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Wu Y.,Chinese Academy of Agricultural Sciences | Wu Y.,Key Laboratory of Agro Environment and Climate Change | Ma Y.,Beijing Institute of Petrochemical Technology
2010 International Conference on Mechanic Automation and Control Engineering, MACE2010 | Year: 2010

Understanding of seasonal drought characteristics of the hilly areas in southern China is helpful to guide reasonably the local environment management. In this paper, the seasonal drought is divided into spring drought (SPD), spring-summer continuous drought (SSD), summer drought (SUD), summer-autumn continuous drought (SAD), autumn drought (AUD), autumn-winter continuous drought (AWD), winter drought (WID) and winter-spring continuous drought (WSD). Based on the monthly precipitation data of the 295 ground-based meteorological stations of southern China and its surrounding regions from 1961 to 2005, a Drought Severity index (DSI) is built firstly and graded into Mild, Moderate, Severe and Extreme, to reflect the spatial patterns of the various drought occurrences in 1961-2005 under the support of GIS technique. The results indicate that: (1) WID, WSD and SPD mainly occur in the west of southern China, SAD and AUD in the southeast. AWD mainly occurs in the west and southeast. SUD is most extensive in the regions. (2) In the SPD, SUD, AUD, AWD and WSD regions, the seasonal drought events always occur along with higher air temperature. Almost all seasons have a trend to become hot. SPD, SAD, WID and WSD are gradually alleviative. SUD and AUD have a trend to become severe. AWD is gradually alleviative until 1983. ©2010 IEEE.

Wu Y.,Chinese Academy of Agricultural Sciences | Gong Z.,China Agricultural University | Liu B.,Chinese Academy of Agricultural Sciences | Li M.,Key Laboratory of Agro Environment and Climate Change | Lu M.,Nanjing University of Information Science and Technology
Nongye Jixie Xuebao/Transactions of the Chinese Society of Agricultural Machinery | Year: 2010

In view of the shortages of traditional agro-meteorological observations and current automatic collecting techniques based on the sensors, an automatic collecting system of agro-meteorology information was built based on remote monitoring technique. Its total devices were composed of collecting front of the field microclimate, collecting front of the video, data collecting device, data transmission device and power equipment. The system highly integrated collection and transmission of the field microclimate data and video information, and automatically collected precipitation, air temperature, air humidity, wind speed, wind direction, photosynthetic active radiation, soil temperature, soil moisture and crop video information. The remote client software could achieve a real-time dynamic display and remote monitoring for all information. The test in Zhengzhou, Hebi, Wenjiang and Jingzhou stations showed that the system had a good performance in automatic collection, integrated transmission, real-time dynamic display and remote monitoring. It provided the basis for automatic identification, disasters information extracting and even crop yields estimation.

Dong Y.-W.,Chinese Academy of Agricultural Sciences | Dong Y.-W.,Key Laboratory of Dryland Farming and Water Saving Agriculture | Yang S.-Q.,Chinese Academy of Agricultural Sciences | Xu C.-Y.,Key Laboratory of Dryland Farming and Water Saving Agriculture | And 5 more authors.
Pedosphere | Year: 2011

Soil quality monitoring is important in precision agriculture. This study aimed to examine the possibility of assessing the soil parameters in apple-growing regions using spectroscopic methods. A total of 111 soil samples were collected from 11 typical sites of apple orchards, and the croplands surrounding them. Near-infrared (NIR) and mid-infrared (MIR) spectra, combined with partial least square regression, were used to predict the soil parameters, including organic matter (OM) content, pH, and the contents of As, Cu, Zn, Pb, and Cr. Organic matter and pH were closely correlated with As and the heavy metals. The NIR model showed a high prediction accuracy for the determination of OM, pH, and As, with correlation coefficients (r) of 0.89, 0.89, and 0.90, respectively. The predictions of these three parameters by MIR showed reduced accuracy, with r values of 0.77, 0.84, and 0.92, respectively. The heavy metals could also be measured by spectroscopy due to their correlation with organic matter. Both NIR and MIR had high correlation coefficients for the determination of Cu, Zn, and Cr, with standard errors of prediction of 2.95, 10.48, and 9.49 mg kg -1 for NIR and 3.69, 5.84, and 6.94 mg kg -1 for MIR, respectively. Pb content behaved differently from the other parameters. Both NIR and MIR underestimated Pb content, with r values of 0.67 and 0.56 and standard errors of prediction of 3.46 and 2.99, respectively. Cu and Zn had a higher correlation with OM and pH and were better predicted than Pb and Cr. Thus, NIR spectra could accurately predict several soil parameters, metallic and nonmetallic, simultaneously, and were more feasible than MIR in analyzing soil parameters in the study area. © 2011 Soil Science Society of China.

