Drought and heat stresses are important threat limitations to plant growth and sustainable agriculture worldwide. Our objective is to provide a review of plant responses and adaptations to drought and elevated temperature including roots, shoots, and final yield and management approaches for alleviating adverse effects of the stresses based mostly on recent literature. The sections of the paper deal with plant responses including root growth, transpiration, photosynthesis, water use efficiency, phenotypic flexibility, accumulation of compounds of low molecular mass (eg proline and gibberellins), and expression of some genes and proteins for increasing the tolerance to the abiotic stresses. Soil and crop management practices to alleviate negative effects of drought and heat stresses are also discussed. Investigations involving determination of plant assimilate partitioning, phenotypic plasticity, and identification of most stress-tolerant plant genotypes are essential for understanding the complexity of the responses and for future plant breeding. The adverse effects of drought and heat stress can be mitigated by soil management practices, crop establishment, and foliar application of growth regulators by maintaining an appropriate level of water in the leaves due to osmotic adjustment and stomatal performance.
The growing world population and the necessity to meet its nutritional needs despite the limited area of agricultural land pose a serious challenge for agriculture. Agriculture is responsible for 80–95% of total ammonia emissions to the atmosphere, but at the same time it has great potential to reduce them. Fertilisation with mineral nitrogen (in particular urea) is responsible for 19.0–20.3% of total ammonia emissions emitted from agriculture. Ammonia emissions have a negative impact on the environment and human health, therefore it is important to minimize the volatilization of ammonia and increase fertiliser efficiency. This is important due to the need to mitigate the negative impact of anthropopressure on the environment in terms of air pollution, negative effect on soils and waters. The application of urease inhibitors during fertilisation with nitrogen fertilisers is one method to reduce ammonia emissions from plant production. Another option to achieve this goal is to reverse the global trend toward maximizing the production of energy crops (intensive fertilisation inevitably increasing ammonia emissions to the environment) for the production of biofuels, which is growing rapidly, taking up arable land that could be used for food production. The aim of the review is to identify the impact of recently introduced technologies for reducing ammonia emissions from urea on agricultural productivity, environment, and crops. It is of importance to reconsider optimization of crop production in arable land, possible owing to the progress in the production, modification, and application of mineral fertilisers and changes in crop structure. A broad debate is necessary with policymakers and stakeholders to define new targets allowing introduction of technologies for conversion of energy crops into energy with a minimal impact on food production and environmental issue.