PHOSPHATE MOBILIZERS FOR WINTER CROPS

To maximize agricultural productivity by revealing the genetic potential of crops, it's important to supply them with biogenic elements throughout the growing season. An essential aspect of winter crop cultivation technology is the restoration of its spring vegetation. The development of winter crops during the early growing season occurs in cool weather and short daylight hours. Therefore it is necessary to provide the crops with important macro and microelements.

As a result of early spring fertilization of cereal crops on underdeveloped and thinned plantings, productive tiling increases. While on well-developed ones, an increase in ear productivity can be observed. To restore the vegetative mass of winter rapeseed, growing in the first weeks after the resumption of vegetation, it is necessary to provide the crop with a sufficient amount of nitrogen to increase yield.

Regarding phosphorus and potassium fertilizers, they are typically applied in the autumn before sowing. However, the amount applied, in comparison to nitrogen, has decreased significantly over the last two decades. It is also important to note that the problem of phosphorus and potassium plant nutrition lies in the fact that the gross reserves of these elements in most soils are significant. Depending on the soil type, the proportion  of available plant elements is small (according to the utilization coefficient). Improving the availability of mobile phosphorus and potassium compounds for plants can be achieved by incorporating phosphorus- and potassium-mobilizing bacterial biologicals into the cultivation technology of agricultural crops.

Groundfix is recommended to incorporate the soil during the early spring fertilization of winter rapeseed and winter cereal crops. The biological increases the efficiency of applied mineral fertilizers and  the availability of mobile forms of phosphorus and potassium in the soil.

A study was carried out in laboratory conditions on the possibility of joint application of the biological product Groundfix with UAN (urea-ammonium nitrate). The investigation was on the effect of the fertilizer on the viability of bacteria for 2 and 4 hours. Sterile tap water served as the control.

In all variations, the titre level of the biological with the addition of UAN was not less than the control. The results show that Groundfix can be used in combination with urea-ammonium nitrate solution. From 2017 to 2020, industrial research was carried out on the application of the Groundfix with UAN in winter rapeseed crops at a rate of 5 l/ha and winter grain crops at a rate of 3 l/ha. This research was carried out from different precursors, soil types and pH levels  (Fig. 1).

Fig. 1. Yield of winter rapeseed and winter cereal crops

Although weather conditions varied across the years of the study, the main patterns of the Groundfix on the soil agrochemical indicators and crop productivity were consistent.

In winter rapeseed crops, the early spring application of 5 l/ha of Groundfix with UAN resulted in an increase in yield from 3.31 to 5.0 c/ha (Fig. 1).

This increase in yield was attributed to an increase in the number of seeds per pod and the weight of 1000 seeds. With the application of 3 l/ha of Groundfix with UAN on winter grain crops, an increase in yield of winter wheat was observed, ranging from 1.9 to 5.3 c/ha, and for winter rye, an increase of 2.2 c/ha was observed too.

It is noteworthy that the most effective results of Groundfix were achieved at earlier application times. The increase in crop yield was due to an increase in the number of grains per ear and the weight of 1000 grains.

Soil samples were taken for agrochemical and microbiological analysis. The analysis showed that the variants with the application of Groundfix almost always exhibited an increase in the mobile forms of phosphorus or its degree of mobility in the crops (Table 2). The growth in mobile forms of phosphorus, depending on the soil type and the development phase of the crop, ranged from 8.8 to 41.4%. The degree of mobility of phosphorus increased in all soil types. The amount of mobile potassium increased from 5.9 to 13.2%. The degree of mobility of exchangeable potassium increased on almost all soil types. The decrease in the number of mobile forms of phosphorus and potassium in some trials is associated with an increase in yield and the corresponding increase in the removal of nutrients with the main production.

To assess the impact of Groundfix on soil biological activity, fungi were isolated from soil samples into pure cultures and their species composition was identified using widely accepted methods (refer to Table 3).

The results of the mycological analysis of the soil showed an increase in the number of saprotrophic species in the areas treated with Groundfix. No doubt that microorganisms in the biological Groundfix actively compete with pathogenic species for space in the soil and thus positively influence the growth and development of the plants. In areas where the Groundfix was applied, the number of saprotrophic microbial species increased by 4.1-41.0%.

The costs of applying Groundfix in production studies, according to standard rates, are 30 and 50 EUR/ha. The calculation of the estimated net profit takes into account the prices as of 17.01.2023, which are 424 EUR for 1 ton of winter rapeseed and 227 EUR for winter wheat*. Thus, the conditional extra income from the application of the biological Groundfix on winter rapeseed ranges from 80,56 to 156,56 EUR/ha, and on winter wheat it ranges from 25,137 to 63,5 EUR/ha.

Therefore, applying the biological Groundfix with UAN during early spring fertilization of winter rapeseed and winter grain crops enhances the availability of mobile forms of phosphorus and potassium in the soil, as well as the effectiveness of the applied fertilizers and crop productivity.

Groundfix is a biological product produced by BTU-CENTER. It contains a complex of cells of the bacteria Bacillus subtilis, Bacillus megaterium var. phosphaticum, Azotobacter chroococcum, Enterobacter sp. with a total number of viable cells (0.5–1.5) × 10^9 CFU/cm3. These bacteria are producers of enzymes, vitamins, phytohormones, amino acids and other physiologically active substances. Groundfix aims to increase the availability and mobility of phosphorus and exchangeable potassium in the soil, besides it increases various forms of nitrogen, enhances the nutrient utilization efficiency from fertilizers by 1.2–1.5 times, facilitates the absorption of silicon by plants, improves soil biological activity and health and positively impacts the subsequent crops. 

The application methods of the biological Groundfix: as part of the main and pre-sowing soil treatment, in the row during sowing and also in early spring fertilization.