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Abstract: Appropriate fertilization practices play a critical role in enhancing crop yields, as well as in achieving sustainable increases in crop production through improving soil quality. In the present study, we examined the effects of long-term fertilization (started in 1986) on crop yield and its sustainability under a double corn (Zea mays L.) cropping system in an Ultisol of southern China. Results showed that although corn yields were higher in the fertilized treatments compared to the unfertilized control, inorganic fertilizer application alone (N and NPK) resulted in declining trends in both corn yields and fertilization effects (defined as the yield difference between the fertilized treatment and the control), especially in the N treatment. In contrast, significant increasing trends in both corn yields and fertilization effects were observed in the manure-applied treatments. Manure amendments significantly increased the contents of soil organic carbon and total N and the availability of soil P and K, while long-term inorganic fertilization alone accelerated soil acidification, especially in the N treatment. In addition, there was no significant correlation between the yield trend and climatic factors (weather trends) over the period of study. Thus, it is likely that the long-term sustainability of corn production under manure application is attributed mainly to the improved soil quality. Our results also suggest that manure amendments, particularly in combination with inorganic NPK, should be the recommended fertilization practice to enhance corn yields and improve soil quality in the Ultisol. [Copyright &y& Elsevier]

Conservation tillage (e.g. no tillage, minimum tillage) is regarded as an effective way to maintain sustainable crop productivity and improve soil quality globally. However, the claim that conservation tillage could improve crop yield are still controversial. It is hypothesized that whether conservation tillage increase crop yield in comparison with conventional tillage (CT) depends on the different conservation tillage practices, for example, no tillage (NT) and strip tillage (ST), and different variables including in agronomic managements, climate conditions, and soil properties. Herein, a meta-analysis was conducted to evaluate how tillage practices affect crop yield and which factors dominate yield performance mostly. Based on the 53 published articles with 290 paired-comparisons across the world, the effects of ST vs. CT and ST vs. NT on crop yield were conducted. It was showed that crop yield under ST had an increasing trend compared to that under CT and NT. Especially, ST significantly increased crop yield by 4.81% in contrast with NT, which indicated that ST might be a promising practice of conservation tillage in terms of crop yield. Under the agronomic managements of continuous cropping, multiple cropping, graminaceous crops, and straw removing, ST significantly increased crop yields by 5.40%, 10.29%, 7.66%, and 7.60% compared to NT, respectively. ST achieved significantly higher crop yield by 5.68% on average and 11.63% as compared to NT under all soil texture and neutral soil. Concerning the climate conditions, crop yield significantly increased by 3.64% under ST as compared to NT in cooler area where mean annual temperature (MAT) was lower than 10°C. Importance analysis indicated that cropping system and MAT were the key factors affecting the performance of tillage practice on crop yield. Overall, present study revealed that ST might be a favorable conservation tillage practice in continuous and multiple cropping systems with graminaceous crop (e.g. maize) in cooler (MAT <10℃) region in terms of yield promotion. This meta-analysis study demonstrated the importance of conservation tillage optimization for food safety and sustainable development of agriculture. • 53 articles with 290 paired-comparisons are used to conduct a meta-analysis. • Strip tillage has similar crop yield in contrast with conventional tillage. • Strip tillage significantly increases crop yield by 4.81% compared with no tillage. • Cropping system and mean annual temperature affect tillage performance. [ABSTRACT FROM AUTHOR]

