A conceptual model of the functioning of a modern intensive organic orchard

Thanks to recent advances in plant biology and agronomy, favorable prerequisites have been created for the practical implementation of the basic principles of organic farming. For instance, the prospects for establishing intensive organic orchards are demonstrated, in which well-tuned technological operations are used to enhance the beneficial effects of ecosystem functions, including biodiversity, soil fertility, and homeostasis.

The primary task of such orchards is to obtain stable, economically justified fruit harvests in various environmental conditions that meet the requirements for organic produce, as well as to eliminate chemical impact on the orchard agroecosystem and ensure the full utilization of its inherent biological potential. A conceptual model of the functioning of an organic orchard is presented in Figure 38.

The basis for creating an organic orchard model should be the selection of both sites that meet regulatory requirements and the best cultivars, combining in one genotype high resistance to major abiotic and biotic (immunity to fungal diseases) stress factors. The selected cultivars are grafted onto regionalized (promising) semi-dwarf or medium-growth rootstocks that react weakly to increases in mineral nutrition levels and are resistant to limiting climatic and soil stressors. Nursery plants are planted according to a specific scheme, and the canopies are subsequently formed in accordance with generally accepted zonal recommendations.

Figure 38 – Conceptual model of the functioning of an organic orchard

A necessary condition for the further successful existence of the ecosystem is the implementation of monitoring of plant status and abiotic factors, which allows for the timely activation of the system's corrective mechanisms.

Corrective mechanisms are a complex of well-tuned technological operations that enhance the beneficial effects of ecosystem functions. The main mechanisms include:

• optimization of the species diversity of grasses and soil fertility in orchard inter-rows. In this process, inter-row sodding is used by forming a stand of naturally growing groundcover grasses of optimal species composition through periodic mowing as they grow to a height of 15–20 cm. The soil in the tree-trunk strip is mulched with straw;
• extensive use of microbiological plant protection products, as well as the conservation and enhancement of the activities of natural enemies of pest species, for example, Lepidozid and Bacicol, including their natural populations, such as the predatory bug Campylomma verbsei;
• selection of the optimal tree canopy formation system.

The ultimate goal in creating an organic orchard model is to ensure the maximum realization of the self-regulation mechanisms of the orchard ecosystem components. In this case, the need for corrective mechanisms is minimized. In our experiments, this period was noted starting from the sixth year of the planting. During this time, the ecological resource of the program for ecological management of pest and beneficial species populations is created, enabling the gradual (by the beginning of commercial fruiting) reduction in the number of treatments against diseases and pests using biological means by at least 2 times (compared to traditional orchards), while simultaneously reducing damage to harvested fruit to an economically acceptable level (4%). At the same time, apple yield in various (even extreme) weather years fluctuates within the range of 18.0–26.0 t/ha. yield, t/ha

2007 2008 2009 2010 2011 2012 2013 2014

Figure 39 – Dynamics of apple yield in a model organic orchard, planted in 2002, t/ha

The summary Table 29 presents the characteristics that favorably distinguish an organic orchard from a traditional one.

It should be noted that the beginning of fruiting in an organic apple orchard occurs one year later, and its operational life is 5–8 years longer than that of a traditional one. At the same time, the fruiting potential of an organic orchard is quite high and reaches 480 t/ha.

At the same time, labor and financial costs during the establishment and operation of organic fruit plantations are incomparably lower than when using traditional orchards (a smaller quantity of planting material; absence of support structures, irrigation, mineral fertilizers, etc.). Table 29 – Intensive orchard models (using apple as a crop) for the southern regions of Russia (Doroshenko et al., 2011)

Intensive orchard

Characteristic Traditional Organic

1 2 3 Cultivar resistance: to fungal diseases medium-susceptible resistant (immune) to abiotic stress factors medium high Growth vigor dwarf semi-dwarf, clonal rootstocks medium-growth Number of trees per 1 ha, pcs. 1250–1666 500–1250 Presence of support yes no Soil management in inter-rows inter-row sodding sodding with sown grasses with directed formation of the species composition of naturally growing grasses Herbicide application permitted not permitted Use of mineral fertilizers high doses: not permitted N120-150

K120-150 Irrigation mandatory optional Proportion of biological preparations in the plant protection system, % 10–15 100 Continuation of table 29

1 2 3 Beginning of commercial fruiting, year 3rd 4th Yield in a young orchard, t/ha no less than 10 7–8 in a mature orchard, 30–35 and more 18–24 and more t/ha. in adjacent years, t/ha 36; 17 23; 18 Service life, years 10–12 15–20 Fruiting resource, t/ha 300–400 270–480

Fruit quality in a modern orchard can be managed directly during its operation. Properly selected technological elements allow for regulating ripening periods, changing fruit size, and improving their shelf life and suitability for processing. By adjusting canopy shape, the soil management system, and the irrigation regime, an agronomist can purposefully change harvest characteristics to meet the specific goals of the farm.

• Regular yield — 24–26 t/ha
• Experimental orchard planting date — 2002
• Safety assessment period — September 2005

Environmental safety of fruits in an organic orchard

Produce grown using organic gardening technologies fully meets strict hygienic and environmental requirements. To confirm this, fruits of the Liberty cultivar apple tree were analyzed as part of field trials. The results of laboratory studies showed that the content of toxic elements, pesticides, and radionuclides in the harvested crop is significantly lower than the maximum permissible limits.