Сhemical composition of apples under spray dressings with mineral fertilizers and edagum biological growth stimulant

Apple fruits as one of the sources of the antioxidants have important alimentary, preventative and medical value. Antioxidants containing in apples include vitamins, such as ascorbic acid (vitamin C), P-actives (vitamin P) and mineral substances, enzymes and other elements [1, 2].

Various factors may influence both biochemical and a chemical composition of apples: grades, age of trees, arrangement of fruits, terms of their maturing and remove, crop range, seedling stock, environment, etc., thus applied fertilizers play an important role in formation of quality of fruits [3]. The mineral elements coming in with fertilizers, form a complex of biochemical indicators of fruits quality, are a part of the major organic compounds [4-6].

The goal of our investigations was to analyze chemical fruits composition of a weedy apple-tree of a grade the Athlete depending on foliar dressing in intensive fruit plantings in the conditions of the leached chernozem.

Meyhods. Experiments (2009-2010) were conducted in fruit plantings of an apple-tree of a grade the Athlete (bedding of 2001) on a weedy clonal seedling stock 62-396 (the bedding scheme — 4,5x1,5 m) in Federal State Unitary Enterprise Michurinskoye (Michurinsk). Soils in the venue of experiments are medium leached medium chernozems. Volume weight in a layer of 0-20 cm — 1,10-1,25 g/cm³, at a depth of 80-100 cm — 1,30-1,35 g/cm3. The maximum hygroscopy of the soil — 6,54%, the minimum moisture capacity of a soil layer of 0-40 cm — 26,9-28,8%, рН a water extract — 5,20-5,65, hydrolytic acidity — 7,90-8,15 mg-eq; average content of a humus 5,2-6,4%. Supplies of available nutrients of the top layers: nitrogen — 3,9-5,8; phosphorus — 6,8-10,4 and potassium — 16,5-19,5 mg / 100g of the soil. Akvarin, edagum, boron (boric acid, in), zinc (zink sulfate, Zn). Akvarin (JSC «Buysky chemical plant», Russia) — complex soluble fertilizer (N ₁₉P ₆ K ₂₀ Mg _1,5 Si _1,4 Fe _0,054 Zn _0,014 Cu_0,01Mn_0,042Mo_0,004Bo _0,02); edagum (JSC «Spetsosnastka M Service», Russia) — humic fertilizer, a natural biological growth and plants development stimulant, developed on the basis of peat, contains humic and fulvic acids, organic acids (amber, oxalic, apple, etc.) amino acids, carbohydrates, vitamins, macro - and microelements in the form of bioavailable organic compounds were used as dressings. Spray dressings of plants were carried out annually (2 or3 times — in an fruit blossom phase, before a June set reduction and in a fruits growth phase) according to the following scheme: the I option — control (water); the II option — akvarin (1 %) + edagum (0,1 %); the III option — akvarin (1 %) + B (0,1 %); the IV option — edagum (0,1 %); the V option — B (0,1 %) and the VI option — edagum (0,1 %) + B (0,1 %) (final concentrations of fertilizers in a tank mix are specified; consumption rate of working solution — 800 l/hectare).

Biochemical indicators were determined by the standard methods: the content of the general forms of nitrogen, phosphorus, potassium, calcium, magnesium — according to methodical recommendations [7, 8], amino acids — as it is described [9]. The analysis of microelements was carried out with the use of the nuclear and adsorptive spectrometry (an optical issue spectrometer of Optima 2100 DV, «Perkin Elmer», the USA).

Statistical processing of the obtained data was carried out using a method of the dispersive analysis [10].

Results

The total content of nitrogen in fruits considerably varied on an annual basis in control and in options with processing edagum, on what weather conditions could influence, especially in the summer of 2010 when accumulation of nitrogen in fruits of an apple-tree was higher than in 2009. Over the application of special mineral and boric fertilizers the content of nitrogen was more stable what probably can be connected with accumulation of nitrogen in leaves (in options with processing by special fertilizers its contents was higher in comparison with control) and a functional condition of plants. In options with the akvarin and edagum they noted the highest content of phosphorus which in this respect considerably varied on an annual basis. Over the application of boron and product edagum in combination with boric fertilizers the content of phosphorus was stable over a period of supervision on an annual basis. Use of special fertilizers in combination with edagum and boric fertilizers promoted increase of the content of potassium in fruits for 22,0-31,0% what positively affects their viability.

