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20 December 2015, Volume 36 Issue 06

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Variation Characteristics of Thermal Resources in Different Agricultural Planting Area in Shaanxi Province

LI Hong-mei, WANG Yu-liang, LEI Xiang-jie, QUAN Wen-ting, HE Hui-juan

2015, 36(06):  653-665.  doi:10.3969/j.issn.1000-6362.2015.06.001

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The distribution and variation characteristics of the thermal resources including average temperature, extreme temperatures and critical temperature (≥0℃ and ≥10℃) indices in Shaanxi province from 1971 to 2013 were analyzed based on the data from 96 meteorological stations by using the methods of linear trend estimation, accumulative anomaly, t-test and GIS technique. The results showed that annual and seasonal average temperature increased significantly in Shaanxi province in recent 43 years (P＜0.05), and maximum increasing in spring at the rate of 0.4℃-10y-1. There was significant correlation between average temperature and other thermal resources elements (P＜0.01).The warming rate of spring average temperature in Guanzhong plain was the largest, and its mutation point was 1997, which was consistent with other regions. Annul and other seasonal average temperature of wind-blown sand area in northern Yuling was the largest increased value, and its abrupt time was the latest in summer. The warming rate of annual and seasonal average temperature in river valley and hills of southern Shaanxi was the least, and its abrupt time was the latest in autumn and winter. The initial day ≥0℃ and ≥10℃ advanced remarkably and the final day showed an insignificantly delaying trend. The biggest advanced of initial day ≥0℃ and ≥10℃ was in Guanzhong plain and wind-blown sand area in northern Yuling, respectively. Influenced by the initial day advancing and the final day delaying, accumulated temperature ≥0℃ and ≥10℃ and their duration were increased significantly by 90.3℃-d-10y-1,74.9℃-d-10y-1,3.5d-10y-1 and 2.4d-10y-1, respectively, especially in Guanzhong plain. The winter average temperature mutation appeared in 1987 and other thermal resources elements occurred abruptly change in the middle and late 1990s. The contours of accumulated temperature ≥0℃ and ≥10℃ remarkably moved westward after 1997. After the abruption, the change ranges of accumulated temperature ≥0℃ and ≥10℃ were the most significantly in Guanzhong plain but the least in Shanbei Loess Plateau.

Impact of ENSO Event on Precipitation and Drought Index in Shandong Province

MA Lu, YANG Dong, QIAN Da-wen

2015, 36(06):  666-673.  doi:10.3969/j.issn.1000-6362.2015.06.002

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Based on the monthly temperature, precipitation data and the standardized precipitation evapotranspiration indices (SPEI) of 18 meteorological stations in Shandong province, the impact of ENSO events on climate change and drought variation were analyzed during recent 53 years in the study area. The results showed that：(1)the mean annual temperature of Shandong province was experienced fluctuation growth trend with a speed of 0.26℃·10y-1 (P＜0.05), but it was not proved a significant relationship with ENSO events. (2)The annual precipitation of Shandong province was also experienced fluctuation growth with a speed of -15.32mm·10y-1 (P＜0.05) and tested a significant negative correlation with the intensity of ENSO events, and the impact of moderate and strong ENSO events were more obvious. The monthly precipitation was lagged 1 to 2 months and 0 to 4 months by warm and cold ENSO events respectively. (3)The SPEI of Shandong province was decreased slowly nearly 53 years, while the frequency and intensity of drought were increased significantly from the 1980s. There were 11 years of domain drought, 4 years of regional drought, 6 years of partial-local drought and 17 years of local drought totally, and the spatial extent of the drought was gradually increased. (4)The intensity of ENSO events and SPEI was examined a significant negative correlation (P＜0.05), and a positive correlation with the drought extent (P＜0.05).

