Wpływ siarczanów na stan odżywienia, plonowanie i jakość owoców pomidora (Lycopersicon esculentum Mill.) uprawianego w systemach bezglebowych
AbstractThe research aimed to determine the influence of varying sulphate levels in nutrient solution on the rate of sulphate ions accumulation in the root zone, the nutritional status of plants, the rate of water and nutrient uptake by plants, and the yields and fruit quality of tomato. The experiments were conducted in the years 2000-2003 in greenhouses and laboratories of the Faculty of Horticulture, Agricultural University of Krakow. Greenhouse tomato cv. Cunero F I was grown in two different systems: a system based on the Nutrient Film Technique (NFT) and an open system without recirculation of nutrient solution (O-WR), using rockwool or coconut fibre as a growing medium. The experimental designs were as follows: — Experiment I: plants grown in three independent NFT units filled with rockwool; sulphate (SW-) levels: unit I — 200, unit II — 400, unit III — 600 mg • dm-3, — Experiment II: plants grown in two independent O-WR units filled with rockwool; sulphate levels: unit 1— 250, unit II — 500 mg - dm-3, — Experiment III: plants grown in independent NFT units filled with coconut fibre (3 units) or rockwool (3 units); sulphate levels: unit I — 200, unit II — 400, unit III — 600 mg • dm-3, — Experiment IV: plants grown in two O-WR units or three NFT units, all filled with coconut fibre; sulphate levels of O-WR: unit I — 200, unit H — 600 mg • dm-3; sulphate levels of NFT: unit I — 200, unit II — 400, unit III — 600 mg • dm-3. It was found that irrespective of the growing system (NFT or O-WR), sulphates accumulated in the root zone of plants. Accumulation was the greatest in units with the highest initial (at the beginning of cultivation) sulphate levels, i.e. 500 or 600 mg • dm-3. In all the experiments, the relative accumulation of sulphates (calculated as a percentage of the initial concentration) was the largest in units with the lowest initial sulphate levels, i.e. 200 or 250 mg • dm-3. The sulphate accumulation in the root zone of tomato plants was higher in the open system without recirculation of nutrient solution (O-WR) than in the closed system with such recirculation (NFT). In O-WR, the final concentration of sulphates (SO42-) constituted 300 to 880% of their initial level, compared with 180 to 550% in NFT. The rate of sulphate accumulation in the plant root zone depended also on the kind of growing medium. In the NFT system, using coconut fibre resulted in the sulphate concentration increased to 1100, 1620 and 1800 mg • dm-3, respectively, in units with the initial levels of 200, 400 and 600 mg - dm'. For rockwool, the concentration of sulphates rose to 800, 1000 and 1100 mg - dm-3, respectively. The sulphate accumulation in the nutrient solution of NFT units was slightly lower when the solution was sampled from organic medium (coconut fibre) than from mineral one (rockwool). In the O-WR system, the differences in the accumulation of sulphates due to the growing medium were even bigger. The concentration of sulphates in nutrient solution affected the nutritional status of tomato plants. The plants fed with solutions containing highest sulphate levels had less calcium and phosphorus and more sulphur, sulphates and nitrogen than those grown in low-sulphate solutions. In the NFT system, regardless of the growing medium (rockwool or coconut fibre), the calcium and phosphorus contents of leaves decreased with the increasing accumulation of sulphates in the root zone, especially for the leaves sampled during the ripening of fruits. Such an effect was even more pronounced in the O-WR system with coconut fibre, for which the amount of sulphate accumulation in the plant root zone was the greatest among all the experiments (about 2700 mg • dm-3). In all the growing systems, higher levels of sulphates in nutrient solution resulted in lower molybdenum contents of leaves. The daily nutrient and water uptake by tomato plants grown in the NFT units filled with rockwool depended mainly on the stage of plant growth, and to a smaller extent on the sulphate level in nutrient solution. The average daily uptake of nutrients by a plant was the following (mg): N — 131.4, P — 31.6, K — 229.6, Ca — 100.7, Mg — 23.2, and the daily uptake of water averaged 1084 cm3. As follows from the research, the initial level of sulphates (SO42) in nutrient solution (200-600 mg • dm-3) had no effect on tomato yields, except for the highest level (600 mg • dm-3) in the O-WR system with coconut fibre, which significantly reduced both the yields and the mean weight of a fruit. The kind of growing medium influenced the yields of tomato. Higher total and marketable yields, by 11.8 and 11.2%, respectively, were obtained from plants grown in rockwool than in coconut fibre. The sulphate concentration in nutrient solution did not affect either fruit acidity or the levels of ascorbic acid and soluble sugars in tomato fruits. On the other hand, it positive¬ly influenced the lycopene content of fruits. The results obtained show that tomato plants are tolerant to large concentrations of sulphates in the root zone: up to 1900 mg per din' of growing medium (coconut fibre) and 1550 mg per dm3 of nutrient solution (when rockwool is used as a growing medium). At such sulphate concentrations, the nutritional status of tomato plants is still optimal and the plants do not show any symptoms of toxicity.
|Other language title versions||Effect of sulphates on plant nutritional status, yielding and fruit quality of tomato (Lycopersicon esculentum Mill.) grown in soilless culture systems|
|Publisher||Uniwersytet Rolniczy im. Hugona Kołłątaja w Krakowie, MNiSW |
|Publishing place (Publisher address)||Kraków|
|Book series /Journal (in case of Journal special issue)||Zeszyty Naukowe Uniwersytetu Rolniczego im. Hugona Kołłątaja w Krakowie. Rozprawy, ISSN 1899-3486, (0 pkt)|
|Publication size in sheets||8|
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