed into the mixture to 5% to maintain germination and barnyard manure can be mixed to 25% which is a good material for pelleting. 3. Insecticides such as heptachlor and S-seven can be used as coating material up to 100% and are good for coating. Mercuric fungicide can be mixed up to 20% but 1% is enough to protect seeds from fungal attack. 4. 10 cool-temperate grasses, 10 legumes and 8 warm-temperate grasses were compared for germination after treated with coating materials only and adding 5% of compound fertilizer (15-15-15) into the mixture and discussions were made from the date. 1) Cool-temperate grasses Coating promoted germination of smooth bromegrass, reed canarygrass and timothy but it did not give good results to orchardgrass, tall fescue and Kentucky bluegrass. Adding fertilizer did not reduce germination of smooth bromegrass, timothy and Italian ryegrass while seeds of orchardgrass, tall fescue, perennial ryegrass and Kentucky bluegrass were susceptible to added fertilizer. 2) Cool-temperate legumes Coating and adding fertilizer to the mixture promoted germination of hairy vetch, alfalfa, Ladino white clover and lupin seed could not germinate with the coating. Coating seemed to fit for legume seeds rather than for grass seeds. 3) Warm-temperate grasses Germination of sorgo, Rhodesgrass, bermudagrass was promoted by the seed coating but there was not the case with pearl millet. Adding fertilizer into the mixture was effective for the germination of Rhodesgrass and bermudagrass.