Recycling agricultural residues in organic farming by on-farm compost production

This practice abstract was elaborated in the BIO4FOOD project: the project is running from November 2020 to October 2023, and is to contribute to reducing crop wastes providing natural protection products, vegetables rich in health-promoting minerals and biofertilizers

Effectiveness of Organic Wastes as Fertilizers and Amendments in Salt-Affected Soils

Excessive salt rate can adversely influence the physical, chemical, and biological properties of soils, mainly in arid and semi-arid world regions. Therefore, salt-affected soils must be reclaimed to maintain satisfactory fertility levels for increasing food production. Different approaches have been suggested to solve these issues. This short review focuses on selected studies that have identified organic materials (e.g., farmyard manures, different agro-industrial by-products, and composts) as effective tools to improve different soil properties (e.g., structural stability and permeability) in salt-affected soils. Organic fertilization is highly sustainable when compared to other options to date when taken into consideration as a solution to the highlighted issues. However, further experimental investigations are needed to validate this approach in a wider range of both saline and sodic soils, also combining waste recycling with other sustainable agronomic practices (crop rotations, cover crops use, etc.)

Towards a Better Understanding of Agronomic Efficiency of Nitrogen: Assessment and Improvement Strategies

Agronomic N-use efficiency is the basis for economic and environmental efficiency, and an effective agro-ecosystem management practice, improving nutrient use efficiency, is a crucial challenge for a more sustainable production of horticultural, industrial and cereal crops. However, discrepancy between theory and practice still exists, coming from large gaps in knowledge on net-N immobilization/mineralization rates in agro-ecosystems, as well as on the effects of indigenous and applied N to crop response. A more thorough understanding of these topics is essential to improve N management in agricultural systems. To this end, the present Special Issue collects research findings dealing with different aspects of agronomic efficiency of N in different agro-ecosystems, and environmental impact derived from fertilization management practices. In particular, the Special Issue contains selected papers, which concern a wide range of topics, including analyzing tools, options of management, calculation equation and modeling approaches

Long-term effects of organic amendments on soil fertility. A review

Common agricultural practices such as excessive use of agro-chemicals, deep tillage and luxury irrigation have degraded soils, polluted water resources and contaminated the atmosphere. There is increasing concern about interrelated environmental problems such as soil degradation, desertification, erosion, and accelerated greenhouse effects and climate change. The decline in organic matter content of many soils is becoming a major process of soil degradation, particularly in European semi-arid Mediterranean regions. Degraded soils are not fertile and thus cannot maintain sustainable production. At the same time, the production of urban and industrial organic waste materials is widespread. Therefore, strategies for recycling such organic waste in agriculture must be developed. Here, we review long-term experiments (3–60 years) on the effects of organic amendments used both for organic matter replenishment and to avoid the application of high levels of chemical fertilizers. The major points of our analysis are: (1) many effects, e.g. carbon sequestration in the soil and possible build-up of toxic elements, evolve slowly, so it is necessary to refer to long-term trials. (2) Repeated application of exogenous organic matter to cropland led to an improvement in soil biological functions. For instance, microbial biomass carbon increased by up to 100% using high-rate compost treatments, and enzymatic activity increased by 30% with sludge addition. (3) Long-lasting application of organic amendments increased organic carbon by up to 90% versus unfertilized soil, and up to 100% versus chemical fertilizer treatments. (4) Regular addition of organic residues, particularly the composted ones, increased soil physical fertility, mainly by improving aggregate stability and decreasing soil bulk density. (5) The best agronomic performance of compost is often obtained with the highest rates and frequency of applications. Furthermore, applying these strategies, there were additional beneficial effects such as the slow release of nitrogen fertilizer. (6) Crop yield increased by up to 250% by long-term applications of high rates of municipal solid waste compost. Stabilized organic amendments do not reduce the crop yield quality, but improve it. (7) Organic amendments play a positive role in climate change mitigation by soil carbon sequestration, the size of which is dependent on their type, the rates and the frequency of application. (8) There is no tangible evidence demonstrating negative impacts of heavy metals applied to soil, particularly when high-quality compost was used for long periods. (9) Repeated application of composted materials enhances soil organic nitrogen content by up to 90%, storing it for mineralization in future cropping seasons, often without inducing nitrate leaching to groundwater

An Overview on Agroecology and Organic Agriculture Strategies for Sustainable Crop Production

Within the new “European Green Deal”, the European Commission defined crucial challenges for the agriculture of future decades, such as making food production more sustainable by considering the local pedo-climatic and socio-economic specificities [...

