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it is necessary to apply a remote sensing-based system for rice cultivation assessment parallel with the field measurements of the crop biophysical parameters. This study aims to map the rice cultivated areas and give an estimate for the expected yield (ton/ha) using Sentinel-2 satellite data. The study was carried out in an experimental site in the Kafr El-Sheikh governorate with a total area of 3240 ha. The multi-temporal Normalized Difference Vegetation Index (NDVI) extracted from nine Sentinel-2 imagery cover the whole summer season. The supervised nearest neighborhood object-based classification method was employed, resulting in a classification map with an overall accuracy of 95% and a kappa coefficient of 0.93. Yield prediction was carried out by using an empirical yield prediction model using the NDVI and the Leaf Area Index (LAI). The LAI was calculated using the Surface Energy Balance Algorithm for Land (SEBAL) model and then validated against the measured LAI. the Mean Absolute Percentage Error (MPAE) was calculated to estimate the error between the measured and predicted LAI and yield. The MPAE was found to be ±6.76% (i.e. ±0.28 m2/m2) with a high correlation between the measured and the calculated LAI with a coefficient of determination (R2 = 0.94). While for the yield, the MPAE was found to be ±6.53% (i.e. ±0.66 ton/ha) and R2 of 0.95. This method is applicable to estimate area and yield of rice in the northern Nile delta in adequate time before harvest.

Soils on riverine floodplains in temperate climate may be characterized by a mollic epipedon, i.e. by dark colour, enhanced content of soil organic matter (SOM), high ‘base’ saturation and developed structure in the topsoil. We studied 124 soil samples from ten central/east European countries to investigate whether SOM in mollic horizons has similar chemical features. We determined carbon contents with a thermal-gradient method to differentiate SOM with varying thermal stability, and carbonates. We characterized SOM by diffuse reflectance infrared Fourier-transform (DRIFT) spectroscopy. According to the World Reference Base for Soil Resources, 102 of the samples fulfilled all criteria of a mollic horizon. Mollic features were not restricted to the uppermost horizon but also detected in buried former surface horizons. Soil colour was mostly the criterion to exclude non-mollic samples. Mollic and adjacent non-mollic horizons contained thermostable SOM, indicating SOM stabilized by interaction with minerals or as black carbon (BC), to very similar extent, up to 20.4% of total soil organic carbon (SOC). However, the correlation between the contents of thermostable SOC and total SOC, the SOC:N ratios of the thermostable fraction, and the smaller extent of metal complexation of carboxyl groups, pointed to a larger contribution of BC to SOM of mollic samples than to SOM in non-mollic samples. Thus, like in mollic horizons in Chernozems and Phaeozems not affected by fluviatile dynamics, SOM in mollic horizons of floodplain soils seemed to consist of SOM affected by natural or anthropogenic fires, constituting a common chemical feature of SOM. Thus, BC may contribute to soil colour and SOM stability in mollic horizons of floodplain soils. However, apart from BC contribution, SOM in mollic horizons of floodplain soils may have further pathways of formation and development, as SOM may be inherited from deposited material or form/transform by degradative or constructive processes. Supplemenatry material: [http://aspace.agrif.bg.ac.rs/handle/123456789/5999]

The purpose of this article is to analyze the changes in salinity of arable soils in the north of Crimea peninsula from 2013 to 2019 using Landsat 8 OLI satellite data in order to obtain additional and objective information about the modern state of soil secondary salinization processes. Comparison of the satellite data of 2013 and 2019 showed that in the area of the North-Crimean Canal there is both a slight expansion of the areas of saline soils and their reduction. The expansion of areas is observed mainly in the coastal zones of lakes and estuaries, and the reduction of areas in the fields, irrigation of which in the analyzed period did not stop. Both expansion and reduction of areas with saline soils did not exceed 10% of the study area. There is no evidence that the expansion of areas of saline soils during the analyzed period was due to the cessation of water supply to the North-Crimean canal.

