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Objective To investigate the relationship between eating habits and childhood obesity by the method of cross-sectional survey in order to provide scientific basis for the prevention and intervention of childhood obesity.Methods We enrolled first-year students in Minhang District of Shanghai who participated in physical examination in 2014.Information was obtained from standardized face to face interviews of their parents or guardians with detailed questions on demographic characteristics,dietary habit,food preference,physical activity,sleep time and so on.Odds ratio (OR) and 95％ CI were calculated by unconditional Logistic regression models.Results Finally,5 752 students were enrolled in the study.The rate of obesity was 15.16％ (boys:18.35％;girls:11.83％) and the rate of over weight was 14.31％ (boys.:15.15％;girls:13.43％).Meat-based diet (OR=1.58,95％ CI:1.32-1.91),skipping breakfast (OR =1.87,95％ CI:1.01-3.46),eating too much caffeine-containing food (OR =1.66,95％ CI:1.09-2.51) and eating fast (OR:3.32-14.95) were associated with an increased risk of childhood obesity.Plant-based diet (OR =0.51,95％ CI:0.35-0.74) and choosy in food (OR:0.38-0.64) were associated with a decreased risk of childhood obesity.Besides,we found that children who preferred meat (OR =2.11,95％CI:1.42-3.14) and cured food (OR =1.42,95％ CI:1.05-1.92) had a higher risk of obesity.Conclusions Our results support the association between eating habits and childhood obesity.

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Objective To investigate the relationship between eating habits and childhood obesity by the method of cross-sectional survey in order to provide scientific basis for the prevention and intervention of childhood obesity.Methods We enrolled first-year students in Minhang District of Shanghai who participated in physical examination in 2014.Information was obtained from standardized face to face interviews of their parents or guardians with detailed questions on demographic characteristics,dietary habit,food preference,physical activity,sleep time and so on.Odds ratio (OR) and 95％ CI were calculated by unconditional Logistic regression models.Results Finally,5 752 students were enrolled in the study.The rate of obesity was 15.16％ (boys:18.35％;girls:11.83％) and the rate of over weight was 14.31％ (boys.:15.15％;girls:13.43％).Meat-based diet (OR=1.58,95％ CI:1.32-1.91),skipping breakfast (OR =1.87,95％ CI:1.01-3.46),eating too much caffeine-containing food (OR =1.66,95％ CI:1.09-2.51) and eating fast (OR:3.32-14.95) were associated with an increased risk of childhood obesity.Plant-based diet (OR =0.51,95％ CI:0.35-0.74) and choosy in food (OR:0.38-0.64) were associated with a decreased risk of childhood obesity.Besides,we found that children who preferred meat (OR =2.11,95％CI:1.42-3.14) and cured food (OR =1.42,95％ CI:1.05-1.92) had a higher risk of obesity.Conclusions Our results support the association between eating habits and childhood obesity.

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Hyper-spectral remote sensing is one of the effective means for prediction of soil nutrients. Taking Wangjiagou small watershed of Three Gorges Reservoir Area as researching zone, based on the soil physicochemical properties, reflective spectrum analysis and measurement, were built predictive models for total phosphorous and total phosphorus concentrations in purple soil. Meanwhile, 33 soil samples from paddy soil were used to validate the prediction models for soil nutrients in purple soil. Results show that the total correlation coefficients between their predicted values and measured values of total nitrogen and total phosphorus concentration in purple soil are 0.672 and 0.498, respectively. Correlation coefficients obtained from predictive model of purple soil nutrients validated by paddy soil samples are 0.550 and 0.124. Therefore, it is reasonable to use hyper-spectrum method to prediction total nitrogen concentration. But prediction accuracy for total phosphorus concentration in purple soil is relatively poor. The prediction model of soil nutrients in purple soil is not suitable for paddy soil.

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Based on a long-term experiment of using hedgerow to control soil and water loss, this paper studied the composition and stability of soil aggregates in a hedgerow-crop slope land. Compared with those under routine contour cropping, the contents of > 0.25 mm soil mechanical-stable and water-stable aggregates under the complex mode hedgerow-crop increased significantly by 13.3%-16.1% and 37.8% -55.6%, respectively. Under the complex mode, the contents of > 0.25 mm soil water-stable aggregates on each slope position increased obviously, and the status of > 0.25 mm soil water-stable aggregates being relatively rich at low slope and poor at top slope was improved. Planting hedgerow could significantly increase the mean mass diameter and geometric mean diameter of soil aggregates, decrease the fractal dimension of soil aggregates and the destruction rate of > 0.25 mm soil aggregates, and thus, increase the stability and erosion-resistance of soil aggregates in slope cropland. No significant effects of slope and hedgerow types were observed on the composition, stability and distribution of soil aggregates.

