v | ok | Kirjasto Aj-K | Sijoituslannoituksen vaikutus kevätvehnän kehitykseen

The placement of fertilizer was studied in the field trial on a clay soil in Southern Finland. The placement of fertilizer in the depth of 8 cm gave 28 per cent greater grain yield of spring wheat, and the placement in the depth of 12 cm 26 per cent greater grain yield than the surface dressing. The growth of shoots on the soil receiving placement was much better than on the soil receiving surface dressing. The results of shoot analyses showed that the placement caused a much greater uptake of nutrients than the surface dressing. The uptake of nitrogen was relatively most increased by the placement, somewhat less that of potassium and least that of phosphorus. The ripening of wheat was speeded up by the placement, which probably was due to the better early uptake of nitrogen and to the better uptake of phosphorus by means of the placing. The superiority of the placement to the surface dressing could be explained by the distribution of nutrients in the experimental soil during the dry early part of the growth season. A great deal of fertilizer nitrogen, phosphorus and potassium remained near the surface of the soil receiving surface dressing, and plants were not able to take up nutrients from the dry surface layer. On the contrary, the placed nutrients were deeper, in moister soil and better within the reach of wheat roots. Any movement of ammonium nitrogen was not found by the used methods. Nitrate nitrogen appeared to move to a greater extent particularly in the irrigated plots.

Tests were conducted to determine if there is a “preconditioning” effect when the greenbug, Schizaphis graminum, the English grain aphid, Macrosiphum avenae, and the corn leaf aphid, Rhopalosiphum maidis are reared on wheat, oats or barley and transferred as adults to wheat, oats or barley. Based on numbers of progeny produced on the second hosts, it was concluded that all three species may be reared on barley, and transferred without detrimental effects on their fecundity to either wheat or oats. Transfer tests of the greenbug from wheat or oats, or of the corn leaf aphid from oats, to other plants, should take into consideration the possibility of “preconditioning” by the original host plants.

Zinc sulphate applied as a 1 % spray at 2-4 weeks after emergence, or at 1 cwt/ ac drilled in, alleviated the symptoms. Grain yield increases were up to 35% higher than in untreated plots. Applications 5 weeks after emergence did not produce significant yield increases. There was an indication that cultural practices can also alleviate the symptoms.

The rate of reduction of kernel moisture in a standing crop of wheat between the physiologic and harvest stages of maturity was influenced by the vapor pressure deficit of the air, hours of sunshine, evaporation, and wind. The date when the crop reached the physiologic stage of maturity varied from year to year and was related to the available soil moisture at the time of seeding and rainfall during the growing season.

"One of the most interesting stories in the world is the story of wheat. No small part of the interest in the story lies in the part wheat will play in the future — as an agricultural commodity ... as a food ... as a raw material for industrial products ... as an article in world trade ... as a part of developing civilization ... as the Staff of Life. This publication, "Wheat — Farm to Market," tells an important part of that story. This is the story of the way wheat is produced on the American farm, and how it makes its way through the world of business, services, and industry to its market. It also is the story of how wheat came to be, of what it promises to become — in the field of hybrid wheat — and of the people and organizations in the wheat industry who grow, handle, and market wheat today."--Foreword.