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Maize, a staple crop in the North China Plain, contributed substantially to agricultural nitrous oxide (N 2 O) emissions in this region. Many studies have focused on various agricultural management measures to reduce N 2 O emissions. However, few studies have investigated soil N 2 O emissions in intercropping systems. The objective of the current study was to investigate whether maize–soybean intercropping treatments could reduce N 2 O emission rates compared with monoculture treatment. This issue was investigated in two differently configured maize–soybean intercropping treatments: 2:2 intercropping (2M2S) and 2:1 intercrop (2MS) including monocultured maize (M) and soybean (S) using a static chamber method. The results showed that there was no distinct yield advantage for intercropping systems. Total N 2 O production from the various treatments was 0.15 ± 0.04–113.85 ± 12.75 μg m −2 min −1 . Cumulative N 2 O emission from the M treatment was 16.9 ± 2.3 kg ha −1 across the entire growing season (three and a half months), which was significantly higher than that of the 2M2S and 2MS treatments by 36.6% and 32.2%, respectively ( P −1 ) induced a considerable soil N 2 O flux. Short-term N 2 O emissions (within 1 week after the two N applications) accounted for 74.4–83.3% of total emissions. Soil moisture, temperature, and inorganic N were significantly correlated with soil N 2 O emissions ( R 2 = 0.246–0.365, n = 192, P 3 − and moisture could be decreased in intercropping treatments during the growing season. These results indicate that maize-soybean intercropping can reduce soil N 2 O emissions relative to monocultured maize.

With the increasing pressure on phosphorus (P) resources and global water eutrophication, the development of sustainable land management is pushed forward by detailed knowledge on the nature and fate of phosphorus (P) in agricultural soils under various long-term fertilizer regimes. Using bulk- (solution 31P nuclear magnetic resonance; P K-edge X-ray absorption near-edge, XANES) and micro- (X-ray fluorescence and XANES) spectroscopic techniques, we investigated the molecular speciation of P in an alkaline soil from plots under wheat-maize rotation with or without chemical P fertilizers for 26 years, since 1990. The long-term experimental results show that P buildup and drawdown were mainly in the inorganic forms in response to P addition and depletion. The added P increased P accumulation in the forms of brushite and deoxyribonucleic acid that preferentially depleted without P addition, indicating that these species were phytoavailable. Although P forms as hydroxyapatite and orthophosphate monoesters were increased under P fertilization, no significant depletions of these P forms were observed when P fertilization was withheld. In contrast, iron-associated P increased with and without P fertilization. These results from this long-term experimental site facilitate understanding of dynamics and availability of fertilizer P and the existing legacy P in soils, with important implications for sustainable P management in these soils and similar soils in other regions.

Soil aggregates provide microhabitats for microorganisms. However, the bacterial communities within various aggregate size fractions under organic amendments have rarely been evaluated especially in sandy soils. A field experiment involving addition of biogas residue (BR), pig manure (PM), biochar (BC), and straw (ST) of a sandy soil was performed to determine the structure of the bacterial community in aggregate size fractions by using high‐throughput sequencing. We found that organic amendments change soil aggregate fractions and nutrient content, alter bacterial diversity and composition, and contribute to the predicted bacterial functions. The BR increased bacterial α‐diversity in 0.25‐mm aggregates. The BC treatment decreased the bacterial α‐diversity in the 0.053‐mm aggregates. Collectively, the effects of organic amendments on the bacterial community varied greatly depending on type of amendments and aggregate size. The BR supported highly diverse bacterial taxa in the

To address the low productivity of sandy farmlands, our study aimed to conduct a comparative study on the effects of different organic amendment (OA) inputs for the potential improvement of crop yield and soil quality in sandy alkaline farmlands through the selection of a suitable OA. This study set up straw (ST) returning as control and chemical fertilizer (CF) treatment as a side control, and chose three OAs returning as treatments, including pig manure (PM), biogas residue (BR), and straw biochar (BC), for improving soil fertility, with all amendments having matched doses of nitrogen (N). The experiment was conducted at the Wuqiao Experimental Station (37&deg, 41 N, 116&deg, 37 E) of China Agricultural University in Hebei Province, China, from October 2012 to September 2016. The cropping rotation was the winter wheat (Triticum aestivum L.)-summer maize (Zea mays L.) rotation system. Through a consecutive four-year field experiment, the principal results showed that three types of OA application significantly increased soil organic carbon from 1.46 g kg&minus, 1 to 8.24 g kg&minus, 1, soil total N from 0.21 g kg&minus, 1 to 0.64 g kg&minus, 1, soil available potassium from 55.85 mg kg&minus, 1 to 288.76 mg kg&minus, 1, and soil available phosphate from 4.86 mg kg&minus, 1 to 65.00 mg kg&minus, 1 in the 0&ndash, 20 cm soil layer. The BR was the most effective in improving soil nutrients as compared with the ST. The PM and BR treatments were more conducive to promoting crop yield by 6&ndash, 20% than ST, and the BC treatment significantly reduced the yield of winter wheat by 19% and summer maize by 8%. As the BR and PM treatments improved the soil nutrient content and significantly increased crop yield, these were the top choices for transforming the low-yield sandy farmlands.

