Reduced tillage is considered as one of the main tools to save biological diversity; however, it increases pressure of diseases, including wheat leaf blotches. The aim of present study was to clarify the impact of reduced soil tillage on the development of winter wheat leaf blotches in different schemes of crop rotation. The impact of different growing technologies on the severity of winter wheat disease was evaluated in a two-factorial experiment: A – soil tillage system, and B – different combinations of wheat pre-pre-crop and pre-crop (wheat, oilseed rape, barley and faba beans). Diseases were assessed every 10 days approximately and total impact of diseases was evaluated by calculating AUDPC (Area under Diseases Progress Curve). Tan spot, caused by Pyrenophora tritici-repentis was dominated disease over the long period, regardless of meteorological conditions. Development of Septoria leaf blotch was not influenced by neither crop rotation nor soil tillage. The level of tan spot was essentially higher after wheat, regardless of the pre-pre-crop. Reduced soil tillage promoted severity of tan spot. Ploughing mitigated effect of previous crops and differences in tan spot level were insignificant. Despite many positive effects of conservation tillage, increasing of fungicide treatment could be necessary, in conditions, when the tan spot is most devastating and widespread wheat disease.

Wheat (Triticum) grain is generally used for food due to its grain quality. The two-factorial trial was conducted in the Research and Study farm 'Pēterlauki', Latvia, with an aim of finding out the soil tillage and crop diversification in rotation effect on winter wheat grain yield and quality. Two soil tillage systems (traditional and reduced) and three crop rotation schemes with different winter wheat (Triticum aestivum) fore-crops (wheat, oilseed rape (Brassica napus ssp. oleifera), faba bean (Vicia faba)) were used. The trial started in 2009. For this paper data from 2016/2017 and 2017/2018 growing seasons was used. Yields harvested in 2017 were significantly (p<0.001) higher than those in 2018 (on average 7.17 t ha -1 in 2017, 6.18 t ha -1 in 2018). The highest yield (8.06 t ha -1 ) was gained in the variant where the fore-crop in 2017 had been faba bean. Crop rotation, including only repeated wheat sowings in both years, showed the lowest yield (on average 5.81 t ha -1 ). Crop rotation with oilseed rape and wheat showed a significant wheat yield increase in the following two-year period in comparison to to repeated wheat sowings. A year as a factor had a significant (p<0.05) impact on crude protein content (%), Zeleny index, volume weight (g L -1 ) and 1000 grain weight (g). Both, volume weight (g L -1 ) and 1000 grain weight, were influenced (p<0.05) by the crop rotation and forecrop. Zeleny index depended on all researched factors. Crude protein content was influenced by soil tillage method (p<0.0016) and fore-crop (p=0.0052). Hagberg falling number was not influenced by any of the investigated factors.

Wheat (Triticum) is one of the three most important field crops used for food in the world, as well as in Latvia. The two-factorial trial was conducted at the Research and Study farm 'Pēterlauki', Latvia, with the aim to find out the effect of soil tillage and crop rotation on winter wheat grain yield formation. Two soil tillage systems (conventional and reduced), and three crop rotations with different winter wheat (Triticum aestivum) proportion in it (100, 67 and 25%) and different fore-crops (wheat, oilseed rape (Brassica napus ssp. oleifera), faba bean (Vicia faba)) were used.

Conservative soil tillage is considered as the main tool to preserve soil fertility, to reduce gas emissions, and to save financial and labour resources. However, majority of researchers have found that different systems of reduced soil tillage increase the occurrence of slugs, weeds and diseases, including wheat diseases. The aim of the present study was to determine the impact of reduced soil tillage on the severity of winter wheat leaf blotches. The influence of different soil tillage systems and crop rotation on the severity of winter wheat disease was evaluated in a two-factorial experiment: A – soil tillage system (A1 – traditional soil tillage with ploughing at the depth of 22–24 cm); A2 – reduced soil tillage with disc harrowing up to the depth of 10 cm); and B – different crop rotations (B1 – continuous winter wheat; B2 – winter wheat and oilseed rape were grown; B3 – crop rotation). The severity of diseases was determined approximately every 10 days during the whole vegetation season, the total disease impact was estimated by calculating the area under the disease progress curve. Tan spot, caused by Pyrenophora tritici-repentis and Septoria tritici blotch, caused by Zymoseptoria tritici dominated in trials during the entire research period. Soil tillage is the most important factor promoting the development of tan spot, continuous wheat sowings also increased the severity of tan spot. The development of Septoria tritici blotch did not depend on the agronomic practice applied.

The most important reason for growing field crops is food consumption. Only some of the total amount of field crop species are mostly used for cultivation in the largest part of arable land. These crops ensure high economic income. This is the reason why biological diversity has decreased. Crop rotation is considered to be an instrument of sustainable cropping system and this is confirmed again nowadays. Higher cereal yields have been gained by including oil crops or pulses in the rotation. Each field crop has its own calorific value (MJ kg-1). Grains / seeds and above-ground biomass may have different calorific values because of their chemical composition. Research results from literature confirm that the average net calorific value of winter wheat (Triticum aestivum) and triticale (Triticosecale) grain and straw are ~17 MJ kg-1 , but the net calorific values for oilseed rape (Brassica napus ssp. oleifera) seeds and straw are-25.70 MJ kg-1 and 16.37 MJ kg-1 , respectively. Oilseed rape is also known as energyrich crop. It is reported that diversified crop rotations also have greater energetic productivity from above-ground biomass (grain / seed yield and by-products) if compared with crops grown in repeated sowings or in monoculture. Crop rotation in combination with different tillage methods (conventional tillage, reduced or minimum tillage and no-tillage) is the way to improve soil quality, but it is not clear whether the soil treatment method has a significant impact on the overall crop rotational energy productivity.