INTERCROPPING AS AN EXAMPLE OF SUSTAINABLE ORGANIC AGRICULTURAL SYSTEMS

Abstract

The concept of agroecosystems is based on the understanding of functioning and mutually complementary connections between living organisms and their environment, which maintain stable, dynamic balance in time and space. The mix cultivation of two or more crops is based on ecological principles. Intercropping as an example of sustainable agricultural systems following objectives such as: ecological balance, more utilization of resources, increasing the quantity and quality of yield and reduce damage to pests, diseases and weeds. Mixed crops have their advantages due to the richer diversity of varieties, the use of natural resources, the positive interactions between crops, the various activity of absorption of nutritional substances from their root system, at different stages of the vegetation period and their characterization with stimulation of their growth and improvement of the production quality and yield. The attempt to bring it to the study experimental field of the Agroecological Center at the Agricultural University - Plovdiv during the vegetation years of 2014 and 2015. This research aims at determining the mutual impact upon combined cultivation of pepper (Capsicum annuum L.) of the variety of Kurtovska Kapiya 1619 and the crops- onion (Allium cepa), basil (Ocimum basilicum), salad beetroot (Beta vulgaris L. ssp. rapacea var. atrorubra krass), celery (Apium graveolens L.), and tagetes (Tagetes minima L.), upon establishment of the impact of the biofertilizer Hemozym Bio No. 5 on biometric parameters and productive properties of crops, and on the study of ‘soil respiration’ upon mixed cultivation of crops. The height values of the plants show that the selected test type - basil, may have undisturbed development without having any inhibition effect under conditions of competition whenever placed in pepper crops, thus defining basil as a suitable crops to be added to the mixed crops. Basil is very suitable for the formation of buffer strips between the separate fields in the vegetable crop rotation, for it provides biological diversity in the farm, has a repellent role by pushing away pests and contributing to the pollination by bees. Celery is a suitable crops for mixed cultivation due to the fact that its requirements towards light, water and nutritional substances are identical to those of the pepper and both crops are no competition to one another because of their proximity, but the determining factor is the positive allelopathic effect of the essential oil substances released by the leaf-stalk part of the celery. The mixed crops in organic vegetable production are beneficial in view of the more complete exhaustion of nutritional substances and preservation of the typical characteristics of the soil and soil fertility. Productivity is the most important indicator upon the cultivation of every crop and is a complex reflection of all impacts throughout the entire vegetation period, as it gives the most accurate idea of the impact of the different factors - year, biofertilizer, crop. It was established that the vegetable crops (pepper, onion, salad beetroot, and celery) and the essential oil crop (basil) had a positive reaction to the applied fertilization with the biofertilizer Hemozym Bio No. 5, as the results showed higher values of the yields for all crops as compared to the non-fertilized control variants of the same. We believe that the mix cultivation of these two crops allows their combination in yard gardening on a small area.