One of the main causes of unfavorable changes occurring in the soil, often leading to its degradation is the excessive chemization of the natural environment while reducing the use of calcium fertilizers. According to the data published by the Central Statistical Office, chemical companies delivered nearly 2400,000 tons of mineral fertilizers to the domestic market for planting crops grown in 2015 recalculated to pure component, i.e. about 4% more than in the analogous, earlier growing season. However, in 2015, the use of calcium fertilizers per 1 ha of agricultural land decreased by 20% compared to the previous year and amounted to only 40 kg. Hence, the very low level of calcium fertilization maintained is insufficient in relation to the acidity level of Polish soils. It should be remembered that growing cereal plants requires the supply of many nutrients, including calcium. It is a nutrient that is important in shaping production and environmental effects. After the introduction of integrated pest management in Poland in 2014, there has been a search for and implementation of environmentally friendly methods to reduce the adverse effects of cereal crops, including maize, on the soil environment. A number of calcium fertilizers offered by various chemical companies are available in the domestic market, hence the large scale producer has a large selection of suitable fertilizers for his/her farm.
Maize belongs to plants quite sensitive to low pH and the accompanying increased concentration of aluminum and manganese ions. It is less demanding than e.g. barley or medicago, but its requirements are still similar to that of winter wheat. Lower pH value at which maize can still yield decently is 5.5-5.8; the upper one is pH 7.5. With the lowering of the reaction, the yield of maize grain decreases, and the yield of green mass also drops to a similar extent. At a pH of 5.5 a yield reduction of 15% can be expected, while at pH 4.5, the drop in the maize yield reaches as much as 40%. Research by UNG in Puławy demonstrated that liming very acidic soil can increase the yield of maize even by 60%.
Currently, the problem of soil pH regulation is solved best by the Polish OrCal organic-mineral fertilizer. It has properties very beneficial for the growth and development of all groups of agricultural plants. Thanks to the calcium content in the form of an active hydrate (Ca(OH)2), the pH of the soil is quickly and permanently elevated (even by 1 to 1.5 pH units within 2-3 months). It is therefore an effective solution for acidified light and medium soils, purchased land and leases, the pH of which quite often oscillates around the level of 4.0-4.5 but also for slightly acidic soils in order to precisely regulate their pH. Another positive feature of the OrCal fertilizer is the content of organic matter. This makes this fertilizer fertilize the soil, increase the share of valuable humus and thus significantly improve the sorption properties of the soil (nitrogen, potassium, microorganisms or water). This is particularly important during periodic drought, which is a frequent and annoying phenomenon in recent years. Through the so-called organics, we introduce nitrogen into the soil (ca. 47kg thereof in one tone of OrCal ), and provide plants with valuable phosphorus in easily absorbed form (approx. 2.5%) as well as potassium (approx. 1.3%) and many other valuable macro and microelements of animal origin, so much needed for the proper development of plants and soil microflora. Bearing in mind the above-mentioned statements, a pilot field study was conducted on the effect of OrCal organic-mineral fertilizer on the growth and development and yielding of maize. The studies compared 4 different levels of mineral fertilization of maize. They were: control object [(0 kg NPK,) NPK, NPK + 1 t/ha OrCal, ½ NPK + 1 t/ha OrCal]. It was demonstrated that the dynamics of the initial maize growth expressed in the yield of plant dry matter in the 6-7 leaf phase was the highest on those plants where the combined mineral fertilization with OrCal was used, in relation to the exclusive NPK fertilization (Fig. 1). The difference between the NPK + 1 t ha OrCal and ½ NPK + 1 t/ha OrCal objects tested and the exclusive NPK mineral fertilization was respectively: 7.5% and 4.4%. Also, the similar effect of the tested levels of mineral fertilization was confirmed in grain yield (Fig. 2). The combined mineral fertilization with OrCal organic-mineral fertilizer was more effective compared to NPK fertilization alone. In the conducted field study, the beneficial effect of OrCal fertilizer, which contains calcium in the form of active hydrate (Ca(OH)2), was also confirmed for faster raising and adjustment of soil pH (Fig. 3). Simplified calculation of maize cultivation presented in this study is only an example of comparison of income obtained from different variants of mineral fertilization. Their goal was to create the basis for making economic decisions as well as far-reaching thoughts on a large-scale farm regarding the fertilization of maize. The presented simplified agricultural calculation was used exclusively to calculate the direct surplus. It was calculated as the difference between the value of production (yield of grain) and direct costs incurred to produce this yield (the cost of fertilizers). When analyzing the data presented in Table 1, it should be treated as very simplified, because they take into account only the cost of mineral fertilization (tab. 1). It clearly shows that the application of half of the NPK mineral fertilizer in combination with 1 ton of OrCal gives an increase of direct surplus from 1 ha of maize cultivation in the amount of almost 83 PLN/ha (tab.1). It is clear from this studies that the use of OrCal in the cultivation of maize increases the profitability of cultivation of this species while limiting the eutrophication of the natural environment with biogens.
OrCal organic and mineral fertilizer is becoming more and more successful on the Polish and global market. Probably because it is a solution that deals with several most important problems at the same time, and its effects are quickly noticed by large scale producers. Regulation of soil reaction, clear improvement of its structure, the possibility of limiting NPK mineral fertilization translate into increased profitability of maize cultivation. Due to the fact that the use of OrCal in maize cultivation proved to be effective, in the Department of Agronomy of the University of Life Sciences in Poznan, field research was also undertaken on the use of this fertilizer in the cultivation of winter oilseed rape. The results of this experiment will be published in the later issue of Przedsiębiorca Rolny.
Table 1. Simplified calculation of cultivation of 1 ha of maize for grain taking into account only the direct costs of mineral fertilization
(data of fertilizer and maize prices by ODR Sielinko, September 2017)
|Type of the fertilizer||Dose||Price PLN/uom||Value PLN/ha||NPK zł/ha||NPK + 1 t OrCal zł/ha||½ NPK + 1 t OrCal zł/ha|
|Enriched superphosphate||100 kg||3,55||355||355||355||177,5|
|Total mineral fertilization||–||–||–||1145,2||1145,2 + 700||572,6 + 700|
|Revenue – grain yield (B)||–||–||–||6391||6706||6601|
|Direct surplus (B-A)||–||–||–||5245,8 a)||4860,8 b)||5328,4 c)|
|Difference||–||–||–||–||– 385 zł/ha b-a)||+ 82,6 zł/ha c-a)|