COPPER — AN UNDERRATED ELEMENT WITH HIGH POTENTIAL - English

COPPER — AN UNDERRATED ELEMENT WITH HIGH POTENTIAL

Copper is a multifunctional element. Like all microelements, it is an active catalyst that accelerates a number of biochemical reactions in plants and participates in the processes of photosynthesis, flowering, seed formation, biological fixation, as well as in the synthesis of protein and lignin, which, along with cellulose, is a component of the lignified tissues of vascular plants and, together with hemicellulose, determines the strength of plant trunks and stems. It is a familiar fact to everyone that copper improves plant resistance to diseases, but plant resistance to fungal diseases depends on the optimal supply of copper.

On the other hand, plants with an increased concentration of Cu also have increased sensitivity to pathogens of a number of diseases. At the same time, an equally important function of copper is its ability to control the formation of DNA and RNA, so its deficiency will noticeably inhibit plant reproduction (reduce grain formation, lead to sterility).

Although the largest copper removal – 53 g per 1 ton of production is typical for sugar beet, this element plays an equally important role in the formation of winter rapeseed yield, although the removal of the element is at the level of 8.5 g, wheat removes it a little more – 10 g. It seems unlikely that copper can affect the yield of rapeseed, because everyone is used to the fact that the yield of this crop depends only on boron and sulfur, right? However, scientists from different countries, having conducted thorough research, have established the undeniable influence of this element on the formation of winter rapeseed yield. For example, a study was conducted at the State Research Institute of Soil Science and Plant Production in Poland on the influence of soil and foliar application of copper sulfate on winter rapeseed crops.

The results of the research showed that the application of copper fertilizers to rapeseed under conditions of low and medium levels of this component in the soil led to an increase in its yield by 2-6%. A statistically significant increase in rapeseed yield was obtained under the influence of foliar copper fertilization at a rate of 250 g/ha and soil application at a rate of 12 kg/ha. Foliar and pre-sowing copper fertilization at a rate of 8 and 12 kg/ha led to a significant increase in the concentration of oil in the seeds of test rapeseed varieties. Under the influence of copper fertilization, a favorable trend was also observed to increase its concentration in the seeds.

In another study conducted at the Rawalpindi Agricultural University in Pakistan (33° 39′ 06.7″ N 73° 04′ 49.6″ E), silver and copper nanoparticles were used in different concentrations, from 5 mg/L to 35 mg/L, for two-time treatment of rapeseed in the phases BBCH 14-19 and BBCH 51-59 (https://doi.org/10.1038/s41598-024-79269-3 ). The results obtained are presented in the table.

Treatments	Combined concentration of silver and copper nanoparticles
Treatments	0 ppm	5 mg/L	10 mg/L	15 mg/L	20 mg/L	25 mg/L	30 mg/L	35 mg/L
Plant height (g)	113.51^f	137.85^bc	133.98^cd	142.30^bc	144.67^ab	152.01^a	126.94^de	122. 19^ef
Number of primary branches plant⁻¹	2.80^d	4.53^b	4.07^bc	3.67^c	5.47^a	5.27^a	4.53^b	4.13^bc
Number of secondary branches plant⁻¹	1.13^c	1.47^b	0.77^d	1.43^b	1.53^ab	1.70^a	1.40^b	1.43^b
Number of silique plant-¹	144.27^f	175.20^bcd	178.93^bc	158.60^def	186.33^b	225.87^a	153.00^ef	144.27^f
Number of seeds siliqua⁻¹	15.05^f	16.12^ef	17.53^cde	19.01^bc	20.31^ab	21.41^a	17.83^cd	16.31^def
Siliqua length (cm)	6.20^c	7.10^b	7.26^b	7.52^ab	7.51^ab	7.96^a	7.22^b	7.07^b
1000-seed weight (g)	2.42^c	2.71^bc	2.81^abc	3.09^ab	3.17^ab	3.3^a	2.74^bc	2.54^c
Biological yield plant⁻¹ (g)	29.29^f	34.25^d	31.32^e	36.74^b	35.13^cd	38.20^a	30.36^ef	35.84^bc
Seed yield plant¹ (g)	7.34^d	7.80^cd	7.49^d	8.30^bc	8.14^c	9.17^a	7.56^d	8.73^ab
Oil yield plant⁻¹	3.07^e	3.27^de	3.16^e	3.58^bc	3.49^cd	4.25^a	3.34^cde	3.86^b
Harvest index (%)	22.67^c	22.76^c	23.42^bc	22.61^c	23.16^bc	23.99^abc	24.92^a	24.36^ab

Values indexed with the same letters are not statistically significant.

*Yield index (YI) is the ratio of grain to the total amount of dry matter of shoots, which is a measure of reproductive efficiency.

As can be seen from the table, the best yield indicators of winter rapeseed were obtained when using a concentration of 25 mg/L. With increasing solution concentration, biometric indicators of crop yield formation decreased, which once again proves that any element, including copper, can only have a positive effect on plants at optimal concentrations; its excess or insufficient amount will block obtaining the desired yield level. This statement is a postulate of the law of optimum, minimum and maximum, according to which the highest yield can be obtained with the optimal presence of a factor, and with an increase or decrease in this factor, the yield will decrease.

However, the above studies in no way claim that boron application for winter rapeseed is not necessary; on the contrary, the combined use of these two elements in crop nutrition technologies will contribute to achieving the planned yield. Thus, according to the results of a three-year experiment (2010–2013) conducted at the Baborówko Research Station (52°35’1.6125”N, 16°38’16.3501”E)), Osiny Research Station (51°27’35.4659”N, 22°2’51.0307”E) and Jelcz-Laskowice Research Station (51°1’48.6194”N, 17°21’36.3187”E) in Poland (doi: 10.17221/24/2015-PSE), it was found that the combined use of copper, boron and sulfur led to an increase in yield by 10%, which is undoubtedly a significant indicator.