Multifactorial experimentation on continuous winter wheat grown in sandy clay soil at Saxmundham, Suffolk

Abstract

We present results from an experiment at Saxmundham measuring the effects of growing different numbers of successive winter wheat crops, each year, from 1971 to 1976; it followed five cropping sequences introduced from 1966 to 1970.From 1971 to 1973 four seed rates, two row spacings and three nitrogen rates were tested in all combinations with four of the previous cropping sequences. The remaining sequence was sown traditionally for continuity. Number of ears, leaf area, yield and nutrient content showed little benefit from increasing or decreasing seed rate, around that usually sown. Rows 15 cm apart gave the largest yield independently of N, because they produced most ears. There was no loss in yield from growing up to eight consecutive crops of winter wheat. 100 kg N/ha was sufficient for maximum yield.From 1974 to 1976 two varieties of different potential (Cappelle-Desprez and Maris Huntsman), chlormequat chloride (CCC), three amounts of N, as single, or as divided dressings, were tested in all combinations with the four cropping sequences. The fifth sequence again was sown traditionally, but with or without autumn-applied N. Maris Huntsman gave a grain yield only 0-22 t/ha larger (4-5%) than that of CappelleDesprez, and mean yields were larger (also by 4-5%) where CCC was given. Divided dressings of N increased yields by 0-11 t/ha (2-2%). The mean increase in yield from adopting all three improvements was 0-5 t/ha (or 11%). Yields of the 10th and 11th consecutive wheats declined, probably because black grass (Alopecurus myosuroides) became abundant. There was a good inverse relationship between losses of N in drainage during winter and subsequent yield and grain nitrogen uptake, which helped to explain large yield variations from year to year. TNTROTinOTTON t ' i e °^[ leT ^a^' which had been given uniform P and K manuring since 1952, was used for a crop sequence The sandy-clay loam (Beccles Series) at the experiment. Yields of continuous wheat (CappelleSaxmundham Field Station, Suffolk (founded in Desprez) were compared from 1968 to 1970 with 1899), which is typical of heavy land in the area, is those after phased-in tests (begun in 1966) of a 2-formed in Chalky Boulder Clay with surface layers year break of Italian ryegrass and beans. The containing much sand (Hodge, 1972). It is plastic purpose was to increase yields (by introducing the when wet, hard when dry and rarely friable. As break and increasing the amounts of N given in such it is better suited to autumn-sown than to spring) and to determine whether take-all (Gaeuspring-sown crops and, with adequate manuring, mannomyces graminis) and eyespot Pseudocercowinter wheat could be expected to yield well, sporella herpotrichoides) were as damaging to wheat However, in Rotation II (the site used for our grown after wheat as they are at Rothamsted (Slope, experiments) the largest mean from any treatment Etheridge & Williams, 1973). Yields were increased during 1900-52 was only 2-7 t grain/ha (Boyd & in the year after the 2-year break (to 4-34 compared Tris...

Removal of phosphorus and potassium from the soil in wheat and barley straw

“…A similar pattern for straw K. content to increase with increasing N rate has been shown on a range of soil types by other workers (Widdowson et al 1980;Ralph & Ridgman 1981;Chaney 1986). Although K acts as a balancing cation for the nitrate anion during uptake, this effect may also be due to the higher N rates shortening the duration of senescence by delaying its start, thereby reducing the amount of K transferred from the stem back to the soil.…”

“…Straw K concentration was consistently negatively correlated with the rainfall 3 weeks before harvest. Leaching of K from crops after anthesis by rainfall before harvest has been indicated by other workers (Gregory et al 1979;Widdowson et al 1980;Loue 1984). There was poor, inconsistent or no correlation with P or K fertilizer applied.…”

Tests of amounts and times of application of nitrogen and of sequential sprays of aphicide and fungicides on winter wheat, following either beans or wheat, and the effects of take-all (Gaeumannomyces graminis var. tritici), on two varieties at Saxmundham, Suffolk 1980–3

“…The weight of 1000 grains was increased INTRODUCTION Yields of winter wheat on the sandy clay loam (Beccles Series) at Saxmundham in the 1960s and early 1970s were often much smaller than chose on silty clay loams at Rothamsted. Widdowson, Johnston & Penny (1980) discussed the problems in the introduction to an earlier paper. During 1971-6 they tested numerous agronomic factors on continuous winter wheat.…”

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

“…These concentrations (Fig. 3) were relatively constant, fluctuations were presumably caused by variation in Exceptions were some large fluctuations of concen-leaching of K from the tissues by rain during the 2 or tration of K in straw which resulted in similar 3 weeks before harvest (Widdowson, Johnston & Penny, 1980). There were relatively small concentrations of P in the wheat at anthesis in 1972, 1976 and 1980 which were associated with small amounts of P in the wheat.…”