Dmitry Kechasov

Postdoktor

(+47) 404 67 991
dmitry.kechasov@nibio.no

Sted
Særheim

Besøksadresse
Postvegen 213, NO-4353 Klepp stasjon

Sammendrag

Recycling of waste fractions from farms and greenhouses might reduce environmental pollution. However, recycling of nutrient solution in greenhouse is risky due to danger of disease spread. Nitrification bacteria can be used for aerobic conversion of ammonia to nitrate in organic waste and may function as stable microbial community protecting against pathogen attacks by enhancing induced systemic resistance of plants. We developed a hydroponic cultivation system “Organoponics” allowing growth of tomato plant on organic fertilizer with recirculation of nutrient solution. Liquid by-product of biogas production has been used as organic fertilizer. A moving-bed bioreactor was integrated in the system for aerobic nitrification of ammonia. Influence of fertilizer composition (organic, mineral matching organic, standard mineral) and addition of plant growth promoting bacteria on biomass distribution, tomato fruit quality were investigated. Plants grown on organic fertilizer were more generative with largest root index. They also produced fruits with significantly larger average size along whole cluster. Addition of the bacteria to root rhizosphere improved yield and quality parameters of plants received organic fertilization and negatively affected the same parameters in plants received mineral fertilization.

Til dokument

Sammendrag

We investigated the effect of supplemental LED inter-lighting (80% red, 20% blue; 70 W m−2; light period 04:00–22:00) on the productivity and physiological traits of tomato plants (Flavance F1) grown in an industrial greenhouse with high pressure sodium (HPS) lamps (235 W m−2, 420 µmol m−2 s−1 at canopy). Physiological trait measurements included diurnal photosynthesis and fruit relative growth rates, fruit weight at specific positions in the truss, root pressure, xylem sap hormone and ion compositions, and fruit quality. In the control treatment with HPS lamps alone, the ratio of far-red to red light (FR:R) was 1.2 at the top of the canopy and increased to 5.4 at the bottom. The supplemental LED inter-lighting decreased the FR:R ratio at the middle and low positions in the canopy and was associated with greener leaves and higher photosynthetic light use efficiency (PLUE) in the leaves in the lower canopy. The use of LED inter-lighting increased the biomass and yield by increasing the fruit weight and enhancing plant growth. The PLUE of plants receiving supplemental LED light decreased at the end of the light period, indicating that photosynthesis of the supplemented plants at the end of the day might be limited by sink capacity. The supplemental LED lighting increased the size of fruits in the middle and distal positions of the truss, resulting in a more even size for each fruit in the truss. Diurnal analysis of fruit growth showed that fruits grew more quickly during the night on the plants receiving LED light than on unsupplemented control plants. This faster fruit growth during the night was related to an increased root pressure. The LED treatment also increased the xylem levels of the phytohormone jasmonate. Supplemental LED inter-lighting increased tomato fruit weight without affecting the total soluble solid contents in fruits by increasing the total assimilates available for fruit growth and by enhancing root activity through an increase in root pressure and water supply to support fruit growth during the night.