Growth Of Winter Barley Research Articles

Effect of soil P status on barley growth, P uptake, and soil microbial properties after incorporation of cover crop shoot and root residues

AbstractBackgroundCover crops (CC) introduced to reduce leaching of nitrate may also improve soil microbial properties and phosphorus (P) uptake in crops that follow. These effects may depend on soil P status and the quality of the CC residues.AimOur aim was to quantify the more persistent effects of incorporation of residues of three different CC species on barley growth and P uptake and whether any response in growth and P uptake was related to soil P status and changes in soil microbial properties.MethodsWe examined the impact of soil P status, CC species, and residue fraction (shoots and/or roots) on the growth of winter barley (Hordeum vulgare) and soil microbial properties. Shoot and root residues from three contrasting CC (oats, Avena sativa; corncockle, Agrostemma githago; lupine, Lupinus angustifolius) were incubated for 2 months in soil with low and medium P status. Dry matter yield and P offtake characterized effects of CC residues on barley while phospholipid fatty acids (PLFAs), neutral lipid fatty acids (NLFAs), and enzyme activity characterized soil microbial properties after barley harvest.ResultsEffects of shoot residues on barley yield and P offtake appeared neutral or positive and not affected by soil P status, while the effect of root residues appeared negative for medium P soil and neutral for low P soil. With lupine shoot biomass, however, barley yield and P offtake increased in both soils. Neither CC treatments nor soil P status affected the microbial community composition (bacterial and fungal specific PLFAs). Lupine roots increased phosphomonoesterase, and lupine residues generally stimulated microbial abundance (total microbial PLFAs) compared to other CC treatments.ConclusionWe conclude that the effect of CC residues on the following crop and soil microorganisms depends on soil P status and that lupine had the largest positive impact on barley growth.

CROP RESIDUE MANAGEMENT STRATEGIES TO REDUCE N-LOSSES—INTERACTION WITH CROP N SUPPLY

Management of the crop residues may provide a means to preserve nitrogen (N) in the agro-ecosystem. In a field study, we examined the effects of barley (Hordeum vulgare L.) residue particle size combined with shallow (10 cm) or deep (20 cm) incorporation on soil N immobilization-mineralization, microbial biomass N dynamics, and plant N uptake. Deep incorporation of ground (<3 mm) residues in the autumn gave an immobilization of 415 mg Nm−2 over 18 days which was 30 % higher than with cut (25 mm) residue, and about twice as much as for shallow incorporation of the same amounts of residue. In the spring, deep incorporation of ground residue mineralized 756 mg N m−2over a 53-day period, comparable to residue-free soil. Ground residue incorporated to 10 cm gave 72 % less mineralization than the residue-free control soil. Microbial biomass N increased during autumn and winter in response to residue applications suggesting that residue carbon remained available for microbial growth, probably because decomposition was N-limited. High N mineralization with deep incorporation of ground residue in the spring was accompanied by a reduction in microbial biomass N, indicating that the mineralized N was derived from microbial N turnover. Growth of winter barley (cv Ermo) was limited 25 % by deep incorporated ground residue, but not significantly by the other treatments. In contrast, spring barley (cv Alexis) was not limited by deep incorporation of ground residue. The sequestration of N for the barley crops constituted less than 4 % of the residue N, and was 45 % to 63 % lower with shallow than with deep residue incorporation. Growth of winter oilseed rape (Brassica napus L. cv Bristol) after the barley crops was generally not influenced by the residue treatment. Overall, the study shows that by management of crop residues it may be possible to regulate soil N mineralization-immobilization and match the N release synchronously with the crop requirement.

