土地利用变化与生态服务功能冲突——以安塞县为例

安塞县位于黄土丘陵沟壑区,经济落后,农业生产水平较低.从土地利用和生态服务功能变化与冲突的角度,分析安塞县农业、环境与生态保护的变化过程与相互作用,指出安塞土地利用变化突出表现为坡地耕垦所引发的土地利用结构的改变;生态服务功能的冲突则主要表现为食物生产与水土保持之间的矛盾.通过资源的有效利用,在实现食物安全的同时,水土流失得到有效控制是完全可能的.     

Periodical characteristics of baseflow in the source region of the Yangtze River

Baseflow,which represents the drainage of groundwater aquifers,is an essential component of runoff in hydrological basins.In the source region of the Yangtze River,the change of baseflow typically reflects the interactions between groundwater system and climatic factors in cold and arid areas.With modified Kalinen separation method,annual baseflow between 1957 and 2009 in this region was estimated and calculated.In comparison with the inner-annual variations of total streamflow,baseflow showed a weaker fluctuation.Before the 1980s,it was in a steady state;and after then,it demonstrated dramatic variations and large amplitudes.Based on the calculation results of baseflow,the real Morlet wavelet method was applied to reveal the periodical characteristics of baseflow as well as the precipitation and air temperature in the study area.It was found that annual baseflow has a 43-year trend as well as a 21-year period and a 7-year period.The 21-year period is most significant,with its wavelet coefficient having the largest fluctuation and amplitude.Summation of wavelet coefficients on these periods exhibits a similar change pattern with respect to that of annual baseflow.The summation curve takes a"W"shape,which means that the baseflow follows a four-stage sequence of descending–ascending–descending–ascending.As analyzed,the relationship among baseflow,precipitation and temperature is implied in the correlation between their normalized wavelet coefficients at different temporal scales.By the significant positive linear correlations both between precipitation and baseflow(correlation coefficient is 0.98)and between temperature and baseflow(correlation coefficient is 0.90)for the 43-year wavelet coefficients,it is suggested that the long-term increasing trends of precipitation and air temperature will lead to an increasing trend of baseflow.For wavelet coefficients of 21-year and 7-year periods,the positive linear correlation between precipitation and baseflow is significant.However,the correlation between air temperature and baseflow is not so evident,especially for the 21-year period.As a conclusion, correlation analysis with normalized wavelet coefficients showed that the change of annual baseflow was contributed mostly by the change of precipitation and secondly by the change of temperature.     

圆盘破茬刀切割玉米根茬运动特性测绘装置设计与试验

免耕播种机是保护性耕作的关键机具之一,其播种质量的好坏在很大程度上影响着保护性耕作的效果。为了优化免耕播种机的关键部件破茬刀,研制了一种圆盘破茬刀切割玉米根茬运动特性测绘装置,该装置能够实现实时地测绘出圆盘破茬刀待测点的运动轨迹。通过对三种圆盘破茬刀的运动轨迹的测绘与试验,得出光面圆盘破茬刀上待测点的运动轨迹为光滑的摆线,半圆型缺口盘和阿基米德螺线盘上待测点的运动轨迹为由不同长度的圆弧组成的云曲线。在此基础上对三种圆盘破茬刀冲击情况、入土滑切角和滑切速度变化进行了分析比较,建立了阿基米德螺线型圆盘破茬刀切割根茬运动的运动学模型。描绘出阿基米德螺线型圆盘破茬刀刃口上点的运动轨迹是由不同长度的圆弧组成的云曲线,建立了阿基米德螺线型圆盘破茬刀刃口上点的运动方程。发现阿基米德螺线型圆盘破茬刀刃口上点的轨迹具备了光面圆盘破茬刀的摆线规律,也具备了半圆型缺口圆盘破茬刀的冲击性,并且滑切角较大,滑切性能更好。通过圆盘破茬刀切割玉米根茬运动特性测绘装置的两因素三水平正交试验分析,得出阿基米德螺线型圆盘破茬刀、机具配重为100 kg时破茬效果达90%以上,破茬率较高。     

