In the past 20 years, extreme weather events (atypical variations of temperature and precipitation in space and time) have increased in Bosnia and Herzegovina, the consequences being significant material damage and decreased crop yields. The aims of the current paper were to investigate the impact of climate change on yield, irrigation requirements and water productivity of maize grown in one of the most important agricultural regions of the country. It used the results of projections of the EBU-POM regional climate model (Eta Belgrade University – Princeton Ocean Model) for the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A1B, A2 and A1B > carbon dioxide (CO2), A2 > CO2 for the 2020s (2010–2039), the 2050s (2040–2069) and the 2080s (2070–2099), and it compared them with the reference period (1961–1990) using measured and modelled data. AquaCrop was calibrated for the study area using data from experimental studies. The model was applied in simulations of future cultivation scenarios considering different irrigation regimes and variations in precipitation, temperature, CO2 concentration and sowing date. The results of simulations indicate that in the 2020s, there will be no significant changes in irrigation needs and yield due to the earlier sowing date and overall shifting of the growing season early in spring. A slightly larger negative impact of climate change will occur by the 2050s and a larger one by the 2080s due to a reduction in precipitation in the summer months. Compared with the reference period, in the 2080s, irrigation requirements are expected to increase by almost 100% (from 100 to 200 mm) and to provide up to 30% greater yield. In the future, water productivity of maize will remain high and will be even greater than current levels for both rainfed and irrigated cultivation due to anticipation and shortening of the growing season, reduction in crop evapotranspiration and increase in CO2 concentration. Due to an increase in precipitation in early spring and its reduction in the May–June period, the blue-to-green water ratio will increase in the future with positive environmental connotations. The productive use of blue water will also increase.

The objective of the present study was to calculate an optimal harvest period for both fresh and ensiled samples of forage maize and to calculate a set of harvest dates (called a harvest window), for which the variety ranking of the fresh forage corresponds with the variety ranking at the optimal harvest period calculated from the ensiled forage. Forage maize is fed almost exclusively as silage, but official variety trials with silage maize determine quality parameters in fresh (i.e. non-preserved) forage. Eight silage maize varieties were monitored at six harvest dates (from 25 to 40% dry matter content) in Merelbeke (Belgium) in 2013–15. At each harvest date, fresh samples were taken and half of the sampled material was ensiled in micro silos for 20 weeks. An optimal harvest period was calculated based on frequently measuring starch concentration and organic matter digestibility for both fresh and ensiled forage. Eventually, harvesting the silage maize at a dry matter content of 32–35% guaranteed an optimal harvest period. Based on the results of eight varieties, reporting variety ranks without going through the ensiling process continues to be a scientifically justified practice in Belgian official variety trials. Varieties with a superior fresh quality keep their leading position after ensiling, but variety differences become smaller after ensiling.

Knowledge of different fractions and availability of boron (B) is essential while studying the response of crops to B. Fractionation provides information about the chemistry of B and quantifies its bioavailability. Such information is potentially valuable for predicting bioavailability, B leaching, dynamics, transformation between chemical forms in soils and environmental impacts. Total B (T-B) is quantified into five fractions: readily soluble (Rs-B), specifically adsorbed (Spa-B), oxide bound (Ox-B), organically bound (Org-B) and residual B (Res-B). Of these, Rs-B is the fraction present in soil solution and adsorbed weakly by soil particles, and is most readily available for plant uptake. It accounts for 1–2% of T-B. The second most plant available form is Spa-B; it may be adsorbed onto clay surfaces or associated with organic matter (OM) in soil. The remaining fractions, Ox-B, Org-B and Res-B, are unavailable for plant uptake. The major portion (generally 87·4–99·7%) of T-B is composed of Res-B. Overall, the relative proportion of B in various fractions is in the order of Res B > Org-B > Spa-B > Rs-B > Ox-B. Several factors such as soil pH, soil OM, clay minerals, iron and aluminium oxides and calcium carbonate content may change the relative proportion of B in various fractions and the transformations among different soil B fractions. Some of the B fractions are correlated with others and exhibit responses in terms of plant growth. Non-specifically adsorbed (Nsa-B) and Spa-B are positively and significantly correlated to some sub-fractions of Ox-B, such as B occluded in manganese oxyhydroxides (Moh-B). The most readily available forms of B for plants are Nsa-B, Spa-B and Moh-B.