Extreme climate change, rapid population growth and economic development drive a growing demand for resources, which lead to energy, food, water and their intertwined nexus becoming increasingly important. Agricultural decisions considering the interconnections among water, energy, and food are critical. The consumption of large amounts groundwater and non-renewable energy by the predominant traditional wheat-maize cropping system has caused a serious water shortage in the North China Plain (NCP), which is a large food production region in China. This situation has strained the relationship between water/energy consumption and food production. It is important to seek synergy in the water-energy-food nexus. This paper proposed a relative index of water-energy-food (WEFRI) based on different values of resource consumption and use efficiency between treatment systems and control system to analyze the synergy between water utilization, energy consumption and food supply in different cropping systems at the field scale. The goal is to seek a sustainable cropping system to balance crop production while reducing energy consumption and water depletion. In this case, different systems including monocropped maize (Zea mays) (MM), intercropped maize and soybean (Glycine max) (MS), relay cropped of maize with pea (Pisum sativum) (MP) and potato (Solanum tuberosum) (MO), rotation of maize with spinach (Spinacia oleracea) (MI) and ryegrass (Secale cereale) (MR), and using traditional wheat-maize (Triticum aestivum) (MW) as a control. MM, MS, MP and MO were the best systems within a particular range of food supply reduction. The WEFRI of the MM/MS system was the highest (2.96/2.78). Compared to the MW system, the groundwater consumption of MM/MS was reduced by 73.84%/73.84%, and non-renewable energy inputs were reduced by 48.01%/48.30%; however, the food supply decreased by 48.05%/51.70%. The WEFRI of the MP system was 1.98. In comparison with the MW system, the groundwater consumption of the MP system was reduced by 28.46%, and the non-renewable energy inputs were reduced by 42.68%. However, the food supply decreased by 37.13%. The WEFRI of MO system was 1.92. Compared to the MW system, the groundwater consumption of MO was reduced by 11.47%, non-renewable energy inputs were reduced by 32.14%, and the food supply only decreased by 26.27%. In conclusion, we theoretically proposed the following references for cropping systems in the NCP: MM and MS are implemented when the areas has extreme water shortages, MO is implemented when a less than 30% reduction in the food supply capacity is acceptable, and MP is recommended if a 30%–40% reduction in the food supply is acceptable.

Diversified cropping systems can enhance soil condition and increase system productivity worldwide. To reduce the negative effects that accompany the continuous winter wheat&ndash, summer maize (WM) double-cropping in the North China Plain (NCP), diversified crop rotation (DCR) needs to be considered. The objective of this study is to evaluate the effect of DCR on soil health and wheat productivity as compared to a continuous WM double-cropping. A field experiment (37&deg, 41&prime, N, 116&deg, 37&prime, E) was established in the NCP including a traditional WM double-cropping as a baseline. During 2016/2017&ndash, 2017/2018, the control is winter wheat&ndash, summer maize&rarr, winter wheat&ndash, summer maize (WM&rarr, WM) and seven DCRs as follow: fallow&rarr, summer maize (F&rarr, WM), spring maize&rarr, summer maize (Ms&rarr, winter wheat&rarr, summer maize (W&rarr, sweet potato&rarr, summer maize (Psw&rarr, spring peanut&rarr, summer maize (Pns&rarr, summer peanut&rarr, summer maize (WPn&rarr, WM) and potato&ndash, silage maize&rarr, summer maize (PMl&rarr, WM). Our results indicated that DCRs significantly changed certain soil health indicators in 2016/2017 compared with the control, where F&rarr, WM rotation significantly decreased soil pH by 2.7%. The DCRs, especial Psw&rarr, WM and Pns&rarr, WM rotations showed a potential positive effect on soil health indicators at the end of the second year (2017/2018) compared with the control, where sweet potato increased soil organic carbon (SOC), total nitrogen (TN), available phosphorus (AP), urease activity (UA) and alkaline phosphatase activity (APA) in 2017/2018 by 5.1%, 5.3%, 13.8%, 9.4%, and 13.5%, respectively. With the spring peanut, TN, AP, and soil APA were increased by 2.1%, 13.2%, and 7.7%, respectively. Although fertilizer and irrigation input of DCRs were lower than the control, no significant decrease was observed on actual wheat yield as compared to the control (7.79 Mg/ha). The finding of this study highlights the value of DCRs, especially, Psw&rarr, WM rotations over WM double-cropping in the NCP.