Effects of sowing date and vernalisation on the growth of winter barley and its resistance to powdery mildew (Erysiphe graminis f.sp. hordei)

SUMMARYDetailed studies on the production of individual leaves, and the development of powdery mildew on them, were made in field plots of winter barley sown on different dates. The greater severity of the disease on early‐sown than on later‐sown seedlings during the autumn and winter can probably be explained mainly by changes in the abundance of inoculum and the suitability of the weather for infection. Results from glasshouse experiments suggest that the differences may be reinforced by direct effects of vernalisation on the susceptibility of seedlings to the disease. Contrary effects of sowing date on mildew severity during summer are probably due to the progressively greater resistance to mildew of the later‐formed than of seedling leaves, and the earlier appearance of corresponding leaves on early‐sown than on later‐sown plants. Early sowing can also increase the total number of leaves produced per stem. Therefore, because resistance of the leaves increases progressively, the maximum degree of resistance expressed by the later‐formed (e.g. flag) leaves will often be greater on early‐sown than on later‐sown plants.

Rhizodeposition by field-grown winter barley exposed to 14CO 2 pulse-labelling

Winter barley ( Hordeum vulgare L. cultivar ‘Marinka’) was grown in the field in 30 stainless steel cylinders arranged in ten triplets. At four growth stages (Feekes Stage 4, 6–7, 10.3–4 and 10.5.4–11.1), the shoots of two or three triplets were exposed to 14CO 2 for 8 – 10 h using a closed, temperature-regulated cabinet. Five days after labelling, the barley was cut at ground level and the cylinders retrieved for analyses. Below-ground transfer of 14C was divided into macro-roots (roots isolated by soil washing), macro-root-free soil, and rhizosphere (root and microbial) respiration. Additional labelled cylinders were left in the field and retrieved at crop maturity on 2 August or 11 October. At tillering 83% of the macro-root C was in the top 0–15 cm soil layer decreasing to 69% at maturity. At tillering, 43.2% of total 14C recovered was translocated below-ground, 10.1%, 6.0% and 27.0% being recovered in macro-roots, macro-root-free soil, and as rhizosphere respired 14C, respectively. The corresponding values at early grain filling were 1.9, 9.7 and 2.3%. From tillering to early grain filling the proportion of labelled C in the 0–15 cm soil layer decreased from 88 to 69% for macro-roots and from 66 to 36% for root-soil systems. The half life of 14C in macro-root-free soil was 4–48 days depending on root growth intensity. At crop maturity, grain, straw and macro-roots yielded 292.5 g C m −2, 448.5 g C m −2 and 79.7 g C m −2, respectively. The total below-ground transfer of C during the growth of winter barley was estimated to be 237.2 g C m −2 (2372 kg C ha −1), of which rhizosphere respired C and macro-root C at maturity accounted for 39.5% and 23.7–43.8%, respectively. Below-ground transfer of C corresponded to one-third of the above-ground C harvested at maturity. Excluding root respiration, the rhizodeposition totalled 174.8 g C m −2 of which 66.9% was retained below-ground at crop maturity. The in situ decomposition rates of root and root-derived C were low following crop maturity.

A function for describing nitrogen uptake and dry matter production by winter barley crops

The quantityY, of dry matter produced,Yd, and nitrogen taken up,Yn, during the growth of winter barley, was shown to be a function of thermal time,x, $$Y = (A^{ - 1/n} + \exp ( - kx))^{ - n} $$ wheren is a shape factor,k a rate constant andA the ultimate maximum of the curve. The value ofn was 1.2 for N-uptake and 1.0 for dry matter. The rate constantskN andkd for N-uptake and dry matter production respectively were well related to the date of sowing of the crop as expressed as the number of days after August 31st. The maximum N-uptakeAN was related to sowing date and to rainfall during March preceding harvest;Ad, the maximum dry matter, was related to the time between sowing and the return of the soil to field capacity. These relationships and the function itself were tested by examining the fits of the function to the measured datasets. The relationships may be site specific and their similarity to those derived for winter wheat is discussed.

Vegetative growth of winter barley in relation to environmental conditions and grain yield

SummaryThe object of this study was to investigate the vegetative growth in six barley varieties grown in southern Spain (Granada) during 1979, 1980 and 1981. The results showed that crop dry weight (CDW) was dependent on environmental factors (mean temperature, rain, and radiation) which were the determinants of the two CDW components, leaf area index (LAI) and leaf area ratio (LAR). However, the effects of these climatic factors on crop growth rate (CGR) and on its components, mean leaf area index () and net assimilation rate (NAR), were partially obscured by ontogenetic drift. In addition, a highly significant relationship was demonstrated between CDW (when the LAI reaches its maximum value) and grain yield. This suggests that the pre-anthesis period has a great influence in the determination of grain yield variation in hot, dry areas, where photosynthesis is very limited after ear emergence.

