The effects of nitrogen and irrigation on timothy (Phleum pratense) grown for production of seed: I. Vegetative growth

Abstract

1. Plants of S.48 timothy were established on a 1 ft square pattern for production of seed. Two series of plots, one irrigated and one not irrigated, were treated with three levels of applied nitrogen: 0 (NO), 87 (Nl) and 261 (N2) lb N per acre (0, 97·5 and 292·5 kg N/ha) per annum, for 3 years. In this, the first of two papers, only vegetative aspects of growth are considered. Since the irrigation treatment started only 2 weeks before most of the data were recorded, effects of irrigation on vegetative growth were generally small.2. The number of tillers per plant was increased by application of nitrogen; the lower increment was more effective than the additional nitrogen in the higher dose.3. The weight of tillers per plant was increased by nitrogen at both levels of application. The mean weight of each tiller was increased by nitrogen after the first year, predominantly in the N 2 treatment. In the second year, irrigation also increased the weight per tiller.4. The weight of roots per plant was significantly affected by application of nitrogen. In the first year, the weight was increased by nitrogen in irrigated plots; in the second year the roots were significantly heavier in the Nl treatment than in N0 and N2 treatments, where weights were similar; the same situation existed in irrigated plots in the third year, but in non-irrigated plots the weights of roots were similar in N1 and N2 treatments and were heavier than in the N0 treatment. Irrigation had positive effects on the weight of roots in the first and second years.

The effects of nitrogen and irrigation on timothy (Phleum pratense) grown for production of seed: II. Reproductive growth and yield of seed

“…However, there was no indication of a higher requirement for nitrogen where plots were irrigated, as was found in the work with cereals, and in the third year of the present work irrigation did not increase yield where nitrogen had been applied. It seems possible that the results were influenced by other factors, some of which have been previously presented and discussed (Lambert, 1967), such as the soil moisture deficit, the weight of roots present and the effect of nitrogen on the growth of the plant.…”

“…The timothy was harvested when the majority of the seed was light brown. An area of 4 drills x 7 ft (2-1 m) was used for determination of yield of seed (Lambert, 1967). Material was stored in muslin bags, subsequently threshed in a machine built at N.I.A.E.…”

“…The ears from the central plant in the areas used for determination of yield of seed were cut separately; these central plants were the ones used in spring for counts of numbers of tillers (Lambert, 1967). The ears from these plants were counted and their lengths were measured, and from each plant ten ears of graduated lengths were selected.…”

“…The first part of this paper (Lambert, 1967) described the purpose and layout of the experiment, and presented data on the vegetative growth of S. 48 timothy at a low plant density (30 cm x 30 cm square pattern) for production of seed. The treatments involved were (a) irrigation to field capacity for a period from about 1 week before initiation of inflorescences until 2 weeks before harvest, except for periods of profuse an thesis, and (6) no irrigation; these treatments were applied at three levels of nitrogen: 0, 87 and 261 lb N/acre (0, 97-5 and 292-5 kg N/ha) per annum designated, NO, N l and N2 respectively.…”

Effects of nitrogen fertilisation and irrigation on seed yield and yield components of signal grass (Urochloa decumbens)

“…Irrigation was discontinued after flowering on the basis of previous research (Lambert 1967;Cookson et al 2000). In coolseason perennial grasses, many of the studies on irrigation (Lambert 1967;Hebblethwaite 1977;Chastain et al 2014) and precipitation during anthesis (Abel and Boelt 2018) suggested that wet weather and amount and timing of precipitation could depress pollination, as well reduce yield-component development. Nitrogen as granular ammonium nitrate (340 g N kg -1 ) was spread manually on the soil surface at the appropriate rates for the subplots receiving 25, 50 and 75 kg N ha -1 on 30 October 2009 (21 days after mowing for the first crop) and 25 February 2010 (20 days after mowing for the second crop).…”