An Overview on Agroecology and Organic Agriculture Strategies for Sustainable Crop Production

Within the new “European Green Deal”, the European Commission defined crucial challenges for the agriculture of future decades, such as making food production more sustainable by considering the local pedo-climatic and socio-economic specificities [...

Environmental Sustainability Assessment of Horticultural Systems: A Multi-Criteria Evaluation Approach Applied in a Case Study in Mediterranean Conditions

An increasing interest and sensitivity of consumers and public opinion toward high-quality food products obtained with environmentally-friendly production methods has recently been detected. To this end, one of the key roles could be played by an environmental evaluation of the crop production. This research was performed to test a new multi-attribute decision model (DEXi-met) that is able to estimate the environmental sustainability of different agronomic practices in horticultural rotations. The model was used at the cropping system level on the basis of data from a long-term experiment in organic horticulture. It was tested on different cropping managements under climate change conditions. The DEXi-met mixed model (qualitative and qualitative basic attributes) generated four aggregated attributes to assess sustainability indicators (production capacity, soil, water and resources preservation, and biodiversity conservation) and the overall environmental sustainability. The model validation indicated that the introduction of agro-ecological services crops can increase the environmental sustainability of an organic cropping systems by promoting the whole soil–plant system equilibrium. The application of this tool could help maximize the efficient use of agronomical practices and quantify their environmental sustainability. DEXi-met could help agricultural advisors and policymakers schedule their decisions to find the right compromise between crop yield increase and the impact of agricultural activities

Mapping an Agricultural Field Experiment by Electromagnetic Induction and Ground Penetrating Radar to Improve Soil Water Content Estimation

A growing interest in proximal sensing technologies for estimating soil water content (SWC) will be highlighted. On this matter the objectives of this study were: (1) to use both the combined electromagnetic induction (EMI) sensor and Ground Penetrating Radar (GPR) to characterize an innovative field experiment located in southern Italy, in which different agricultural practices are tested, including a soil hydraulic arrangement; (2) to implement a geostatistical approach in order to merge different geophysical sensor data as auxiliary variables for SWC estimation. The multi-sensor recorded data were: (1) SWC data measured by gravimetric method; (2) Differential Global Positioning System height; (3) apparent electrical conductivity measured by an EMI sensor; (4) depths of soil discontinuities individuated by GPR radargrams interpretation; and (5) amplitude of GPR signal data at two different frequencies. Geostatistical techniques were used both to map all variables and improve the SWC estimation. The findings of this research indicate that: (1) the GPR radargrams identified four reflection events as a consequence of interfaces; (2) the EMI and GPR mapping provided identification of areas with high potential for water stagnation; and (3) the outputs of geophysical sensors can be effectively used as auxiliary tools to supplement the sampling of the target variable and to improve water content estimation

Repeated geophysical measurements in dry and wet soil conditions to describe soil water content variability

There is an increasing interest in the application of geophysical surveys to assess the soil water content (SWC) variation in both spatial and temporal scales. In this work, a geophysical survey was carried out at an experimental farm in dry and wet conditions. We determined the SWC data measured with the gravimetric method, apparent electrical conductivity by electromagnetic induction (EMI) and amplitude of Ground Penetrating Radar (GPR) data at different frequencies. Geophysical sensors are an efficient tool for soil mapping at high resolution; however; there is a need to improve the knowledge on their capabilities and limitations under field conditions, especially for GPR. The geophysical survey provides an example of the application of these techniques to evaluate the spatial variability of SWC in two different water conditions. The contribution of geophysical data in understanding the spatial variability of SWC was investigated applying both the traditional analysis and spatial techniques. The results indicated that the geophysical data captured the spatial variation of SWC in non-invasively way especially in dry condition. However, they also showed the complex interplay between factors controlling SWC and geophysical responses and the drawbacks of geophysical sensors under inhomogeneous water conditions. Our findings also highlighted that EMI survey provides the potential to map the SWC variability within a relatively short time. The results obtained in this research are important from the agronomical viewpoint, since they allow increasing efficiency of irrigation practices, which is important in times characterized by climate change