Understanding the actual impacts of climatic warming on winter-sown wheat production will benefit cultivar breeding efforts and agronomic innovations and may help to improve food security. Therefore, we conducted a comprehensive study across the main Chinese winter wheat cropping regions, comprising field warming experiments at four locations and an analysis of 36 years of winter wheat yield data. In the field warming experiments, an increase of 1.0 °C in nighttime temperature enhanced wheat yield by 10.1% on average ( P < 0.05 ). Warming-induced enhancement of 1000-grain weight explained most of these yield increases. Warming shortened the length of pre-flowering phase by 5.4 days, while it prolonged the length of post-flowering phase by 3.8 days. Grain yield increases with warming were similar across experimental sites, even though warming-induced changes in the length of growth periods decreased with increasing ambient temperature. Our analysis of the historical data set was consistent with our field warming experiments; between 1980 and 2015, the major Chinese cropping regions experienced significant warming, especially in daily minimum temperature. Across the historical data set, daily minimum temperature was positively correlated with wheat yield (142.0 kg ha −1 °C −1 ). Our findings are inconsistent with previous reports of yield decreases with warming and may help to inform policy decisions and agronomic innovations of Chinese wheat production to better cope with future climate warming. [ABSTRACT FROM AUTHOR]

Great efforts have been made on the assessment of the effects of straw managements or tillage practices on rice yield and greenhouse gas (GHG) emissions. However, their interactive effects were not well documented. Based on a seven-year field experiment under a double rice system, we tested the effects of rotary tillage (RT) vs. plough tillage (PT) on rice yield, methane (CH 4 ) and nitrous oxide (N 2 O) emissions with or without straw incorporation. As compared to straw removal, straw incorporation increased rice yield by 12.7% and 1.3% under the PT and the RT, respectively. Straw incorporation significantly stimulated CH 4 emissions under both tillage regimes in the late rice season, while no significant effect occurred in the early rice season. Compared to the RT, PT significantly decreased DOC concentrations and methanogen abundances, resulting in a reduction in CH 4 emission. The PT decreased yield-scaled global warming potential (GWP) with or without straw incorporation by 31.0% and 15.5%, respectively, as compared to the RT. Together, our results indicate that straw incorporation with plough tillage benefits rice production for higher-yield with less GHG emissions in double rice cropping areas. [ABSTRACT FROM AUTHOR]

Enhanced-efficiency nitrogen fertilizer (EENF) has gained considerable attention for improving nitrogen use efficiency and mitigating N 2 O emission in many agro-ecosystems. However, the effectiveness of EENF is highly variable under field condition. The factors influencing the efficacy of EENF are not well understood. Here, a meta-analysis was conducted to investigate the key factors affecting the efficacy of EENF in upland cropping systems. The effects of EENF were found to be similar among maize, wheat, and barley, while they varied among different EENF products. Inhibitors (IS), including nitrification inhibitors (NI), urease inhibitors (UI), and the combination of UI and NI, significantly mitigated N 2 O emission and increased crop yield, resulting in a greater reduction in yield-scaled N 2 O emission compared with slow- or control-releasing fertilizer (S/CRF). Reductions in yield-scaled N 2 O emission response to IS and S/CRF were both greater in arid regions than in humid regions. Soil pH and texture had less impact on the effect of IS than S/CRF. The efficacy of IS and S/CRF were not significant when N use rates were between 120 and 180 kg N ha −1 . Surface broadcasting were unfavorable for mitigating N 2 O emissions with both IS and S/CRF. The impact of tillage on the efficacy of IS and S/CRF was affected by climate. The effectiveness of S/CRF depended more on these factors than did IS. This meta-analysis highlighted the necessity to connect EENF products with specific climatic, soil, and agronomic attributes for predicting their effectiveness. [ABSTRACT FROM AUTHOR]

