Nitrogen fertilizer and wheat in a semi-arid environment. 4. Empirical yield response models and economic factors

1968 ◽  
Vol 8 (35) ◽  
pp. 736 ◽  
Author(s):  
JS Russell

The difficulties in predicting grain yield response to applied nitrogen under conditions of low and variable rainfall are discussed. Three models of grain yield response to applied nitrogen fertilizer for each of two strategies are proposed, based on data from field experiments carried out in the wheat growing areas of South Australia. In the first strategy (nitrogen applied at sowing) the parameters are May-August rainfall, October mean maximum temperature and one of three alternative site criteria, initial soil nitrate content (0-6 inches sampled shortly before sowing), 15-atmospheres soil moisture percentage (0-6 inches), or estimated nitrogen status. In the second strategy (nitrogen applied in late winter) the parameters are similar, except that May-July rainfall replaced May-August rainfall and a statistical relationship between yield response due to late application as compared with application at sowing was used. The response surfaces were examined using a calculated most profitable rate of application with a range of grain : fertilizer price ratios from 2 to 8. These calculations emphasize the importance of economic factors in affecting fertilizer use in areas where responses are small and variable. The limitations of the models and problems associated with the use of predicted climatic criteria are discussed. There is a need for further studies to iteratively test and modify these empirical models and ultimately to develop mechanistic models. Further study is also suggested on field aspects of late application and the possible role of both plant analysis and the single ion nitrate electrode for site characterization.


1968 ◽  
Vol 8 (31) ◽  
pp. 223 ◽  
Author(s):  
JS Russell

The response of Gabo wheat to nitrogen fertilizer at 52 sites in the wheat growing areas of South Australia during 1956-61 was examined in relation to climatic factors by a stepwise multiple regression analysis using a computer. The ten dependent variables were the linear and quadratic coefficients obtained by fitting orthogonal polynomials to response curves of various parameters (grain yield, grain + straw yield, harvest index, grain nitrogen percentage, and grain nitrogen yield) to applied nitrogen at each of the 52 sites. The 23 independent variables were the amounts of rainfall and evaporation during the growing period, maximum and minimum temperatures and estimates of high temperature stress during spring and amount of rainfall immediately after sowing at each site. The climatic variables examined explained 46.5, 64.3, and 64.3 per cent of the variation in the response to nitrogen fertilizer of grain yield, grain + straw yield, and grain nitrogen yield respectively. The positive effects of increasing amounts of winter rainfall on yield response to applied nitrogen were marked. On the other hand, the negative effects of high maximum temperatures in the latter part of the growing period, particularly during October, on yield response were also evident.



Soil Research ◽  
2017 ◽  
Vol 55 (4) ◽  
pp. 341 ◽  
Author(s):  
Craig A. Scanlan ◽  
Ross F. Brennan ◽  
Mario F. D'Antuono ◽  
Gavin A. Sarre

Interactions between soil pH and phosphorus (P) for plant growth have been widely reported; however, most studies have been based on pasture species, and the agronomic importance of this interaction for acid-tolerant wheat in soils with near-sufficient levels of fertility is unclear. We conducted field experiments with wheat at two sites with acid soils where lime treatments that had been applied in the 6 years preceding the experiments caused significant changes to soil pH, extractable aluminium (Al), soil nutrients and exchangeable cations. Soil pH(CaCl2) at 0–10cm was 4.7 without lime and 6.2 with lime at Merredin, and 4.7 without lime and 6.5 with lime at Wongan Hills. A significant lime×P interaction (P<0.05) for grain yield was observed at both sites. At Merredin, this interaction was negative, i.e. the combined effect of soil pH and P was less than their additive effect; the difference between the dose–response curves without lime and with lime was greatest at 0kgPha–1 and the curves converged at 32kgPha–1. At Wongan Hills, the interaction was positive (combined effect greater than the additive effect), and lime application reduced grain yield. The lime×P interactions observed are agronomically important because different fertiliser P levels were required to maximise grain yield. A lime-induced reduction in Al phytotoxicity was the dominant mechanism for this interaction at Merredin. The negative grain yield response to lime at Wongan Hills was attributed to a combination of marginal soil potassium (K) supply and lime-induced reduction in soil K availability.



1987 ◽  
Vol 38 (4) ◽  
pp. 681 ◽  
Author(s):  
AS Hodgson ◽  
DA MacLeod

Foliar-applied nitrogen (N) fertilizer was investigated as a means of ameliorating the damage to cotton of waterlogging associated with extended furrow irrigation of a cracking grey clay. Dissolved urea was applied at 0, 5, 10 and 20 kg N ha-1 to the cotton foliage one day before furrow irrigations lasting 4, 8, 16 and 32 h. Treatments were repeated at three crop irrigations. Storms following the first two irrigations delayed the recovery from waterlogging and reduced treatment differences. However, foliar-applied N significantly increased late square and green boll numbers after the third irrigation, and produced more open bolls and heavier lint yields than the control treatment at harvest. Lint yields increased by 2.8, 5.9, 8.4 and up to 10.5 kg ha-1 per kg of foliar N applied before irrigations lasting 4, 8, 16 and 32 h, respectively. From this interaction it was concluded that foliar-applied N ameliorated the effects of waterlogging. Nevertheless, in the most severe waterlogging treatment, yield response to foliar N reached a limit, indicating that some other factor had become limiting.



