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Fertirrigare il pomodoro giova al prodotto e all’ambiente.
No full textFertirrigare il pomodoro giova al prodotto e all’ambiente
Determination of SPAD Threshold Values in order to optimise the nitrogen supply in processing tomato.
No full textThis work deals with the use of SPAD-502 (Minolta - Japan), as a tool to assess the crop N status across the growing season and to manage N fertilization of processing tomatoes. The SPAD-502 permits prediction of plant N status from measurements of leaf transmittance. For practical use of this instrument, it is necessary to develop threshold values, below which decrease in yield would be expected. A procedure for the calculation of SPAD threshold values (STVs) was set using data obtained in a trial on processing tomato conducted in 2002 at the Experimental Farm of the University of Padova at Legnaro, Italy. The trial was included in a long-term experiment, aimed at comparing the effects of different type of fertilization on crop yield and soil fertility. Three ways of crop residue management (incorporation of previous crop residues, incorporation of the residues plus addition of 1 t ha-1 of dried chicken manure, removal of the residues) were factorially combined with 5 increasing rates of N (0, 60, 120, 180, 240 kg ha-1). The SPAD measurements were carried out at 2-5 days-interval. At harvest, fruits were collected and weighed. Linear-plateau equations were developed for calculating the relationships between SPAD values and relative tomato yield. The abscissa of the break-point in the linear-plateau regressions, corresponding to the SPAD value below which yield decreases, was defined 'SPAD Threshold Value' (STV). This paper describes the procedure step-by-step and gives STVs for tomato cv. Perfectpeel
Effects of osmopriming treatments on seed germination of two types of radicchio (cichorium intybus var. silvestre)
No full textTo improve germination of two types of radicchio ('Rosso di Chioggia', RCh, and 'Bianco di Chioggia', WCh) various pre-sowing treatments were evaluated. A non-soaked control was compared with seeds primed for 2, 4, 6, 8 hours in plain water (hydropriming) or in solutions containing the following concentration of polyethylene glycol (PEG 6000) and potassium nitrate (KNO3): a) PEG at -0.5, -0.9 and -1.7 MPa; b) KNO3 at -0.12, -0.24 and -0.52 MPa. After soaking, seeds were rinsed and placed in petri-dishes at 20 or 27°C germination temperature. Pre-sowing treatments affected the germination percentage more than the mean time of germination, and the effects were more evident in RCh and when 20°C germination temperature was applied. Generally, the higher germination percentage was obtained with longer hydropriming (6-8 hrs) and with short treatment (2 hrs) with osmotic compounds. KNO3 proved to be less effective than PEG which gave, on average, the best results at -0.5 and -0.9 MPa water potential
The use of SPAD-502 chlorophyll meter for dynamically optimising the nitrogen supply in potato crop: A methodological approach
No full textThe management of N fertilization through a method called "dynamic optimisation of nitrogen supply" requires the assessment of crop nitrogen status throughout the growing season. A tool for plant analysis, that aroused interest recently, is the hand-held chlorophyll meter SPAD-502 (Minolta - Japan), which permits prediction of leaf nitrogen status from measurements of chlorophyll content in potato. For practical use of this instrument, it is necessary to develop threshold values, above which no increase in yield would be expected. A procedure for the calculation of chlorophyll meter threshold value was set using data obtained in a trial on potato conducted in 1997 at the Experimental Farm of the University of Padova at Legnaro, Italy. The trial was included in a long-term experiment on nitrogen fertilization carried out on different soil types. The experiment was carried out on 108 vegetation boxes of 4 m2 area (2x2 m) and 0.8 m depth. According to a randomised complete block design with 3 replicates, 6 increasing rates of N (0, 50, 100, 200, 300, 400 kg ha-1) were factorially combined with 3 soil types (clay, siltyloamy, sandy), in either presence or absence of residues of the previous wheat crop. Linear-plateau equations were developed for calculating the relationships between SPAD values and relative tuber yield and this equation allowed the calculation of STV (SPAD Threshold Value) which represents the limit below which a reduction in yield occurs. This paper describes the procedure step-by-step and gives STVs for potato cv. Primura
The use of SPAD-502 chlorophyll meter for dynamically optimizing the nitrogen supply in potato crop: A methodological approach