Influence of Chlorocholine Chloride on Grain Growth of Winter Barley (Hordeum distichonL. cv. Igri) in the Field

Green, C. F., Dawkins, T. C. K. and McDonald, H. G. 1985. Influence of chlorocholine chloride on grain growth of winter barley (Hordeum distichon L. cv. Igri) in the field.—J. exp. Bot. 36:1126-1133. Chlorocholine chloride was applied to winter barley either in the Spring or Autumn. It increased grain number per unit crop area. Rates of incorporation of dry matter into the grain were decreased, but the period of growth was extended by the treatments. Overall the final mean grain weight was reduced so that no advantages in terms of yield resulted from the increased grain numbers. Key words— Chlormequat, chlorocholine chloride, CCC, Hordeum distichon L., barley, grain growth, grain weight, senescence, grain yield. Correspondence to: Department of Agriculture and Horticulture, University of Nottingham, School of Agriculture, Sutton Bonington, Loughborough, Leicestershire LE12 5RD, U.K.

A comparison of the root and shoot growth of winter barley and winter wheat, and the effect of an early application of chlormequat

SUMMARYIn a field experiment where winter wheat and winter barley were sown on the same date, the patterns of root growth of the two species were similar, with a few roots reaching a depth of at least 120 cm. Roots senesced sooner in barley, in association with earlier maturity of the shoots and grain. The number of shoots and leaf area index of the barley were greater than for the wheat, but rates of dry-matter production until anthesis of the barley were similar in both species. The grain yield of wheat was about 10% heavier than for barley. Where chlormequat had been applied in early December at the 3- to 4-leaf stage, when shoot apices of both species were still vegetative, root density of the winter wheat in the following March and April was slightly greater than for untreated plants, but the difference disappeared later. For winter barley there was no effect of chlormequat on root growth until July when root length tended to be greater at depth after the chlormequat treatment. The chlormequat treatment significantly shortened stem length, but did not significantly affect the number of shoots, crop dry weight or grain yield of either species.

Effects of waterlogging and drought on winter wheat and winter barley grown on a clay and sandy loam soil

The effects of winter waterlogging and a subsequent drought on the growth of winter barley and winter wheat have been examined. We used lysimeters containing soil monoliths with facilities to control the water table and a mobile shelter to control rainfall. Winter wheat was grown on a clay and on a sandy loam, but winter barley only on the clay soil. Lysimeters were either freely-drained during the winter or waterlogged with the water table 10 cm below the soil surface from 2 December until 31 March (that could occur by rainfall with a return period of 2 to 3 years). The lysimeters then were either irrigated so that the soil moisture deficit did not exceed 84 mm, or subjected to drought by limiting rainfall (equivalent to a 1 in 10 dry year in the driest area of England) so that the deficits reached maximum values of 150 mm in the clay and 159 mm in the sandy loam by harvest. Winter waterlogging restricted tillering and restricted the number of ears for all crops; grain yield of the winter barley was decreased by 219 g/m2 (30%), and that of winter wheat by 170 g/m2 (24%) and 153 g/m2 (21% on the clay and sandy loam respectively. The drought treatment reduced the straw weight of winter barley by 75 g/m2 (12%) but did not significantly depress the grain yield. For winter wheat on the clay, where the soil was freely-drained during the winter, drought depressed total shoot weight by 344 g/m2 (17%) and grain weight by 137 g/m2 (17%), but after winter waterlogging, drought did not further depress total or grain weight. In contrast, the winter wheat on the sandy loam was not significantly affected by drought. From these results, which are discussed in relation to other experiments in the United Kingdom, it seems that winter waterlogging is likely to cause more variation in the yield of winter barley and winter wheat than drought.