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. Long-term trial was started in 2009, however, the data from 2016/2017, 2017/2018 and 2018/2019 growing seasons was used for this report. The highest average wheat yield was harvested in 2017 (7.17 t haE−1), and it was significantly (p is less than 0.001) higher than yields in 2018 and 2019 (on average 6.18 t haE−1 and 5.68 t haE−1, respectively). Crop rotation with winter wheat proportion 25%, in which faba bean was wheat fore-crop, showed the highest average grain yield (7.35 t haE−1), but the lowest yield was obtained in rotation with 100% wheat proportion (on average 5.52 t haE−1). Crop rotation scheme had a significant influence on the yield (p is less than 0.001) and 1000 grain weight (p is less than 0.001). Forecrop influenced the yield (p is less than 0.001), number of spikes per 1 square m (p is less than 0.001), and number of grain per spike (p=0.008) significantly. Soil tillage did not affect the studied parameters importantly. Conditions of the trial year affected all parameters significantly.

The present research was carried out to investigate the effects of different fertilizer treatments on grain yield and yield components of spring wheat (Triticum aestivum L.) ‘Harenda’ cultivar. The five treatments were as follows: control (standard NPK fertilization), standard NPK fertilization plus liquid NPK (10-11-11) fertilizer, standard NPK fertilization plus liquid NPK (10-11-11) fertilizer with microelements, standard NPK fertilization plus calcium micronized suspension fertilizer, and standard NPK fertilization plus Cu, Mn, Zn, Ca micronized suspension fertilizers. The field trials were conducted in 2017 at the Experimental Site of Institute of Soil Science and Plant Cultivation – State Research Institute in Puławy, Poland. Applications of calcium micronized suspension foliar fertilizer and a mixture of Cu, Mn, Zn, Ca micronized suspension fertilizers significantly increased grain yield of spring wheat, respectively by 44.5% and 38.6% in comparison with control (standard NPK fertilization). These fertilizer treatments also enhanced yield components of spring wheat. Moreover, micronized suspension fertilizers (Ca and the mixture of Cu, Mn, Zn, Ca) had a significant effect on ear number and thousand grain weight of spring wheat compared to control and NPK fertilizers. Liquid NPK and micronutrient-enriched NPK fertilizers had a significant effect on thousand grain weight compared to control.

Superabsorbents are hydrophilic polymers that can absorb large amounts of water. These studies show that the use of superabsorbent may significantly reduce the negative effects of drought stress on plants. However, their use in the field cultivation has so far been minimal. The price of hydrogels has recently decreased significantly. This was the reason for starting research described in this work, in which the experimental plant was the winter wheat cultivar ‘Lucullus’ – the cereal which is the most intensively cultivated in Poland. The field experiment was conducted in the years of 2014 – 2016, in the Agricultural Experimental Station (AES) in Osiny, Poland, in 4 repetitions. TerrahydrogelAqua was evaluated in the following doses: 1) control without hydrogel, 2) 10, 3) 20 and 4) 30 kg•haE-1. Before harvesting, the plant samples were taken to determine the yield structure elements. After harvesting, grain yield at 15% moisture content was determined. The influence of hydrogel on winter wheat grain yield varied in individual years. On average, the yield of wheat grain from the treatment with a dose of 30 kg•haE-1 of hydrogel was significantly higher than from the control treatment or the treatment with a dose of 10 kg•haE-1 of hydrogel. The mean values of yield structure features, i. e. ear grain yield and weight of thousand grain were the highest at the dose of 30 kg•haE-1 of hydrogel. The effect of hydrogel on the average number of plants and ears per unit area and on the number of grains per ear was not found.

In some regions of the world, there is a risk of limiting crop production due to the growing pressure of biotic and abiotic factors. It is mostly connected with the forecasted climatic changes. Hence, alternative methods for supporting plant growth are sought for, and among them, biostimulants can play a significant role. The three-year (2009 – 2011) field experiment with spring barley (Hordeum vulgare L.) was conducted in Poland to assess the response of grain yield, yield components, as well as the content and uptake of N, P and K in grain to differentiated times and to a dose of seaweed (Ecklonia maxima Osbeck) biostimulant Kelpak application. Preparation was applied in a dose of 2 L haE-1 at BBCH 22 (early treatment) or in a dose of 2 L haE-1 at BBCH 31 (late treatment), as well as two times, 1.5 L haE-1 each, in both phases. The study indicated that the biostimulant had a favourable effect on the root weight, grain number per spike, thousand grain weight and seed yield in early treatment as compared with the control. Early application also had a positive effect on N and P uptake in the grain yield. Favourable response of barley to the application of biostimulant shows the usefulness of the seaweed extract in the cultivation technology of this crop.