Distribution Characteristics of Soil Total Nitrogen in Low-efficiency Forest Land in the Northern Windy Desert Area of Jingbian County

[Objectives]The paper was to investigate the distribution characteristics of soil total nitrogen in low-efficiency forest land in the northern windy desert area of Jingbian County.[Methods]The distribution of soil total nitrogen in the 0-40 cm soil layer of 5 towns in the northern windy desert area of Jingbian County was studied through field sampling and laboratory detection.[Results]The average soil total nitrogen contents of Hongdunjie Town,Haizetan Town,Huanghaojie Town,Ningtiaoliang Town,Dongkeng Town and windy desert area in the 0-20 cm soil layer were 0.259,0.224,0.242,0.248,0.431 and 0.275 g/kg,respectively.The soil total nitrogen content in Dongkeng Town was higher than those in other towns,while there was little difference among other regions.The average total nitrogen contents in the 20-40 cm soil layer were 0.239,0.285,0.113,0.262,0.349 and 0.241 g/kg,respectively.The soil total nitrogen content in Huanghaojie Town was slightly lower than those in other towns,while that in Dongkeng town was higher.The variation coefficient of soil total nitrogen content in the survey area was greater than 30%,and there was great difference in spatial distribution.With the increase of soil depth,there was little change in soil total nitrogen content,namely the soil total nitrogen contents in 5 towns and windy desert area were not statistically different in the 0-40 cm soil layer.According to the nutrient grading standard of the second national soil survey,the soil total nitrogen content in the survey area was in the deficiency grade.[Conclusions]The research will provide a scientific guidance for the healthy and sustainable development of vegetation in arid regions.

Formation mechanisms and remediation techniques for low-efficiency artificial shelter forests on the Chinese Loess Plateau

The construction of artificial shelter forests(ASFs)has resulted in substantial ecological,economic,and societal benefits to the Chinese Loess Plateau(CLP).However,the health and benefits of ASFs are being increasingly threatened by the formation of low-efficiency artificial shelter forests(LEASFs).In this study,LEASFs are systematically analyzed in terms of their status,formation mechanisms,and developmental obstacles.The key restoration techniques and schemes were summarized to improve the quality and efficiency of LEASFs.LEASFs are formed by relatively complex mechanisms,but they arise mainly due to poor habitat conditions,improper tree species selections,mismatch between stands and habitat,extensive forest management measures,and human interferences.The restoration and improvement of LEASFs are hindered by water deficits,mismatch between stands and habitat,single management purpose,and low efficiency.LEASFs are becoming more complex due to their wide range,the challenges associated with their restoration,and insufficient technological measures for their restoration.The key techniques of the quality and efficiency improvement of LEASFs include basic forest tending methods,near-natural restoration,multifunction-oriented improvement,and systematic restoration.An understanding on the formation mechanisms of LEASFs and a scientific approach toward their restoration are urgently needed and critical for the ecological protection and high-quality development of LEASFs on the CLP.Based on these analyses,we recommend strengthening the monitoring and supervision of LEASFs,considering the bearing capacity of regional water resources,implementing multiple restoration techniques,promoting multifunction-oriented ecological development,and exploring new management concepts to achieve the sustainable development of ASFs on the CLP.

The Type of Low-yielding Fields,Using Direction and Land Fertility Building Measures in Suiping County

Using the evaluation indicator system for arable land fertility in Suiping County,this paper analyzes some factors influencing agricultural production,such as physical and chemical properties of soil,site conditions,soil management,and soil nutrients concerning various types of low-yielding fields in the county. In accordance with the dominant soil constraint factors and main direction of improvement,the lowyielding fields in the county are divided into four types: irrigation improvement type,waterlogging drainage type,barren soil fertilization and barrier layer type. Finally this paper offers specific guidance on the construction of arable land.

Actuality and Improvement Measures of Mediumand Low-yielding Farmland in Liaoning Province

In order to improve the quality of cultivated land in Liaoning Province in the light of local conditions, medium- and low-yielding farmland in Liaoning Province are divided into various zones according to characteristics of the terrain, and the practical and feasible improvement measures are put forward based on the current situation and main existing problems in the medium- and low-yielding farmland in different areas,

Distribution Characteristics of Soil Organic Carbon in Degraded Forest Land in the Sandstorm Area of Jingbian County,Shaanxi Province

[Objectives]To explore the distribution characteristics of soil organic carbon in degraded forest land in the sandstorm area of Jingbian County,Shaanxi Province.[Methods]The distribution characteristics and abundance of 0-20 cm shallow soil organic carbon in 5 towns in the sandstorm area in the north of Jingbian County were studied by field sampling and indoor detection.[Results]The average soil organic carbon contents in Hongdunjie Town,Haizetan Town,Huanghaojie Town,Ningtiaoliang Town and Dongkeng Town were 2.93,3.21,2.53,2.54 and 4.08 g/kg,respectively,which were all lower than the national background value(31.00 g/kg).The coefficients of variation of soil organic carbon content in Hongdunjie Town,Huanghaojie Town and Dongkeng Town were 59.04%,35.97%and 47.55%,respectively,with higher coefficients of variation and larger differences in spatial distribution.The organic carbon content of Haizetan Town and Dongkeng Town was above the abundance,accounting for 70%and 50%,which were relatively rich,while the soil organic carbon content of Hongdunjie was relatively scarce.The average content of soil organic carbon in the sandstorm area was 3.03 g/kg,which was also lower than the national background value.The coefficient of variation was 46.53%,showing high coefficient of variation and large difference in spatial distribution.In addition,20.41%of the average content of soil organic carbon in the sandstorm area was in the deficient level,and 79.59%were in the medium or above level.[Conclusions]The study of distribution characteristics of soil organic carbon in degraded forest land in the sandstorm area of Jingbian County will better serve the precise management of soil resources.