Large quantities and many varieties of agricultural organic wastes are produced in China annually. Applying agricultural organic wastes to soil plays an essential role in coping with the environmental pollution from agricultural wastes, solving the energy crisis and responding global climate change. But there is little information available on the effects of different agricultural organic wastes on soil greenhouse gas (GHG) emissions. The objectives of this study were to investigate and compare the impacts of different organic wastes on soil GHG emissions during a 4-year field experiments in the North China Plain, as well as analyze the influential factors that may be related to GHG emissions. The treatments were: crop straw (CS), biogas residue (BR), mushroom residue (MR), wine residue (WR) and pig manure (PM) returning to soil, as well as a control with no organic waste applied to soil but chemical fertilizer addition only (CF). The results showed that compared with CF treatment, organic material applied to soil significantly increased GHG emissions and emissions followed the order of WR(27,961.51 kg CO2-eq/ha/yr) > PM(26,376.50 kg CO2-eq/ha/yr) > MR(23,366.60 kg CO2-eq/ha/yr) > CS(22,434.44 kg CO2-eq/ha/yr) > BR (22,029.04 kg CO2-eq/ha/yr) > CF(17,402.77 kg CO2-eq/ha/yr), averagely. And considering the affecting factors, GHG emissions were significantly related to soil temperature and soil water content. Different organic wastes also affected soil total organic carbon (TOC), microbial carbon (MBC) and dissolved organic carbon (DOC) contents, which related to GHG emissions. Further analysis showed that characteristics of organic wastes affected GHG emissions, which included C-N ratio, lignin, polyphenol, cellulose and hemicellulose. Our study demonstrates that biogas residue returning to soil emitted minimum GHG emissions among these different types of organic wastes, which provided a better solution for applying organic wastes to mitigate soil GHG emissions.

Monocropped maize is being discussed as a possible alternative to the conventional wheat-maize cropping system in order to conserve water in the North China Plain. To evaluate the economic and environmental consequences of converting cropping systems, wheat-maize, monocropped maize systems with and without irrigation are compared through a joint use of economic analysis, emergy evaluation and life cycle assessment in this study. According to the economic analysis results, the wheat-maize system has higher grain yield and levels of economic profit but a lower ratio of income to costs compared to monocropped maize systems with and without irrigation. The emergy evaluation results show that monocropped maize systems have higher levels of sustainability. Their environmental loading ratios are 8.16%–26.7% lower and the emergy sustainability indexes are 10.20%–30.52% higher than those of wheat-maize system, respectively. The life cycle assessment results reveal lower potential environmental impacts for monocropped maize systems and their total potential environment impact indexes are 39.59%–40.30% lower than that of wheat-maize system. These results indicate monocropped maize will be an effective measure to resolve the current issue of environmental pressures caused by the conventional wheat-maize system in the North China Plain.

Nitrogen fertilizer is required to meet grain targets, but the fossil fuel consumption and greenhouse gas emissions resulting from its use are a barrier to achieve low C agriculture. The objective of this study is to evaluate the net global warming potential (GWP) of maize and soybean monoculture and maize-soybean intercrop systems with an ecosystem-level C budget and determine the optimal N fertilizer requirement of maize-soybean intercrop based on the GWP in CO2 -eq during cropping season. The field experiment had five treatments: maize and soybean monoculture receiving 240 kg N ha−1 and maize-soybean intercrop receiving 120, 180 and 240 kg N ha−1 for three years (2012, 2013, and 2014). Considering greenhouse gas (GHG: CO2, CH4 and N2O) emissions from the field plots, indirect GHG emissions from agricultural inputs (e.g., fertilizer, diesel and pesticides) and CO2 fixation by crops, soybean monoculture was the net C source due to its lower net primary production, while all maize monoculture and intercrop treatments were net C sinks except for the maize-soybean intercrop receiving 240 kg N ha−1 in 2013. Maize monoculture was the largest C sink due to its higher net primary production, even though it had significantly (p