2020 ◽  
Vol 71 (9) ◽  
pp. 795 ◽  
Author(s):  
Therese M. McBeath ◽  
Evelina Facelli ◽  
Courtney A. E. Peirce ◽  
Viran Kathri Arachchige ◽  
Michael J. McLaughlin

The ability to utilise foliar-applied phosphorus (P) as a strategy to increase the P status and yield of grain crops grown in dryland regions with variable climates is attractive. Several P formulations with varying pH, accompanying cations and adjuvants were tested for their effectiveness as foliar fertilisers for wheat (Triticum aestivum L.) plants, first under controlled and then under field conditions. Experiments under controlled conditions suggested that several formulations with specific chemistries offered promise with respect to wheat fertiliser-P recovery and biomass responses. These formulations were then evaluated in two field experiments, and although wheat grown at the sites showed substantive responses to soil-applied P, there was no significant grain-yield response to foliar-applied P. Following the limited responses to foliar-applied fertiliser in the field, we used an isotopic dilution technique to test the hypothesis that the variation in responses of wheat to foliar addition of P could be explained by a mechanism of substitution, whereby root P uptake is downregulated when P is taken up through the leaves, but this was proven not to be the case. We conclude that foliar P application cannot be used as a tactical fertiliser application to boost grain yield of wheat in dryland regions.



1984 ◽  
Vol 24 (125) ◽  
pp. 250 ◽  
Author(s):  
PE Bacon ◽  
DP Heenan

The growth, nitrogen use and yield of rice cv. lnga were examined in three experiments in 1978, 1979 and 1980. In each experiment, one rate of nitrogen was applied at six different times between permanent flood and three weeks after panicle initiation. Application of 50 kg N/ha in 1978 and 70 kg N/ha in 1980 at permanent flood increased yield. A higher rate (100 kg N/ha) at permanent flood in 1979 greatly increased vegetative growth but had little effect on grain yield. The grain yield response to 100 kg N/ha in 1979 significantly increased when application was delayed until panicle initiation. Nitrogen topdressing up to 14 d after panicle initiation resulted in an increased percentage of filled florets per panicle and heavier grains compared with application 14-21 d before panicle initiation. Delaying nitrogen application till 2 1 d after panicle initiation resulted in lower numbers of florets per panicle and consequently reduced yield.



2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Kelly A. Nelson ◽  
Peter P. Motavalli ◽  
William E. Stevens ◽  
John A. Kendig ◽  
David Dunn ◽  
...  

Research in 2004 and 2005 determined the effects of foliar-applied K-fertilizer sources (0-0-62-0 (%N-%P2O5-%K2O-%S), 0-0-25-17, 3-18-18-0, and 5-0-20-13) and additive rates (2.2, 8.8, and 17.6 kg K ha−1) on glyphosate-resistant soybean response and weed control. Field experiments were conducted at Novelty and Portageville with high soil test K and weed populations and at Malden with low soil test K and weed populations. At Novelty, grain yield increased with fertilizer additives at 8.8 kg K ha−1in a high-yield, weed-free environment in 2004, but fertilizer additives reduced yield up to 470 kg ha−1in a low-yield year (2005) depending on the K source and rate. At Portageville, K-fertilizer additives increased grain yield from 700 to 1160 kg ha−1compared to diammonium sulfate, depending on the K source and rate. At Malden, there was no yield response to K sources. Differences in leaf tissue K(P=0.03), S(P=0.03), B(P=0.0001), and Cu(P=0.008)concentrations among treatments were detected 14 d after treatment at Novelty and Malden. Tank mixtures of K-fertilizer additives with glyphosate may provide an option for foliar K applications.