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A 16-year field experiment was conducted in a ridge culture paddy field in the hilly region of Sichuan Basin, aimed to investigate the distribution characteristics of stable carbon isotope natural abundance (delta 13C) in soil humus fractions. The soil organic carbon (SOC) content in the paddy field under different cultivation modes ranked in the order of wide ridge culture > ridge culture > paddy and upland rotation. In soil humus substances (HS), humin (HU) was the main composition, occupying 21% - 30% of the total SOC. In the extracted soil carbon, humic acid (HA) dominated, occupying 17% - 21% of SOC and 38% - 65% of HS. The delta 13C value of SOC ranged from -27.9 per thousand to -25.6 per thousand, and the difference of the delta 13C value between 0-5 cm and 20-40 cm soil layers was about 1.9 per thousand. The delta 13C value of HA under different cultivation modes was 1 per thousand - 2 per thousand lower than that of SOC, and more approached to the delta 13C value of rapeseed and rice residues. As for fulvic acid (FA), its delta 13C value was about 2 per thousand and 4 per thousand higher than that of SOC and HA, respectively. The delta 13C value of HU in plough layer (0-20 cm) and plow layer (20-40 cm) ranged from -23.7 per thousand - -24.9 per thousand and -22.6 per thousand - -24.2 per thousand, respectively, reflecting the admixture of young and old HS. The delta 13C value in various organic carbon fractions was HU>FA>SOC>rapeseed and rice residues>HA. Long-term rice planting benefited the increase of SOC content, and cultivation mode played an important role in affecting the distribution patterns of soil humus delta 13C in plough layer and plow layer.

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This paper quantitatively described the changes of agroecosystem functions before (2003) and after (2007) the implementation of Gaolong land consolidation project in Hechuan of Chongqing. Engineering design and shadow price were integrated to quantify the effects of the project on the functions, and cost-benefit analysis was used to further explain the economic meanings of the functions, and to analyze the changes of the agroecosystem services value under effects of the project. Compared with that before the land consolidation, the agroecosystem services value after the land consolidation was somewhat improved, with the largest increment of nutrient cycling function and the smallest change of soil conservation function. In the implementation of the project, the changes of the agroecosystem services value induced by farmland water conservancy, field road building, and land-leveling engineering mainly manifested in the change of disturbance function. From the 7th to 35th year after the project, the cost benefit would have a rapid increase, and tended to be stable after then, giving a weak ecological pressure and little services value loss, and benefiting the improvement of regional ecological environment.

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A 13 year experiment was conducted to study the effects of conservational tillage on the aggregate composition and organic carbon storage in purple paddy soil of Sichuan Basin. The results showed that under no-tillage and ridge culture (rice-rape) (NR-RR), no-tillage and plain culture (rice-rape) (NP-RR), no-tillage and ridge culture (rice-green manure) (NR-RGM), tillage and ridge culture (rice-rape) (TR-RR), and tillage and plain culture (rice-rape) (TP-RR), the proportion of macroaggregates in 0-10 cm soil layer was 23%, 69%, 9%, 36%, and 28% higher than that under conventional tillage (CT) (12%), respectively, while in 10-20 cm soil layer, this proportion under conservational tillage was 9%-38% lower than that under CT. The organic carbon storages in the macroaggregates at the depth of 0-10 cm were 13%, 31% and 32% higher under no-tillage and ridge culture (rice-fallow) (NR-RF), NR-RR and NR-RGM than under CT, respectively, while that at the depth of 10-20 cm was 28%-54% lower. The differences in organic carbon storage between macro- and microaggregates were smaller in 10-20 cm layer than in 0-10 cm layer. Under conservational tillage, the organic carbon storage was 8%-28% higher in 0-10 cm layer but 4%-22% lower in 10-20 cm layer, compared with that under CT. After converted from CT to conservational tillage for 13 years, the mean organic carbon sequestration rate was 53 g x m(-2) x a(-1) and 25 g x m(-2) x a(-1) at the depths of 0-10 cm and 10-20 cm, while under CT, it was 26 g x m(-2) x a(-1) and 33 g x m(-2) x a(-1), respectively. Conservational tillage was favorable to the formation of macroaggregates in surface soil layer and the enhancement of soil total organic carbon storage.

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The terrestrial ecosystem may be either a source or a sink of CH4 in rice paddies, depending, to a great extent, on the change of ecosystem types and land use patterns. CH4 emission fluxes from paddy fields under 4 cultivation patterns (conventional plain culture of rice (T1), no-tillage and ridge culture of rice (T2), no-tillage and ridge culture of rice and wheat (T3), and rice-wheat rotation (T4)) were measured with the closed chamber technique in 1996 and 1998 in Chongqing, China. The results showed that differences existed in CH4 emission from paddy fields under these land management practices. In 1996 and 1998, CH4 emission was 71.48% and 78.82% (T2), 65.93% and 57.18% (T3), and 61.53% and 34.22% (T4) of that in T1 during the rice growing season. During the non-rice growing season, CH4 emission from rice fields was 76.23% in T2 and 38.69% in TI. The accumulated annual CH4 emission in T2, T3 and T4 in 1996 decreased by 33.53%, 63.30% and 65.73%, respectively, as compared with that in T1. In 1998, the accumulated annual CH4 emission in T1, T2, T3 and T4 was 116.96 g/m2, 68.44 g/m2, 19.70 g/m2 and 11.80 g/m2, respectively. Changes in soil physical and chemical properties, in thermal and moisture conditions in the soil and in rice plant growth induced by different land use patterns were the dominant causes for the difference in CH4 emission observed. The relative contribution of various influencing factors to CH4 emission from paddy fields differed significantly under different land use patterns. However, the general trend was that chlorophyll content in rice leaves, air temperature and temperature at the 5 cm soil layer play a major role in CH4 emission from paddy fields and the effects of illumination, relative humidity and water layer depth in the paddy field and CH4 concentration in the crop canopy were relatively non-significant. Such conservative land use patterns as no-tillage and ridge culture of rice with or without rotation with wheat are thought to be beneficial to reducing CH4 emission from paddy fields and are, therefore, recommended as a significant solution to the problems of global (climatic) change.

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