The distribution of Arion lusitanicus Mabille and the damage caused by the slug were studied in 1993-2009. A total of 38 sites were examined, characterised in terms of location, time of appearance and density of the slug, type and size of crops affected, and degree of damage to plants. At the start of the 1990s A. lusitanicus occurred only around Rzeszów and in the Sub-Carpathian region. In 1997 it started to appear in other regions of Poland. The rate of its spread was found to have increased significantly, particularly in the past few years. The slug mainly colonises urban areas (30 sites), and much less often -other areas (8 sites). The slug densities were the greatest in cultivations. The degree of damage done by the slug varied among plant species. Brassicas, lettuce, beetroot, carrots, beans, strawberries, numerous ornamental flower plants and some weeds were the most damaged. The increase in the spread of A. lusitanicus poses a serious threat to the biodiversity of native habitats and to garden-cultivated plants.
Operational research, i.e. searching for optimal solutions in a situation of uncertainty and risk, can also be used to support decisions to purchase expensive agricultural machinery. Although Polish farmers receive subsidies from the EU, it does not mean they do not need to make well-thought-out purchases, because wrong purchase decisions will have long-term consequences while using machinery. The article presents the results of the IFOP – the system which has been available on the Internet for several years. It collects data on farming machinery and vehicles based on users' voluntary but subjective opinions. The authors of this article developed an original multi-criteria method of evaluating the quality of these specific products, which enabled them to make relevant rankings of brands. It is an algorithmic-heuristic method, which uses pairwise comparison tools to determine the significance ratios of the criteria. This article presents the results of the 1
st
and 2
nd
IFOP edition (Race Ranking), which included several dozen brands of tractors registered in Poland. More than fifty qualitative (
Q
) and non-qualitative (
C
) traits of farm tractors were taken into account. According to Polish farmers, Valtra – a Finnish brand of farm tractors, part of the AGCO concern, was the most versatile (
Q
= 4.39 and
Q
&
C
= 4.23). These tractors received the best opinions for their functionality, durability, ergonomics and safety.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.