毛乌素沙地典型地形断面土壤水分动态

基于毛乌素沙地的野外观测资料,对毛乌素沙地典型地形断面土壤水分动态进行分析。结果表明,土壤水分季节变化可划分为土壤水积聚期、消耗期和稳定期;根据土壤水分垂直变化可把土壤剖面划分为土壤水分易变层、利用层和调节层;沿着坡度减小的方向,各地形断面对应层次的土壤水分含量逐渐升高,丘间地土壤水分含量明显高于该断面上其余各点。     

不同放牧制度对荒漠草原短花针茅空间异质性的影响

在不同放牧制度下,以荒漠草原短花针茅植物种群为研究对象,采用GS＋软件和地统计学分析方法对其空间异质性分布进行了研究。结果显示：对照区和划区轮牧区或自由放牧区都表现出很强的空间自相关性,且结构是导致短花针茅空间变异的主要因素。对照区、划区轮牧区和自由放牧区,短花针茅空间格局的分形维数相近,都接近于2。不同放牧制度下短花...     

定安县稻作区水稻控释肥合理施用研究

通过田间试验,在海南定安县稻作区对水稻控释肥的适宜用量和施用方法进行优化研究。结果表明,一次性施用控释肥与当地常规分次施肥相比,可提高水稻株高、有效穗数、穗长、每穗粒数、千粒重,降低秕粒率,改善经济性状;每667 m2一次基施控释肥40 kg即可满足水稻本田期的营养需求,比常规分次施肥增产8.8%～12.6%,增收66.2～85.6元。     

MAP贮藏对甜樱桃品质的影响

对甜樱桃的贮藏保鲜试验表明,MAP与专用保鲜剂结合可有效地保持果实的鲜食品质,减少果实的腐烂和褐变,降低果实的呼吸强度,延长果实的贮藏期.‘红灯‘甜樱桃贮藏保鲜80 d果实的腐烂率为3.62%;对照果实只贮藏了40 d.‘雷尼‘甜樱桃贮藏保鲜110 d果实的腐烂率为2.1%,褐变率为0,果柄抽干率为0.32%;对照果实只贮藏了50 d.     

SA+CaCl2对菊花花瓣生理和花期的影响

以不同浓度的水杨酸(SA+CaCl2)水溶液对菊花"兼六香菊"品种全株喷雾处理,测定整个花期花瓣中可溶性蛋白、可溶性糖含量、超氧化物歧化酶(SOD)活力、超氧阴离子(O2-)产生速率、丙二醛(MDA)含量以及相对电导率的变化.结果表明:不同浓度的SA+CaCl2均能提高花瓣中可溶性蛋白和可溶性糖含量、SOD活力和降低了O2-产生速率、MDA含量和相对电导率,花期有不同程度的延长,其中以SA 15 mg/L+CaC12160 mg/L处理效果较佳.     

一步法RT-PCR检测柑橘鳞皮病毒

柑橘鳞皮病是一种极具破坏性的柑橘病害,广泛分布于南美及地中海地区。我国目前缺乏对该病害的快速检测技术。以柑橘鳞皮病毒(CPV)的外壳蛋白基因(CPG)为靶标,初步建立了一步法RT-PCR快速检测体系,扩增产物与NCBI数据库中已知CPVCPG的核苷酸序列进行比对,2者序列间同源性超过99%。     

东莞市"绿韵"生态园区生物变化调查

东莞市"绿韵"生态园区经过近4年的建设,植物种类从原来的175种上升到263种,各类品种资源丰富,布局合理;鸟类、蛙类、蜘蛛、蛇类等野生动物日渐增多,有害昆虫种类数从原来的41种降到36种,主要害虫的种群密度在下降,有益昆虫种类数从原来的8种上升到14种,大多数有益昆虫的种群密度在上升;作物病害的种类数从原来的55种下降到34种,一些主要作物病害发病率在下降。