scholarly journals RESPONSE OF WINTER WHEAT TO N AND WATER: GROWTH, WATER USE, YIELD AND GRAIN PROTEIN

1989 ◽  
Vol 69 (4) ◽  
pp. 1135-1147 ◽  
Author(s):  
M. H. ENTZ ◽  
D. B. FOWLER

Nitrogen and water are important variables that influence both grain yield and quality of wheat. The present study was conducted to investigate the combined effects of N and water on the growth, water use, yield and grain protein concentration of stubbled-in winter wheat produced in Saskatchewan. Seven field experiments were conducted between 1984 and 1986 on a range of soil types. Irrigation to approximately 150% of normal growing season precipitation significantly increased grain yield in five of the seven trials. A significant water × N interaction was recorded for grain yield in the remaining two trials. Grain yield response to irrigation averaged 10.9 kg ha−1 mm−1 at total available N levels above 140 kg ha−1. In trials where residual soil NO3–N to 61 cm averaged 40 kg ha−1, 62% of the grain yield increase was due to fertilizer N while 38% of the grain yield increase was due to the interaction between water and fertilizer N. Increases in grain yields due to N and water were attributed to increased levels of pre-anthesis dry matter, a higher number of kernels per square meter and an improved water use efficiency (kg ha−1 grain mm−1 total crop water use). The semidwarf cultivar Norwin and the tall cultivar Norstar responded similarly to N fertilization. In one trial, where moisture conditions were very favorable, a water × cultivar interaction indicated a greater response of Norwin to irrigation. The Gompertz equation was used to describe grain protein concentration-N response. The coefficient that describes the initial lag phase of this function was correlated with dry matter at anthesis (r = 0.97**) and root zone extractable water at stem elongation (r = 0.85**). These observations demonstrate that as pre-anthesis growing conditions improve more N is required to produce an increase in grain protein concentration above a minimum 8.2%.Key words: Wheat (winter), water use, nitrogen

1996 ◽  
Vol 36 (4) ◽  
pp. 443 ◽  
Author(s):  
MG Mason ◽  
RW Madin

Field trials at Beverley (19911, Salmon Gums (1991; 2 sites) and Merredin (1992; 2 sites), each with 5 rates of nitrogen (N) and 3 levels of weed control, were used to investigate the effect of weeds and N on wheat grain yield and protein concentration during 1991 and 1992. Weeds in the study were grasses (G) and broadleaf (BL). Weeds reduced both vegetative dry matter yield and grain yield of wheat at all sites except for dry matter at Merredin (BL). Nitrogen fertiliser increased wheat dry matter yield at all sites. Nitrogen increased wheat grain yield at Beverley and Merredin (BL), but decreased yield at both Salmon Gums sites in 1991. Nitrogen fertiliser increased grain protein concentration at all 5 sites-at all rates for 3 sites [Salmon Gums (G) and (BL) and Merredin (G)] and at rates of 69 kg N/ha or more at the other 2 sites [Beverley and Merredin (BL)]. However, the effect of weeds on grain protein varied across sites. At Merredin (G) protein concentration was higher where there was no weed control, possibly due to competition for soil moisture by the greater weed burden. At Salmon Gums (G), grain protein concentration was greater when weeds were controlled than in the presence of weeds, probably due to competition for N between crop and weeds. In the other 3 trials, there was no effect of weeds on grain protein. The effect of weeds on grain protein appears complex and depends on competition between crop and weeds for N and for water at the end of the season, and the interaction between the two.


