Spring wheat (Triticum aestivum) yield and grain protein responses to N fertilizer in topographically defined landscape positions

2001 ◽  
Vol 81 (4) ◽  
pp. 505-514 ◽  
Author(s):  
F. Walley ◽  
D. Pennock ◽  
M. Solohub ◽  
G. Hnatowich

A 3-yr field study was initiated in 1996 to examine the different grain yield and grain protein responses of wheat to varied N fertilizer rates in a typical glacial till landscape in Saskatchewan, Canada. Our objective was to assess the agronomic and economic feasibility of variable rate fertilizer (VRF) N application for wheat. Results suggest that spring soil water status largely determined the yield and the protein content of wheat both within different years of the study and between different landscape positions within a given year. Although grain yield was strongly related to spring soil water and was predictable on that basis, the grain yield response of wheat to fertilizer N additions was highly variable due, in part, to the dual role that N played in determining both grain yield and grain protein content. As a consequence of the unpredictable nature of the varied response of wheat to N fertilizer additions, there was little economic rationale for using VRF strategies in the 3 yr of this study. However, in the long-term, we believe that VRF N application strategies can be employed to manage N inputs from the perspective of managing and replacing harvested N. Key words: Variable rate fertilizer application, precision farming, nitrogen application, N fertilizer, Saskatchewan

1981 ◽  
Vol 21 (111) ◽  
pp. 424 ◽  
Author(s):  
WM Strong

Eighteen fertilizer trials, each with five levels of nitrogen (N) and three levels of phosphorus (PI, were conducted on black earth soils of the Darling Downs to establish optimal economic rates of N fertilizer in commercial, irrigated wheat crops. The optimal economic rate of N with a fertilizer: wheat price ratio (kg N: kg grain) of 5:l, the yield response of 100 kg/ha of applied N, the yield without fertilizer, and the yield with fertilizer not limiting were calculated from derived yield response relations at each site. A multi-variate regression procedure was used to determine which soil or crop management factors significantly influenced the rate of N needed to optimize wheat yield. Delay in planting after June 1 and the level of residual mineral N in the soil at planting had strong negative effects on the response to fertilizer and the optimal rate of fertilizer required. The results indicate that yields of irrigated wheat may be below the economic optimum because of sub-optimal applications of N. Other soil and management factors such as available soil P and number of irrigations also affected grain yield. At 1 3 sites low protein wheat (< 1 1.4�1~) was produced with all but the highest two rates of N fertilizer and at two sites even the highest rate produced low protein wheat. The effect of N fertilizer applied at planting on grain protein concentration was changed by the yield response to the fertilizer application. Grain protein concentration was curvilinearly related (R2 = 0.81) to relative grain yield (yield as a proportion of the maximum yield); grain protein was at its minimum at a relative yield of 0.5. Although heavy rates of N fertilizer at planting increased grain protein concentration on a few sites, usually these applications led to an inefficient use of N fertilizer; apparent incorporation of fertilizer N into grain decreased with increasing rate of fertilizer.


1982 ◽  
Vol 22 (115) ◽  
pp. 54 ◽  
Author(s):  
WM Strong

On the Darling Downs the growth and yield of a semi-dwarf wheat (cv. Oxley) under supplementary irrigation was increased by the application of up to 400 kg/ha of nitrogen (N) at planting. Nitrogen at 50 or 100 kg/ha applied at the boot stage to supplement 100 kg/ha applied at planting increased grain yield by 459 and 478 kg/ha, respectively. However, yields were still below those where all the N was applied at planting. In contrast, supplementary N (0, 25, 50 or 100 kg/ha) at flowering or after flowering generally did not increase grain yield. One exception to this was where only 50 kg/ha was applied at planting; an additional 100 kg/ha at flowering increased grain yield by 602 kg/ha. Applied at planting, more than 200 kg/ha of N was needed to produce premium grade wheat (i.e. protein content above 11.4%). To achieve this protein content where 100 kg/ha had been applied at planting an additional 100 kg/ha was needed at the boot stage or 50 kg/ha at flowering. Applied after flowering, up to 100 kg/ha of additional N produced wheat of a protein content too low to attract a premium payment. A similar quantity of N was assimilated whether the entire N application was applied at planting or where the application was split between planting and boot or flowering. Less N was assimilated when the application was split between planting and after flowering. More N was assimilated from soil than from foliar applications at the boot stage. Soil and foliar applications were equally effective at flowering in increasing the amount of N assimilated as well as the grain protein content. However, after flowering foliar application was the more effective method. The application of N at flowering to increase the protein content of this semi-dwarf cultivar is not an attractive commercial practice. The price ratio of premium to Australian Standard White wheat in recent years (<1.071 ) is less than that needed (1.0954-1.3013) to justify splitting the N application to lift grain protein content above 11.4% at the expense of yield.


