90% yield increase of red pepper with unexpectedly low doses of compost soluble substances

To ensure sustainable agriculture productivity and environmental quality, composts are considered for the substitution of chemical fertilizers. These materials are applied to soil at 20-30 dry matter ton ha-1 year-1 doses to contribute organic carbon and nitrogen and minerals to compensate soil nutrient depletion. Recently, soluble substances isolated from urban compost, applied to soil at 1.55 dry matter ton ha-1 dose, have been reported to enhance tomato plant growth and productivity more than the sourcing compost. To realize the full potential of these substances for developing ecofriendly agriculture, proving the above effects for other plant species and studying dose-effect relationships seemed necessary. In the present study, an experimental plan for the cultivation of red pepper was undertaken. The soil and the compost derived soluble substances were the same as in the previous tomato cultivation study. In this study, however, the soluble substances were applied to the soil at 0-700 dry matter kg ha-1 doses. The reported results show that the soluble substances did not yield detectable soil chemical composition changes relatively to the control soil. However, the plant leaf chlorophyll content, growth and productivity increased to maximum values upon increasing the soil treatment dose up to 35-140 kg ha-1. The most remarkable results were the maximum productivity increases observed for the 140 kg ha-1 treatment dose compared to the control soil. The increases amounted to 90 % for the precocious crop yield, to 66 % for the total crop production and to 17 % for the per fruit weight. The discovery that the highest effects occur at such low treatment dose prospects using the above soluble substances to enhance plant growth and productivity, while minimizing the potential environmental impact of conventional fertilizers. The results offer worthwhile research scope to explain the observed dose effect pattern.