Residual plastic film decreases crop yield and water use efficiency through direct negative effects on soil physicochemical properties and root growth.

Film mulching has been extensively used to improve agricultural production in arid regions of China. However, without sufficient mulch film recovery, large amounts of residual film accumulated in the farmland, which would affect crop yield and water use efficiency (WUE). In order to comprehensively analyze the effects of residual film on crop yield and WUE, and clarify its influencing mechanism, present study adopted a meta-analysis to systematically evaluate the impacts of residual film on soil physicochemical properties, crop root growth, yield, and WUE. The results showed that residual film significantly increased soil bulk density and the soil moisture content in 0-20 cm soil layer, but decreased soil porosity, soil organic matter, soil total nitrogen content, and soil moisture content in >20 cm soil layer, especially when residual film amount was >400 kg ha-1. Residual film significantly reduced crop root dry weight, root length, root diameter, root volume and root surface area. Generally, crop yield and WUE decreased with the increase of residual film amount; and crop yield was reduced by about 14.00 % when the residual film amount increased by 1000 kg ha-1. In average, crop yield and WUE under film residual condition were significantly decreased by 13.46 % and 9.21 %, respectively. The negative effects of residual film on root growth, yield and WUE were greater for cash crops (cotton, tomato and potato) than for cereal crops (wheat, maize). The structural equation model indicated that residual film generated indirect negative effects on crop yield and WUE by directly affecting soil physicochemical properties and crop root growth, with the standard path coefficients of -0.302 and - 0.217, respectively. The results would provide a theoretical basis for reducing residual film pollution on farmland and promoting the green and sustainable development of agriculture.

Legacy effects of wheat season organic fertilizer addition on microbial co-occurrence networks, soil function, and yield of the subsequent maize season in a wheat-maize rotation system.

Organic fertilizer can alleviate soil degradation. While numerous studies have explored the immediate impacts of organic fertilizer on soil properties and crop production, the legacy effects of organic fertilizer addition remain less understood. This research investigated the subsequent effects of organic fertilizer addition during the winter wheat season on soil microbial community structure, co-occurrence networks, soil function, and summer maize yield from 2018 to 2020. Six fertilization treatments were implemented as chemical nitrogen fertilizer (N) alone or combined sheep manure and nitrogen fertilizer (SMN) at low, medium, and high fertilization levels during the winter wheat season, with only N fertilizer applied during the maize season. The findings revealed significant variations in bacterial and fungal community structures between the SMN and N treatments. The SMN treatments increased the relative abundance of Proteobacteria, Actinobacteria, and Bacteroidetes and decreased the relative abundance of Rokubacteria, Acidobacteria, Gemmatimonadetes, Chloroflexi, and Nitrospirae compared to the N treatment. The SMN treatments had higher fungal network connectivity and lower mean path distance and modularity than the N treatment, resulting in heightened sensitivity of fungi to environmental changes. The legacy effects of organic fertilizer changed the functional potential of the N and C cycles, with keystone taxa such as Proteobacteria, Actinomycetes, Acidobacteria, Gemmatimonadetes, Bacteroides, and Ascomycota significantly correlating with functional genes related to the C and N cycles. Surprisingly, no significant differences in summer maize yield occurred between the SMN and N treatments. However, the random forest model revealed that the SMN treatments had significantly higher explanatory power of soil microbial community structure for maize yield (74.31%) than the N treatment (13.07%). These results were corroborated in subsequent studies and underscore the legacy effects of organic fertilizer addition on soil microbial communities. This research offers valuable insights into organic fertilizer use for enhancing soil quality and sustaining agricultural productivity.

Optimized tillage improves yield and energy efficiency while reducing carbon footprint in winter wheat-summer maize rotation systems.

Conventional tillage consumes a lot of energy and produces a lot of greenhouse gases (GHGs), with quite limited contribution to food production. Optimizing tillage practices is an important measure to save energy, protect the environment and increase productivity. Based on this concept, a field experiment of two years duration (2019-2021) was performed to assess the impacts of various tillage techniques on grain yield, energy balance, carbon footprint (CF), and economic benefits of a winter wheat-summer maize rotation system in the Loess Plateau of China. The treatments included conventional tillage (CT), no-tillage (NT), ridge cultivation with no-tillage (RNT), and occasional tillage (OT). This study is the first to evaluates the economic and environmental benefits of OT and RNT in dry farming. The total annual average greenhouse gas emissions calculated through the life cycle assessment are 2869.2-3407.6 kg CO2-eq·ha-1, and the energy consumption and output are 28.2-37.7 GJ ha-1 and 575.2-659.0 GJ ha-1, respectively. The net ecosystem economic benefit is 26,206.6-34,787.4 CNY ha-1. Compared with CT, annual crop yields of RNT, OT and NT have increased by 13.5%, 15.4% and 4.0%, respectively, energy utilization efficiency has increased by 47.8%, 31.2% and 35.3%, and carbon footprint has been reduced by 79.3%, 46.2% and 73.2%, economic efficiency has increased by 32.7%, 29.8% and 19.6%, respectively. Despite reducing energy consumption and carbon footprint, NT has no significant impact on annual crop yields. Optimizing tillage practices (RNT and OT) can achieve higher economic and environmental benefits. The Z-score shows that RNT in dryland agroecosystems can be used as a promising tillage practice to boost crop productivity, energy efficiency and economic efficiency, reduce CF, and achieve sustainability. RNT can be selected as the recommended agricultural management measure suitable for areas with similar climatic patterns in the Loess Plateau.