In maize (Zea mays L.), final grain yield is largely determined by kernel number at harvest. The goal of this research was to assess the source of kernel loss and identify the main factors in the process of kernel formation among maize hybrid genotypes comprising semi-compact (JH5) and compact (LD9066) genetic backgrounds (with contrasting tolerance to stand density) under field conditions. Field experiments were conducted in 2014 and 2015. Two hybrids were grown at three sowing dates (early April: SD1, early May: SD2, and late May: SD3) and under three plant densities: D1 (5.25 plants m−2), D2 (6.75 plants m−2), and D3 (8.25 plants m−2). Two sources of kernel loss were assessed and associated with 1) silks failing to emerge from the husk 7 days after silking (loss1) and 2) kernel abortion during the grain-filling period (loss2). The results demonstrated that floret number was significantly influenced by maize hybrid: the semi-compact maize hybrid JH5 had more florets than did the compact maize hybrid LD9066. However, the final kernel number per plant (FKNP) of JH5 was slightly lower than that of LD9066. JH5 had a larger value for both loss1 and loss2 than did LD9066 (22.6% vs 11.9% and 21.0% vs 12.1%, respectively). Moreover, sowing date and plant density also significantly influenced the source of kernel loss. SD1 exhibited a greater value of loss1 than did SD2 and SD3 (24.9%, 15.8% and 11%, respectively) but a lower value of loss2 than did SD2 and SD3 (10.0%, 20.6% and 19.6%, respectively). Plant density had no significant effect on loss1; however, the highest plant density (D3) resulted in the highest loss2 among three plant densities (9.4%, 15.9% and 25.9%). The dynamics of visible silking showed that JH5 requires more time (+1.5 days) to reach 50% maximum visible silks than does LD9066 and has a lower proportion of maximum visible silks at the seventh day after silking. In addition, the apical kernels of JH5 had a relatively longer Dmax (days needed to reach the maximum grain-filling rate) and greater Gmax (maximum grain-filling rate) than did those of LD9066 (+0.5 day and +3.5 mg kernel−1 d−1, respectively). However, the Wmax (kernel weight at the maximum grain-filling rate) and P (active grain-filling period) of JH5 were much lower than those of LD9066 (-6.4 mg kernel−1 and −8.2 days, respectively). Compared with the semi-compact hybrid, the compact hybrid showed an enhanced ability to resist abiotic stress tolerance, with good fertilization synchronization and a low percentage of kernel abortion. These above-mentioned traits should be considered in breeding programs to further increase the maize yield in China.

Intercrop systems can exhibit unique soil properties compared to monocultures, which influences the microbially-mediated processes leading to greenhouse gas emissions. Fertilized intercrops and monocultures produce different amounts of N2O, CO2 and CH4 depending on their nutrient and water use efficiencies. The objective of this study was to compare the fluxes and seasonal emissions of N2O, CO2, and CH4 from a maize–soybean intercrop compared to maize and soybean monocultures, in relation to crop effects on soil properties. The experiment was conducted during 2012, 2013 and 2014 at the WuQiao Experimental Station in the North China Plain. All cropping systems received urea-N fertilizer (240 kg N ha−1 applied in two split applications). The cropping systems were a net source of CO2 and a net sink of CH4, with significantly (P

In recent years, China has developed a series of disposal methods and corresponding recycling systems to deal with agricultural wastes, as well as to mitigate climate change. The objective of this paper is to evaluate the net greenhouse gas emissions (NGHGE) and crop yields of three types of typical recycling systems, based on case studies in the North China Plain. These systems are the CC system, “crop production-crop production” by returning crop straw to the soil; CPC system, “crop production-pig rearing-crop production” by returning pig manure to the soil; and the CPBC system, “crop production-pig rearing-biogas production-crop production” by returning biogas residue to the soil. The overall results show that a reduction of 15.18% in NGHGE was achieved with the CPC system compared with a system where no pig manure was returned to the soil. NGHGE of CPBC system achieved a reduction of 352.25% compared with no biogas being produced and no pig manure being returned. These results imply that the development of recycling agriculture, i.e., manure reuse and biogas production, is a superior method to reduce GHG emissions. Additionally, compared with CC system, crop yields improved by 17.75% and 18.68% in the CPC and CPBC systems, respectively, which is an important factor in guaranteeing food security. Therefore, compared with non-recycling practices, by reusing organic wastes, these recycling systems reduced the total GHG emissions and increased crop yields. Accordingly, agricultural recycling offers a promising system for dealing with large volumes of waste, responding to global climate change, and ensuring food security in China.

Due to rapid economic growth and dramatic urbanization in China in the recent 30 years, the traditional model for grain production dominated by small-size household farms is gradually being broken, while large-scale farming is becoming increasingly common. However, the information on relationships of environmental and economic consequences of grain production on different farm size has been lacking. In this study, life cycle assessment and economic analysis are used to compare environmental and economic performance of wheat-maize double-cropping system on small, medium and large farm size in North China Plain (NCP). The life cycle assessment indicates that, compared to the small-farm, area-based environmental impact index (EIA) is decreased by 2.4% and 3.4% for the medium-farm and large-farm, yield-based environmental impact index (EIY) is increased by 14.3% for the medium-farm while decreased by 3.4% for the large-farm. The economic analysis shows that the yield-based profits (EPY) for the medium-farm and large-farm are 83.4% and 71.7% lower than that for the small-size farms but the expansion of farm size contributes to the improvement of incomes of workers and owners of the farms together. Generally, the potential environmental impacts of grain production on the same area farmland will possibly change due to the difference of farm size, but expanding farm size will not directly and obviously improve the potential environmental consequences of grain production in the NCP. The larger size farm earns the more net income annually, but the conventional small-farm has the better revenue at the point of yield-based profit. Moreover, a scenario analysis represented that the EIY and EPY for the medium-farm and large-farm would be improved by 1.1%–47.1% and by 11.1–267.3%, respectively, by improved fertilization, irrigation and machines practices. Clearly, the advanced agricultural practice is the key point to improve the environmental and economic consequences for grain production in the NCP. Therefore, it is not scientific to only emphasize the expansion of farm size but, meanwhile, not to promote the implementation of advanced agricultural practices for the environmental and economic consequences of grain production in the NCP.

