Limited effects of crop foliar Si fertilization on a marginal soil under a future climate scenario.

Growing crops on marginal lands is a promising solution to alleviate the increasing pressure on agricultural land in Europe. Such crops will however be at the same time exposed to increased drought and pathogen prevalence, on already challenging soil conditions. Some sustainable practices, such as Silicon (Si) foliar fertilization, have been proposed to alleviate these two stress factors, but have not been tested under controlled, future climate conditions. We hypothesized that Si foliar fertilization would be beneficial for crops under future climate, and would have cascading beneficial effects on ecosystem processes, as many of them are directly dependent on plant health. We tested this hypothesis by exposing spring barley growing on marginal soil macrocosms (three with, three without Si treatment) to 2070 climate projections in an ecotron facility. Using the high-capacity monitoring of the ecotron, we estimated C, water, and N budgets of every macrocosm. Additionally, we measured crop yield, the biomass of each plant organ, and characterized bacterial communities using metabarcoding. Despite being exposed to water stress conditions, plants did not produce more biomass with the foliar Si fertilization, whatever the organ considered. Evapotranspiration (ET) was unaffected, as well as water quality and bacterial communities. However, in the 10-day period following two of the three Si applications, we measured a significant increase in C sequestration, when climate conditions where significantly drier, while ET remained the same. We interpreted these results as a less significant effect of Si treatment than expected as compared with literature, which could be explained by the high CO2 levels under future climate, that reduces need for stomata opening, and therefore sensitivity to drought. We conclude that making marginal soils climate proof using foliar Si treatments may not be a sufficient strategy, at least in this type of nutrient-poor, dry, sandy soil.

Effect of Deep Placement Fertilization on the Distribution of Biomass, Nutrients, and Root System Development in Potato Plants.

The study was carried out in designed pots-rhizoboxes. Root systems were evaluated using computer scanning to determine total length, root area, and root diameter. The study showed a favorable effect of deep placement of fertilizers on total yield, increasing biomass yield by 7-17% relative to surface fertilization. The largest biomass increase under the influence of deep fertilization was obtained in the case of tuber yield, in which a yield increase of 18-34% was obtained. Higher yields of potato tubers were obtained under depth fertilization compared to surface application of fertilizers. Under the influence of deep fertilization at a depth of 20 cm, the uptake of nitrogen and phosphorus by potato biomass increased by 20-21%. Increased depth of fertilization increased the proportion of nitrogen accumulated in the tubers, while in the case of phosphorus, no effect of depth on P distribution was shown. An analysis of root system parameters showed a positive effect on increases in length and total root area under deep fertilization of potato plants. Based on the study, it was found that the distribution of dry matter, nutrients, and potato root development parameters were most optimal when fertilizer granules were applied at a depth of 20 cm.

Field assessment of organic amendments and spring barley to phytomanage a Cu/PAH-contaminated soil.

The INTENSE project, supported by the EU Era-Net Facce Surplus, aimed at increasing crop production on marginal land, including those with contaminated soils. A field trial was set up at a former wood preservation site to phytomanage a Cu/PAH-contaminated sandy soil. The novelty was to assess the influence of five organic amendments differing in their composition and production process, i.e. solid fractions before and after biodigestion of pig manure, compost and compost pellets (produced from spent mushroom substrate, biogas digestate and straw), and greenwaste compost, on Cu availability, soil properties, nutrient supply, and plant growth. Organic amendments were incorporated into the soil at 2.3% and 5% soil w/w. Total soil Cu varied from 179 to 1520 mg kg-1, and 1 M NH4NO3-extractable soil Cu ranged from 4.7 to 104 mg kg-1 across the 25 plots. Spring barley (Hordeum vulgare cv. Ella) was cultivated in plots. Changes in physico-chemical soil properties, shoot DW yield, shoot ionome, and shoot Cu uptake depending on extractable soil Cu and the soil treatments are reported. Shoot Cu concentration varied from 45 ± 24 to 140 ± 193 mg kg DW-1 and generally increased with extractable soil Cu. Shoot DW yield, shoot Cu concentration, and shoot Cu uptake of barley plants did not significantly differ across the soil treatments in year 1. Based on soil and plant parameters, the effects of the compost and pig manure treatments were globally discriminated from those of the untreated, greenwaste compost and digested pig manure treatments. Compost and its pellets at the 5% addition rate promoted soil functions related to primary production, water purification, and soil fertility, and the soil quality index.

Influence of the catchment area use on the water quality in the Utrata River.

The present paper discusses the impact of land use and seasons on the concentration of nutrients in the waters of the Utrata River (Pruszków Poviat, Mazowieckie Voivodeship) from April 2018 to March 2019. The pollution of rivers by nutrients is a major problem for society. Surface water is a source of drinking water, water used for industrial and agricultural purposes. With the increasing pollution of rivers, the purification process for these purposes becomes more expensive and more challenging. To assist in carrying out activities aimed at reducing the inflow of biogenic substances into large river systems and then down to the Baltic Sea, we analyzed the spatial and temporal dynamics of loads from the entire Utrata River catchment area. We divided the entire catchment area into three impact zones: grasslands and wastelands, urbanized areas, and agricultural land and examined changes in nutrient concentrations (total phosphorus, nitrate nitrogen, ammonium nitrogen) in each of the zones. The results were statistically processed using the 1-factor ANOVA method with the p-value of significance below 0.05. Research indicates an increase in the concentration of total phosphorus and nitrogen forms down the course of the river in urban and agricultural areas with persistently low concentrations of these biogenic substances in grasslands.