Changes of the Accumulated Temperature above 10℃ in East China

TANG Bao-qi，YAN Jun-ping，LI Ying-jie

2015, 36(06):  674-682.  doi:10.3969/j.issn.1000-6362.2015.06.003

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Based on the surface temperature data of the 86 stations in East China during 1961 to 2013, the author analyzed the variation of accumulated temperature steadily above 10℃ and discussed the characteristics of climatic zones during 1961 to 2013 by using trend analysis, Kriging spatial interpolation method, Mann-kendall mutation test and Pearson correlation analysis. The results showed:(1) in recent 53 years, the accumulated temperature steadily above 10℃ and the duration days were increasing at the rate of 89.71℃-d-10y-1 (P＜0.01) and 2.96 d-10y-1 (P＜0.05) respectively in East China, this phenomenon was mainly because of the advance of beginning date and the delaying of ending date. Furthermore, the advancing of beginning date was more influential than the delaying of ending date. (2) The accumulated temperature steadily ≥10℃ and duration days presented an obvious latitude and vertical zonal characteristic. And the change rate showed a decrease trend from east to west, from the centre to the north and south. (3) Under the background of global warming, the climatic zone had a trend of extending to northward and eastward in East China. South subtropical zone and central subtropical zone was gradually expanding, respectively shift 1.2 and 2.2 degrees. While north subtropical zone and temperate zone showed a decreasing trend. The northern boundary of mid-subtropical zone shifted 2.0°. Overall the climatic zones shifted northward. (4) Responding to temperature rose, the heat resources highlighted the sustained days increased, and the beginning date advanced as well as the ending date delayed. The correlation between the accumulated temperature and the average temperature was the best.

Spatiotemporal Variation and Sensitivity of Reference Crop Evapotranspiration during Growth Season in Northern Xinjiang

LI Si-si, ZHANG Fei-yun, BAI Lei, LI Lan-hai

2015, 36(06):  683-691.  doi:10.3969/j.issn.1000-6362.2015.06.004

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Based on daily meteorological data from 20 meteorological stations from 1966 to 2012, ET0 was calculated during crops growing season by using the Penman-Monteith equation. The spatiotemporal variation of ET0 and its sensitivity to key climatic factors were analyzed by using of the Mann-Kendall test, the factors' dedication rate, and sensitive coefficients. The results showed that the average ET0 in Northern Xinjiang was 939.43mm, and the ET0 decreased at the rate of 16.30mm·10y-1 in last 47 years, with an abrupt change in 1981 according to the Mann-Kendall trend test. Low ET0 values occurred in mountain regions, while high values were found in the Junggar basin and piedmont plain. Average wind speed played the most important role with regards to changes in ET0, followed by temperature, vapor pressure, and sunshine hours. ET0 was sensitive to vapor pressure negatively, and sensitive to temperature, average wind speed, and sunshine hours positively in Northern Xinjiang. The values of sensitive coefficients to climatic factors were temperature, vapor pressure, wind speed, and sunshine hours. The promoting effect of elevated vapor pressure, less wind speed, and less sunshine hours on ET0 was stronger than the reducing effect of increased temperature, which was the key reason that ET0 decreased generally during crops growth season in Northern Xinjiang.

Temporal and Spatial Variation of Reference Crop Evapotranspiration and Contribution of Main Factors in the Middle Area of Shandong Province

HUAN Hai-jun，YANG Zai-qiang, LIU Yan, XIA Fu-hua

2015, 36(06):  692-698.  doi:10.3969/j.issn.1000-6362.2015.06.005

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Based on the meteorological data in the middle areas of Shandong Province from 1980 to 2014, the reference crop evapotranspiration(ET0) was calculated by Penman-Monteith model, the spatial and temporal distribution characteristics of the main meteorological factors and ET0 of different time scales were analyzed, and the contribution to ET0 changes of different time scales made by main meteorological factors was also discussed with a method based on sensitivity coefficient. The results showed that annual average ET0 of the plain was 1165.8mm, and the mountainous area was 1144 6mm in the past 35 years,which had an extremely significant reduction trend in the plain, at the rate of 22.2mm·10y-1(P<0.01).The seasonal average ET0 from high to low was summer, spring, autumn and winter, which had an increasing trend in spring and a reduction trend in other seasons. The maximum monthly average ET0 appeared at June, the minimum value appeared at January, and annual distribution presented parabolic shape.The main space distribution of all time scales was basic synchronization. Annual and seasonal average ET0 was sensitive to the changes of relative humidity and it tended to increase. The sensitivity of monthly average ET0 to main meteorological factors had different changing rules by the month. The most sensitive factor which affected monthly average ET0 was relative humidity from March to June, September and October, wind speed in January, February, November and December, percentage of sunshine in July and August. According to the main contribution rate, wind speed had the largest contribution to the annual average ET0, seasonal and monthly average ET0 was different between main contribution factors while the main contribution factors at the time scale in plain and mountain was basically the same. The total contribution rate of four main meteorological factors could basically explain the reasons of ET0 changing of different scales.