Removal of three bromophenols (BPs), namely, 2-bromophenol (2-BP), 4-bromophenol (4-BP), and 2,4-dibromophenol (DBP), from aqueous solutions using hazelnut shell-derived activated carbon (HSAC) as ...

Agriculture causes 10–12% of global GHG (CO2, CH4 and N2O) emissions. GHG emissions from Chinese agriculture have been estimated at 819.97 Mt CO2-equivalence (CO2-eq); among them, total annual GHG emissions from the production of grain and livestock have been estimated at 374 Mt CO2-eq and 445 Mt CO2-eq, respectively. Because of food demand, food production has intensified, resulting in the separation of crop production and livestock rearing. This separation has increased the application of outside resources and agricultural waste, aggravating GHG emissions and other ecological and environmental problems. This research attempts to mitigate GHG emissions by improving soil carbon sequestration of crop production and decreasing emissions from swine-rearing waste. Net GHG emissions (NGHGE) between an integrated system and a separated system are compared in this study from a life-cycle perspective. The causes of different GHG emissions between these two systems are analyzed and mitigation strategies are proposed. The results show that the NGHGE of crop-swine integrated and separated systems were 24,917.95 kg CO2-eq/ha/yr and 27,732.70 kg CO2-eq/ha/yr, respectively, for 215 head of pigs. The integrated system reduced GHG by 1381.33 kg CO2-eq/yr mainly due to the recycling and reuse of pig manure in croplands. Meanwhile, the integrated system increased soil carbon storage by 35.92% compared with the separated system, although it increased soil CH4 and N2O emissions. In conclusion, these results indicate that through a series of methods, such as recycling agricultural waste, the integrated system can reduce net GHG emissions by 10.15% compared with separated systems. Although much work remains to adopt the integrated system to reduce GHG emissions, the crop-swine integrated system should be given priority to mitigate anthropogenic net GHG emissions.

Recycling wasted biomass as organic fertilizer has been an important road to develop sustainable agriculture. Emergy evaluation (EME) is a widely used method to evaluate sustainability of agricultural systems. However, the contribution of recycled biomass on emergy efficiency and sustainability of investigated systems cannot be comprehensively and reasonably represented, to some extent, by the currently used forth emergy rule. In this study, therefore, an “emformation” concept is introduced to illustrate that the recycled biomass derived from different agricultural processes only contains the emergy stored in its organic matter. Meanwhile, a formulas is designed to account the energy contribution of recycled biomass for recycling agricultural systems. A case study on wheat-maize double-cropping systems fertilized by crop straw (CS), pig manure (PM), wine residue (WR), biogas residue (BR) and mushroom residue (MR) in the North China Plain is performed to compare with the system only applying mineral fertilizer (CK). Several emergy-based indices, such as unit emergy value (UEV), nonrenewable resource efficiency (NRE), recycle yield ratio (RYR), emergy yield ratio (EYR), emergy loading ratio (ELR) and emergy sustainability index (ESI) are calculated, in which the EYR and ESI are modified to reflect the influence of applying recycled biomass on the sustainability of recycling agricultural systems. Result shows that the UEVs and NREs of the CS, PM, WR, BR and MR are 22.0%–77.3% higher than that of the CK, the RYR of the CS is 31.6% lower than that of the PM, WR, BR and MR, the modified EYRs of the CS, PM, WR, BR and MR increase by 67.6%–81.4% compared to the CK, the ELR are 8.4%–75.4% higher for the PM, WR and MR but 6.7%–29.1% lower for the CS and BR than that of the CK, the modified ESI of the CS, PM, WR, BR and MR increase by 3.5%–136.8% compared to the CK. Generally, the results illustrate that the modified approach contribute to achieving more reasonable evaluation results for agricultural systems involving recycled biomass. The wheat-maize systems fertilized by recycled biomass consume the more emergy and nonrenewable resources to generate the unit product. The recycling agricultural systems show the higher sustainability, in which recycling biogas residue into field as organic fertilizer shows the best recycling benefits.

