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The intensification of specific land management operations (tillage, herbicide, etc.) is increasing land degradation and contributing to ecosystem pollution. Mulches can be a sustainable tool to counter these processes. This is particularly relevant for rural areas in low-income countries where agriculture is a vital sector. In this research, the environmental impact of different rates of wheat residues (no residues, 25, 50, 75, and 100%) in corn silage cultivation was evaluated using the life cycle assessment (LCA) method under conventional tillage (CT) and no-tillage (NT) systems in a semi-arid region in Karaj, Iran. Results showed that in both tillage systems, marine aquatic ecotoxicity (ME) and global warming potential (GWP) had the highest levels of pollution among the environmental impact indicators. In CT systems, the minimum (17,730.70 kg 1,4-dichlorobenzene (DB) eq.) and maximum (33,683.97 kg 1,4-DB eq.) amounts of ME were related to 0 and 100% wheat residue rates, respectively. Also, in the CT system, 0 and 100% wheat residue rates resulted in minimum (176.72 kg CO2 eq.) and maximum (324.95 kg CO2 eq.) amounts of GWP, respectively. However, in the NT system, the 100% wheat residue rate showed the minimum amounts of ME (11,442.39 kg 1,4-DB eq.) and GWP (120.21 kg CO2 eq.). Also, in the NT system, maximum amounts of ME (17,174 kg 1,4-DB eq.) and GWP (175.60 kg CO2 eq.) were observed with a zero wheat residue rate. On-farm emissions and nitrogen fertilizers were the two factors with the highest contribution to the degradation related to environmental parameters at all rates of wheat residues. Moreover, in the CT system, the number of environmental pollutants increased with the addition of a higher wheat residue rate, while in the NT system, increasing residue rates decreased the amount of environmental pollutants. In conclusion, this LCA demonstrates that the NT system with the full retention of wheat residues (100%) is a more environmentally sustainable practice for corn silage production. Therefore, it may be considered one of the most adequate management strategies in this region and similar semi-arid conditions. Further long-term research and considering more environmental impact categories are required to assess the real potential of crop residues and tillage management for sustainable corn silage production. [ABSTRACT FROM AUTHOR]

Agricultural activity is the major anthropogenic source of nitrous oxide (N2O) emissions from terrestrial ecosystems. Conservation agriculture including crop residue management can play a key role in enhancing soil resilience to climate change and mitigating N2O emissions. We investigated the effects of crop residue rates, including 100 % (R100), 50 % (R50), and residue removal (R0), on N2O emissions in corn-wheat rotation under conventional (CT) and no-tillage (NT) systems. The key factors evaluated affecting N2O emissions included soil temperature, soil moisture, soil ammonium, and soil nitrate concentrations. Results showed that the N2O emissions increased with the increasing rate of residue under both CT and NT systems. Both R100 and R50 significantly (p <.05) increased the N2O emissions compared to R0 during the annual rotation cycle. Soil moisture and mineral nitrogen (ammonium and nitrate) were the main driving factors that stimulated N2O emission in both CT and NT systems. In the NT and CT systems, cumulative N2O emissions showed a significant increase with R50 (+75.5 % in NT, +36.5 % in CT) and R100 (+134 % in NT, +40 % in CT) as compared to R0. Furthermore, no significant differences were found between R100 and R50 in the CT system, while in the NT system significant increases were observed for R100 compared to R50. Overall, our study justified as a first approach only during the first year that crop residue removal led to decreased N2O emissions under semi-arid conditions. However, due to the deteriorating impact of crop residue removal on crop productivity and soil C sequestration, this management method cannot be considered a sustainable agronomic practice. We suggest long-term studies to determine the appropriate rate of postharvest crop residue to achieve less N2O emissions and climate-friendly agricultural practices. [ABSTRACT FROM AUTHOR]

Soil loss from root crops is an increasingly significant problem studied for some species, such as potatoes, sugar beets, carrots, celery, and onions. It reduces soil fertility and, subsequently, soil productivity. For leek (Allium porrum) and groundnut (Arachis hypogaea), however, there is little information to date. More research on this topic could help farmers reduce the process of soil degradation. In some countries, such as Turkey, the production of these crops is perennial to supporting rural communities and ensuring food security. Therefore, it is important to quantify soil losses from leek and groundnut crops in Turkey. This study investigated the factors affecting soil losses and the cost of nutrients lost with the transported soil by analyzing randomly selected plants from 45 harvested leek and groundnut plots. Our results showed that soil losses reached 3.99 Mg ha−1 per harvest for leek and 1.04 Mg ha−1 for groundnut. Prevailing soil moisture explained 59% of the variability in the leek harvest and soil texture and bulk density for leek yield at harvest. In the groundnut harvest, 53% of the variability was explained by antecedent soil moisture and clay fraction for the groundnut yield at the time of harvest. The estimated annual cost of nutrients losses was $US 3.75 ha−1 for leek and $US 0.76 ha−1 for groundnut. It can be concluded that leek and groundnut harvesting causes soil and nutrient losses with considerable economic costs. Therefore, awareness should be raised among farmers and users. In addition, policymakers should consider the management of soil loss by crop harvesting (SLCH) processes. [ABSTRACT FROM AUTHOR]

Appropriate management of crop residue plays a key role in mitigating greenhouse gas emissions. However, it has been inadequately implemented in general agricultural management practices. In a field investigation using static chambers, we evaluated the effects of crop residue at three different rates - 100 % (R 100), 50 % (R 50), and residue removal (R 0) - on carbon dioxide (CO 2) efflux. The field study was conducted in corn-wheat rotation under conventional (CT) and no-tillage (NT) systems in a semi-arid region. The main results showed that CO 2 efflux was positively correlated with higher soil temperature (0.43–0.79) and microbial biomass carbon (0.66–0.89). The crop residue treatments affected these traits. A strong positive relationship between CO 2 efflux and the crop residue (R2 = 0.96, CT and R2 = 0.9 for NT) was observed. In the CT system, significant increases were detected among residue rates on cumulative CO 2 efflux, where R 100 and R 50 resulted in 36 % and 25 % higher cumulative CO 2 efflux, respectively, than R 0. In contrast, there was no significant difference in cumulative CO 2 efflux among the crop residue retention (R 100 and R 50) and removal (R 0) treatments under the NT system. Our study revealed that crop residue retention led to increased CO 2 efflux under the CT system in semi-arid conditions during the first year of application, while under the NT system, CO 2 efflux was not impacted by crop residue. Our results indicate that there is considerable potential for improving soil management practices in the context of soil degradation, climate change, increasing crop productivity, and carbon (C) sequestration. • CO 2 emissions are correlated with soil temperature and microbial biomass carbon as well as with crop residue. The crop residue treatments affect these traits. • Full retention of crop residue mitigates CO 2 emissions under the no-tillage system. • The implementation of the results improves the conservation of soils' productivity, and fights climate change. [ABSTRACT FROM AUTHOR]