Conservation tillage improves the yield of summer maize by regulating soil water, photosynthesis and inferior kernel grain filling on the semiarid Loess Plateau, China.

BACKGROUND: Poor inferior kernel grain filling is a challenge that limits summer maize yield. The effect and mechanism of conservation tillage on improving grain filling of inferior kernel in semi-arid rained areas remain uncertain and there has been little research on tillage management integrated with straw mulching to improve soil water content and photosynthesis in the Loess Plateau region. A 2 year (2019-2020) field experiment was established to study the impact of tillage practices on soil water content and summer maize root system morphology, photosynthetic capacity, inferior kernel grain filling, and grain yield. Treatments included reduced tillage (RT), no tillage (NT), and conventional tillage (CT). RESULTS: Under RT and NT, the final 100-kernel weight and maximum and mean grain filling rates were higher than CT. Reduced tillage and NT increased soil water content at the jointing stage, silking stage and grain filling stage in comparison with CT. They increased root system morphology and dry matter accumulation, net photosynthetic rate, transpiration efficiency, and stomatal conductance in comparison with CT, and they also decreased intercellular CO2 concentration, and they increased chlorophyll content and above-ground dry matter accumulation in comparison with CT. Reduced tillage and NT increased evapotranspiration of maize, and ultimately, increased grain yield by 17% and 14%, respectively, in comparison with CT. CONCLUSION: Conservation tillage could promote summer maize photosynthetic capacity and grain filling of inferior kernels by regulating soil water content and root system morphology. © 2021 Society of Chemical Industry.

Removal of Ammonia Emissions via Reversible Structural Transformation in M(BDC) (M = Cu, Zn, Cd) Metal-Organic Frameworks.

NH3 is the most important gaseous alkaline pollutant, which when accumulated at high concentrations can have a serious impact on animal and human health. More importantly, NH3 emissions will react with acidic pollutant gases to form particulate matter (PM2.5) in the atmosphere, which also poses a huge threat to human activities. The use of adsorbents for NH3 removal from emission sources or air is an urgent issue. However, there are difficulties in the compatibility between high adsorption capacity and recyclability for most conventional adsorbents. In this work, a structural transformation strategy using metal-organic frameworks (MOFs) is proposed for large-scale and recyclable NH3 adsorption. A series of M(BDC) (M = Cu, Zn, Cd) materials can transform into one-dimensional M(BDC)(NH3)2 after NH3 adsorption, resulting in repeatable adsorption capacities of 17.2, 14.1, and 7.4 mmol/g, respectively. These MOFs can be completely regenerated at 250 °C for 80 min with no adsorption capacity loss. Besides, breakthrough and cycle tests indicate that Cu(BDC) and Zn(BDC) show good performance in the removal of low concentrations of NH3 from the air. Overall, combining the advantages of high adsorption capacity and recyclability due to the reversible structural transformation, Cu(BDC) and Zn(BDC) can be employed as ideal adsorbent candidates for NH3 removal.

Yield and gas exchange of greenhouse tomato at different nitrogen levels under aerated irrigation.

Significant global warming increases over the last century have resulted in recent research focused on practices to reduce greenhouse gas (GHG) emissions. Agricultural management practices, such as nitrogen (N) fertilization and aerated irrigation (AI), have significantly increased crop yields by improving soil water and fertilizer availability, and have been widely adopted in recent years. However, the interactive impact of different growing seasons and management practices in the greenhouse on GHG emissions is unclear. This greenhouse study was conducted during Spring and Autumn cultivation periods in Yangling, China with five N application rates (0, 50, 150, 200,250 kg ha-1) and two irrigation methods (AI and conventional irrigation [CK]). The results indicated that AI and N application both increased tomato yield, but also increased soil CO2 and N2O emissions. The temperature was 4 °C higher during Spring cultivation than during Autumn cultivation, which significantly (P < 0.05) increased soil emissions of CO2, N2O, and net GHG by 10.6%, 43.8%, and 12.3%, respectively. However, the yield in Spring cultivation only increased by 5.1% (P > 0.05). Thus, among the selectable cultivation seasons, the cooler season (Autumn) along with AI and 200 kg N ha-1, was recommended to farmers to avoid adverse effects of a warming environment. AI and 150 kg N ha-1 in Spring cultivation could be recommended as an alternative measure to local farmers. Our results suggest that in a future warmer climate, reducing nitrogen fertilizer rate in conjunction with the use of AI will remain important practices for maintaining crop yield while reducing soil net GHG emissions. There is an urgent need to transform current management practices to offset the negative impacts of climate change.