The maize sole cropping system solves problems related to ground water resource shortages and guarantees food security in the North China Plain. Using optimal sowing dates is an effective management practice for increasing maize yield. The goal of this study was to explore an optimum sowing date for high-yield maize. Six sowing dates (SDs) from early April to late June with intervals of 10 to 20 days between SD—SD1 (early April), SD2 (mid to late April), SD3 (early May), SD4 (mid to late May), SD5 (early June), SD6 (late June)—were applied from 2012 to 2017. The results showed that yield was correlated with the sowing date based on the thermal time before sowing (r = 0.62**), which was defined as the pre-thermal time (PTt), and that the yield was steadily maintained at a high level (&gt, 10,500 kg ha−1) when PTt was greater than 479 °C. To satisfy the growing degree-days required for maturity, maize needs to be sown before a PTt of 750 °C. Data analysis of the results from 2014, 2015, and 2017 revealed the following: i) Most of the grain-filling parameters of late-sown dates (SD4, SD5 and SD6) were better than those in early-sown dates (SD1, SD2, and SD3) in all years, because of the high daily maximum temperature (Tmax) and wide diurnal temperature (Td) from silking to blister (R1–R2) of early-sown dates. The weight of maximum grain-filling rate (Wmax) of SD3 decreased compare with SD4 by the narrow Td from blister to physiological maturity (R2–R6) in all years (−5, −12, and −33 mg kernel−1 in 2014, 2015, and 2017, respectively). ii) In 2017, the pollination failure rates of early-sown dates were 8.4~14.5%, which was caused by the high Tmax and Td of R1–R2. The apical kernel abortion rates were 28.6 (SD2) and 38.7% (SD3), which were affected by Tmax and Td during R2–R6. iii) Compared with late-sown dates, the wide Td of early-sown dates in R1–R2 was caused by higher Tmax, but the narrow Td in R2-R6 was caused by higher Tmin. Our results indicate that high-yielding maize can be obtained by postponing the sowing date with a PTt of 480~750 °C, which can prevent the negative effects of the high Tmax of R1–R2 and high Tmin of R2–R6 on kernel number and weight formation. Moreover, these above-mentioned traits should be considered for heat tolerance breeding to further increase the maize yield.

The policy of land rental activity from fragmented to concentrated farmland has been overwhelming encouraged by the Chinese government. The land management policy has paid more attention on the investigation of its economic and social performances of land rental activity, while information on its environmental consequence is still lacking. This study, therefore, compared the environmental and economic performances of small (SF) and large scale (LF) farms based on emergy evaluation (EME), life cycle assessment (LCA) methods, and economic analysis (EA), which reflected a land rental activity from fragmented to concentrated farmland in the North China Plain (NCP). The EME results showed that the environmental loading ratio of the LF was 5.0% lower, while the emergy yield ratio and emergy sustainability index of the LF were 1.48% and 8.0% higher, respectively, than that of the SFs. The LCA results demonstrated that the area-based and yield-based environmental impact indices of the LF were 28.8% and 18.3% lower than that of the SF, respectively. These results indicate that the environmental consequences of the cropping system were improved when the farmland was managed in a concentrated model instead of a fragmented model. In addition, the EA results showed that the income to cost ratio of the LF was reduced by 47.46% compared to that of the SF, due to high land rental costs in the LF. Nevertheless, the total profit of the LF was 1719.3% higher than that of the SF due to its lager farm scale. Also, the owner's total profit of the SF was increased by 195.5% compared to the farming by themselves in their own farmland instead of renting them out. These results showed that scale management can promote both managers who rented out and into the farmland to increase their annual total incomes. In conclusion, the concentrated farmland would be a platform for the improvement of environmental consequences of cropping systems in the NCP.

A number of new rural management models have emerged to solve the problems of economic backwardness, insufficient resource utilization, and technical shortages in rural areas in the context of poverty alleviation to the rural revitalization strategy in China. However, the influence of new rural management model under all countermeasures for rural sustainable development with a comprehensive perspective is lacking. Therefore, exploring whether the new rural management model meets the requirements of sustainable development is an urgent issue. From the theory of system metabolism and emergy accounting method, this study classified the government funds for poverty alleviation measures as import resources, and analyzed the metabolic structure, efficiency, and the rural development factors of Chehe Village before and after poverty alleviation measures are carried out (the year of 2012 and 2019) to verify whether the new model was sustainable. According to the results of this study, the new management model of Chehe Village declined the rural system sustainability with the emergy sustainability index decreasing from 1.96 in 2012 to 0.32 in 2019. With the development of economy, the system metabolic efficiency of Chehe Village promoted and the metabolic structure became more reasonable manifesting in the decline of emergy use per unit GDP and the increase of emergy exchange rate. Moreover, production and livelihood had been highly valued in Chehe Village. In conclusion, it is feasible to add countermeasures of poverty alleviation and rural revitalization into the village system metabolism. The new management model of Chehe Village needs to change exogenous force into endogenous force to meet the requirements of rural sustainable development.

