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Open access

Józef Babik and Waldemar Kowalczyk

Determination of the Optimal Nitrogen Content in a Fertigation Medium for the Greenhouse Cucumber Grown on Slabs of Compressed Straw

In the years 2004-2008, research work was carried out whose aim was to determine the optimal nitrogen fertilization dose for greenhouse cucumbers grown on mats made of compressed, finely shredded straw. In the experiments, the short-fruited variety of the greenhouse cucumber, Milenium F1, was used. The level of nitrogen in the nutrient solution was varied in the range of 200-350 mg·dm-3. The nitrogen content in the solution in the amount of 200 mg·dm-3 was not sufficient and caused the cucumber yield to fall. The increasing N concentrations in the medium were found to have a significant effect on the nitrogen content in the indicator parts of cucumber plants. The highest nitrogen content was found in the plants fertilized with a nutrient solution containing the highest concentration of N-NO3, which was 350 mg·dm-3. Cucumber plants grown on straw need to be more intensely fertilized with nitrogen for about 1/3 of the growing season, and then to have its level in the fertigation medium reduced for the remaining part of the cultivation period.

Open access

Jacek Dyśko, Waldemar Kowalczyk and stanisław Kaniszewski

The Influence of pH of Nutrient Solution On Yield and Nutritional Status of Tomato Plants Grown in Soilless Culture System

The aim of the studies conducted in the years 2004-2006 was determination the influence of nutrient solution of different pH on the yield and nutritional status of tomato plants grown in soilless culture in organic and inert medium. Tomato plants were grown on slabs made of shredded rye straw and on slabs of peat and rockwool. The plants were fertilized with standard nutrient solution of different pH: 4.5, 5.0, 5.5, 6.0, 6.5. Nutrient solution pH and the kind of applied growing substrates were exerted significantly influence on the height of total and marketable yield of tomato cv. Blitz F1. Early yield was not depended on pH of nutrient solution and the kind of using substrates. The highest total and marketable yield was observed in tomato grown in rockwool slabs. For all the growing media, the highest yield of tomatoes was obtained after feeding the plants with the nutrient solution of pH 5.5. The kind of growing substrates and pH of nutrient solution were significantly differenced the nutritional status of tomato plants. Despite of considerable differentiation of means concentration of mineral nutrient in tomato leaves, the plant growth and development were proper. Concentration of mineral nutrients was comprised at the optimum range of nutritional status of tomato plants. The pH of nutrient solution at the range of 4.5-6.0 was not exerted significantly influence on nutritional status of tomato plants with nitrogen, potassium and magnesium. With the increase of the pH nutrient solution the average phosphorus, iron and manganese content was decreased. The higher concentration of nitrogen, calcium and magnesium was occurred in tomato plants cultivated in organic substrates than in rockwool. The phosphorus and manganese content was higher in the leaves of tomato plants grown in rockwool compared to those in the organic media. Tomato plants grown in the straw substrate contained lower concentrations of potassium and iron and more calcium in comparison to peat.

Open access

Urszula Smolińska, Beata Kowalska, Waldemar Kowalczyk and Marcin Horbowicz

Effect of Rape and Mustard Seed Meals on Verticillium wilt of Pepper

The effect of plant material from Brassicaceae plants - the mustard seed meal and rapeseed meal, added to soil or peat substrate, on Verticillium wilt of pepper was evaluated in laboratory and greenhouse conditions. It was stated that the addition of these materials decreased infestation of pepper vascular vessels caused by Verticillium dahliae. The decomposition of rapeseed meal and mustard seed meal increased concentration of ammonia, the compound toxic to many pathogens. The increase of total bacteria, actinomycetes, spore forming bacteria were also observed. The materials from Brassicaceae plants positive influenced on plant development and chlorophyll content in pepper leaves.

Open access

Urszula Smolińska and Waldemar Kowalczyk

Abstract

Soil with the spores of fungi in dormant stage from previous years infections belonging to the genus Fusarium caused significant loss of onion yield in Poland. The most important form of Fusarium inoculum in the field are chlamydospores, which may survive in soil for many years. There are no available methods to eradicate chlamydospores from soil environment. Inspired by data from the literature and own prelimi–nary observation, we evaluated the effect of application of Brassicaceae plant material to the soil infested with F. oxysporum and F. solani isolates, which are pathogenic to onion. Obtained results showed that addition of fresh plant material from B. juncea and B. alba had no effect on amount of Fusarium propagules in the soil. Moreover amendment of infested soil with dry plants or milled seeds of B. juncea or B. nigra significantly stimulated the population of Fusarium in the soil.