2003 ◽  
Vol 140 (4) ◽  
pp. 395-407 ◽  
Author(s):  
R. E. RUSKE ◽  
M. J. GOODING ◽  
S. A. JONES

Field experiments were conducted over 3 years to assess the effect of a triazole fungicide programme, and additions of strobilurin fungicides to it, on nitrogen uptake, accumulation and partitioning in a range of winter wheat cultivars. Commensurate with delayed senescence, fungicide programmes, particularly when including strobilurins, improved grain yield through improvements in both crop biomass and harvest index, although the relationship with green area duration of the flag leaf (GFLAD) depended on year and in some cases, cultivar. In all years fungicide treatments significantly increased the amount of nitrogen in the above-ground biomass, the amount of nitrogen in the grain and the nitrogen harvest index. All these effects could be linearly related to the fungicide effect on GFLAD. These relationships occasionally interacted with cultivar but there was no evidence that fungicide mode of action affected the relationship between GFLAD and yield of nitrogen in the grain. Fungicide treatments significantly reduced the amount of soil mineral N at harvest and when severe disease had been controlled, the net remobilization of N from the vegetation to the grain after anthesis. Fungicide maintained the filling of grain with both dry matter and nitrogen. The proportionate accumulation of nitrogen in the grain was later than that of dry matter and this difference was greater when fungicide had been applied. Effects of fungicide on grain protein concentration and its relationship with GFLAD were inconsistent over year and cultivar. There were several instances where grain protein concentration was unaffected despite large (1·5 t/ha) increases in grain yield following fungicide use. Dilution of grain protein concentration following fungicide use, when it did occur, was small compared with what would be predicted by adoption of other yield increasing techniques such as the selection of high yielding cultivars (based on currently available cultivars) or by growing wheat in favourable climates.


2014 ◽  
Vol 41 (3) ◽  
pp. 227 ◽  
Author(s):  
Sebastian Kipp ◽  
Bodo Mistele ◽  
Urs Schmidhalter

Yield and grain protein concentration (GPC) represent crucial factors in the global agricultural wheat (Triticum aestivum L.) production and are predominantly determined via carbon and nitrogen metabolism, respectively. The maintenance of green leaf area and the onset of senescence (Osen) are expected to be involved in both C and N accumulation and their translocation into grains. The aim of this study was to identify stay-green and early senescence phenotypes in a field experiment of 50 certified winter wheat cultivars and to investigate the relationships among Osen, yield and GPC. Colour measurements on flag leaves were conducted to determine Osen for 20 cultivars and partial least square regression models were used to calculate Osen for the remaining 30 cultivars based on passive spectral reflectance measurements as a high-throughput phenotyping technique for all varieties. Using this method, stay-green and early senescence phenotypes could be clearly differentiated. A significant negative relationship between Osen and grain yield (r2 = 0.81) was observed. By contrast, GPC showed a significant positive relationship to Osen (r2 = 0.48). In conclusion, the high-throughput character of our proposed phenotyping method should help improve the detection of such traits in large field trials as well as help us reach a better understanding of the consequences of the timing of senescence on yield.


1997 ◽  
Vol 48 (1) ◽  
pp. 67 ◽  
Author(s):  
G. Fathi ◽  
G. K. McDonald ◽  
R. C. M. Lance

The interaction between nitrogen (N) rate and post-anthesis moisture stress in 6 cultivars of barley (Clipper, Stirling, Weeah, Schooner, Chebec, and Skiff) was examined. Plants were grown in a glasshouse at 2 rates of N under well-watered conditions until 3 days after ear emergence, when the stress treatment was started. Yield and grain protein concentration (GPC) responses and changes in the dry matter and N content of the straw and grain in the main stem and tillers were examined separately. Nitrogen increased grain yield in all cultivars except Weeah, with Skiff and Stirling being the most responsive. Post-anthesis stress did not reduce yields at the low N rate but large reductions occurred at the high N rate in all cultivars; the yields of Stirling, Chebec, and Skiff were most affected. At the low N rate, stress did not significantly affect kernel weight and GPC, but kernel weight declined and GPC increased at the high N rate. Compared with the main stem, tillers produced smaller grain with a lower GPC. The responses to N and water stress, and the different sensitivities of cultivars to stress, were largely due to the effects of the treatments on the growth of the tillers. In Stirling, Chebec, and Skiff, grain yield and kernel weight from the tillers were greatly reduced by stress, whereas Clipper showed relatively little effect of N and stress on yield and kernel weight. Net remobilisation of dry matter was increased by stress but not by N treatment, and the amount remobilised varied between genotypes. At the high N rate, post-anthesis stress increased the N content per kernel and net remobilisation of N. Although genotypes differed in the net amount of N remobilised and in the N harvest index, there was little variation in GPC between cultivars. The work demonstrated that reductions in yield and kernel weight and increases in GPC from post-anthesis stress can be greater when plants are grown at a high rate of N than when the supply of N is limited. The different responses to stress and N among the 6 cultivars were associated, in part, with the pattern of tiller development. However, there appeared to be differences in the sensitivity of grain filling to stress independent of the responses in tillering. While the net remobilisation of dry matter and N differed between cultivars, the amounts did not appear to be related to differences in kernel weight or GPC.