Today, the global food security is one of the most pressing issues for humanity, and, according to Food and Agriculture Organisation (FAO), the increasing demand for food is likely to grow by 70% until 2050. In this current condition and future scenario, the agricultural production is a critical factor for global food security and for facing the food security challenge, with specific reference to many African countries, where a large quantities of rice are imported from other continents. According to FAO, to face the Africa’s inability to reach self-sufficiency in rice, it is urgent “to redress to stem the trend of over-reliance on imports and to satisfy the increasing demand for rice in areas where the potential of local production resources is exploited at very low levels” The present study was undertaken to design a new method for land evaluation based on soil quality indicators and remote sensing data, to assess and map soil suitability for rice crop. Results from the investigations, performed in some areas in the northern part of the Nile Delta, were compared with the most common approaches, two parametric (the square root, Storie methods) and two qualitative (ALES and MicrioLEIS) methods. From the qualitative point of view, the results showed that: (i) all the models provided partly similar outputs related to the soil quality assessments, so that the distinction using the crop productivity played an important role, and (ii) outputs from the soil suitability models were consistent with both the satellite Sentinel-2 Normalize Difference Vegetation Indices (NDVI) during the crop growth and the yield production. From the quantitative point of view, the comparison of the results from the diverse approaches well fit each other, and the model, herein proposed, provided the highest performance. As a whole, a significant increasing in R2 values was provided by the model herein proposed, with R2 equal to 0.92, followed by MicroLES, Storie, ALES and Root as R2 with value equal to 0.87, 0.86, 0.84 and 0.84, respectively, with increasing percentage in R2 equal to 5%, 6% and 8%, respectively. Furthermore, the proposed model illustrated that around (i) 44.44% of the total soils of the study area are highly suitable, (ii) 44% are moderately suitable, and (iii) approximately 11.56% are unsuitable for rice due to their adverse physical and chemical soil properties. The approach herein presented can be promptly re-applied in arid region and the quantitative results obtained can be used by decision makers and regional governments.

This experiment was conducted to investigate the effect of nano-fertilizer on seed germination and the first stages of bitter almond growth compared to other chemical fertilizers under saline conditions. In this regard, nuts were soaked in salt solutions of NaCl as 1, 3, and 5 ds m−1 for 48 h prior to stratification. Subsequently, the seeds were sown in perlite and treated by different concentrations of urea, ammonium sulfate, and nano-fertilizer at 0, 25, 50, and 100% for each fertilizer under different saline concentrations then stratified at 6 °C for 8 weeks. The treatments were arranged in a randomized complete block design in factorial experiment with three replicates and 25 seeds for each. Germination and first stages of growth measurements were estimated. Our results revealed that pre-treating seeds of bitter almond rootstock with 50% of nano-fertilizer under saline conditions markedly increased germination measurements, stem length and diameter, elongation of secondary and primary roots/plant, and number of secondary roots/plant relative to urea and ammonium sulfate fertilizers, thus throughout its vital role in increasing the moisture content of seed which in turn increased germination percentage and rate. Additionally, all the amount of nano-fertilizer was covered by plants via slow and continuous release of fertilizer, therefore producing stronger seedlings. Hence, we can conclude to use the nano-fertilizer nanourea modified with hydroxyapatite nanoparticles as a source for N, P, and Ca nutrients under saline conditions.

From 2011 to 2013 the MOCCCASIN project (MOnitoring Crops in Continental Climates through Asimillation of Satellite INformation) was carried out financed by the European Commission 7th Framework Programme. During the project, two field campaigns (2011 and 2012) were carried out at two sites (Odoyev and Plavsk) in the Tula region of Russia. During these two campaigns, observations were made at selected winter-wheat fields consisting of phenological stage, biomass samples, hemispherical photographs, spectral properties of the canopy and the soil as well as ancillary information about the field. Meteorological observations from synoptic and agrometeorological stations were collected from the stations in and surrounding the Tula region. Finally, a large trajectory throughout the whole Tula region was surveyed in order to collect fields with different crop types. Data access via doi 10.7910/DVN/CG0UQB.

