Weifeng Zhang

High yield and high nitrogen use efficiency are blocked by various abiotic stress, especially in arid, salinity and irrigation deficiency agricultural production system. While systematic solutions are crucial strategies, the translation of problem-solving approaches into field-scale practical applications remains insufficient. This study aimed at designing a high yield and high efficiency production system by combined enhanced-efficiency fertilizers (EEFs) and best agronomic practices. The effects were examined through a 3-years (from 2020 to 2022) maize field experiment in a typical region, Hangjinhou Banner, inner Mongolia, China. The results show that 15–18 Mg ha⁻¹ yield (80% of yield potential) can be realized under various stress conditions by adopted the new designed system. In this system, nitrogen (N) fertilizer input can be reduced from 380 kg ha⁻¹ (higher yield practice) to 250 kg ha⁻¹ (balance above-ground uptake), fertilization times can be reduced from 3 to 1, and the nitrogen use efficiency (NUE) can be increased to over 57.9%. The key is to reduce nutrient losses, prolong nutrient supply and control nutrient concentration by using enhanced efficiency fertilizer and increase crop yields from 13.5 to 15 Mg ha⁻¹.

Carbon peak and carbon neutrality are the top priorities for global sustainability1,2. However, the optimal strategy is unclear because minor attention has been given to smallholder farmers' activities. This study used farming data from 4547 smallholder farmers in 356 smallholder communities across China and life cycle assessment methods to evaluate carbon mitigation progress on three major grain crops in China between 2009 and 2019 and the carbon neutrality strategy for 2030 and 2060. The results showed that small farmers in China changed their practices of farming, i.e., from straw burning to straw retention in the soil between 2009 and 2019. These significant changes decreased the three crops' greenhouse gas (GHG) emission intensities by 56.2%. The estimated GHG mitigation at the national scale was 617 Tg CO2-eq in the ten-year period. The national actions for controlling straw burning were driven by the two-wheel innovation of technologies and policies. However, other low-carbon technologies have yet to be widely adopted due to insufficient innovations and have contributed less or even more negatively to carbon neutrality. Therefore, the current staple grain production system is still a net emitter. By transferring the successful approach from no straw burning to other farming practices, including nutrient management, tillage, irrigation, non-flooded aerobic rice and closing the yield gap, could lower the GHG intensity to -0.16, -0.16, -0.11 t CO2-eq t-1 for rice, wheat, and maize, respectively, achieving carbon neutrality in 2060. This research also implies that the involvement of multiple factors through integrated policies and technological innovation is critical to achieving carbon neutrality in grain production.

Cellulose, a kind of polymer containing abundant functional groups, has widespread use in the adsorptive removal of environmental pollutants. An efficient and environmental friendly polypyrrole (PPy) coating approach is employed to modify the agricultural by-product straw derived cellulose nanocrystal (CNC) into excellent property adsorbents for removing the heavy metal ion of Hg(II). The FT-IR and SEM-EDS results demonstrated that PPy is formed on the surface of CNC. Consequently, the adsorption measurements proved that the obtained PPy-modified CNC (CNC@PPy) possesses a remarkably enhanced Hg(II) adsorption capacity of 1095 mg g⁻¹, owing to a plentiful functional group of doped Cl element on the surface of CNC@PPy by forming Hg₂Cl₂ precipitate. The results of the study suggest that the Freundlich model is more effective than the Langmuir model at describing the isotherms, while the pseudo-second order kinetic model is better suited to correlating with the experimental data compared to the pseudo-first order model. Further, the CNC@PPy exhibits an outstanding reusability, capable of maintaining 82.3% of its original Hg(II) adsorption capacity after five successive adsorption cycles. The findings of this work reveal a method to convert the agricultural by-product into high performance environmental remediation materials.

