Effects of nitrogen on crop development and grain growth of winter wheat in relation to assimilation and utilization of assimilates and nutrients.

Abstract

Grain growth and yield components of winter wheat cv. Lely were studied in a field experiment in 1976 with 4 rates of N (50, 100, 100 + 50 or 100 + 100 kg N/ha). Growing conditions were characterized by a high level of solar radiation, warmth, ample nutrient supply and no damage by diseases. N raised grain number/m2 from 16 700 to 20 600 and grain yield from 640 to 821 g dry wt./m2. Grain growth duration was short, due to warmth, but the rate of the grain filling was very high (from 24.0 to 29.2 g/m2 day during the effective grain-filling period). A high grain yield was associated with a high grain N content which resulted in a grain protein yield ranging from 63.8 to 107.1 g/m2 with increased N rate from 50 to 200 kg/ha. The carbohydrate demand of the grains was provided by current photosynthesis and relocation of stem reserves. The latter was reflected in a decline of the stem wt. after the mid-kernel filling stage. N and P demands of the grains were supplied by withdrawal from the vegetative organs (leaves, stem, chaff) and to a large extent by post-floral uptake and assimilation. Under the prevailing growing conditions the grains turned out to be very strong sinks for carbohydrate, N and P as shown by the harvest indices. Additional N dressings increased the harvest indices of DN, N and P from 0.40 to 0.48, from 0.75 to 0.81 and from 0.91 to 0.93 resp. It was suggested that a more restricted vegetative crop development at high N levels and a longer duration of root activity, photosynthesis and grain growth after anthesis would considerably favour grain yield. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Defining Fertilization Strategies for Sorghum (Sorghum bicolor (L.) Moench) Production Under Sudano-Sahelian Conditions: Options for Late Basal Fertilizer Application

“…Bodson et al [33] studied the split of N fertilizer on wheat and found that applying N fertilizer twice at stem elongation and at flag leaf stages gave similar yields with higher grain quality compared to traditional practice with 3 applications at tillering, stem elongation and leaf flag stages. Furthermore, a number of studies showed the potential of increasing grain yield and grain protein through late-season N application under rainfed conditions [34,35] and in irrigated conditions [36,37]. These authors found that the yield increase with N late-application depended on the native soil N supply, previous soil N uptake, plant developmental stage, and yield potential.…”

Heterotic and seed rate effects on nitrogen efficiencies in wheat

“…Nitrogen fertilizer is a key input to North European wheat production, with an average 197 kg N/ha applied to wheat crops in the UK in 2002 (Goodlass et al 2003). Nitrogen in the crop is strongly correlated with canopy size and duration, light interception, grain numbers per unit area and thus grain yield (Spiertz & Ellen 1978;Evans 1993;Peltonen 1993;Sylvester-Bradley et al 1997). Additionally, N applications can increase grain protein concentration, increasing end use value, especially for milling markets (Gooding & Davies 1997).…”

Nitrogen, Sustainable Agriculture and Food Security: A Review

“…High yielding wheat cultivars grown under temperate climatic conditions in the Flevopolder, The Netherlands (photo taken by the author). For details: see Spiertz and Ellen (1978).…”

“…This value is usually high in cereals and tuber crops, e.g. : 0.60-0.80 for wheat (López-Bellido et al, 2008;Spiertz and Ellen, 1978) and 0.70-0.80 for potato (Biemond and Vos, 1992)), but somewhat lower in legumes (Chapman et al, 1985). Cereals do reallocate N from the leaves to the grains, while in root crops most N is retained in crop residues.…”