High-temperature stress (HTS) at the grain-filling stage in spring maize (Zea mays L.) is the main obstacle to increasing productivity in the North China Plain (NCP). To solve this problem, the physiological mechanisms of HTS, and its causes and impacts, must be understood. The HTS threshold of the duration and rate in grain filling, photosynthetic characteristics (e.g., the thermal stability of thylakoid membrane, chlorophyll and electron transfer, photosynthetic carbon assimilation), water status (e.g., leaf water potential, turgor and leaf relative water content) and signal transduction in maize are reviewed. The HTS threshold for spring maize is highly desirable to be appraised to prevent damages by unfavorable temperatures during grain filling in this region. HTS has negative impacts on maize photosynthesis by damaging the stability of the thylakoid membrane structure and degrading chlorophyll, which reduces light energy absorption, transfer and photosynthetic carbon assimilation. In addition, photosynthesis can be deleteriously affected due to inhibited root growth under HTS in which plants decrease their water-absorbing capacity, leaf water potential, turgor, leaf relative water content, and stomatal conductance. Inhibited photosynthesis decrease the supply of photosynthates to the grain, leading to falling of kernel weight and even grain yield. However, maize does not respond passively to HTS. The plant transduces the abscisic acid (ABA) signal to express heat shock proteins (HSPs), which are molecular chaperones that participate in protein refolding and degradation caused by HTS. HSPs stabilize target protein configurations and indirectly improve thylakoid membrane structure stability, light energy absorption and passing, electron transport, and fixed carbon assimilation, leading to improved photosynthesis. ABA also induces stomatal closure to maintain a good water status for photosynthesis. Based on understanding of such mechanisms, strategies for alleviating HTS at the grain-filling stage in spring maize are summarized. Eight strategies have the potential to improve the ability of spring maize to avoid or tolerate HTS in this study, e.g., adjusting sowing date to avoid HTS, breeding heat-tolerance varieties, and tillage methods, optimizing irrigation, heat acclimation, regulating chemicals, nutritional management, and planting geometric design to tolerate HTS. Based on the single technology breakthrough, a comprehensive integrated technical system is needed to improve heat tolerance and increase the spring maize yield in the NCP.

Rising worldwide cancer incidence and resistance to current anti-cancer drugs necessitate the need for new pharmaceutical compounds and drug delivery system. Two novel series of biscoumarin (1-4) and dihydropyran (5-16) derivatives were synthesized via a one-pot multicomponent condensation reaction and evaluated for their antitumor activity in vitro. The X-ray crystal structure analysis of four representative compounds 2, 7, 10 and 13 confirmed the structures of these compounds. Compounds 1-4 showed the most potent antitumor activity among the total 16 derivatives. More interestingly, preliminary mechanism studies revealed that the most potent compound 4 induced apoptosis and arrested the cell cycle at the S phase in HUTU80 cells. Additionally, the increased accumulation of HUTU80 cells in the sub G1 peak further pointed to the occurence of the cell apoptosis. The selectivity index analysis demonstrated that all the biscoumarin compounds (SI=3.1-7.5) possess higher selectivity towards intestinal epithelial adenocarcinoma cell line (HuTu80) than positive control drug carboplatin (SI=1.6-1.8). The biscoumarin compounds also showed no obvious acute toxicity on mice.

Adsorption characteristics of Fe(III) ions onto thiocyanato-functionalized silica gel sorbent were investigated under various conditions of contact time, initial metal concentration and temperature. The equilibrium isotherms, kinetics and thermodynamics of Fe(III) ions adsorption onto the surface of thiocyanato-functionalized silica gel from aqueous solution were investigated. Batch kinetic studies showed that an equilibrium time of 30 min was required for the adsorption of Fe(III) ions onto thiocyanato-functionalized silica gel. The estimated maximum capacities of Fe(III) ions adsorbed by thiocyanato-functionalized silica gel were 112.2 mg g−1. The equilibrium adsorption data of thiocyanato-functionalized silica gel for Fe(III) ions best fitted to the Langmuir isotherm since the correlation coefficients for the Langmuir isotherm were higher than that for the Freundlich and Dubinin–Radushkevich isotherms. The kinetic data were well described by the pseudo-second-order model. Spontaneous, endothermic and random characteristics of the process were confirmed by thermodynamic analysis.

