Variation between years in growth and nutrient uptake after anthesis of winter wheat on Broadbalk field at Rothamsted, 1969–84

Abstract

Dry weight, nutrient content and other properties of winter wheat were measured from anthesis to maturity between 1969 . From 1969 the cultivar CapelleDesprez was grown either as a first wheat, in the rotation potatoes, beans, wheat, or as a second wheat, in the rotation fallow, wheat, wheat. From 1979 to 1984 the cv. Flanders was grown in the rotation fallow, potatoes, wheat and in this period the wheat was given fungicide sprays. Grain yield of Cappelle-Desprez grown as a first wheat was greater with 96 than with 144 kg N/ha in spring. First wheats yielded much more than second wheats with 96, but not with 144 kg N/ha. Second wheats had more eyespot and take-all, but less mildew, than first wheats. Mildew was more severe with the larger amount of N. Grain yield of Flanders as a first wheat was greater than that of Cappelle-Desprez. Yield of Flanders was greater with 144 than with 96 kg N/ha and it was greater still on plots given 96 kg N/ha plus 35 t/ha farmyard manure. Other properties in addition to grain yield were changed by cultivar, rotation and manuring.Examination of the variation between years showed relationships among properties and between some of them and grain yield. Many of the relationships were independent of cultivar or husbandry. Relationships between weather factors and some properties, but not grain yield, were detected. Grain yield of first wheats was closely related to number of grains/m 2 , but the relative importance of number of ears/m 2 and number of grains per ear varied from year to year. Yield was positively related to dry weight per grain in Flanders, but negatively in Cappelle-Desprez. The weight of straw was usually less than that of the total above-ground crop at anthesis, but varied between years in a similar manner. The amount of N in grain plus straw was generally well related to the amount of N in the wheat at anthesis, although the changes in N content after anthesis ranged from a loss of 9 kg/ha to a gain of 51 kg/ha. The uptake of N, P and K was more closely related to dry weight than to nutrient concentration.Variation between years in the proportion in the ear of 14 C supplied to the flag leaf was similar to that of 14 C supplied to the next lower leaf, but was different for 14 C supplied before and after anthesis, and did not relate to other properties.Date of anthesis ranged from 7 June to 5 July. A model incorporating responses to photoperiod, vernalization and temperature accounted for 78% of the variance in date of anthesis. The duration of the period from anthesis to leaf senescence ranged from 33 to 60 days and was linearly related to mean temperature above a base of 7-5 °C. Dry weight per grain was negatively correlated with mean temperature between anthesis and leaf senescence; a relationship including an adjustment for number of grains/m 2 fitted both cultivars.The amount of N in grain plus straw and percentage of N in grain dry matter were decreased by increased rainfall during the 3-week period following the application of N fertilizer in spring. An additio...

Nitrogen and dry matter partitioning of barley grown in a dryland environment

“…However, there appeared to be potential for significant N uptake during grain filling even in crops with high N reserves. Other work on wheat (Woodruff 1972;Cox et al 1985;Thome et al 1988) and sorghum (Muchow 1990) has also indicated a close link between DM and N accumulation. In these studies, an average of 130 g DM was accumulated per g of N taken up.…”

Genotype, sowing date and plant spacing influence on high-yielding irrigated wheat in southern New South Wales. II. Growth, yield and nitrogen use

“…There were, however, big differences in N uptake between 1983 (maximum uptake 19 g/m2), 1984 (26 g/m2; assuming N harvest index of 75%) and 1985 (36 g/m*). Measured uptake in 1983 and 1985 levelled off between the flag leaf stage and anthesis, much earlier than in high-yielding wheat crops at higher latitudes (Spiertz and De Vos 1983;Thorne et al 1988). This occurred even when crops were topdressed in that period, and N should have been readily available in the soil.…”

“…In addition, excessive pre-anthesis growth in early sowings increased lodging, and as a result yield generally had a negative association with dry weight at anthesis. Even for May sowings, anthesis dry weights were, for example, some 200 g/m2 higher than for high-yielding crops in Western Europe (Spiertz and Ellen 1978;Thorne et al 1988) because continued production during the winter months in Australia more than offset the somewhat lower crop growth rates around anthesis in both g m-2 day-' (21 v. 25) and g/MJ (2.3 v. 3.0). Higher respiration losses and shorter days may have caused these lower crop growth rates.…”

Modelling crop physiology for integrated decision making

“…At the simplest level it can provide a tool to look at or allow for the effects of a single variable. Thorne et al (1988) and Chalabi, Day, Willington & Biscoe (1988) looked at aspects of grain growth in wheat, and associated the process in a simple way with the expected effects of temperature. In the former case it showed the impact of temperature on inter-annual yield variation through effects on grain size in a classical experiment at Rothamsted.…”