Xu X.,Shaanxi University of Science and Technology | Zhang M.,Shaanxi University of Science and Technology | Jia M.,Shaanxi University of Science and Technology | Song J.,Key Laboratory of Agro Environment and Climate Change | Ma X.,Northwestern Polytechnical University
Gaofenzi Cailiao Kexue Yu Gongcheng/Polymeric Materials Science and Engineering | Year: 2015

The bamboo fiber (BF) was acetylated and blended with poly (butylene succinate) (PBS). The effects of acetylation condition on mechanical properties, the crystallization properties and thermal properties of bamboo fiber/PBS composites were investigated. Molecular dynamics simulation was used to study the compatibility of composites. The results show that the acetyl is introduced into the bamboo fiber in FT-IR. The mass ratio of bamboo fiber, acetic anhydride and ice acetic acid set as 1∶2.16∶9.18, the amount of catalyst as 0.15% of bamboo fiber at 50℃ for 2 h, the (Ac-BF)/PBS composites get the best mechanical properties, crystallization and thermal properties. Molecular simulations results show that strong interaction exists between Ac-BF and PBS matrix. The lower Flory-Huggins interaction parameters (χ) and mixed energy (Emix) show a more stable system of Ac-BF/PBS composites. The interface compatibility is effectively improved which verify the performance improvement of the composites. © 2015, Editorial Board of Polymer Materials Science & Engineering. All right reserved.

Yang S.-Q.,Chinese Academy of Agricultural Sciences | Yang S.-Q.,Key Laboratory of Agro Environment and Climate Change | Wang Y.-S.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Xie X.-J.,Northwest University, China | And 2 more authors.
Chinese Journal of Applied Ecology | Year: 2014

The effect of swine manure application on nitrate nitrogen leaching was investigated in the Yellow River irrigation area of Ningxia. The field experiment was conducted with 3 Treatments: Traditional fertilization 225 kg N kg·hm-2 without swine manure(CK), traditional fertilization with swine manure 4500 kg · hm-2(T1) and traditional fertilization with swine manure 9000 kg·hm-2(T2). Nitrate nitrogen leaching rates were measured for 30, 60, 90 cm depth soil layers with a resin core absorption method. The results indicated that the nitrate leaching losses of T1 and T2 treatments ranged from 9.33 to 14.04 kg·hm-2(pure nitrogen), which accounted for 4.2% - 6.2% of applied nitrogen fertilizer. Compared to CK, the nitrate leaching losses of T1 and T2 increased by 2.6% and 2.1% at 30 cm depth, increased by 1.5% and decreased by 1.3% at 60 cm depth, decreased by 8.7% and increased by 4.0% at 90 cm depth, respectively. The difference did not reach statistical significance among CK and T1 and T2 in nitrate leaching loss at 30, 60 and 90 cm depths. However, there was a declining trend of nitrate leaching at deep soil layers of treatments. The key period of nitrate leaching loss was from spring reviving to early filling stage, which had a higher daily leaching loss than the average of the whole growth period, and accounted for 58.7%-75.3% of total leaching loss. Compared with CK, the yields of T1 and T2 increased by 9.3% and 12.5%, respectively.

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