No full textThe management of N fertilization through a method called "dynamic optimization of nitrogen supply" requires the assessment of crop nitrogen status throughout the growing season. A tool for plant analysis, that increased interest recently, is the hand-held chlorophyll meter SPAD-502 (Minolta - Japan), which allows leaf nitrogen status from measurements of chlorophyll content in potato. The data from this instrument is necessary to calculate some threshold values below which N supply is necessary to avoid yield losses. A procedure for the calculation of chlorophyll meter threshold value was set using data obtained in a potato trial conducted in 1997 at the Experimental Farm of the University of Padova at Legnaro, Italy. The trial was included in a long-term experiment on nitrogen fertilization conducted on different soil types. The experiment was conducted on 108 vegetation boxes of 4 m2 area (2x2 m) and 0.8 m depth. A randomized complete block design was used with three replicates of six increasing rates of N (0, 50, 100, 200, 300, 400 kg ha-1) factorially combined with 3 soil types (clay, silty-loamy, sandy), in either the presence or absence of residues of the previous crop (wheat straws). Linear-plateau equations were developed for calculating the relationships between SPAD values and yield and this equation allowed the calculation of STV (SPAD Threshold Value) which represents the limit below which a reduction in yield occurs. The procedure described in this work appears to be suitable for supplementary N management in potato crop. It can be used very easily for decision making on time and rate of supplementary N to potato
The use of SPAD-502 chlorophyll meter for dynamically optimizing the nitrogen supply in potato crop: First results
No full textAn experiment was conducted on potato cv. 'Primura' to test the usefulness of SPAD threshold values in decision making for supplemental nitrogen supply in 2000. A non-fertilized control was compared with nine fertilized treatments receiving 30 kg ha-1 of N (urea 46% N) at crop emergence plus supplementary nitrogen which was applied as follows: i) five treatments provided increasing rates of N (30, 90, 150, 210 o 270 kg N ha-1, urea 46% N) distributed 18 days after emergence, (conventional fertilization, CF); ii) four treatments provided supplemental nitrogen application (urea, 46% N) when the SPAD values fell below the critical value of 39 SPAD (dynamic fertilization, DF). This critical level corresponds to 10% deviation from threshold value of 45-45 SPAD calculated in a previous work. Each time, increasing rates of N were distributed to the soil (30, 60 or 90 kg N ha-1 - 30 DF, 60 DF and 90 DF), or 9.2 kg N ha-1 was applied via foliar spray (foliar DF). In these treatments, the number of N applications and the total amount of N distributed to the crop were 4, 3, 3 and 5, and 120, 150, 210 and 76 kg N ha-1, respectively. Yield response to CF treatments were optimum with 180 kg N ha-1 (180 CF = 30+150 kg N ha-1). Yield of DF treatments did not differ from 180 CF. These results, particularly 30 DF and foliar DF treatments had amount of N distributed reduced by 30% and 60% as compared to 180 CF
Correction: Cyclophosphamide pulse regimen in the treatment of alveolitis in systemic sclerosis (Journal of Rheumatology (2002) 29 (731-736))
No full textCyclophosphamide pulse regimen in the treatment of alveolitis in systemic sclerosis. J Rheumatol 2002;29:731-6. The correct name of the co-author M. Proietti is Michele Proietti
First attempt to force gladiolus and liatris in a floating system
No full textAutumn crops of Gladiolus and Liatris were grown under a plastic greenhouse to compare a floating system technique (FST) with a control (C) represented by a traditional growing management (soil and solid fertilizers). The work was aimed at evaluating if FST is suitable for these crops and at studying the cut flower production response to various nutrient solutions, which were: only water (W), calcium nitrate (CN) (5 mol m-3), full-strength Hoagland (FH) and half-strength Hoagland (HH). On Liatris, aeration and no-aeration of solutions were also tested. Periodically, during the growing season, the observations regarded: plant height, relative amount of chlorophyll in leaves (SPAD values), date of flowering. At harvest, the qualitative traits of each spike were evaluated (whole stem and inflorescence length, floret number and visual score). Moreover, the fresh and dry weight and the total N content of plants were measured, as well as the composition of waste nutrient solutions. Crop response to FST varied with species. The Gladiolus performed better when grown on soil with a traditional production system (C), giving longer spikes than FST. FST proved to be suitable for Liatris cultivation and both Hoagland solutions gave taller stems, longer inflorescences and higher quality score, than the control (C). Plain water or calcium nitrate solution appeared to be not suitable for these species. Liatris plants behaved similarly in aerated and nonaerated solutions. In both species, the highest N plant content was observed in both Hoagland solutions, but waste HH solution showed a considerably lower concentration of nutrients
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