A Preliminary Investigation of Low Yield Reason of Camellia oleifera in Dehong Prefecture

[Objective] The paper was to preliminarily investigate the low yield reason of Camellia oleifera caused by fruit and flower dropping in Dehong prefecture. [Method]Pollen viability of C. oleifera was determined using I-KI and TTC （2,3,5-triphenyl tetrazolium chloride） method, the germination rate of pollen was determined by in vitro culture method, the pollen tube growth was observed by the fluorescent microscope through aniline blue dyeing, and the effects of different pollination methods on fruit setting rate of C. oleifera was analyzed. [Results] The pollen viability and the quantity of pollen tube of C. oleifera with good fruiting were significantly higher than the plants with poor fruiting, but their pollen germination rate had no significant differences; cross pollination was conducive to fruiting setting of C. oleifera. [Conclusion] The growth and development condition of C. oleifera pollen had important effect on the yield of C. oleifera in Dehong prefecture.

SLED联合HP对脓毒症合并重症急性肾损伤患者炎性应激、血流动力学参数及肾功能的影响

目的:探讨持续低效血液透析(sustained low-efficiency dialysis,SLED)联合血液灌流(hemoperfusion,HP)对脓毒症合并重症急性肾损伤患者炎性应激、血流动力学参数及肾功能的影响。方法:82例脓毒症合并重症急性肾损伤患者依据随机数据表法分为对照组(n=41)和观察组(n=41),两组患者均给予常规支持治疗,在此基础上对照组患者给予连续性肾脏替代治疗(continuous renal replacement therapy,CRRT),观察组患者给予SLED联合HP治疗。比较治疗前后两组的炎性因子、血液流变学参数及肾功能指标。结果:对照组与观察组治疗前C反应蛋白(CRP)、白细胞计数(WBC)、降钙素原(PCT)、平均动脉压(mean arterial pressure,MAP)、氧合指数(oxygenation index,OI)、尿素氮(BUN)、血肌酐(Scr)水平比较差异无统计学意义(P>0.05);与组内治疗前水平相比,治疗后两组CRP、WBC、PCT、BUN、Scr水平均显著降低,MAP、OI水平均显著升高,差异有统计学意义(P<0.05);与对照组治疗后水平相比,治疗后观察组CRP、WBC、PCT、BUN、Scr水平均显著降低,MAP、OI水平均显著升高,差异有统计学意义(P<0.05)。结论:SLED联合HP方案治疗脓毒症合并重症急性肾损伤,可有效抑制机体炎症因子的释放,改善血流动力学及肾功能,具有重要临床价值。

Crafting host materials for narrowband blue OLEDs with low efficiency roll-off by the medium-ring strategy

The pursuit of high-performance narrowband blue organic light-emitting diodes(OLEDs)is of paramount importance in both academic research and industrial applications.While obvious strides have been made in the design of narrowband blue emitters,the development of appropriate host materials has evidently trailed behind.Herein,we introduce a medium-ring strategy for crafting host molecules based on the heptagonal tribenzo[b,d,f]azepine(TBA)unit.The twisted three-dimensional(3D)architecture of the TBA framework not only endows the host molecules with fast hole-transporting pathways but also effectively reduces exciton quenching.Equipped with two TBA units,DTBA,synthesized with ease,demonstrates a huge horizontal orientation factor(Θ//)of 93.5%and a broad emission spectrum for accelerating the energy transfer process in the emitting layer,which contributes to enhancing device performance.We have fabricated high-performance narrowband blue OLEDs using DTBA as the host,FIrpic as the phosphor sensitizer,and the widely used boron-nitrogen-containing multiple resonance emitter BCz-BN.These devices exhibit a maximum external quantum efficiency(EQEmax)as high as 31.0%with an impressively lowefficiency roll-off.Even at a high luminance level of 10,000 cd m^(-2),the EQE value remains noteworthy at 20.3%,marking a significant advancement in BCz-BN-based devices.

Potential promoted productivity and spatial patterns of medium-and low-yield cropland land in China

With a continuously increasing population and better food consumption levels, im- proving the efficiency of arable land use and increasing its productivity have become funda- mental strategies to meet the growing food security needs in China. A spatial distribution map of medium- and low-yield cropland is necessary to implement plans for cropland improvement In this study, we developed a new method to identify high-, medium-, and low-yield cropland from Moderate Resolution Imaging Spectroradiometer （MODIS） data at a spatial resolution of 500 m. The method could be used to reflect the regional heterogeneity of cropland productiv- ity because the classification standard was based on the regionalization of cropping systems in China. The results showed that the proportion of high-, medium-, and low-yield cropland in China was 21%, 39%, and 40%, respectively. About 75% of the low-yield cropland was lo- cated in hilly and mountainous areas, and about 53% of the high-yield cropland was located in plain areas. The five provinces with the largest area of high-yield cropland were all located in the Huang-Huai-Hai region, and the area amounted to 42% of the national high-yield cropland area. Meanwhile, the proportion of high-yield cropland was lower than 15% in Hei- Iongjiang, Sichuan, and Inner Mongolia, which had the largest area allocated to cropland in China. If all the medium-yield cropland could be improved to the productive level of high-yield cropland and the low-yield cropland could be improved to the level of medium-yield cropland, the total productivity of the land would increase 19% and 24%, respectively.