Significant efforts have been made to assess the impact of tillage regimes on crop yields and/or greenhouse gas (GHG) emissions across single crop growing season. However, few studies have quantified the impact across a whole rotation cycle in multiple cropping systems. Utilizing on a long-term tillage experiment with the rice–wheat rotation system in East China, we examined the GHG emissions under different tillage practices with or without crop straw incorporation. Results showed that compared to the no-straw control, straw incorporation increased wheat yield by 28.3% ( P < 0.05), irrespective of tillage practices, but had no significant effect on rice yield. Although straw incorporation did not significantly affect CH 4 emissions during the wheat season and N 2 O emissions during the whole rice–wheat cycle, it significantly stimulated CH 4 emissions by 98.8% ( P < 0.01) during the rice season. Also, there were no significant differences in CH 4 and N 2 O emissions between tillage practices during the wheat season. Compared to plowing, rotary tillage increased CH 4 emissions significantly by an average of 38.8% ( P < 0.01) but had no significant impacts on N 2 O emissions during the rice season. Across the rotation cycle, annual yield-scaled global warming potential of CH 4 and N 2 O emissions under no-tillage plus rotary tillage was 26.8% ( P < 0.01) greater than that of rotary tillage plus plowing with or without straw incorporation. Significant interactions between soil tillage and straw management practices were found on annual GHG emissions, but not on crop yields. Together, these results indicate that plowing in the rice season plus rotary tillage in the wheat season may reduce GHG emissions while increasing crop yield in rice–wheat cropping areas. [ABSTRACT FROM AUTHOR]

Organic amendment often affects both crop yield and greenhouse gas (GHG) emission. Yet the impact of organic amendment on yield gains and GHG emissions is still unclear, particularly in long-term soybean-wheat cropping system. Based on a 30-year soybean-wheat cropping system experiment, the impact of organic amendments (i.e. straw and manure) on soil properties, crop yield, N 2 O and CH 4 emissions, and net ecosystem economic budget (NEEB) were investigated. The treatments were: chemical NPK fertilizer (NPK), chemical NPK plus low amount of wheat straw (NPKLS), chemical NPK plus high amount of wheat straw (NPKHS), chemical NPK plus pig manure (NPKPM), chemical NPK plus cattle manure (NPKCM), and a control with no fertilizer applied (CK). The long-term straw and manure amendments enhanced soybean yield by 13.1% and 44.0%, and improved wheat yield by 6.4% and 9.9%, respectively. Meanwhile, they stimulated N 2 O emissions by 25.1% and 49.0% respectively, without significant effect on CH 4 emissions, compared to the chemical NPK fertilizer treatment (NPK). The results of structural equation model showed that soil properties tested explained 76% of the variations observed in N 2 O emissions, which were directly affected by soil nitrification capacity, pH and denitrification capacity. Although straw and manure amendments increased the total GHG emissions investigated by 25.7% and 48.6% respectively, they showed insignificant effects on the greenhouse gas intensity (GHGI), and increased NEEB by 8.6% and 21.1%, respectively, compared to the NPK treatment. This indicates that the benefits arising from crop yield improvement through the use of organic amendments can cover the carbon fees caused by increased GHG emissions. Our findings suggest that organic amendment can be an effective strategy to simultaneously increase crop yield while mitigating greenhouse gas emissions from the perspective of carbon fees. [Display omitted] • Organic amendments stimulated total GHG emissions of N 2 O and CH 4. • Soil properties tested explained 76% of the variation in N 2 O emissions. • Organic amendments improved yield without increasing the greenhouse gas intensity. • Straw and manure amendments increased the net ecosystem economic budget. [ABSTRACT FROM AUTHOR]

Abstract: To learn the historical response of cropping system to climate change will benefit the strategy decision of future cropping adaptation. In this paper, we conducted an integrated analysis of the climate records of seventy-two meteorological stations and the records of crop yields over the period 1970–2009 in Northeast China. It was found that over these forty years, the daily mean, maximum and minimum temperatures during crop growing season increased on average by 0.34°C, 0.28°C, 0.43°C every ten years, respectively. No significant change in the precipitation was found, although the differences between years were large. After de-trending the agronomic technique contributions to the increments of crop yields, the historical warming had led to great annually increments of 16.6kgha−1, 15.5kgha−1 and 3.2kgha−1 in rice, corn and soybean yields, respectively. According to the historical warming level, present cropping boundaries can be theoretically extended northward about 80km with a prolonged growing period by 10 days compared to the 1970s. Actually, the growth durations of newly approved varieties of rice, corn and soybean have really prolonged by 14.0 days, 7.0 days and 2.7 days since the 1950s, respectively. The actual growing periods of rice and corn have also respectively prolonged by 6 days and 4 days due to the adjustment of sown and harvest dates by the farmer since 1990s. The existing rice cropping region has been extended northward 80km in the 2006 compared to the 1970. These actual responses were consistent with the theoretical calculation according to the historical warming trends. Our results demonstrate that cropping system owns the potential to progressively and actively adapt to the global warming for high yield through a comprehensive strategy. [Copyright &y& Elsevier]

