The productivity and chemical composition of Altai wild ryegrass as influenced by time of irrigation and time and rate of N fertilization.

The effects of five times of irrigation, two times of N-fertilizer application and four rates of N-fertilizer application on the seed yield, dry matter yield, N, P, NO3-N, Ca, Mg, and K content and K/(Ca+Mg) ratio of Altai wild ryegrass (Elymus angustus Trin.), were studied from 1974 to 1977. No clear-cut methods to maximize the seed yield on irrigated land were found. Highest dry matter yields were obtained from grass given three irrigations and 400 kg N/ha per year. Spring applications of N fertilizer resulted in forage with a higher N content than fall applications. The N content of the forage increased with increasing levels of N fertilizer, whereas the P content of the forage was reduced by N fertilizer applications. Toxic levels of nitrates can be expected from spring applications of 400 kg N/ha. This danger was reduced if N fertilizer was applied in the fall. The Ca, Mg and K content increased with increasing levels of N fertilizer. The K/(Ca+Mg) ratio indicated that there was little danger of gras...