1992 ◽  
Vol 32 (3) ◽  
pp. 383 ◽  
Author(s):  
AD Doyle ◽  
CC Leckie

Grain yield, protein, and nitrogen uptake responses are reported for 6 wheat fertiliser experiments in northern New South Wales which were representative of sites that were highly responsive, moderately responsive, and non-responsive to nitrogen (N) fertiliser applied at sowing. Apparent recoveries of applied N of 33-57% in the grain were recorded where grain yield was steeply increasing in response to additional applied N. Where yield increases were smaller in response to increments of N fertiliser, N recovery was 22-3096, but where further N application increased grain protein content but not grain yield, apparent recovery of additional fertiliser N fell below 20%. Apparent recovery was less than 10% in experiments where there was no yield response to N fertiliser. The implications for fertiliser recommendations are discussed relative to potential premium payment for wheat protein levels. It was concluded that established premium payments are too low to make N application an economic proposition to increase grain protein levels in the absence of grain yield responses.


1996 ◽  
Vol 36 (6) ◽  
pp. 665 ◽  
Author(s):  
WM Strong ◽  
RC Dalal ◽  
EJ Weston ◽  
JE Cooper ◽  
KJ Lehane ◽  
...  

Cereal production in the summer-dominant rainfall region of Australia, especially the north-east, has relied heavily on natural soil fertility. Continued cereal production has so depleted the fertility of some soils that corrective strategies are required to restore the production of high protein wheat needed for domestic and export markets. Application of nitrogen (N) fertilisers, along with other strategies to improve soil N status, was evaluated between 1987 and 1994 on a Vertisol located in an area of unreliable winter rainfall. Responses of wheat grain yield and protein content to applied N (0-150 kg/ha) under zero tillage (ZT) and conventional tillage (CT) were determined each year, except 1991 when severe drought prevented wheat sowing. The ZT practices increased grain yields, particularly in 1988 and 1992-93 when antecedent soil water supplies were moderate (about 1 m wet soil in 1988 and 1992) or low (about 0.6 m wet soil in 1993), apparently due to increased antecedent soil water. Tillage practice had little effect on available nitrate-N (kg/ha) to 1.5 m, but the greater water supply in ZT soil usually benefited the wheat crop when N was applied. Applying N increased returns from 5 of the 7 crops because of grain yield and/or grain protein responses. Grain yield responses were inconsistent in the year of fertiliser application where no N fertiliser had been applied to preceding crops. Nevertheless, grain protein usually increased with increasing N application at sowing, except in 1994, when drought after sowing prevented secondary root development and fertiliser uptake. Where N was applied with each successive crop, the crops receiving small N applications (0, 12.5 or 25 kg/ha.crop) produced grain of a low protein concentration (<10%) and lower yields (<90% maximum yield) than crops which received larger N applications (75 kg/ha.crop). Profits were substantially reduced where the rate of N applied was insufficient to raise grain protein concentration to >11.5%, due to the low market value of low protein wheat, or because of lower grain yields. Routine N application to crops over the period 1987-94, which included the longest drought (1990-94) in the lifetime of most producers, caused similarly inconsistent grain yield increases but increased grain protein concentrations (>11.5%) in all except the first crop (1987). Increased frequency of high protein wheat and a high anticipated market value of the higher protein grain should encourage greater producer confidence with routine application of N throughout this region.


1998 ◽  
Vol 49 (7) ◽  
pp. 1067 ◽  
Author(s):  
A. F. van Herwaarden ◽  
G. D. Farquhar ◽  
J. F. Angus ◽  
R. A. Richards ◽  
G. N. Howe

