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.

The rapid increase of the world population constantly demands more food production from agricultural soils. This causes conflicts, since at the same time strong interest arises on novel bio-based products from agriculture, and new perspectives for rural landscapes with their valuable ecosystem services. Agriculture is in transition to fulfill these demands. In many countries, conventional farming, influenced by post-war food requirements, has largely been transformed into integrated and sustainable farming. However, since it is estimated that agricultural production systems will have to produce food for a global population that might amount to 9.1 billion by 2050 and over 10 billion by the end of the century, we will require an even smarter use of the available land, including fallow and derelict sites. One of the biggest challenges is to reverse non-sustainable management and land degradation. Innovative technologies and principles have to be applied to characterize marginal lands, explore options for remediation and re-establish productivity. With view to the heterogeneity of agricultural lands, it is more than logical to apply specific crop management and production practices according to soil conditions. Cross-fertilizing with conservation agriculture, such a novel approach will provide (1) increased resource use efficiency by producing more with less (ensuring food security), (2) improved product quality, (3) ameliorated nutritional status in food and feed products, (4) increased sustainability, (5) product traceability and (6) minimized negative environmental impacts notably on biodiversity and ecological functions. A sustainable strategy for future agriculture should concentrate on production of food and fodder, before utilizing bulk fractions for emerging bio-based products and convert residual stage products to compost, biochar and bioenergy. The present position paper discusses recent developments to indicate how to unlock the potentials of marginal land.

In view of modern worldwide research carried out in the context of broadly understood soil chemistry and monitoring of the natural environment, the methods of assessing the risk of Zn contamination in soil and agricultural crops based on the analyses of Zn concentration in the soil solution have gained more recognition. Accordingly, research on the evaluation of the effects of selected soil properties on changes in solid/solution partitioning coefficient (K d ), the total concentration and activity of zinc in the soil solution was undertaken in this study. The study was based on the microplot field experiment. Investigated soil factors were as follows: soil texture, pH, organic carbon content and the degree of Zn contamination. The results indicated that zinc activity in the soil solutions was very high and comparable to the total concentration of zinc. The investigated soil properties significantly influenced the K d , the total concentration of zinc, as well as the concentration of Zn 2? in the soil solution. The total concentration and activity of zinc in the soil solution increased with increasing Zn content in the soil and rising soil acidity, while they decreased with increasing the content of organic carbon and clay particles. The values of K d increased significantly with rising soil pH and total Zn content and decreased with increasing soil organic content. Observed K d values were significantly higher in soil with 13 % clay than in soil with 7 % clay.

The effects of mineral and organic fertilization on the contents of Fe, Cu, Zn, Mn, B and Mo in soil and in the soil solution as well as on availability of these elements for crops were investigated in the long-term field trial. The highest contents of Zn, Fe, Mn and Cu in soil and soil solution were observed in the treatment with the lowest pH (NPK). In this same combination the content of B and Mo was the lowest. The concentration of Zn, B and Fe in the soil solution significantly increased under farmyard manure application. Liming significantly decreased contents extractable by 1 mol/L HCl forms of Mn and Zn and significantly increase the content of Mo in the soil. Regardless of fertilization applied, microelement concentrations in the soil solution are sufficient for fulfilling nutritional needs of plants cultivated during the trial.

Under the conditions of a long‐term fertilizer experiment, this study aimed to determine the contents of total and exchangeable aluminium in soil as well as the Al concentration in the soil solution. Additionally, Al speciation was evaluated with the use of the MINTEQA2 software. The results obtained indicated that under the conditions of long‐term application of different mineral fertilizers or farmyard manure, the soil reaction changed to a great extent (pH 3.58–6.78). At the same time, the content of total Al in soil fluctuated from 18.85 to 22.13 g/kg and that of exchangeable Al ranged from 1.42 to 102.66 mg/kg. The concentration of Al in the soil solution was highly differentiated (5.19–124.07 μmol/L) as well as that of free aluminium ions (Al3+) (0–16.9 μmol/L). In acidic soils, aluminium complexes with organic matter are the predominant forms of Al in the soil solution. In soils with neutral soil reaction, there were no free aluminium ions. Soil liming and addition of organic amendment were the treatments that restricted the presence of toxic aluminium forms in soil.