IMPACT OF NITROGEN TOPDRESSING ON THE QUALITY PARAMETERS OF WINTER WHEAT ( TRITICUM AESTIVUM L.) YIELD

.

There are more lands planted with wheat in the world than with any other crop.It provides 20 percent of the world's caloric consumption, even 50 percent for the world's poorest, and it provides 20 percent of their protein consumption, too (W W F 2016/2017).The total global wheat output exceeded 749.3 million tons in 2016, according to FAOSTAT data (FAO, 2017).Wheat is also one of the most important cereals in Hungary and Turkey as well with a high economic value.The goal of wheat production is twofold: providing quantity and quality as well.Milling and baking qualities of wheat are mainly determined by the genetic basis; however, it can be infl uenced by management techniques as well (P , 1981; G et al., 1996; V et al., 1996; P , 2010).The determination of wheat milling quality is very complex, however, the quality measurements lean on the kernel hardness, protein, starch, internal insect infestation, colour, disease, size, and moisture parameters (P , 2003).Baking quality of wheat fl our is determined by grain protein concentration (GPC) and its composition, and is highly infl uenced by environmental factors such as nitrogen (N) fertilisation management (X , 2019).The protein content of wheat crops has important impacts on their nutritional quality for humans and livestock and on their functional properties in food processing.(S & H , 2002).Economic value of winter wheat is aff ected by the genotype, cropping year, agroclimatic parameters as well as the agronomic applications and coordination (G , 2006; V , 2008).Nitrogen (N) is one of the macronutrients required for plant growth, with high eff ect on quality and quantity values of winter wheat.The quality of wheat varieties is strongly infl uenced by year and genotype eff ects, and the eff ects of the management systems are also determinative on some physical and gluten quality characters of the grain (R et al., 2016).H and co-workers (2014) also presented that increasing levels of N topdressing and increased number of applications had benefi cial eff ects on the protein content as well as on wet gluten values of wheat grain.S and co-workers (2005) found that increasing fertiliser dose applications had preferable eff ect on the protein and gluten contents, as well as quality improvement had been proved.K and T (2010) described that the increasing rate of N fertilisation application as well as the additional organic fertilisers infl uenced the biomass production and N uptake of winter wheat.The aim of the study was to investigate change in qualitative parameters of the winter wheat varieties sown in two crop seasons with diff erent level and split/undivided doses application of nitrogen fertilisation.

Materials and methods
In years 2017 and 2018, a fi eld trial of high milling and baking quality winter wheat (Triticum aestivum L.) varieties were set up under identical agronomic conditions using split-plot design (10 m 2 /plot).The trial was established at the experimental fi eld of the Szent István University, Crop Production Institute, Hungary.Soil type of the experimental fi eld was sand based brown forest soil (Chromic Luvisol).The textural classifi cation of the soil was sandy loam with parameters shown in Table 1.The agronomic characteristic of the soil was neutral sandy soil with variable clay content.The soil structure was susceptible regarding compaction.The water retaining characteristics were poor due to the high sand fraction.The soil was exposed to drought impacts.The two-year experiment was set up in split-plot design with nine plot replications regarding each experimental factor such as variety and N application (time and dose) in each investigated year.The plots were sown and harvested with plot machines.Apart from N topdressing, all other agronomic treatments as well as sowing and harvesting were identically applied to all plots to study the impact of N treatments independently.N fertiliser topdressing was applied in single or split doses.N was applied in form of ammonium nitrate (NH 4 NO 3 ); the amounts are indicating the N content in this paper, not the molecule.N was investigated in 6 diff erent variants: 4 levels single and 2 levels split dose treatments.Single application: 0, 80, 120, and 160 kg ha -1 N, split doses application: 80+40 kg ha -1 and 120+40 kg ha -1 in two applications.Applications were done at tillering stage in the case of single application, while split dose treatment was applied at the stage of tillering and heading.There was no N application in autumn in any of the crop years.The present study examined the performance of fi ve high baking quality winter wheat varieties Mv Karéj, Mv Nádor, Mv Toldi, Mv Toborzó, and Alföld.Grain yields of the winter wheat varieties were sampled and measured from each harvested plot.The protein, test weight, thousand grain weight, and baking quality parameters were measured from harvested wheat grain.Analyses were done at the research laboratory of the Szent Istvan University Crop Production Institute.Near infrared (NIR) spectroscopic equipment Mininfra Scan-T Plus Acta Alimentaria 49, 2020

version (A
, 2016) was used to measure gluten, protein, and Zeleny sedimentation values of whole grains.Falling number was also studied to determine amylase enzyme activity in the fl our.The Hagberg Falling Number (HFN) Perten Type:1400 system, which meets the requirements of the AACC (American Association of Cereal Chemist) No.56-81.04,ICC (International Cereal Chemist) No. 107/1, and PN EN ISO 3093:2010 standards, was used to determine the falling number.The OS 1 type equipment by the ISO 7971-3:2019 standard was used to measure test weight.Thousand grain weight and test weight were measured with the KERN EMS and the Sartorius MA-30 precision scales.Farinograph (Valorigraph) instrument had been used to describe baking quality of the dough.ANOVA module of the statistical software SPSS V.23 was used for the statistical analyses.