2001 ◽  
Vol 81 (3) ◽  
pp. 373-383 ◽  
Author(s):  
G. P. Lafond ◽  
Y. T. Gan ◽  
A. M. Johnston ◽  
D. Domitruk ◽  
F. C. Stevenson ◽  
...  

The recent advances in no-till seeding technology are providing new N management options for crop production on the prairies. The objectives of this study were to evaluate the potential interaction between P and N fertilizer on winter wheat production in a one-pass seeding and fertilizing system and to determine the feasibility of side-banding all N requirements using urea or anhydrous ammonia at planting as compared with the current practice of broadcasting ammonium nitrate early in the spring. Three forms of N fertilizer (urea, anhydrous ammonia, ammonium nitrate), three rates of N (50, 75 and 100 kg ha–1) and three rates of P (0, 9 and 17 kg P ha–1) were investigated. Urea and anhydrous ammonia were applied during the seeding operation, whereas ammonium nitrate was broadcast the following spring. Applying P fertilizer to the side and below the seed at planting with rates > 9 kg Pha–1 increased grain yield in 3 out of 6 site-years when ammonium nitrate was broadcast early in the spring. The positive yield response to P corresponded to soil test levels of 24 kg P ha–1. With soil test levels greater than 34 kg P ha–1, grain yield response to P fertilizer was not observed. When urea was banded at planting, together with P fertilizer, the yield increases with the increased P rates was shown only in 1 out of 6 site-years. At 5 of th e 6 site-years, grain protein concentration was not affected by P fertilizer; while for 1 site-year, the high rate of P fertilization decreased grain protein concentration. Responses of total grain N and P yields to P fertilization were parallel to the corresponding responses of P fertilization to grain yield, and were rarely associated with N or P concentrations in the grain. Applying N fertilizer at rates of 50 to 100 kg N ha–1 increased winter wheat grain yields by 3 to 8% in 3 out of 6 site-years. The high N rates increased grain protein concentrations in all 6 site-years. Grain protein concentration was 6% greater with N fertilizer applied as ammonium nitrate in early spring than when banding urea or anhydrous ammonia at planting. More consistent improvements in grain yield and grain protein concentration were obtained when the N fertilizer was applied as ammonium nitrate in the spring. Further research is required to determine the benefits of applying some of the crop’s N fertilizer requirements at planting, to reduce the risks of N stresses when the spring application is delayed because of adverse weather or soil conditions. Key words: Ammonium nitrate, anhydrous ammonia, grain yield, nitrogen timing, phosphorus, protein, urea


2010 ◽  
Vol 61 (15) ◽  
pp. 4303-4312 ◽  
Author(s):  
Matthieu Bogard ◽  
Vincent Allard ◽  
Maryse Brancourt-Hulmel ◽  
Emmanuel Heumez ◽  
Jean-Marie Machet ◽  
...  

