The 2017/2018 wheat season showed record yields and began with excellent quality results. The first grains to reach the market are those from the north of Argentina, historically characterized by good protein levels. However, as yields increased in the core region, some quality parameters weakened. In net terms, the attributes of average quality of the samples that entered the Rosario Board of Trade’s laboratory have been below that those obtained for the same date last year, although this attributes still meets the requirements of the demand.
The almost finished 2017/2018 wheat harvest had a record yield, reaching the national average of 33.4 quintals per hectare. In this way, 17.5 million tons were consolidated with a sowed area of 5.34 M ha.
In terms of quality, wheat grain protein is one of the parameters with the highest incidence in the cereal’s price. However, there are many factors and interactions that define the protein content: the available nitrogen, the sowing date, the time of fertilizer application, the genotype, the health, the level of other nutrients, the environmental conditions and the type of soil. Some of them are external to agronomic management while others can be controlled.
During this productive season 2017/18, the producers bet heavily on the technological package, mainly in the dose of nitrogen and fungicides. However, not only the amount of nitrogen is important to define the quality of the grain, but also the phenological stage in which this practice is carried out. One of the possible ways to achieve a higher protein content is the application of nitrogenous fertilizer near the flowering period; when some performance components are defined. In this way, the nitrogen would be directed to produce more protein and not more number of grains, since these would be practically defined beforehand. This practice is known as late fertilization. Nevertheless, as mentioned at the beginning, there are numerous factors that define the amount of protein in the grain.
One of the causes of the high yields obtained in the region was possibly the good fertilization at the beginning of the crop cycle that was aimed to produce more number of grains. In this sense, there is a strong negative correlation between yield and protein content. This is because nitrogen is diluted in a greater number of grains (more yields). Consequently, the exceptional yields obtained in the area of influence to Rosario may not have good protein levels.
In addition to the good weight obtained, the mild temperatures together with the low luminosity prolonged the grain filling. In this stage, the process of accumulation of carbohydrates (starch) predominates over the proteins one (vitreous layer). As a result, the white belly grains appeared with that typical yellowish color.
The Rosario Board of Trade gives an account of that situation by issuing the results obtained in approximately 645,000 tons of milling wheat entered into the laboratory in the period from 11/23/2017 to 12/23/2017. The merchandise comes from our Board of Trade’s influential zone, which is the north of the country and the central region; the latter characterized by its record yields.
As can be seen in the following graph, the protein content in 2017 (data from the first samples) is at 10.0%, marking a slight drop compared to 10.1% evidenced the previous year. The average of the last 8 years amounts to 10.8%, which shows that in 2017 -for the moment- we are below that figure.
The yellow grains reached 8.1% in the first samples of 2017, a value close to the record of 2015 of 8.3%. Keeping in mind that we are analyzing the last 8 years.
Finally, the hectolitre mass in 2017 with 79.2 kg / hl is surpassing the historical average of the last 8 years that had registered a 78.8 kg / hl. Although in comparison with the last season, this figure has a drop of 0.7 kg / hl in the absolute value of the registry (2016 the hectolitre mass was 79.9 kg / hl).
It is necessary to mention that these are preliminary results and there is still a long way to go. The wheat season, generally speaking, is very good in terms of prices, commercialized level and acceptable quality, even after having seen high yields.