Effects of Different Mulching Models on Soil Moisture and Summer Maize Yields

HU Ya-jin, WU Shu-fang, FENG Hao, CAO Han

2015, 36(06):  699-708.  doi:10.3969/j.issn.1000-6362.2015.06.006

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To explore the effects of different mulching modes on soil moisture, summer maize yield, and water use efficiency (WUE) in semi-humid drought-prone area, the field experiment was conducted at water-saving irrigation station, Yangling, Shaanxi province from June to October in 2014. Four treatments, including the ridge with plastic film and dent with wheat straw (PSM), flat plot with plastic film-mulched (PM), flat plot with wheat straw (SM), and flat plot without mulch as the control (CK), were designed in the experiment. The soil moisture and its variation during the growth season of summer maize were dynamically monitored by using of TRIME-TDR and EM50, and water use efficiency (WUE) under different mulching modes was analyzed. The results showed that after precipitation of 30.5mm, the treatment of PSM had the most obvious effect on water collection, while after two days of rainfall, the highest soil moisture, as 35.8%, was in the layer of 0-40cm. After 6 days rainfall, the soil moisture in the layer of 0-40cm decreased by 10.3%, 2.9%, 1.8% and 0.2% under the treatments of CK, PSM-F, PM and SM, respectively, while the soil moisture of the treatment of PSM-B increased by 10.4%. For the treatment of PSM, soil moisture in the ditch and the ridge was very different during the dry season, and similar during rainy season. Soil water storage in the layer of 0-20cm of all mulch treatments was significantly higher than that of CK, particularly in PSM. After the seeding stage, soil water storage in the layer of 20-100cm was lower in all mulch treatments than in CK. Soil water storage in the layer of 100-200cm was highest in SM treatment and lowest in PSM treatment. There was a significant positive correlation between the yield of summer maize and the soil water consumption during jointing stage to filling stage (r=0.98*). The yields of summer maize with PSM, PM and SM increased by 95.3%, 83.1% and 55.4% than that of CK, and WUE increased by 75.7%, 71.0% and 58.8% than that of CK, respectively. The results indicated that SPM treatment increased the yield of summer maize and WUE, which was recommended to apply to semi-humid drought-prone region.

Effects of Biochar on the Key Soil Nitrogen Transformation Processes in Agricultural Soil

ZHANG Xing, ZHANG Qing-wen, LIU Xing-ren, XU Ying-chun，REN Jian-qiang

2015, 36(06):  709-716.  doi:10.3969/j.issn.1000-6362.2015.06.007

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Biochar, as an unique soil amendment, can effectively improve soil structure, improve the ability of absorbing nutrients, reduce greenhouse gas emissions and increase biological nitrogen fixation. Therefore, it has great prospects in agriculture production and mitigating climate change. Biochar input will directly affect the agricultural soil nitrogen cycle and transformation, so this review focuses on the effects of biochar on soil nitrogen transformation processes such as nitrogen mineralization, nitrification, denitrification, the relevant nitrogen loss, and biological nitrogen fixation processes and relevant mechanisms. Based on the review on published literature, we proposed that the future research should strengthen the mechanism nitrogen transformation and the long-term positive or negative effects of biochar on environment, to carry out research on related microbial community diversity, abundance and activity in terms of soil, as well as biochar studies should be based on a unified standard to clearly distinguish the effect of different biochar and its mechanism.

