Alleviation of Soil Aluminum Phytotoxicity in a Typical Paddy Soil in Southern China by Using Weak Organic Acids

Weak organic acids including tartaric and citric acids were applied to a typical paddy soil in southern China to test their effects on rice in the field for three years. Their effects were also compared with top dressings of the two acids, basal application of diammonium acid phosphate, calcium carbonate, and the control. The results showed that rice grain yield of the citric acid treatment was significantly higher than that of the control and the same difference was also observed for the filled spikelets per panicle. There were no significant difference among all the treatments and the control on the accumulation of above ground dry matter. However the root dry matter, length, peroxidase activity, and white root number of citric acid treatment were significantly higher than that of the control, while no significant differences among other treatments were observed. Basal application of citric acid played a positive role on this soil.     

外源C、N干扰下吉林黑土区农田土壤动物组成与结构

2011年5月至9月作物生长期间,采用手拣法、改良干漏斗与湿漏斗三种方法,对吉林黑土区7种外源C、N干扰处理,即对照组（不施肥,CK）、0.5倍、1.0倍和2.0倍的外源C和N处理（C0.5、C1.0、C2.0、N0.5、N1.0、N2.0）农田土壤动物组成与结构进行研究。在作物生长季节,5次采样共获得土壤动物56 886只（未鉴定标本80只）,隶属3门11纲23目3亚目79科（总科）。数据分析显示,农田土壤动物主要集中在0～5 cm,基本上是随着土壤剖面加深而呈现下降趋势;与对照（CK）相比,农田土壤动物个体数与类群数随外源C浓度升高而呈递增趋势;农田大型土壤动物个体数随外源N浓度升高呈递减趋势;农田中小型土壤动物个体数随外源N浓度升高呈递增趋势。在研究时段内,土壤动物个体数与类群数于5—8月份呈现出上升趋势,9月份出现下降。方差分析显示,外源C、N干扰对农田中小型土壤动物个体数与类群数以及大型土壤动物类群数影响显著（p＜0.01）,农田土壤动物个体数与类群数在作物生长季节内变化显著（p＜0.01）。外源C、外源N分解释放出的养分与中小型土壤动物个体数、类群数以及大型土壤动物类群数密切相关。外源C有益于农田土壤动物功能群、大型与中小型农田土壤动物群落组成多样化。     

基于Retinex图像增强的不同光照条件下的成熟荔枝识别

为了满足自然环境下荔枝采摘机器人视觉定位系统的有效性和实时性的要求,针对不同光照条件的荔枝彩色图像,采用基于双边滤波的Retinex图像增强算法凸显图像中的荔枝果实和果梗,对增强处理后的图像在HSI颜色空间中进行H分量旋转的处理,再对旋转处理后的H分量进行Otsu自动阈值分割去除荔枝图像果实和果梗外的复杂背景;然后通过将双三次插值算法和传统的模糊C均值（FuzzyC-Mean）算法融合,对去背景后的荔枝图像在YCbCr颜色空间中进行Cr分量模糊聚类分割,实现荔枝果实和果梗的识别。荔枝图像的分割试验结果表明：该算法对晴天顺光、逆光、遮阴、阴天顺光等光照条件的荔枝图像能够有效地分割,对阴天弱光照、果实被遮阴条件下的荔枝也能较好的识别,并保持荔枝果实和果梗区域的完整性,4种光照条件荔枝图像分割正确率分别为96%、90%、89.3%和88.9%,成熟荔枝识别的正确率达到了90.9%,该研究为水果采摘机器人的室外作业的实时性和有效性提供指导。     

农村土地综合整治的内在驱动力分析

为充分发挥农村土地综合整治的积极作用,从理论上探究其与城乡统筹发展的关系,从历史角度对其进行定位,并进行理论升华。在对农村土地整治内涵剖析的基础上,从经济、社会、政治3个方面分析农村土地综合整治的内在驱动力,揭示了农村土地综合整治对社会经济的积极影响,进而对农村土地综合整治进行了理性思考,最后从规划管理、决策机制、产权制度、收益分配、主导主体和配套制度等方面提出相关的对策建议,该文为进一步推进农村土地综合整治提供了较好的理论支撑和实践参考。     