"Haying-off" was studied by comparing wheat responses to applied nitrogen (N) at 3 sites in southern New South Wales, which differed in the amount and timing of rainfall during crop growth. At a site where the crops encountered little water deficit, dry grain yield increased from 607 g/m2 for a low-N control crop to 798 g/m2 for a high-N crop. At a site with severe terminal drought, dry grain yield decreased 24% from 374 g/m2 for the control, to 284 g/m2 for the highest N crop. At the third site, yields increased with small applications of N, whereas greater applications resulted in a negative yield response. At the 2 latter sites, the crops that showed decreased yield with applied N had clearly hayed-off. At all sites, irrespective of water status, N application resulted in increases in biomass at anthesis, spike density, kernels per spike, and kernel number. Kernel weight decreased in response to additional N at all sites, but most markedly at the haying-off sites, where it decreased by up to 38%. Harvest index increased in response to N at the high-rainfall site, but decreased in crops that hayed-off. Grain protein increased in response to N at all sites, with a range from 9% to 18% at the haying-off sites. The apparent retranslocation of assimilates to grain contributed 37-39% of grain yield (depending on N supply) at the high-rainfall site, compared with 75-100% at the haying-off sites. In contrast, when apparent retranslocation was expressed in relation to biomass at anthesis, it remained relatively constant, amounting to 23-26% at the high-rainfall site and 24-28% when crops hayed-off. By anthesis, high-N crops extracted more soil water than the low-N crops. By maturity the most severely hayed-off crop had extracted 10 mm less soil water than a low-N crop, but at the high rainfall site the high-N crops extracted 20 mm more soil water than the control crops. The weather conditions between anthesis and physiological maturity were relatively mild, with no daily maximum temperatures above 30ºC and no sudden increases in evaporative demand. Thus, there appeared to be 3 processes leading to haying-off. Firstly, the results confirm previous studies showing that haying-off was associated with reduced post-anthesis assimilation in response to a lack of soil water. The water deffcit was due to vigorous vegetative growth stimulated by a high level of soil N and was not associated with heat shocks or sudden increases in evaporation. Secondly, the most severely hayed-off crop failed to extract soil water fully, leading to a further reduction in post-anthesis assimilation. Thirdly, there was inadequate apparent retranslocation of pre-anthesis reserves to compensate for the lack of post-anthesis assimilation.


1994 ◽  
Vol 45 (1) ◽  
pp. 93 ◽  
Author(s):  
DP Heenan ◽  
AC Taylor ◽  
BR Cullis ◽  
WJ Lill

A long term field experiment began in 1979 at Wagga Wagga, N.S.W., to compare the sustainability of a range of rotation, tillage and stubble management systems on a red earth. This paper reports yield, yield components and grain protein of wheat for 1979-90. Rotations considered were alternating lupin-wheat (LW), lupin-wheat-wheat (LWW), continuous wheat (WW) with and without N fertilizer (100 kg N/ha), and alternating sub-clover-wheat (CW). Soil N supply at the start of the experiment was high following many years of sub-clover based pasture. From 1979 to 1983, there was a negative grain yield response to N fertilizer and no response to a legume in rotation except in the drought of 1982 when low yields were recorded from LW. Thereafter, a positive grain yield response was usually produced to N fertilizer in WW rotations, until 1989 and 1990, when these crops displayed aluminium toxicity sym ptoms. Overall, average grain yields from legume rotations were higher than WW with added N fertilizer. Since 1983, LW rotations consistently produced higher mean grain yields than CW, but mean grain protein and total N uptake were lower. Yields and N uptake by the second wheat crop in a LWW rotation indicated little carryover of benefits from the lupins. Slightly higher mean grain yield and harvest index, but lower mean grain protein, were produced by direct drilling, compared with cultivation before sowing, following lupins or sub-clover. However, retaining stubble rather than burning in autumn consistently reduced grain yields. There was no evidence that early burial of wheat stubble following summer rain, rather than incorporation in autumn, improved grain yield or total N uptake. The build-up of giant brome grass and diseases, particularly where stubble was retained and crops direct-drilled, casts some doubt on the long term sustainability of these short term rotations in this environment.


2001 ◽  
Vol 81 (4) ◽  
pp. 459-467 ◽  
Author(s):  
G. Manning ◽  
L G Fuller ◽  
D N Flaten ◽  
R G Eilers