Impacts of Elevated CO2 Concentration and Temperature Increasing on Growth and Yield of Late Rice

CAI Wei-wei, WAN Yun-fan, AI Tian-cheng, YOU Song-cai, LI Yu-e, WANG Bin

2015, 36(06):  717-723.  doi:10.3969/j.issn.1000-6362.2015.06.008

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Atmospheric CO2 concentration has been increasing, it is necessary to reveal the impact of elevated CO2 concentration and temperature on rice growth and yield, which could provide basis references for national food security evaluation in future climate change. A modified open-top chamber was used to simulate relative 60μL·L-1 CO2 concentration increment and 2℃ temperature increasing in late rice field. Three treatments were arranged in randomized blocks and three replicates. Treatments were the control OTC (CK, ambient CO2 concentration and temperature), temperature increased by 2℃ (IT), temperature increased by 2℃ plus CO2 concentration elevated by 60μL·L-1 (IT+IC). The plant height, tillers, Chlorophyll content, leaf area index, yield and yield components of late rice were investigated. The results showed that elevated temperature increased significantly the plant height, with 3cm improvement in whole growth season, while there was no influence under elevated atmospheric CO2 concentration and temperature synchronously. About 20 days after transplanting, the elevated temperature had positive effects on tillers and increased 1 stem per hole, but the combination of elevated CO2 and temperature had no influence. The elevated temperature improved 0.8 SPAD leaf chlorophyll content and leaf area index, while elevated CO2 and temperature had no influence on chlorophyll content. Elevated CO2 and temperature increased significantly grain yield by 14.0%. But the elevated temperature was not significant influence, because elevated temperature increased the sterile rate and decreased thousand grain weights, which resulted in the insignificant increase of grain yield.

Effect of High Temperature Stress on Rice Spikelet Differentiation and Degeneration during Panicle Initiation Stage

WANG Ya-liang, ZHANG Yu-ping, ZENG Yan-hua, WU Hui, XIANG Jing, CHEN Hui-zhe, ZHANG Yi-kai, ZHU De-feng

2015, 36(06):  724-731.  doi:10.3969/j.issn.1000-6362.2015.06.009

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Pot experiments were conducted under artificial climate chambers conditions to assess the effect of high temperature stress on rice spikelet differentiation and degeneration during panicle initiation stage. Two indica rice cultivars with different heat-tolerance levels, ‘Huanghuazhan’ (heat-tolerant) and ‘Fengliangyou6’ (heat-sensitive), were subjected to treatments in artificial climate chambers for 7 days of high temperature stress (40℃, 10：00-15：00) and natural temperature(32℃, 10：00-15：00) at four different periods as follows: bud differentiation stage (I), branch and floret differentiation stage (II), spikelet differentiation to pistil-stamen formation stage (Ⅲ), pistil-stamen formation to pollen meiosis stage (Ⅳ), meanwhile the rice grown in ambient was as CK. The results indicated that, (1)high temperature stress increased the number of panicle initiation day, delayed rice heading date, and significantly reduced panicle weight, grain number per panicle，seed-setting rate and 1000-grain weight, especially at period Ⅳ, there were more reduction in ‘Fengliangyou6’ than in ‘Huanghuazhan’.(2)Spikelet differentiation and degeneration exerted significance difference among treatments of four periods, high temperature stress reduce the number of spikelet differentiation at periodsⅠand Ⅱ, but ‘Huanghuazhan’'s spikelet differentiation number increased after treating at periodⅡ. High temperature tress significantly increased the ratio of spikelet degeneration of two cultivars at period Ⅲ and Ⅳ, especially it was up to 67% at period Ⅳ, and the ratio of spikelet degeneration of ‘Fengliangyo6’ was higher than ‘Huanghuazhan’. (3) Spikelet differentiation and degeneration on secondary branches were more seriously affected by high temperature than primary branches.

Relationship between the Grain Filling Characteristics of Hybrid Rice and Temperature and Light Factors

