Mulching has become an important practice in modern field production. Plastics are the most widespread mulching materials, and especially black polyethylene is used almost everywhere due to its low price and proved positive results in production. Together with its still growing popularity, there is increasing concern about the environmental effects of using such vast amounts of plastics in agriculture without solutions for sustainable and safe disposal of the material. There have been several attempts to try to find safe and environmentally friendly alternative materials to replace plastic mulches. The use of biodegradable films is increasing because they can be left safely in the field after harvesting, but they are not very durable and are much more expensive than plastics. Another alternative is paper. This article reviews the published research on paper mulches and discusses the opportunity that they offer for solving the problems of the immense use of plastics in agriculture and the associated environmental threat. Different mulching materials have been used for different agricultural and horticultural species in different climatic environments, and results vary according to the chosen approach, growing practices, conditions and species, so generalizations are hard to make. One advantage of paper mulches is that they do not create the disposal problems that plastic films always and partially degradable bio-films often do in long-term use. Paper mulches break down naturally after usage and incorporate into the soil. Laying paper mulches in large scale farming is a problem to be solved. The quality of the paper needs to be adapted or improved for mulching purposes, and its price needs to be more competitive with that of plastic mulches. The review shows that there is considerable potential for using paper mulches in agriculture and horticulture.

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The effect of different paper mulches and two different biodegradable plastic mulches on the yield of field-grown cucumber (Cucumis sativus L.) was examined. The studies were conducted during two climatically different growing seasons 2011 and 2012 in Southern Finland. All the mulches increased the yield as compared to bare ground. In 2011, cucumbers on all the mulches with a dark upper surface produced higher yields than those on kraft paper alone. In 2012, when the average temperatures were lower than in 2011, there were no differences in yield between different types of mulches. Soil temperatures of the experimental plots were monitored throughout the growing seasons. The mulches with a dark-colored upper surface increased the soil temperature more than the ones with a light-colored upper surface. The soil warming effect of the mulches was greater during early season and diminished when the plants grew larger and their leaves covered most of the mulch surface. There was no need for weed control except in uncovered plots. In conclusion, during both years dark-colored paper mulch was comparable to biodegradable film in yield production and could replace it as a mulch material in cucumber production.

Meristems from 25 -90-year-old oak (Quercus robur L and Q. petraea Matt.) trees and seed embryos were pretreated with polyvinyl pyrrolidone, ascorbic acid, cysteine and citric acid solutions. Tissues were cultured mostly on a WPM medium supplemented with different combinations and concentrations of growth regulators. All the different pretreatments showed a positive effect against the otherwise very rapid and harmful browning of the explants, but ascorbic acid (100 mg dm -3) proved to be the most effective. Shooting was induced from seed embryos and meristems originating from adult trees. Rooted plantlets were obtained from explants of seed embryos.