Abstract: Crop model projections and historical data analyses have shown that global warming may cause serious decrease in crop productivity, however, many uncertainities remain on the impact quantification due to the unclear understanding of actual crop response. Therefore, we performed a three-year field warming experiment with free air temperature increase (FATI) facility to investigate the actual response of midseason rice growth in East China. There were four treatments (AW: all-day warming; DW: daytime warming; NW: nighttime warming; CK: ambient control) with three replicates. This FATI facility presented a good simulation of the local air temperature pattern with an increase in the daily mean temperature of about 1.1–2.0°C during rice whole growth duration compared to the ambient control. Warming shortened the pre-heading phase respectively by 3.3d, 1.7d and 2.0d in the AW, DW and NW plots, while the post-heading phase stayed almost unchanged. During the three years, warming slightly decreased the aboveground biomass by an average of 9.1%, 10.3% and 3.3%, and the grain yield by an average of 0.9%, 6.4% and 6.1% in the AW, DW and NW plots, respectively. Warming tended to decrease rice photosynthesis rate and stimulate the nighttime respiration rate. It also enlarged the flag leaf area and increased its chlorophyll content. No significant difference and interaction in the actual response of rice growth were found between the warming regimes. The above evidences suggest that the expected warming less than 2.0°C may not cause significant decrease in rice productivity in East China. [Copyright &y& Elsevier]

Increasing crop biodiversity often increases agro-ecosystem services, however, the effects of crop biodiversity on crop yield and environmental benefits are still unclear. Thus, we conducted a 4-yr field experiment in northeastern China including continuous maize (CM), continuous soybean (CS), maize and soybean rotation (M-S), and maize and soybean intercropping (M/S) to evaluate the crop productivity, economic returns, carbon footprint (CF) and carbon sustainability index (CSI) among the cropping system regimes. Compared with CM treatment, M-S and M/S achieved lower energy yield (EY) and maize equivalent economic yield (MEEY), but higher economic returns. The mean annual net revenue of M-S treatment was 7.2% higher, and the mean annual benefit: cost ratio of M-S and M/S treatments were 12.0% and 8.8% higher than those of CM treatment. Based on the life cycle assessment (LCA), lower CFs were observed in the M-S and M/S systems. The CF per unit of area (CF A) of M-S and M/S treatments was 21.4% and 51.3% lower than that of the CM treatment, respectively. The CF per kg of energy yield (CF EY) of M/S treatment was 35.4% lower, compared with that of the CM treatment. The CF per kg of maize equivalent economic yield (CF MEEY) under M/S treatment was 44.0% lower, than that of the CM treatment. Moreover, CF per unit of economic output (CF E) of M/S treatment was 45.0% lower than that of the CM treatment. The highest CSI was observed in M-S treatment, and it was 61.4% higher than that of CM treatment. Our findings indicate that diversified crop practice (e.g. maize-soybean intercropping and rotation systems) could achieve lesser carbon footprint and higher profitability, however, might compromise grain or energy yield. [Display omitted] • The productivity, profitability, and environmental costs of different cropping systems were evaluated. • Diversified crop practice had lesser carbon footprint and higher profitability. • Maize-soybean intercropping systems is an alternative to the traditional maize monoculture system in northeastern China. [ABSTRACT FROM AUTHOR]