Results and discussion
Protein and gluten contents of the tested wheat grain samples indicate that N supply had high eff ect on examined varieties in accordance with earlier research results (P , 1981; V et al., 1996; P , 2010).There were varietal diff erences, too, as untreated plots had remarkable diff erences between varieties.Especially increasing dose applications had remarkable eff ect in the experimental year 2017.
One-way ANOVA test in Table 2 clarifi es the results statistically; results are discussed case by case.Table 3 gives information on N application eff ects on test weight at the studied winter wheat varieties.Test weight (kg hl -1 ) values slightly decreased in some of the tested varieties by the increasing level of undivided N application, but the changes found were not signifi cant.In addition, positive eff ect of split dose treatment had been detected, except in case of Mv Nádor 80+40 kg ha -1 to 120 kg ha -1 N application.The highest result had been recorded for the Alföld 120+40 kg ha -1 split dose application with 79.2 kg hl -1 and the lowest for Nador as 74.9 kg hl -1 .However, split dose N application did not present signifi cant changes among the tested winter wheat varieties, similar results were reported by P ( 1981) and H and co-workers (2014).Table 4 gives the results of the thousand kernel weight values with the eff ect of undivided/ split dose of N supply.Thousand kernel weight value decreased slightly in most of the cases for the increeasing undivided/split level of N applications, however, increasing number of N treatments had better eff ect in the comparison of 80+40 kg ha -1 to 120 kg ha -1 and 120+40 kg ha -1 to 160 kg ha -1 , except Mv Toborzó comparison of 120+40 kg ha -1 to 160 kg ha -1 .Mv Nádor and Mv Toldi showed signifi cant diff erences by the one-way ANOVA test of thousand kernel weight.Similar results were reported by S and co-workers ( 2005) and H and co-workers (2014).The highest thousand grain weight was recorded on the untreated Karéj plot with 46.7 g/thousand kernel weight, and the lowest was detected on an Alföld plot treated with undivided 160 kg ha -1 N application resulting 38.0 g/thousand kernel weight.Based on the results of the experiment, it can be stated that increasing levels of N topdressing had signifi cant eff ect on grain protein content in all studied winter wheat varieties, either in split or undivided dose applications.Figure 1 and Table 2 show the grain protein values in 2017-2018.Protein amounts changed from 9.9% to 16.0%.Highest value was observed on the Alföld plot with split 120+40 kg ha -1 N application (16.0%), and the lowest, 9.9%, was obtained on Karéj untreated plot.Split dose application did not have signifi cant eff ect compared to the same amount of undivided application., 2010; R i et al., 2016).Figure 2 and Table 2 show strong eff ect of N application on grain gluten content regardless of crop year, variety, or split/undivided application.Among the evaluated samples, the Alföld plot had the highest value (36.8%),where 120+40 kg ha -1 split N doses had been applied.In addition, Karéj had the lowest value with 18.4% on the untreated plot, and split dose application did not have signifi cant eff ect on gluten content compared to the same amount of undivided application.Gluten, % The results obtained show that all increasing levels of N applications aff ected the baking quality of the investigated winter wheat varieties, in accordance with the fi ndings of earlier research results (S & H , 2002; G , 2006; P , 2010), shown in Figure 3.The lowest value, 53, was recorded in the case of Alföld on the untreated plot, and the best value, 100, was found for Toborzó on the 120+40 kg ha -1 split dose N applied plot.As well as increasing levels of N fertilisation, increasing number of the applications also had positive impact on baking quality of tested winter wheat varieties.Varieties Alföld and Karéj demonstrated signifi cant diff erences, and the split application of 80+40 and 120+40 kg ha -1 resulted 2.9% better values compared to 120 and 160 kg ha -1 single applications.N addition had no signifi cant eff ect on falling number (Table 2), however, Zeleny sedimentation number increased with increasing doses of N regardless of the variety.Baking quality score

Conclusions
Rising amounts of N topdressing and the increased number of fertiliser applications were proved to have favourable impact on the crop yield and quality, on the amount of protein content, as well as on gluten values of tested winter wheat varieties.There were diff erences between the protein and quality results of the two cropping seasons due to meteorological diff erences; however, all parameters of the experimental agronomic techniques applied and all 5 wheat varieties used for both cropping seasons were identical.Among the investigated varieties, Alföld had the highest protein and gluten contents, and Mv Toborzó had the best baking quality among the tested varieties.Increasing doses of N application had signifi cant eff ect on Zeleny sedimentation number, but no eff ect of split application was detected.N treatment had no signifi cant eff ect on falling number.Increasing doses of N treatment had no signifi cant eff ect on test weight, but split application gave better results compared to single treatment with the same dosage.* The authors are grateful for the fi nancial support of the Tempus Public Foundation and NVKI of the Government of Hungary.

Table 1 .
Soil type of the experimental fi eld at Szent István University, Crop Production Institute, Hungary

Table 4 .
Impact of N topdressing applications on thousand kernel weight of wheat varieties.