Diversified crop rotations have been suggested to reduce grain yield losses from the adverse climatic conditions increasingly common under climate change. Nevertheless, the potential for climate change adaptation of different crop rotational diversity (CRD) remains undetermined. We quantified how climatic conditions affect small grain and maize yields under different CRDs in 32 long‐term (10–63 years) field experiments across Europe and North America. Species‐diverse and functionally rich rotations more than compensated yield losses from anomalous warm conditions, long and warm dry spells, as well as from anomalous wet (for small grains) or dry (for maize) conditions. Adding a single functional group or crop species to monocultures counteracted yield losses from substantial changes in climatic conditions. The benefits of a further increase in CRD are comparable with those of improved climatic conditions. For instance, the maize yield benefits of adding three crop species to monocultures under detrimental climatic conditions exceeded the average yield of monocultures by up to 553 kg/ha under non‐detrimental climatic conditions. Increased crop functional richness improved yields under high temperature, irrespective of precipitation. Conversely, yield benefits peaked at between two and four crop species in the rotation, depending on climatic conditions and crop, and declined at higher species diversity. Thus, crop species diversity could be adjusted to maximize yield benefits. Diversifying rotations with functionally distinct crops is an adaptation of cropping systems to global warming and changes in precipitation.

The aim of the study was to compare 10 winter triticale varieties according to their traits useful for cultivation in organic farming. The study was carried out in the years 2014–2017 in the experimental organic farm of the Institute of Soil Science and Plant Cultivation–State Research Institute in Pulawy (Poland). The highest-yielding varieties under organic conditions were Pizarro and Subito. Borowik cultivar showed the highest competitive ability against weeds. The highest number of weeds was found in the Leontyno cultivar, which was connected to the lowest plant density, the lowest weight of the above-ground parts of the canopy and smaller value of tillering coefficient. The most affected by the fungal pathogens Drechslera tritici-repentis (Died.) Shoem. and Puccinia striiformis Schwein. were Fredro and Algoso. Cluster analyses indicated that the most useful cultivars for cultivation in the organic system were: Borowik, Subito, and Tomko, which all showed higher yielding potential, bigger competitiveness against weeds, and average resistance against fungal pathogens. Pizarro, Tulus, and Twingo, which showed high resistance to fungal pathogens with lower competitiveness to weeds, were classified to the second group of usefulness. The least useful for the organic system were: Algoso, Fredro, Grenado, and Leontyno.

The aim of this paper was to evaluation functional diversity in rhizosphere soils of new quality varieties of winter wheat cultivation in organic farming. Field experiments were carried out in 2017 and 2018. Twelve commercial winter wheat varieties were selected for testing: Arktis, Bellisa, Estivus, Fidelius, Hondia, Jantarka, KWS Ozon, Linus, Markiza, Ostka Strzelecka, Pokusa, and Rokosz. Winter wheat cultivars were chosen for their high yielding potential and good tolerance to fungal diseases. In the plant production conducted in accordance with the principles of organic farming, the selection of the best quality varieties is a key element of agrotechnics. The samples of rhizosphere soils were collected each year in two seasons: spring and summer. The basic parameters of soil biological activities and microbial biodiversity indicators were determined. The high variability of biological activity and functional diversity of rhizosphere soils in the growing season between particular varieties of winter wheat was observed. The rhizosphere soils from varieties such as Bellisa, Arktis, Jantarka, Fidelius, Ostka Strzelecka, Pokusa, Rokosz and KWS Ozon were characterized by high biological activity and functional biodiversity. On the other hand, the soils collected from the varieties Estivus, Fidelius, Jantarkaand Hondia were characterized by medium and low biological activity and biodiversity indices. The highest yield was found in winter wheat varieties such as Bellisa, Fidelius and Jantarka. The results of these analyses allows for a more complete characterization of the yield potential of the tested varieties and their suitability for cultivation in the conditions of organic farming, taking into account the biological activity of soils.

In Poland, rapeseed production has been the fastest growing branch of plant production since 2000. Rapeseed yields have increased 2.5 times in the last 20 years. The main reason for this trend was the implementation of obligations resulting from legal acts by Member States relating to increasing the share of RES in the structure of primary energy production, and in particular relating to the share of biofuels in fuels used in transport. In Poland in the years 2010–2020, about 1.0–1.6 million tonnes of rape seeds were used for this purpose annually. Due to the fact that biofuel production competes for raw materials with the food economy, at the end of the first decade of the 21st century, many representatives of various circles intensified their voices, calling for withdrawal from the policy supporting the biofuel sector, which may have resulted in a decrease in oilseed plant cultivation areas. As a result of the research conducted here, it was determined that the place of oilseed rape in the sowing structure will be taken by rye, triticale and, on good soils, by wheat. Compared to rape, their production is characterised by lower income per 1 ha; in the years 2013–2019, these differences amounted to: wheat—8 EUR, triticale—102.3 EUR, and rye—168 EUR. This situation will deteriorate the value cereal cultivation sites and will result in a decrease in their yields. On the basis of the conducted research, the estimated value of rape as a forecrop for wheat, triticale, and rye was, respectively: 103.7; 64.6 and 46.7 EUR. An additional advantage of oilseed rape is that it is an excellent bee resource and is classified as a commodity crop, i.e., one from which significant amounts of honey can be obtained, with a net value of EUR 55 per hectare. In addition, in many agricultural holdings, as a result of forecasted changes in plant production, there will be an accumulation of field work during the harvest period, which will also affect the worse use of machinery and storage areas. The consequence of increasing the area under which cereal crops and their supply can grow may be the decline in production profitability and thus the income situation of farms, but this will be assessed at the next stage of research.

In the research carried out in 2018–2020 at the Plant Breeding and Acclimatization Institute, the vigor of seed potatoes from two production systems—organic and conventional—was examined. The characteristics of the tubers and the plants grown from them were assessed. It was found that seed potatoes from the organic system were characterized by features showing symptoms of weaker vigor, i.e., a shorter resting period, a smaller percentage of germinating eyes, a smaller mass of sprouts produced, and a shorter length of the longest sprout. The weaker vigor of seed potatoes from the organic system was reflected in the development and yield of the plants derived from them. It was expressed in weaker emergence, lower stem number, and smaller yield per plot. However, there were no differences in the yield structure. A large varietal differentiation was demonstrated for most of the studied traits. The differences in the vigor of individual cultivars were not related to the length of the growing season. The conditions prevailing in the research years had the greatest impact on the length of tuber dormancy, the percentage of germinating eyes, and the percentage of plant emergence.

A change in agricultural policy in the European Union aims, among other things, to halve the use of pesticides and increase the share of organic farming to 25% by 2030. One of the challenges associated with this target will be the control of plant fungal diseases. The key methods in organic farming include the selection of less susceptible crop varieties. In order to test this method, a long-term trial of organic farming in Eastern Poland was established. In total, 41 different winter wheat varieties were grown from 2018 to 2022 and their resistance to fungal leaf diseases was monitored. Brown rust was found to be the disease causing the highest infestation towards the end of vegetation, often exceeding 80% of the flag leaf area. However, yield reductions were mainly related to the severe occurrence of leaf Septoria. Other leaf diseases such as tan spot, yellow rust, powdery mildew, and fusariosis were of little importance and only occurred at low infestations of Septoria and brown rust. The course of the weather was found to have a significant effect on disease incidence. Drought occurring in May and June significantly increased the incidence of brown rust and Septoria, while prolonged rains increased tan spot and Fusarium infestation. Greater overall infestation occurred in years with high average temperatures. Ten varieties with high resistance to foliar fungal diseases were selected and can be recommended for organic farming.