Phosphorus is one of the important metabolic elements for living organisms, but excess phosphorus in water can lead to eutrophication. At present, the removal of phosphorus in water bodies mainly focuses on inorganic phosphorus, while there is still a lack of research on the removal of organic phosphorus (OP). Therefore, the degradation of OP and synchronous recovery of the produced inorganic phosphorus has important significance for the reuse of OP resources and the prevention of water eutrophication. Herein, a novel FeOOH-loaded aminated polyacrylonitrile fiber (PAN_AF-FeOOH) was constructed to enhance the removal of OP and phosphate. Taking phenylphosphonic acid (PPOA) as an example, the results indicated that modification of the aminated fiber was beneficial to FeOOH fixation, and the PAN_AF-FeOOH prepared with 0.3 mol L⁻¹ Fe(OH)₃ colloid had the best performance for OP degradation. The PAN_AF-FeOOH efficiently activated peroxydisulfate (PDS) for the degradation of PPOA with a removal efficiency of 99%. Moreover, the PAN_AF-FeOOH maintained high removal capacity for OP over five cycles as well as strong anti-interference in a coexisting ion system. In addition, the removal mechanism of PPOA by the PAN_AF-FeOOH was mainly attributed to the enrichment effect of PPOA adsorption on the fiber surface’s special microenvironment, which was more conducive to contact with SO₄•⁻ and •OH generated by PDS activation. Furthermore, the PAN_AF-FeOOH prepared with 0.2 mol L⁻¹ Fe(OH)₃ colloid possessed excellent phosphate removal capacity with a maximal adsorption quantity of 9.92 mg P g⁻¹. The adsorption kinetics and isotherms of the PAN_AF-FeOOH for phosphate were best depicted by pseudo-quadratic kinetics and a Langmuir isotherm model, showing a monolayer chemisorption procedure. Additionally, the phosphate removal mechanism was mainly due to the strong binding force of iron and the electrostatic force of protonated amine on the PAN_AF-FeOOH. In conclusion, this study provides evidence for PAN_AF-FeOOH as a potential material for the degradation of OP and simultaneous recovery of phosphate.

Apples have become a major source of income for smallholder farmers in Bohai Bay. However, the annual productivity of apples in the area is relatively low and the interannual yield gap varies drastically. Identifying the apple yield gap and interannual production constraints can potentially promote the sustainable development of apple production. Based on track monitoring data of 45 smallholder farmers from 2016 to 2018, the yield gap and constraint factors were determined by adopting boundary analysis methodology. The results showed that the yield potential of apples during 2016–2018 was 75, 108, and 87 t ha⁻¹, and actual yields were 36.8, 52.3, and 35.2 t ha⁻¹, respectively. The explainable yield gaps were 40.5, 56.9, and 55.1 t ha⁻¹. Soil, management, and climatic factors limit apple yield improvement. Among these, low temperatures during the bud break and flowering periods can induce yield losses. Soil nutrient content and fertilizer management are also important limiting factors that have polynomial relationships with yield. Too much fertilizer and high levels of nutrients in the soil have already caused yield losses in some fields. Sound scientific guidance to help farmers adopt reasonable management techniques adapted to climate change is necessary to close the yield gap.

Elevated inputs of nitrogen (N) fertilizer have played a key role in feeding an increasing global population, but also caused many environmental problems due to emissions of reactive N (Nr) to air and water worldwide, especially in China. To better understand the improvements to N management required to reduce impacts in China, we compiled a long-term N budget over the period 1961-2018, quantified historic changes in N inputs, crop uptakes and losses, and compared them with required N inputs to satisfy food security and critical N inputs to protect the environment in view of acceptable losses of ammonia to air and nitrate to water. Nitrogen inputs required to satisfy the food demand of China were 14, 21, 27 and 29 Tg N yr-1 in 1961, 1980, 2000 and 2018, respectively, while the actual N inputs were 4, 25, 39 and 48 Tg N yr-1, respectively, exceeding the required input after 1980. Since 2000, the actual N inputs also exceeded the critical N inputs in view of ammonia emissions to air (35 Tg N yr-1) and nitrate leaching to groundwater (28 Tg N yr-1) that are needed to protect biodiversity and human health. We show that a reduction in N input from 48 to 31 Tg N yr-1, which reconciles food production with environmental safety, can be achieved through the effective recycling of manure, balanced N fertilization and integrated soil-crop system management. Such a 'win-win' would improve air and water quality and protect the environment and human health through improved resource use efficiencies, reduced N fertilizer use and decreased Nr losses.

Compost represents an important input for sustainable agriculture, but the use of diverse compost types causes uncertain outcomes. Here we performed a global meta-analysis with over 2,000 observations to determine whether a precision compost strategy (PCS) that aligns suitable composts and application methods with target crops and growth environments can advance sustainable food production. Eleven key predictors of compost (carbon-to-nutrient ratios, pH and salt content electric conductivity), management (nitrogen N supply) and biophysical settings (crop type, soil texture, soil organic carbon, pH, temperature and rainfall) determined 80% of the effect on crop yield, soil organic carbon and nitrous oxide emissions. The benefits of a PCS are more pronounced in drier and warmer climates and soils with acidic pH and sandy or clay texture, achieving up to 40% higher crop yield than conventional practices. Using a data-driven approach, we estimate that a global PCS can increase the production of major cereal crops by 96.3 Tg annually, which is 4% of current production. A global PCS has the technological potential to restore 19.5 Pg carbon in cropland topsoil (0–20 cm), equivalent to 26.5% of current topsoil soil organic carbon stocks. Together, this points to a central role of PCS in current and emerging agriculture.