LU Kui-dong,NING Jin-hua,SONG Zhong-hua, ZHANG Yan-gui, XIE Bai-cheng

2015, 36(06):  732-738.  doi:10.3969/j.issn.1000-6362.2015.06.010

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Based on the super hybrid rice ‘Yueyou6135’ field investigate data at different sowing stage from 2011 to 2013, the grain weight was counted once 5 days from head sprouting to ripe period, and the grain filling rates were calculated. Meanwhile, grain filling rates and grained weight models were erected according to every day temperature and sunshine duration. Relationship between rice varieties and meteorological factors and the optimal meteorological condition on rice grouting were determined. The results showed that the relationship grain filling rates and grain weight with temperature and sunshine duration were linear duality function, but the relationship grain filling rates and grain weight with temperature and photoperiod were binary quadratic functions. The relationship between grain filling characteristics with different temperature factors are superior to sunshine duration, the relationship between different temperature factors and temperature and photoperiod with grain weight are superior to grain filling rates. The daily minimum temperature and sunshine duration are important factors to hybrid rice ‘Yueyou6135’. To some extent, it affects the hybrid rich grain filling rates. When accumulated temperature reach 900℃·d and the sunshine duration is close to 300 hours, the grain weight get to maximum value, it show that grain filling process is tend to complete, the grain plumpness gained the ideally. Therefore, the results will offer some theorists’ basis to hybrid rice planting, or making the most of meteorological resources and arrange rational sowing stage.

Influence of Light Quality and Photoperiod on Growth and Nutritional Quality of Three Leaf-color Lettuce Cultivars under Weak Light

YU Yi, LIU Wen-ke

2015, 36(06):  739-745.  doi:10.3969/j.issn.1000-6362.2015.06.011

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Three leaf-color lettuces were hydroponically cultivated in culturing room with artificial light in greenhouse to investigate the influence of light quality and photoperiod on their growth and nutritional quality. The results showed that the yield of three kinds of lettuce was mainly affected by photoperiod and the nutritional quality was primarily influenced by combined action of light quality and photoperiod. Extension of lighting period enlarged the leaf area of the three kinds of lettuce. Fresh weight unit leaf area of green lettuce and red lettuce didn’t changed much when the light quality and photoperiod altered. However, fresh weight unit leaf area of purple lettuce responded to the change of photoperiod differently with the variation of light quality. Shoot fresh weight of three lettuce improved more than 100% when the lighting period prolonged. The effects of photoperiod on nutritional quality of the three kinds of lettuce differed when the light quality varied. When under RB 1:2 light, total phenols and flavonoid relative contents, ascorbic acid and soluble protein contents dropped greatly after treated with lighting period extension. And anthocyanin and soluble sugar contents of red lettuce improved significantly when lighting period extended, while ascorbic acid and soluble protein contents decreased. Total phenols relative content of purple lettuce increased, but ascorbic acid content reduced. However, when under RB 2:1 light, total phenols and flavonoid relative contents of green lettuce increase remarkably, but ascorbic acid content lessened. And phenols and flavonoid relative contents, ascorbic acid, soluble sugar and soluble protein contents of red lettuce dropped strikingly. Total phenols relative content of purple lettuce improved significantly under treatment lighting period extension. To summarize，extending lighting period could enhance the yield of the three kinds of lettuce, and this phenomenon could be free from the effect of light quality. Extension of lighting period could lifted the contents of anthocyanin and soluble sugar of red lettuce under RB 1:2 light. While under RB 2:1 light, nutritional quality of green lettuce and purple lettuce could be improved greatly by lighting period extension.

Effects of Simulated Warming and Precipitation Enhancement on Litter Decomposition of Stipa krylovii Steppe

DAN Mu-chun, YANG Jie, HOU Hong, ZHANG Li-xing, SONG Bing-yu

2015, 36(06):  746-754.  doi:10.3969/j.issn.1000-6362.2015.06.012

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In this study, open top chambers (OTCs) were used to simulate warming. Three treatments, warming (W), precipitation enhancement(P), warming combine with precipitation enhancement(WP) were set in comparison with natural state to investigate the litter decomposition rate of main species in Stipa krylovii steppe including Stipa krylovii, Cleistogenes squarrosa, Artemisia frigida and the community littlers. The results showed that: (1) after one year of decomposition, the fraction of mass remaining of all litter types in warming treatment were higher than those of control, so warming slowed down the decomposition rate of the litters. The interactive effect of warming and precipitation enhancement on the mass remaining fraction of all litter types was consistent with that of warming tratment, but the influence of warming on the the litter decomposition was greater. However, enhanced precipitation had no significant influence on the litter mass remaining faction. (2)Warming did not influence the litter decomposition process of different litter types, while enhanced precipitation significantly accelerated the decomposition processes of Cleistogenes squarrosa. Warming combining with enhanced precipitation influenced decomposition of Artemisia frigida strongly. (3)Analysis of variance showed that the effects of warming and enhanced precipitation on litter decomposition were mainly related to the litter types and the duration of decompostion. (4) Olso negative index model was used to simulate the litter mass loss processs, which showed that under warming treatment the k values (characterization of decomposition rate) of all the litter types except for Artemisia frigida were lower than the control, while in enhanced precipitation treatment the k values were higher for Stipa krylovii and Cleistogenes squarrosa but lower for Artemisia frigida and coummity litters compared to the control. The interactive effect of warming and enhanced precipitation on k values of all the litter types was consistent with that of warming, but the k values under warming and precipitation enhancement treatment were higer than those of warming. Our results suggested that the litter decomposition rate of Stipa krylovii steppe in Inner Mongolia would tend to slow down under future climate change. Warming and precipitation variation due to climate change have important influence on litter decomposition,but few researches focused on the interactive effect of warming and precipitation variation on the litter decomposition.