Livestock husbandry in China is rapidly changing in structure from traditional backyard rearing toward large-scale and intensive production. In this study, a joint use of life cycle assessment, emergy evaluation and economic analysis provides different but complementary standpoints for comparison of four typical pig production models. The results show that the income/cost ratio, labor productivity and daily weight gain for specialized pig farms (SF), thousand pig farms (TF) and hundred thousand pig farms (HTF) are increased by 23.0–36.5%, by 338.7–946.7% and by 2.0–9.8%, respectively, compared to the backyard pig farm (BF). However, the area-based and yield-based potential environmental impacts for the SF, TF and HTF increase by 975.0–9121.9% and by 19.5–43.5%, respectively, compared to the BF. Meanwhile, the emergy-based sustainability of the SF, TF and HTF is 56.5–88.7% lower than that of the BF, whereas the use efficiency of non-renewable resources of the SF increased 17.6–50.4% compared to the BF, TF and HTF. Generally, the larger production scale causes better economic benefits and worse environmental consequences. Nevertheless, to some extent, expanding the scale of livestock production is necessary for the current development of the livestock sector in China. However, the scale must be moderated to avoid serious environmental impacts. In this study, the specialized farm is suggested to be a good choice for livestock production in China. Moreover, policymakers should promote moderate-scale farms to adopt advanced and integrated production practices for livestock husbandry. This will effectively improve the economic and environmental performance of livestock production in China.

In the North China Plain, groundwater tables have been dropping at unsustainable rates of 1 m per year due to irrigation of a double cropping system of winter wheat and summer maize. To reverse the trend, we examined whether alternative crop rotations could save water. Moisture contents were measured weekly at 20 cm intervals in the top 180 cm of soil as part of a 12-year field experiment with four crop rotations: sweet potato→ cotton→ sweet potato→ winter wheat-summer maize (SpCSpWS, 4-year cycle); peanuts → winter wheat-summer maize (PWS, 2-year cycle); ryegrass–cotton→ peanuts→ winter wheat-summer maize (RCPWS, 3-year cycle); and winter wheat-summer maize (WS, each year). We found that, compared to WS, the SpCSpWS annual evapotranspiration was 28% lower, PWS was 19% lower and RCPWS was 14% lower. The yield per unit of water evaporated improved for wheat within any alternative rotation compared to WS, increasing up to 19%. Average soil moisture contents at the sowing date of wheat in the SpCSpWS, PWS, and RCPWS rotations were 7, 4, and 10% higher than WS, respectively. The advantage of alternative rotations was that a deep rooted crop of winter wheat reaching down to 180 cm followed shallow rooted crops (sweet potato and peanut drawing soil moisture from 0 to 120 cm). They benefited from the sequencing and vertical complementarity of soil moisture extraction. Thus, replacing the traditional crop rotation with cropping system that involves rotating with annual shallow rooted crops is promising for reducing groundwater depletion in the North China Plain.

Monocropping systems, which currently dominate China&rsquo, s major grain production regions, contribute to resource scarcity and environmental pollution. Intercropping has the potential to improve resource use efficiency. However, prior studies of intercropping systems have generally focused on ecological, economic, and social consequences. Here, we make a comparative ecological sustainability analysis on energy capture and efficiency of maize monocropping and maize&ndash, soybean intercropping systems through emergy evaluation based on field experiments performed from 2012 to 2014. We find that maize monocropping shows higher sustainability than maize&ndash, soybean intercropping in the North China Plain at present. Quantitative results indicate that for maize monocropping, the emergy yield ratio (EYR) and emergy sustainability index (ESI) are 13.7% and 21.1% higher than that of intercropping systems, and the environmental loading ratio (ELR) is 7.3% lower than that of intercropping systems. To further test, we applied three levels of nitrogen fertilizer in intercropping systems (120 kg ha&minus, 1, 180 kg ha&minus, 1, 240 kg ha&minus, 1), and find that a reduced rate of N fertilizer for intercropped system leads to higher sustainability (ESI 5.3% higher) but still lower sustainability than maize monocropping. Key drivers of the different sustainability outcomes are decreased energy output and a larger proportion of labor input associated with intercropping systems.

A new diffusive gradients in thin films (DGT) device, using Pb(II) ion-imprinted silica (IIS) as the binding agents and commercial cellulose acetate dialysis (CAD) membrane as the diffusion layer (CAD/IIS-DGT), has been developed and evaluated for sampling and measurement of free Pb(II) species. The CAD/IIS-DGT devices were successfully applied to the measurement of free Pb(II) species in synthetic solutions, in natural freshwaters and in industrial wastewaters. The CAD/IIS-DGT provides reliable results over pH range of 4.5-6.5 and a wide range of ionic strength from 1.0×10(-3) to 0.7 mol L(-1). The concentrations of the free Pb(II) species in synthetic solution containing different concentrations of ligands measured by CAD/IIS-DGT showed a good agreement with the value measured by Pb-ion selective electrode. Field deployments of the CAD/IIS-DGT devices allowed accurate measurements of the concentrations of free Pb(II) species.