BIOLOGICAL CHARACTERISTICS OF THE AQUATIC PLANTS AZOLLA CAROLINIANA AND EICHHORNIA CRASSIPES AND THEIR RESOURCE VALUE IN AGRICULTURE UNDER THE CONDITIONS OF THE REPUBLIC OF KARAKALPAKSTAN

Abstract

The article studies the biological characteristics and the resource value in agriculture of the aquatic plants Azolla caroliniana and Eichhornia crassipes under the conditions of the Republic of Karakalpakstan. Azolla caroliniana, a small floating plant 0.7-1.8 cm in size, reproduces mainly vegetatively and, owing to its symbiosis with the cyanobacteria Anabaena azollae, is able to fix atmospheric nitrogen; it can therefore replace mineral nitrogen fertilizers in rice fields and serve as a protein-rich supplementary feed in livestock farming. For Eichhornia crassipes it was established that the plant multiplies to 16-22 units per week and up to 30-40 under favourable conditions, with an optimal water temperature of +25 to +30 C. The phytoremediation capacity of Eichhornia crassipes, that is, its role in absorbing heavy metals and harmful elements from drainage water, is substantiated scientifically; the plant also has potential for treating collector-drainage water and for producing biogas or organic compost. Taking into account the invasive nature of these species, recommendations are given on their management and control, in particular on cultivating them only in specially monitored closed water bodies.