Analysis on the Drought Characteristics in Different Growth Stages of Spring Maize in Shanxi Province

ZHANG Zu-guang, HAO Wei-ping, LI Hao-ru, MAO Li-li, GAO Xiang

2015, 36(06):  754-761.  doi:10.3969/j.issn.1000-6362.2015.06.013

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Based on the data of daily temperature and precipitation in spring maize growth stages collected from 15 observation meteorological stations in Shanxi province from 1981 to 2011, relative moist index(M) in different spring maize growth stages were calculated, and combined with coupling degree between precipitation and spring maize water requirement, the variability of drought of recent 31 years in growth stages of spring maize in Shanxi province were analyzed. The results indicated that，(1) in recent 31 years, the highest drought frequency of 86.95% occurred in seeding to jointing stage of spring maize in Shanxi province, in which there was most serious water scarcity, and the coupling degree between precipitation and spring maize water requirement was only 0.41, which was the lowest during the spring maize growth stage, and most of the droughts were moderate drought, strong drought and severe drought; In sowing to seeding stage of spring maize, the drought frequency was 82.47%, and most of the droughts were moderate drought, strong drought and severe drought, the coupling degree between precipitation and spring maize water requirement in northern and middle part was 0.45 and 0.41 respectively, but the precipitation was matched with the spring maize water requirement in southern Shanxi. In jointing to tasseling stage of spring maize, the coupling degree between the precipitation and spring maize water requirement was 0.69, the drought occurrence frequency was 51.51%, and most of the droughts were slight; the drought occurrence frequency was 32.58%-43.33% in tasseling to milky maturity and milky maturity to full maturity stage of spring maize, in which most of the drought was slight drought, and precipitation was generally matched with the spring maize water requirement. (2)Drought occurrence frequency was decreased and coupling degree between precipitation and spring maize water requirement was increased from Northern to Southern Shanxi. The proportion of moderate, severe and extra severe drought occurrence frequency to all the drought occurrence frequency were highest in sowing to seeding of spring maize, which was up to 86.73%,79.43% and 72.88% in Northern, Middle and Southern Shanxi, respectively.

Estimation of Rice Canopy LAI with Different Growth Stages Based on Hyperspectral Remote Sensing Data

XIN Ming-yue, YIN Hong, CHEN Long, ZHANG Mei-ling, REN Zhi-yong, MIAO Jing

2015, 36(06):  762-768.  doi:10.3969/j.issn.1000-6362.2015.06.014

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To explore the relationship between hyperspectral reflectance, vegetation indexes and LAI, the experiment was conducted from 2011 and 2012. Rice canopy hyperspectral data was measured at different growth stages by using the ASD Field Spec Hand Held portable field spectrometer, rice canopy leaf area index (LAI) was collected at the same time by using SUNSCAN canopy analysis system. LAI estimation model was established and the simulation results were compared. The results showed that LAI was better simulated by spectral log form heading stage to maturity stage, but could not simulated by reflectance during the stage of tillering to heading. Among all of vegetation indexes estimation methods, LAI was best simulated by MSAVI (modified soil-adjusted vegetation index) [758, 805], the correlation coefficient between simulating data and testing data was significant (R=0.7754). From the heading stage to maturity stage, LAI was best simulated by MSAVI [758, 817], the correlation coefficient between simulating data and testing data was significant (R=0.6488). The results indicated that MSAVI could simulated LAI of rice at different growth stages.