1992 ◽  
Vol 43 (5) ◽  
pp. 949 ◽  
Author(s):  
GK McDonald

The responses of wheat to applications of nitrogenous fertilizer were examined between 1988 and 1990 at 10 sites in South Australia which were considered to be marginally deficient in N. Nitrogen rates ranged from 0 kg N/ha to 150 kg N/ha and the experiments were sown after a range of crops and pastures. Nitrogen often increased early crop vigour and subsequent vegetative growth but significant increases in grain yield occurred at three of the 10 sites only; at the remaining sites there was no significant response or there was a reduction in yield at the highest rates of N. Kernel weights fell and grain protein concentration increased at most sites as the rate of N increased. The total amount of N per kernel was relatively constant across the N treatments at each site and across the 10 sites it varied less than the starch content per kernel. Grain protein concentration therefore was affected more by the amount of starch deposited in the grain than by the total amount of nitrogen. The amount of dry matter remobilized post-anthesis, calculated from changes in dry weight, was high and at the majority of sites was increased with applications of nitrogenous fertilizer. Despite the generally large amount of dry matter remobilized, this appeared to be used inefficiently during grain filling and there was little evidence that it greatly contributed to grain growth and grain protein concentration. The relationship between starch content per kernel and N content per kernel varied between sites: in some cases starch and N were negatively correlated, while in other instances there was a positive correlation or no correlation. The data suggest that high grain protein concentration at high levels of N are not a direct consequence of increased mobilization of dry matter and greater translocation of N to the grain. Dry matter production at anthesis was correlated with the amount of growth after 10 weeks but generally this increased dry matter production was of no benefit to yield. It is concluded that in the medium rainfall areas of the state, there is no advantage to be gained from improved early vigour, except perhaps where poor early growth is due to inadequate management.


1997 ◽  
Vol 48 (2) ◽  
pp. 241 ◽  
Author(s):  
M. Lotfollahi ◽  
A. M. Alston ◽  
G. K. McDonald

Two experiments were conducted in pots 105 cm deep and 11 cm in diameter to determine the effects of subsoil nitrogen (N) on grain yield and grain protein concentration (GPC) of wheat (Triticum aestivum L. cv. Molineux). In both experiments, KNO3 was applied in solution at different times and depths in the profile. In the first experiment, in which a sandy soil low in available N was used, application of 150 mg N at 60 cm, 2 weeks after anthesis, significantly increased grain yield and GPC. The N was taken up gradually by the plant after N was applied. Adding N to the subsoil increased root growth and this resulted in increased water use and water use efficiency. Although there was an increase in the rate of N uptake by the roots, the main factor that influenced the utilisation of subsoil N was the root length density. In the second experiment, the effects of depth and time of N application, and of a reduction in post-anthesis water supply, were determined. A more fertile soil was used than the one in the first experiment. There were 5 KNO3 treatments: nil N; 150 mg N applied to the topsoil at sowing; 75 mg N to the topsoil and 75 mg N to the subsoil (60 cm depth) at sowing; 150 mg N to the subsoil at sowing; 75 mg N to the topsoil at sowing and 75 mg N to the subsoil 1 week after anthesis. The effect of post-anthesis water stress was assessed by allowing the topsoil to dry and then supplying half the amount of water used by the well-watered control treatment at 60 cm in half of the pots. Adding N increased yield and GPC but there was no significant difference in yield and GPC between the different N treatments. When N was applied to the topsoil only, most of it was used by the wheat plants or leached to the subsoil by anthesis; post-anthesis uptake of N depended on the amount of N in the subsoil. Adding N, irrespective of the depth of placement or time of application, increased water use and water use efficiency. In both experiments, increasing the availability of N in the soil after anthesis reduced the amount of N that was remobilised from the roots and stem to the grain. The recovery of applied N in both experiments was high (about 80%). These experiments have shown that N available in the subsoil after anthesis can be used very efficiently and can contribute to both grain yield and GPC. A critical factor in the efficient use of this N appears to be root length density in the subsoil.


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