1978 ◽  
Vol 18 (93) ◽  
pp. 554 ◽  
Author(s):  
RJK Myers

Responses of dryland grain sorghum to applied nitrogen were examined in three field experiments at Katherine, Northern Territory, in 1969-70, 1970-71 and 1971-72. Rates of nitrogen up to 89 kg ha-1 in the first season and up to 200 kg ha-1 in subsequent seasons were used. The crops were sampled at floral initiation, mid-elongation, anthesis, and maturity. The three growing seasons were rated as below average, above average and average, respectively, for grain sorghum production. Nitrogen response was strongly season-dependent, Maximum yields (adjusted to 14 per cent moisture) were: 1969-70, 2280 kg ha-1, with 22.4 kg N ha-1 applied (with lower yields at higher rates of nitrogen) ; 1970-71,7730 kg ha-1 with 150 kg N ha-1 applied; and 1971-72,4440 kg ha-1 with 200 kg N ha-1 applied. These represented increases of 6, 50, and 62 per cent, respectively, over the zero nitrogen treatments. Applied nitrogen increased grain numbers per head and individual grain weight, but had no significant effect on head numbers. Applied nitrogen increased yields of nitrogen and phosphorus in plant material, and increased nitrogen concentration in plant parts. Apparent recoveries of nitrogen fertilizer ranged from 0 to 40 per cent, depending on year and rate applied. An approximate balance sheet suggested substantial losses from the mineral nitrogen pool in 1970- 71, a year of above average rainfall. Significant interactions between nitrogen and phosphorus fertilizer occurred only with grains per head and thousand grain weight.



Agronomy ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 228 ◽  
Author(s):  
Alison Vogel ◽  
Frederick Below

Yield reductions occur when corn (Zea mays L.) is continuously grown compared to when it is rotated with soybean [Glycine max (L.) Merr.]; primarily due to soil nitrogen availability, corn residue accumulation, and the weather. This study was conducted to determine if a combination of agronomic practices could help overcome these causative factors of the continuous corn yield penalty (CCYP) to obtain increased corn yields. Field experiments conducted during 2014 and 2015 at Champaign, IL, U.S.A. assessed the yield penalty associated with continuous corn verses long-term corn following soybean. Agronomic management was assessed at a standard level receiving only a base rate of nitrogen fertilizer, and compared to an intensive level, which consisted of additional N, P, K, S, Zn, and B fertility at planting, sidedressed nitrogen fertilizer, and a foliar fungicide application. Two levels of plant population (79,000 verses 111,000 plants ha−1) and eight different commercially-available hybrids were evaluated each year. Across all treatments, the CCYP was 1.53 and 2.72 Mg ha−1 in 2014 and 2015, respectively. Intensive agronomic management improved grain yield across rotations (2.17 Mg ha−1 in 2014 and 2.28 Mg ha−1 in 2015), and there was a 40 to 60% greater yield response to intensive management in continuous corn verses the corn-soybean rotation, suggesting intensified management as a method to mitigate the CCYP. With select hybrids, intensive management reduced the CCYP by 30 to 80%. Agronomic management and hybrid selection helped alleviate the CCYP demonstrating continuous corn can be managed for better productivity.



1976 ◽  
Vol 86 (2) ◽  
pp. 373-377 ◽  
Author(s):  
M. R. J. Holmes ◽  
J. R. Devine ◽  
F. W. Dunnett

SummarySeven field experiments were made on the effect of two harvesting dates on the nitrogen requirements of sugar beet. All were on Rauceby series soils overlying oolitic limestone in Lincolnshire.Nitrogen fertilizer increased sugar yield in all experiments, and yield was considerably higher at the mid-December harvest than in early October. On average, the sugar-yield response to nitrogen was greater at the late harvest, and the requirement for nitrogen was about 45 kg/ha higher then than at the early harvest. Sugar content was depressed less at the late harvest than at the early by increasing nitrogen rate.These results suggest that farmers should apply more nitrogen to fields that they plan to harvest late than to early-harvested fields; they also have implications for the conduct and interpretation of nitrogen response experiments on sugar beet.



1968 ◽  
Vol 8 (32) ◽  
pp. 340 ◽  
Author(s):  
JS Russell

The response of Gabo wheat to applied nitrogen at 52 sites in the wheat growing areas of South Australia during 1956-61 was examined in relation to soil and cultural factors, as separate groups and together with climatic factors, by a stepwise multiple regression analysis using a computer. The 10 dependent variables were the linear and quadratic coefficients obtained by fitting orthogonal polynomials to response curves of various parameters (grain yield, grain + straw yield, harvest index, grain nitrogen percentage, and grain nitrogen yield) to applied nitrogen at each of 52 sites. The independent variables were 14 soil properties, such as total nitrogen content and initial nitrate status, and 6 cultural characteristics, including date of sowing and period of cultivation. In addition, 23 climatic variables were also included in analysis considering all independent variables. Of the soil variables the most potent was initial nitrate content of the 0-6 inch horizon. Date of sowing was the most potent cultural variable. The proportion of variance explained in the final analysis by the variables examined was greatest for grain nitrogen yield (73.0 per cent) and grain + straw yield (72.1 per cent). The value for grain yield was 48.9 per cent. Differences between nitrogen and phosphorus response in a semi-arid environment and the theoretical and practical implications of these differences are discussed in relation to the predictive value of soil analyses.



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