We thank the authors for their thought-provoking comments on our paper. Most of the commentators agree that soil organic carbon (SOC) sequestration is important for improving the quality of soil, however they argue that we have overstated the potential of soil carbon sequestration. We welcome the comments and appreciate that the issue of SOC sequestration has always been somewhat factious (Schlesinger, 2000). We shall address the significance of the quantity “4 per mille”, reported sequestration rates, the limitation of carbon sequestration with time, and nutrient requirements. We clarify that our paper (Minasny et al., 2017) mainly deals with potentials for the 20 countries and regions, where SOC sequestration can also be seen as a way to improving the resilience of the soil to future climate change, that is, improving adaptation rather than mitigation. We believe that in some parts of the world where food security is threatened, the benefit of soil carbon management for adaptation should be stressed more than for mitigation. This is the reason why the 4 per mille initiative explicitly includes food security (Chabbi et al., 2017; Soussana et al., 2015). We need to add that the “4 per mille Soils for Food Security and Climate” initiative is just one of many national and global initiatives on SOC sequestration for mitigating climate change. The Intergovernmental Technical Panel on Soils (ITPS) of the Global Soil Partnership (GSP) discussed incorporating the topic of SOC in the IPCC Assessment Report (ARs), from AR6 onwards. The IPCC has also put a focus on soil in their upcoming special report “Climate Change and Land” (http://www.ipcc.ch/report/sr2/). The recent FAO Global Symposium (GSOC17) assembled experts engaged in FAO, GSP and its ITPS, IPCC, UNCCD-SPI and WMO activities to work together for the common goal of appropriate SOC management as part of overall sustainable soil management within the climate change mitigation and adaptation, sustainable development, Land Degradation Neutrality (LDN) and food security agendas (http://www.fao.org/about/meetings/soil-organic-carbon-symposium/en/). The Global Research Alliance on Agricultural Greenhouse Gases (GRA) focused on opportunities to reduce agricultural greenhouse gas emissions and increase soil carbon sequestration while still helping to meet food security objectives (http://globalresearchalliance.org/about/). The Common Agriculture Policy in the EU is currently being revised to include the potential use of SOC as an indicator. The 4 per mille initiative was launched at COP21, where the Paris Agreement was adopted, and one of the main aims of the Paris Agreement is to stop the planet from warming an additional two Celsius degrees. The two-degree target, although suggested by scientists through modelling work, was chosen more for political and pragmatic reasons whereby countries could agree on a target that they could work towards (Tollefson, 2015). And of course, there are many scientific critiques of this target (Knutti et al., 2016). Similarly, the 4 per mille initiative comes from a politically-driven aspiration, and our paper (Minasny et al., 2017) is a response to such an aspiration, to seek and outline possibilities based on current knowledge. The important concept is that soil and agriculture are part of the solution, and it is an interim and evidence-based solution that we can implement. Now we shall respond to each of the commentaries.

The digital elevation model based on SRTM is very convenient for a wide range of studies but requires correction due to the influence of forest vegetation. The present study was conducted to analyse the effect of boreal forests on altitudes, aspects and slopes calculated from the SRTM. A DEM based on topographic maps at 1:100 000 scale was used as a reference. The linear regression analysis showed low data correlation in forested areas. The presence of different types of forests and felling in the woods leads to a complex distribution of deviations from the SRTM. A simple correction method was proposed, using a forest mask, built according to Landsat, and forest heights indicated on the topographic maps. After correction, the correlation coefficient between the altitudes increased by 0.05–0.14, the share of matching aspects by 1–4% and the share of matching slopes by 2–8%.

Pollution of the urban environment by human disturbances and activities is a negative externality of urbanization, therefore becoming a great concern due to the serious problems associated with human health. The mobilization of heavy metals into the biosphere by human activities has become an important process in the geochemical recycling of these metals. Though the risks of exposure to road dust have been reported to be higher for individuals than those in soil, little attention has been paid to the occurrence characteristics of heavy metals in dust and its associated health risks to the population. In the present studies, the physical, chemical and spectral signatures gained from dust and soil constituents would be differentiated based on their reflectance in specific bands of the electromagnetic spectrum. It is expected that the analysis of road dust and soil samples will indicate spectral signatures exhibiting differences in specific wavelengths of the spectrum, hence, indicating their spectral discrimination, as well as the presence of heavy metals showing its reflectance based on its concentration. The expected outcome of this study can be used to provide a theoretical basis for controlling the risk of heavy metals exposure to population.

There was studied impact of the bitter almond seeds preliminary steeping on the development of plants at the first stages of development in conditions of saline waters irrigation in the greenhouse experiment ambient in phytotron. It was established that steeping the seeds in excessive salt solution results in enhanced plants tolerance to the soil salinization and saline waters irrigation. This is evidenced by the obtained regularities of influence on the development of plants of biochemical character (content of proline, chlorophyll and carotinoids, total carbon); chemical (content of basic chemical elements); morphological (rate of the plants height and stalk diameter growth, leaf-area duration). The introduction of developed technology into nursery science will permit to improve the tolerance of seedlings to salinization of soils and irrigation waters.

