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Heutzutage möchten Golfspieler ihre sportlichen Aktivitäten saison- und witterungsunabhängig durchführen. Dies führt meistens zu einer Übernutzung der Abschlagflächen und schließlich zu einer stark verminderten Rasenqualität. Der damit verbundene, hohe Pflegeaufwand ist nicht unerheblich. Im Rahmen dieser Studie wurde das Hybridrasensystem CombiGrass der Firma Eurogreen auf verschiedenen Abschlagflächen von vier ausgewählten Golfanlagen mit Naturrasen verglichen. Es wurden die Parameter Ebenflächigkeit, Drehwiderstand, Kraftabbau, Energierückgabe, vertikale Deformation und Bodenfeuchtigkeit bestimmt. Außerdem wurde die projektive Bodendeckung der Rasennarbe vor und nach mehreren Golfabschlägen untersucht, um mögliche Unterschiede im Grünanteil zwischen Natur- und Hybridrasen festzustellen. Zusätzlich wurden eine quantitative Golfspielerbefragung und eine qualitative Expertenbefragung der Head-Greenkeeper durchgeführt. Die Messergebnisse der Untersuchungen wurden direkt mit den Ergebnissen beider Befragungen verglichen. Durch die Verwendung von CombiGrass, insbesondere unter feuchten Bedingungen und in schattigen Lagen, konnten Bespielbarkeit und Standfestigkeit sowie das Erscheinungsbild und die Ebenflächigkeit auf Abschlagflächen verbessert werden. Des Weiteren wurde eine Reduzierung von herausgeschlagenen Divots, Rasenkrankheiten und Materialaufwand zur Pflege und Instandhaltung festgestellt.
Soil versus foliar iodine fertilization as a biofortification strategy for field-grown vegetables
(2015)
Iodine (I) biofortification of vegetables by means of soil and foliar applications was investigated in field experiments on a sandy loam soil. Supply of iodine to the soil in trial plots fertilized with potassium iodide (KI) and potassium iodate directly before planting (0, 1.0, 2.5, 7.5, and 15 kg I ha-1) increased the iodine concentration in the edible plant parts. The highest iodine accumulation levels were observed in the first growing season: In butterhead lettuce and kohlrabi the desired iodine content [50–100 μg I (100 g FM)-1] was obtained or exceeded at a fertilizer rate of 7.5 kg IO3--I ha-1 without a significant yield reduction or impairment of the marketable quality. In contrast, supplying KI at the same rate resulted in a much lower iodine enrichment and clearly visible growth impairment. Soil applied iodine was phytoavailable only for a short period of time as indicated by a rapid decline of CaCl2-extractable iodine in the top soil. Consequently, long-term effects of a one-time iodine soil fertilization could not be observed. A comparison between the soil and the foliar fertilization revealed a better performance of iodine applied aerially to butterhead lettuce, which reached the desired iodine accumulation in edible plant parts at a fertilizer rate of 0.5 kg I--I ha-1. In contrast, the iodine content in the tuber of sprayed kohlrabi remained far below the targeted range. The results indicate that a sufficient spreading of iodine applied on the edible plant parts is crucial for the efficiency of the foliar approach and leafy vegetables are the more suitable target crops. The low iodine doses needed as well as the easy and inexpensive application may favor the implementation of foliar sprays as the preferred iodine biofortification strategy in practice.
Iodine biofortification of butterhead lettuce (Lactuca sativa)viafoliar sprays was investigated infield trials, focusing on assessing the influence of the time and application method. The iodine (I)concentrations in the edible plant parts increased when potassium iodide (KI) and potassiumiodate (KIO3) solutions were sprayed at doses up to 0.25 kg I ha–1on different dates close to har-vest. Crop yield and marketable quality were not significantly affected by I treatments. A greaterefficacy of KI was frequently observed and probably related to its lower point of deliquescenceand smaller anion size in comparison with KIO3. KI sprays on butterhead lettuce at different timesof the day resulted in a higher I enrichment when applied at 11:00 and 15:00 h. The diurnal varia-tion in I uptake may reflect the impact of fluctuating climatic conditions at the time of application.Iodine treatments at different application dates near harvest led to an increasing I concentrationin the vegetable produce that could be related to the rising shoot fresh mass and leaf area.When KI and KIO3were sprayed simultaneously with commercial calcium fertilizers, fungicidesor insecticides, I accumulation in butterhead lettuce was not negatively affected or in some caseseven significantly enhanced. The results show that foliar sprays of KI and KIO3are an effectivemethod to biofortify butterhead lettuce with I and this approach may easily be implemented as aroutine method in commercial cultivation.