Open access

Stanisław Kaniszewski, Jacek Dyśko, Waldemar Kowalczyk, Jan Wojtysiak, Zbigniew Wrocławski and Katarzyna Dziedziczak

Effect of Nitration of Organic Materials on Nitrogen Availability and Yield of Tomato in Soilless Culture

In the cultivation of horticultural plants in greenhouses the most commonly used substrate is rockwool, while organic substrates are used in an unprocessed state. Cultivation in organic substrates, after they have been suitably processed, also makes it possible to obtain high yields at levels similar to those in rockwool cultures. Fibrous organic substrates, due to the wide C:N ratio, are characterized by high biological sorption towards nitrogen, causing N deficiency during the initial period of plant growth. In 2007-2009, a study was conducted, the aim of which was to determine the effect of nitration of fibrous organic substrates (sawdust, rye straw, flax shives) with nitric acid on nitrogen availability and the yields produced by tomato plants. The process of nitration of the organic substrates was carried out with the use of 10% HNO3. The appropriate pH of the substrates after the process of nitration was obtained by washing the substrates with water. As a result of nitration the levels of nitrogen fixed in lignin compounds and simpler polysaccharides increased to about 2%. Nitration of the organic substrates increased nitrogen availability to plants in the first five weeks of culture. Subsequently, the N-NO3 content in the nutrient solution collected from the nitrated substrates was at the same level as for the nonnitrated substrates. The yields produced by tomato plants depended on both the nature of the substrate and whether or not it had been nitrated with nitric acid. The most useful organic substrate for soilless culture, retaining good structure during the growing period, was the substrate of sawdust. The substrate of straw was found to undergo quick biodegradation, therefore its usefulness for soilless culture was low. The highest yield of tomato was obtained from the cultures on rockwool and on the nitrated sawdust substrate; the lowest yield was produced on the straw substrate.

Open access

Urszula Smolińska, Beata Kowalska, Waldemar Kowalczyk, Magdalena Szczech and Aleksandra Murgrabia

Abstract

Sclerotinia sclerotiorum (Lib.) de Bary is considered as one of the most harmful soilborne pathogens, which reduces productivity of horticultural crops. Currently used chemical or biological methods for the eradication of S. sclerotiorum from a soil are not very effective. The aim of this study was to evaluate the possibility of eradication of S. sclerotiorum sclerotia from a soil using the Trichoderma isolates, which were multiplied on the organic carriers prepared from agro-industrial wastes and by-products: WsA (wheat straw + apple pomaces), WsP (wheat straw + potato pulp) and T-GRAN (dry onion rind, apples and strawberry pomaces, rapeseed meal). The results showed that soil amendment with organic materials overgrown with the Trichoderma fungi had a significant reducing effect on S. sclerotiorum. Especially effective was the carrier WsA overgrown with T. virens TRS114, which completely prevented the survival of sclerotia of S. sclerotiorum regardless of the dose of application. Less effective was the WsP carrier. However, addition WsP overgrown with T. atroviride TRS40 at the 5% w/v, resulted in survival only 6.7% of sclerotia. In the greenhouse experiments with lettuce, the application of granulates T-GRAN into the soil had different impact on S. sclerotiorum depending on the conditions to the pathogen development. In conducive conditions, an addition of the organic substances without Trichoderma significantly decreased the yield of lettuce plants. A positive effect on the growth of plants was observed after the application of T-GRAN overgrown with Trichoderma.

Open access

Magdalena Szczech, Anna Szafirowska, Waldemar Kowalczyk, Justyna Szwejda-Grzybowska, Agnieszka Włodarek and Robert Maciorowski

Abstract

Application of beneficial bacterial strain B125 (Enterobacter sp.) and strain PZ9 (Bacillus sp.) in lettuce transplants production significantly enhanced seed germination and plant biomass. The best effect was obtained when the mixture of B125 and PZ9 was used. Combined application of these bacteria significantly increased transplants biomass, which was about 45% higher than that in the control. However, after planting these transplants in organic field, generally, there were no differences in yield and nutrient content in plants treated and not treated with the bacteria, except for nitrogen and vitamin C. The lettuce grown from transplants treated with bacterial mixture B125 + PZ9 contained significantly higher nitrogen than plants from other treatments. Opposite to nitrogen, bacterial applications decreased the amount of vitamin C. The growth and organic lettuce composition was affected by planting time. The yield was higher in spring, but the concentration of nutrients in these plants was lower than that in plants harvested in autumn. Climatic and light conditions in the late season were the reasons for increased dry matter content, minerals, phenolic compounds, and vitamin C, as well as high concentration of nitrates.