The objective of this study was to compare landform element complexes (LEC) and soil series as discrete management units for variable rate N fertilizer application. Crop response attributes including grain yield, and grain protein concentration were studied in ten intensively sampled transects in an undulating glacial till soil-landscape near Miniota, Manitoba. In 1997, a year with growing season precipitation 37% below average, median grain yield tended to increase with both N fertilizer and with convergent character in the landscape (upper < mid < lower). Varcoe soils, located predominantly within the lower LEC, were generally more productive than Newdale soils. Grain protein concentration increased with N fertilizer, but tended to decrease with convergent character in the landscape (upper > mid > lower), and was lowest in the Varcoe series. In 1998, growing season precipitation was 62% above average. Grain yield responses to N fertilizer were greater, due in part to declining N fertility in the check and 45 kg ha–1 treatments. Trends among LEC were opposite to those in 1997, as median grain yield estimates tended to decrease with convergent character in the landscape (upper > mid > lower). Grain yield was modeled as a function of estimated plant-available N supply within each LEC and soil series. Modeled 1997 grain yield maxima were 2077, 2261 and 2485 kg ha–1 in the upper, mid and lower LEC. Estimated plant-available N supply at the yield maxima were 89, 130 and 130 kg N ha–1, respectively. In 1998, the relative order of modeled maxima among LEC was reversed. Grain yield of 2501, 2355 and 2227 kg ha–1 were predicted in the upper, mid and lower LEC. Estimated plant-available N supply at the yield maxima were 146, 142 and 154 kg N ha–1, correspondingly. In 1997, plateau yields were 2379, 2495 and 2325 kg ha–1 for Newdale, Varcoe and Angusville series, respectively, where the Varcoe series responded most strongly to estimated plant-available N supply. The corresponding estimated plant-available N supply values at the modeled maxima were 195, 139 and 110 kg ha–1. In 1998, plateau yields were 2343, 2253 and 2285 kg ha–1 for Newdale, Varcoe and Angusville series, respectively. The corresponding estimated plant-available N supply values at the modeled maxima were 136, 148 and 155 kg ha–1. Successful variable-rate fertilization by LEC or soil series will require long-term empirical study to establish risk-based grain yield-N relationships, and to determine if an economic advantage over conventional fertilization practices exists. Key words: Variable-rate fertilization, nitrogen, wheat yield, grain protein concentration, soil-landscape


2018 ◽  
Vol 17 (03) ◽  
pp. 289-292
Author(s):  
Pranesh ◽  
S. Ramesh

AbstractProtein energy malnutrition (PEM) is prevalent in south-east Asian countries including India. Breeding and introduction of grain protein-rich varieties of legumes such as dolichos bean is considered as cost-effective approach to combat PEM. Exploitation of genetic variability within germplasm accessions (GAs) and/or breeding populations is the short-term strategy for identification and delivery of protein-rich dolichos bean cultivars to cater to the immediate needs of the farmers and target population. A set of 118 dolichos bean genotypes consisting of 96 GAs and 20 advanced breeding lines (ABLs) and two released varieties (RVs) was field evaluated in augmented deign for dry grain yield per plant and their grain protein contents were estimated. The grain protein content among the genotypes ranged from 18.82 to 24.5% with a mean of 21.73%. The magnitude of estimates of absolute range, standardized range, and phenotypic coefficient of variation (PCV) for grain protein content was higher among GAs than those among ABLs + RVs. However, average grain protein contents of GAs were comparable to those of ABLs + RVs. Nearly 50% of the genotypes (mostly GAs) had significantly higher grain protein content than those of RVs, HA 3 and HA 4. The grain protein contents of the genotypes were poorly correlated with grain yield per plant. These results are discussed in relation to strategies to breed grain protein-rich dolichos bean cultivars.


1989 ◽  
Vol 69 (3) ◽  
pp. 515-523 ◽  
Author(s):  
D. C. MACKAY ◽  
J. M. CAREFOOT ◽  
T. G. SOMMERFELDT

In an 8-yr experiment on an irrigated Dark Brown Chernozemic soil, four rates of N (0, 34, 67 and 101 kg ha−1), applied annually with 45 t ha−1 of manure containing softwood shavings (avg. of 46% dry wt) produced a linear yield response (from 3.5 with the check to 4.3 t ha−1 at the highest rate) of barley grain (Hordeum vulgare L. 'Galt'). There were large differences in yields among years, which could be attributed to weather factors, but there was no significant N × year response. Protein content increased linearly (from 11.2 to 13.5%), and both kernel weights and "test weights" (kg hL−1) decreased slightly but significantly with N applications. There was a pronounced "residual" effect of N rates on both grain yield (from 3.8 to 6.3 t ha−1) and protein content (from 10 to 13%) in the first year after applications of manure and N fertilizer ceased. These effects decreased rapidly and had practically disappeared by the end of the 3rd yr, although yields of all treatments remained high (about 5 t ha−1). Organic matter and N contents of the soil were increased by 70 and 41%, respectively, from the cumulative applications of shavings manure. It is concluded that application of manure containing large quantities of softwood shavings has a negligible effect on the N fertilizer requirements of the crop being grown. Beneficial residual effects of N fertilizer applied with the manure may result because of buildup of NO3-N throughout the soil profile, and likely also because of N release from readily mineralized organic compounds or microbial biomass. However, this effect was not reflected in soil tests for readily mineralizable N by NO3 incubation or KCl digestion methods and the effects were practically dissipated after 3 yr. The recovery of applied N fertilizer by the crops was high at all rates (61–79%), and essentially all of the N applied (fertilizer + manure) was accounted for by crop removal + increased soil N. Key words: Mineralizable-N soil tests, Chernozemic soil, repeated fertilizer applications, residual effects


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