International audience; The ‘4 per mille Soils for Food Security and Climate’ was launched at the COP21 with an aspiration to increase global soil organic matter stocks by 4 per 1000 (or 0.4 %) per year as a compensation for the global emissions of greenhouse gases by anthropogenic sources. This paper surveyed the soil organic carbon (SOC) stock estimates and sequestration potentials from 20 regions in the world (New Zealand, Chile, South Africa, Australia, Tanzania, Indonesia, Kenya, Nigeria, India, China Taiwan, South Korea, China Mainland, United States of America, France, Canada, Belgium, England & Wales, Ireland, Scotland, and Russia). We asked whether the 4 per mille initiative is feasible for the region. The outcomes highlight region specific efforts and scopes for soil carbon sequestration. Reported soil C sequestration rates globally show that under best management practices, 4 per mille or even higher sequestration rates can be accomplished. High C sequestration rates (up to 10 per mille) can be achieved for soils with low initial SOC stock (topsoil less than 30 t C ha−1), and at the first twenty years after implementation of best management practices. In addition, areas which have reached equilibrium will not be able to further increase their sequestration. We found that most studies on SOC sequestration only consider topsoil (up to 0.3 m depth), as it is considered to be most affected by management techniques. The 4 per mille number was based on a blanket calculation of the whole global soil profile C stock, however the potential to increase SOC is mostly on managed agricultural lands. If we consider 4 per mille in the top 1m of global agricultural soils, SOC sequestration is between 2-3 Gt C year−1, which effectively offset 20–35% of global anthropogenic greenhouse gas emissions. As a strategy for climate change mitigation, soil carbon sequestration buys time over the next ten to twenty years while other effective sequestration and low carbon technologies become viable. The challenge for cropping farmers is to find disruptive technologies that will further improve soil condition and deliver increased soil carbon. Progress in 4 per mille requires collaboration and communication between scientists, farmers, policy makers, and marketeers.

Extreme heat waves and droughts are common natural disasters in European Russia. The frequency and severity of heat waves have been on the rise in recent decades across Europe—a trend that is projected to continue into the 21st century. These disasters have complex social, economic, and environmental consequences reaching beyond their geographical boundaries. The extreme heat wave of 2010 had global-scale impacts on food security and regional-scale impacts on ecosystem functioning, air quality, and health. The outcomes were exacerbated by the forestry management and crop rotation practices employed in the region. The century-long economic preference for fast-growing conifers resulted in large uniform single-species even-aged pine stands, which are at least 2.5 times more likely to support fire ignition and to spread than dark-coniferous or mixed stands. Although extreme conditions result in fires that burn through all forest types indiscriminately, uniform pine stands encourage rapid fire growth and spread to uncontrollable levels. Similarly, a recent focus on more economically profitable late-spring crops resulted in the long-term depletion of soil moisture from expanded sunflower and corn cropping, which resulted in decreased soil moisture storage across cultivated lands, leaving them vulnerable to even minor droughts. The major drought of 2010 led to widespread crop yield declines and failure; however, only 2 % of the fields with late-spring crops that were cultivated in 5 of 10 years were impacted by drought, versus 63 % of comparable fields where late spring crops were planted in 8 of the 10 years.

Legacy soil data have been produced over 70 years in nearly all countries of the world. Unfortunately, data, information and knowledge are still currently fragmented and at risk of getting lost if they remain in a paper format. To process this legacy data into consistent, spatially explicit and continuous global soil information, data are being rescued and compiled into databases. Thousands of soil survey reports and maps have been scanned and made available online. The soil profile data reported by these data sources have been captured and compiled into databases. The total number of soil profiles rescued in the selected countries is about 800,000. Currently, data for 117, 000 profiles are compiled and harmonized according to GlobalSoilMap specifications in a world level database (WoSIS). The results presented at the country level are likely to be an underestimate. The majority of soil data is still not rescued and this effort should be pursued. The data have been used to produce soil property maps. We discuss the pro and cons of top-down and bottom-up approaches to produce such maps and we stress their complementarity. We give examples of success stories. The first global soil property maps using rescued data were produced by a top-down approach and were released at a limited resolution of 1 km in 2014, followed by an update at a resolution of 250 m in 2017. By the end of 2020, we aim to deliver the first worldwide product that fully meets the GlobalSoilMap specifications.