Changes in the dynamics of humus of the soil content in the continuous sowing of cotton

Abstract

This article is one of the only long-term scientific experiments in Central Asia, which has been conducted for 96 years since 1926 at the Scientific Research Institute of Cotton Breeding, Seed Production and Agrotechnology in Kibray district of Tashkent region. Option 1 monoculture, 30 t / ha fertilizer per hectare + 30 kg / ha phosphorus per year, Option 2 monoculture, N P K 250:175: 125 kg / ha per year and Option 3 monoculture, absolute fertilizer, control options humus content 96 analytical scientific data on changes during the year. In the article, the highest decrease in humus content was observed in the control variant where was not used fertilizers, the amount of humus after 20 years was 21.4% or 11.4 t / ha compared to the initial amount, after 40 years it was 30.9% or 16.46 t / ha, after 60 years it was 35.7% or 19.05 t / ha, after 80 years it was 49.3% or 26.29 t / ha, and 54.3% or 29.17 t / ha after 96 years, this indicator is 12.2% -6,487 t / ha. In the experiment, the highest rate of humus reduction for 96 years was 54.3% in the control variant, 30 t / ha of manure + 25 kg / ha per year in P2O, 47.5% in variant 1, N P K 250:175:125 kg / year. The norm was found to decrease by 36.9% in variant 2, where the norm was applied.