Fundamentals of rational nutrition and fertilization systems for vineyards

The efficiency of mineral nutrition of grapes decreases as the optimal fertilizer dose is approached. With an excess of nutrients, yield drops, and berry quality deteriorates. For fertilizers to provide maximum return, an agronomist must calculate doses based on the laws of absorption, translocation, and accumulation of elements in grapevine organs.

Four main factors influence how grapes absorb nutrients:

• soil fertility;
• the intensity of microbiological processes within it;
• the heat and moisture balance;
• the cultivation technology used.

A vineyard grows in the same place for several decades, annually extracting large volumes of nutrients from the soil with the harvest and vine shoots. Regular machinery passes and soil tillage alter its mechanical and chemical composition. The ground becomes compacted, and humus content, carbonate levels, and nutrient reserves decrease. It is important for an agronomist to replenish this deficit without disturbing the balance in the soil-plant system.

Soil and climatic nutrition factors

Grapevines grow successfully in a wide variety of soils — from fertile chernozems, sierozems, and krasnozems to poor sandy and stony soils. Depending on soil conditions, vineyards are characterized by varying degrees of vine vigor and productivity. Vineyard yield is always limited by the nutrient element in minimum supply.

The fertilizer requirements of grapes differ across various soil types. In some foreign viticulture regions, vines show a weak response to phosphorus application due to its high content in the ground. At the same time, a pronounced deficiency of this element has been identified in some domestic soils. A similar situation exists with potassium: in some regions, an excess is noted, while in the carbonate soils of other areas, plants lack potassium.

An imbalance of elements in the soil often triggers vine diseases. An excess or deficiency of calcium, iron, copper, or aluminum causes chlorosis and other pathologies that reduce yield and degrade berry quality. Soil temperature and humidity also affect the nutrient uptake processes. Absorption decreases at extremely low or high temperatures. Uptake is more active at optimal humidity levels, and the fertilizers themselves increase the drought resistance of the vines. An agronomist should apply different forms, doses, and timing of fertilizer application on waterlogged or insufficiently moist soils during periods of extreme temperatures.

Influence of biological characteristics and developmental stages

The intensity and selectivity of nutrient uptake by roots depend on the grape cultivar and rootstock. According to field trials, cultivar-rootstock combinations significantly affect the accumulation of substances in leaves:

• the Aligoté cultivar on Berlandieri x Riparia Kober 5BB and Riparia x Rupestris 101–14 rootstocks accumulates more nitrogen and potassium compared to own-rooted vines;
• the nitrogen and phosphorus content in the leaves of the Fetească Albă cultivar is higher than in the Aligoté cultivar;
• the choice of rootstock significantly changes the accumulation level of total nitrogen, phosphorus, and potassium in the leaves of various cultivars.

Nutritional needs change as vines age. During canopy formation, the nitrogen requirement for building vegetative mass is significantly higher than during the fruiting or senescence stages of the vines. Nitrogen is also urgently needed by the vine during rejuvenation. This means that plant nutrition must be strictly differentiated at different stages of ontogeny.

• Duration of grape cultivation in one place — several decades
• Peak accumulation of N, P, K in leaves — flowering stage
• Maximum nitrogen requirement — formation and rejuvenation of vines

The rates of nutrient uptake throughout the season depend on the rhythm of physiological processes and the harvest ripening time. Nitrogen is consumed most actively during the first growing season period to build young organs:

• shoots;
• leaves;
• inflorescences;
• berries.

In experiments with the Rkatsiteli cultivar, the relationship between nutrition levels in different years and yield was evaluated. It was established that the largest quantity of total nitrogen, phosphorus, and potassium accumulates in grape leaves during the flowering stage. During the berry ripening stage, the content of elements gradually drops, reaching a minimum after harvesting and during the period of shoot maturation.

When determining the timing, forms, and application rates of fertilizers, the cultivar characteristics of plants are taken into account. Differences in nutrient uptake are determined by numerous factors, in particular, the productivity of leaves and shoots, the rate of vegetative mass growth and economic harvest, the nature of the development of the root system, and the size of the yield. Different levels of absorption and metabolism are observed in small bushes in Crimea and vigorous ones in the Krasnodar Territory, Moldova, and especially in Central Asia. In this case, the degree of plant development and cultivar productivity play an important role. High-yielding bushes use fertilizers in larger quantities and more efficiently than low-yielding ones. At the same time, it is known that the regular application of fertilizers increases the productivity of a cultivar.

Fig. 61. N, P, K content in the leaves of grape cultivars:

Riesling (R), Chasselas (Ch), Aligoté (A), and Cabernet Sauvignon (K) depending on rootstocks (101 Riparia X Rupestris 101–14; 5BB — Berlandieri X Riparia Kober 5BB; 41B — Chasselas X Berlandieri 41B).

The need for nutrients and their degree of utilization in different grape cultivars can vary depending on meteorological conditions. Thus, for plants of the Rkatsiteli cultivar in the Chechen-Ingush ASSR in wet years, the N:P:K ratio in the leaves was 4:1:1, and in dry years — 3:1:0.9. The absorption capacity of grape plants of different usage directions also differs. The nitrogen requirement for vigorous table cultivars is greater than for wine cultivars. L. N. Gordeeva established that for the formation of a good yield, it is important to enhance nutrition during the initiation and development of embryonic inflorescences in the central buds of the eyes.

For each organ of the grapevine, the accumulation and use of nutrients are specific. The most nitrogen is accumulated in leaf blades, then in roots, leaf petioles, and the least — in shoots and perennial parts; there is more phosphorus in petioles, leaf blades, and shoots, and less in roots and perennial parts; there is more potassium in leaf petioles and shoots, and less in leaf blades, roots, and perennial parts (Bondarenko, 1965, 1972). These patterns depend on the cultivar, rootstock, age, vigor, and productivity of the plants, meteorological conditions, soil, and cultivation technology of grapes, which is also important to consider when determining the forms, rates, and timing of fertilizer application.