Relaunch cropping on marginal soils by incorporating amendments and beneficial trace elements in an interdisciplinary approach.

In the EU and world-wide, agriculture is in transition. Whilst we just converted conventional farming imprinted by the post-war food demand and heavy agrochemical usage into integrated and sustainable farming with optimized production, we now have to focus on even smarter agricultural management. Enhanced nutrient efficiency and resistance to pests/pathogens combined with a greener footprint will be crucial for future sustainable farming and its wider environment. Future land use must embrace efficient production and utilization of biomass for improved economic, environmental, and social outcomes, as subsumed under the EU Green Deal, including also sites that have so far been considered as marginal and excluded from production. Another frontier is to supply high-quality food and feed to increase the nutrient density of staple crops. In diets of over two-thirds of the world's population, more than one micronutrient (Fe, Zn, I or Se) is lacking. To improve nutritious values of crops, it will be necessary to combine integrated, systems-based approaches of land management with sustainable redevelopment of agriculture, including central ecosystem services, on so far neglected sites: neglected grassland, set aside land, and marginal lands, paying attention to their connectivity with natural areas. Here we need new integrative approaches which allow the application of different instruments to provide us not only with biomass of sufficient quality and quantity in a site specific manner, but also to improve soil ecological services, e.g. soil C sequestration, water quality, habitat and soil resistance to erosion, while keeping fertilization as low as possible. Such instruments may include the application of different forms of high carbon amendments, the application of macro- and microelements to improve crop performance and quality as well as a targeted manipulation of the soil microbiome. Under certain caveats, the potential of such sites can be unlocked by innovative production systems, ready for the sustainable production of crops enriched in micronutrients and providing services within a circular economy.

EPR Spectroscopy as a Tool to Characterize the Maturity Degree of Humic Acids.

The major indicator of soil fertility and productivity are humic acids (HAs) arising from decomposition of organic matter. The structure and properties of HAs depend, among others climate factors, on soil and anthropogenic factors, i.e., methods of soil management. The purpose of the research undertaken in this paper is to study humic acids resulting from the decomposition of crop residues of wheat (Triticum aestivum L.) and plant material of thuja (Thuja plicata D.Don.ex. Lamb) using electron paramagnetic resonance (EPR) spectroscopy. In the present paper, we report EPR studies carried out on two types of HAs extracted from forest soil and incubated samples of plant material (mixture of wheat straw and roots), both without soil and mixed with soil. EPR signals obtained from these samples were subjected to numerical analysis, which showed that the EPR spectra of each sample could be deconvoluted into Lorentzian and Gaussian components. It can be shown that the origin of HAs has a significant impact on the parameters of their EPR spectra. The parameters of EPR spectra of humic acids depend strongly on their origin. The HA samples isolated from forest soils are characterized by higher spin concentration and lower peak-to-peak width of EPR spectra in comparison to those of HAs incubated from plant material.

The influence of a dam reservoir on water quality in a small lowland river.

The paper presents the effects of the dam reservoir in Komorów on the water quality in the Utrata river. The implementation of the adopted objective involved a comparison of water quality at two points, above and below the reservoir. The Utrata River is polluted with biogenic compounds throughout the whole section studied. COD content also indicates significant contamination exceeding permissible limits. A positive effect of the reservoir on water quality in the river was also observed in terms of the content of dissolved oxygen, with concentration increasing below the reservoir. The reservoir had a positive effect on reducing the concentration of total phosphorus in the water. Water in the Utrata below the reservoir showed higher values of chemical oxygen demand (CODMn) than above the reservoir. There were no differences in the concentration of NH4+ and NO3- ions in the water before and after the reservoir.

Discussion paper: Sustainable increase of crop production through improved technical strategies, breeding and adapted management - A European perspective.

During the next decade it will be necessary to develop novel combinations of management strategies to sustainably increase crop production and soil resilience. Improving agricultural productivity, while conserving and enhancing biotic and abiotic resources, is an essential requirement to increase global food production on a sustainable basis. The role of farmers in increasing agricultural productivity growth sustainably will be crucial. Farmers are at the center of any process of change involving natural resources and for this reason they need to be encouraged and guided, through appropriate incentives and governance practices, to conserve natural ecosystems and their biodiversity, and minimize the negative impact agriculture can have on the environment. Farmers and stakeholders need to revise traditional approaches not as productive as the modern approaches but more friendly with natural and environmental ecosystems values as well as emerging novel tools and approaches addressing precise farming, organic amendments, lowered water consumption, integrated pest control and beneficial plant-microbe interactions. While practical solutions are developing, science based recommendations for crop rotations, breeding and harvest/postharvest strategies leading to environmentally sound and pollinator friendly production and better life in rural areas have to be provided.

Frequently asked questions about in vivo chlorophyll fluorescence: practical issues.

The aim of this educational review is to provide practical information on the hardware, methodology, and the hands on application of chlorophyll (Chl) a fluorescence technology. We present the paper in a question and answer format like frequently asked questions. Although nearly all information on the application of Chl a fluorescence can be found in the literature, it is not always easily accessible. This paper is primarily aimed at scientists who have some experience with the application of Chl a fluorescence but are still in the process of discovering what it all means and how it can be used. Topics discussed are (among other things) the kind of information that can be obtained using different fluorescence techniques, the interpretation of Chl a fluorescence signals, specific applications of these techniques, and practical advice on different subjects, such as on the length of dark adaptation before measurement of the Chl a fluorescence transient. The paper also provides the physiological background for some of the applied procedures. It also serves as a source of reference for experienced scientists.