关于我国发展适于深加工优质专用玉米的思考

 介绍了我国玉米生产的现状、存在问题以及世界玉米生产和加工情况,提出我国玉米生产发展的方向为稳定普通玉米生产,迅速扩大专用玉米生产,从粉、糖、酒、酸、油5个方面研究、开发相应的加工技术,从而发挥我国玉米资源优势,解决玉米相对过剩的问题,为玉米深加工的长远发展打下基础。     

Long-term trends in the abundance of Mediterranean wetland vertebrates: From global recovery to localized declines

Biodiversity loss is unevenly distributed in space and time. Species have reached critically low population sizes in some areas, and remain abundant in others. Similarly, some species may benefit from successful conservation plans, while others still experience severe population depletions driven by negative impacts of human activities. Although several indicators have been proposed to measure the fate of biodiversity, they are generally only implemented globally so their relevance for regional assessment is still unclear. Here, we calculated the first regional trend in the Living Planet Index for the Mediterranean wetlands (Med LPI), an indicator that summarizes the fate of global biological diversity based on the temporal trends in abundance of vertebrate populations. The Med LPI was based on 1641 vertebrate populations of 311 species recorded in Mediterranean wetlands from 1970–2008, in 27 different countries. We investigated whether trends in the Med LPI differed between eastern and western Mediterranean countries, which have different socio-economic contexts. Finally, we assessed whether and how the trend in the Med LPI was robust to changes in the number and identity of species considered. We found that, at the Mediterranean scale, the Med LPI increased steeply, which could be taken at first sight, as a general recovery of wetland biodiversity in this biogeographical region. However, we found highly contrasting spatial trends within the Mediterranean region: the average trend was positive for western and negative for eastern countries. Moreover, we showed that depending on the method used to estimate the trend in Med LPI, it can be sensitive to the number and identity of the species considered. We suggest that understanding the regional discrepancies of the trend in biodiversity indicators as well as their robustness to the species represented in the index will enhance progress assessment towards global and regional conservation strategies.     

气候条件对冬小麦穗粒数的影响研究

长期定位试验研究气候条件对冬小麦穗粒数的影响结果表明 ,冬小麦穗粒数主要受返青后 5日滑动平均气温首次≥ 4℃之日～雌雄蕊原基分化时 (即拔节开始天数 )的影响 ,并受其至挑旗期平均最低气温和至抽穗期日照时数的制约。各因素对冬小麦穗粒数的影响大小依次为天数 >日照时数 >平均最低气温。冬小麦高产栽培还应协调好穗数、穗粒数和千粒重三者之间的关系     

植保四轴飞行器的模糊PID控制

针对当前植保四轴飞行器在作业过程中自身载荷发生改变后的飞行控制性能下降、抵抗环境扰动能力差的问题,该文改进了传统比例积分微分(proportion,integration,differentiation,PID)控制算法,提出了一种模糊PID控制算法。该文通过研究四轴飞行器的姿态解算和飞行原理,设计了以STM32系列的单片机为核心处理器的四轴飞行控制系统。采用AHRS模块实时解算飞行器姿态参数,结合模糊控制和PID控制算法调节电机的输出量来控制飞行姿态。试验结果表明:与传统PID相比,模糊自整定PID控制算法适应性强,参数整定简单,系统的动态响应能力和稳定性获得了提高,实现了四轴飞行器的稳定飞行。该文为植保无人机控制算法研究提供了一定的参考。     

云贵高原岩溶地区生态气候类型区划

利用主成分分析和动态逐步聚类方法进行气候类型区划，较好地综合了多种气候，地理和生态因素，避免了只考虑了几个经验性气候要素作为区划指标的某些弊端，使区划结果更客观定量，更符合实际情况。     

Cross-enhancement: enhanced biodegradation of isothiocyanates in soils previously treated with metham sodium

Rates of degradation of 2-propenyl isothiocyanate (PrITC), benzyl isothiocyanate (BeITC) and 2-phenylethyl isothiocyanate (2-PeITC) in a soil known to biodegrade methyl isothiocyanate (MITC) at an accelerated rate, but never previously exposed to the other ITCs, were higher (persistence in soil increased by 1150, 80 and 100%, respectively,) than in a similar non-degrading soil. The rate of degradation of the same three ITCs was significantly lower in sterilised (autoclaved) soils than in the degrading soil. These results indicate that the three ITCs are susceptible to enhanced cross-biodegradation in soils where enhanced biodegradation of MITC has been induced by use of metham sodium soil fumigant. When Brassica plant tissue containing sinigrin (2-propenyl glucosinolate) as the predominant glucosinolate (GSL) was added to the degrading soil, the amount of PrITC present after 24 h was significantly lower than in the non-degrading soil at the same amendment rates. The toxicity to an insect test organism of the PrITC produced from the biofumigant plant tissue was correlated with the concentration of PrITC measured in the two soils, with 67% more plant tissue required in the degrading soil to cause 100% mortality as in the non-degrading soil (3.0 vs 5.0 mg g⁻¹). The effectiveness of biofumigation using ITC-producing Brassica plants may be diminished in soil suffering from enhanced biodegradation of MITC.     

藕炭疽病病原及生物学特性

 该病为国内首次报道,在南宁、贵港等市县近年来有日趋严重之势。4~5月见病,夏秋时节病重,病叶率达70%以上。     

The crucial role of calcium interacting with soil pH in enhanced biodegradation of metam-sodium

Enhanced biodegradation of soil-applied pesticides has long been correlated with soil pH above ca 6.5-7.5, but the possibility of confounding or interdependence with calcium, given that soil calcium concentration increases exponentially as pH rises above that range, has not previously been studied. Enhanced biodegradation of the broad-spectrum biocide metam-sodium was readily induced de novo in a naturally acid sandy soil (pH 4.2 measured in 0.01 M CaCl2) by multiple treatments, but only when the pH and calcium concentration were raised simultaneously using calcium carbonate (lime). Enhanced biodegradation was not induced when soil pH alone was raised with magnesium carbonate, nor when calcium alone was raised using calcium chloride. In limed sand treated monthly for 12 months, the degradation rate increased to where dissipation was complete within 24 h of application after the fifth metam-sodium treatment at pH 7.8 and after the eighth metam-sodium treatment at pH 6.8. Pesticide concentration was reduced, but not eliminated, at pH 5.8 and was unchanged at pH 4.8. When metam-sodium was applied bi- and tri-monthly, the degradation rate also increased when soil pH was raised with calcium carbonate, but to a lesser extent than with monthly applications. In an acid loam soil amended to the same pH values with calcium carbonate and treated monthly, there was no correlation between soil pH or calcium concentration and degradation. The results reveal the crucial interdependence of pH and calcium concentration in enhancement of biodegradation of soil-applied pesticides, but confirm that the phenomenon ultimately depends on interaction with soil type and frequency of application factors, all of which probably together act to affect the abundance, composition and activity of the soil microbial biomass.