Also accumulation of potassium in fruits was influenced by weather conditions. This way, the vegetative period of the year 2010 was critical for plants. In June - July the average daily temperature was 10-12 °C higher than the long-term average annual. During the daytime in the shade it was 38-41, in the sun — 50-52 °C, and abnormally high temperatures were accompanied by almost total absence of a precipitation: the sum of a precipitation for June – I and the II decade of July made 20% from the long-term average annual. In July – August average daily temperature was 12-15 °C higher than the long-term average annuals, during the daytime being 38-43 °C in the shade and 52-55 °C on the sun against almost full lack of a precipitation: their sum for July - August equaled 10% from mean annual values. Average daily humidity was no higher than 40%, and during the daytime fell to 12-15%.

These weather conditions also led to the increased accumulation of calcium in the fruits, especially in options with edagum and complex application of fertilizers and a humic preparation processing.

The content of magnesium in the fruits with using only edagum product remained at the level of control, the highest content of magnesium on the average for 2 years was noted in the option with a combination of akvarin, boron and edagum.

In the ratio of calcium, potassium and magnesium the shift towards accumulation of two last microelements was noted under dressings consisting of akvarin and edagum in combination with microelements.

The quantity of microcells in fruits considerably differed on an annual basis. The highest content of zinc and boron was revealed in the options with akvarin in combination with boron and edagum.

The content of amino acids in fruit production is caused by hereditary properties of a grade, however in many respects it also depends on nitrogenous nutrition and influence of external factors [11]. From the group of defined amino acids the highest contents of arginine, leucine, methionine, valine, a proline and threonine (2010) was revealed. Probably considerable variation of amounts of free amino acids in the fruits is generally connected with biotic factors. On an annual basis the most stable content was one of valine in the options with application of akvarin in the combination with edagum and boron, the highest one (on the results of 2 years of researches) – under the application of edagum dressing.

In 2010 the highest content of a proline was registered in the option with the application of spray dressings of apple-trees with a 0,1% humic agent; besides, the inverse relationship between the content of a proline and the total potassium in the fruits (of =-0,6632) was discovered. Also the application of edagum promoted significant increase of arginine, tryptophan and threonine content of the fruits. The highest quantity of methionine in apples was discovered in the control and in the option with boron processing.

Under the application of natural biological stimulant of growth the content of anthocyans and chalcones in apples increased.

While using spray dressings the quantity of pectose in apples decreased in comparison with the control (table 1) that testifies the more active proceeding processes of the maturing of fruits and the necessity of their additional processing by special substances for long-term storage.

Table 1. The content of pectinaceous substances (%) in fruits of an apple-tree of a grade the Athlete depending on the option of dressing (Federal State Unitary Enterprise Michurinskoye, Michurinsk, 2010)

The ratio analysis of sugars and acids in the fruits revealed the optimum value of coefficient under the application spray dressings. The maximum influence on these indicators was noted under processing edagum with boron.

Table 2. The content of sugars and acids in the fruits of an apple-tree of a grade the Athlete depending on the option of dressings (Federal State Unitary Enterprise Michurinskoye, Michurinsk, 2010)

Thus, depending on the applied fertilizers the content of the basic nutritious elements in the fruits increases. Processing with preparations of akvarin and edagum causes 33,1 and 49,5% increase of the phosphorus content respectively, under their application with boric fertilizers the accumulation of potassium increases to 22,0-31,0% what promotes the storage. Edagum dressing reduces acidity and raises sugar content that is favours a sugar-acid index. The option with the application of edagum product is characterized by the maximum content of valine. The content of water-soluble pectin increases to 24,0% under joint processing with akvarin and edagum. The inverse relationship of quantity of a proline and the total potassium is discovered.