Impacts of nutritional management
The correct supply must go from application via sowing to the phases of greatest demand of the plants, via foliar fertilization, which can be carried out according to the need of each phenological stage of the crop.
Thus, some studies were conducted in the experimental area of 3tentos, with the aim of evaluating the application of macro and micronutrients in the wheat cultivar TBIO Toruk, correlating yield values and hectoliter weight with different vegetation indices.
Experiment in TBIO Toruk cultivar
The treatments were applied at the rubber and anthesis stages and the evaluations consisted of the NDRE (Normalized Difference Red Edge), NDVI (Normalized Difference Vegetation Index) and EVI2 (Enhanced Vegetation Index) vegetation indices, estimated from flights of drone equipped with multispectral camera, as well as grain yield and hectoliter weight.
There was no significant difference between the treatment means for the vegetation indices, however, there was a positive linear correlation between the NDVI and EVI2 indices, as well as in the grain yield. As already noted by Pradhan et al. (2018), the highest value found for NDVI in wheat was in the initialization and flowering stages. The higher the biomass and the chlorophyll content, the higher the NDVI values, indicating good conditions for growing the crop (VARIANI, 2011).
In this study, it was possible to verify that the hectoliter weight varied little between treatments. However, the treatments which in their composition had manganese and nitrogen contents, increased around 15 and 14% in yield, when compared to the control without foliar application of nutrients.
Importance of manganese
Manganese acts in several pathways of the plant, among them, it participates in the photolysis reaction of water in photosystem II, in the formation of chlorophyll and in the formation, multiplication and functioning of chloroplasts (FLOSS, 2011). The main photoreceptor in green plant chloroplasts is chlorophyll. This is mainly made up of magnesium and nitrogen atoms.
Importance of Nitrogen
The addition of nitrogenous foliar products can benefit all components of wheat yield, to a greater or lesser extent (ZAGONEL et al., 2002). Thus, an adequate amount of nitrogen is essential to increase productivity.
Foliar application of nutrients is a complementary tool to base fertilization. It is an efficient way to provide specific nutrients and according to the availability or requirement of the crop, and the application of manganese and foliar nitrogen in wheat provided an increase in grain yield.
FLOSS, E.L. Physiology of cultivated plants: the study is behind what is seen. 5. ed. Passo Fundo-RS, 2011. 734 p.
PRADHAN, S.; SEHGAL, V.K.; BANDYOPADHYAY, K.K.; SAHOO, R.N.; PANIGRAHI, P.; PARIHAR, C.M.; JAT, S.L. Comparison of vegetation indices from two ground based sensors. Journal of the Indian Society of Remote Sensing, vol. 46, no. 2, p. 321-326, 2018.
VARIANI, C. Active optical sensor as a tool for nitrogen application in wheat. 2011. 109 f. Dissertation (Masters) - Postgraduate Program in Plant Science, Federal University of Rio Grande do Sul, Porto Alegre, 2011.
ZAGONEL J.; VENÂNCIO, W.S.; KUNZ, R.P.; TANAMATI, H. Nitrogen doses and plant densities with and without growth regulator affecting wheat, Cultivar OR-1. rural science.