再生水及盐溶液入渗与蒸发对土壤水盐和碱性的影响

为研究再生水利用对土壤盐碱性影响的特殊性,采用室内大型土槽试验,对比研究了清水、再生水和钠吸附比(sodium adsorption ratio,SAR)分别为3、10和20(mmolc/L)0.5的盐溶液入渗与蒸发10次(模拟灌溉2a)期间对土壤及土壤溶液盐分迁移累积和碱性的影响。结果表明:与清水相比,再生水和SAR值为20(mmolc/L)0.5的盐溶液处理中0～40cm深度壤土含水率较高,80～120cm砂土含水率的增加产生滞后现象;再生水和盐溶液入渗与蒸发后土壤中盐分产生累积,累积量为9.54%～51.83%,而再生水处理中淋洗液带出的盐分最多,是其他处理的1.09～1.42倍。清水、再生水和盐溶液处理土壤溶液钠吸附比(SAR)<3(mmolc/L)0.5,土壤pH值<8.5,再生水和盐溶液入渗与蒸发引起土壤碱化的风险较低。再生水入渗与蒸发后土壤溶液中K+和Ca2+在土体中的迁移分布与清水和盐溶液处理不同,再生水对土壤中Cl-有较强的淋洗作用,长期再生水灌溉过程中土壤K+、Ca2+和Cl-的迁移和淋洗需要引起重视。试验结果对农业中长期安全合理利用再生水具有指导意义。     

广东省稻瘟病病区分析及划分

分析了广东省2010-2019年各地稻瘟病的发生情况,结合地域方位、稻瘟病发生面积、水稻种植面积等,对广东水稻主栽县(市、区)进行了稻瘟病级别划定。结果显示,广东稻瘟病重发区主要集中在粤北。另外,粤西湛江、茂名、阳江和云浮等部分地区呈点状重发分布;零星发生区主要集中在粤东、珠江三角洲和粤西部分地区。     

青蛤人工育苗试验

青蛤潜居泥沙中生活,移动性小,适宜滩涂养殖,且近几年对其苗种的需求量日益增加,沿海各地均在开展青蛤人工育苗试验和生产。我们于2005年7月-10月底,利用投放较大颗粒的附着基、浮游期采用过滤海水、稚贝附着后改用室外土池流水培育的新工艺,在430m2水体中培育壳长4mm-9mm的青蛤苗种总计1亿粒。     

鱼腥藻藻蓝蛋白的提取

对鱼腥藻藻蓝蛋白的大规模提取方法进行了初步的探索。对实验室精细的小规模分离提取方法进行了简化。用0．01mol／L磷酸盐缓冲液浸提，经3次反复冰融渗透震荡处理，使细胞破碎，释放藻蓝蛋白，然后离心分离。用磷酸缓冲液反复提取至上清液透明。采用这种方法从鱼腥藻中提取藻蓝蛋白，可处理的样品规模大，藻蓝蛋白得率高达98．8％，并且操作方法简便，节约药品，成本低。     

HACCP体系在斑点叉尾鮰人工繁殖中的应用

在江西峡江和赣州进行了HACCP（Hazard Analysis and Critical Control Point）体系在斑点叉尾鮰（Ictalurus punctatus）人工繁殖中的应用研究.应用HACCP的基本原理,对整个斑点叉尾鮰人工繁殖过程进行危害分析,确立了亲鱼培育池的选择、亲鱼种质选择、亲鱼产卵池的选择、受精卵孵化、苗种培育、水质监测、饲料供应、日常管理等8个关键控制点,提出了相应的预防措施、关键限值、监控措施以及超过关键限值时的纠正措施,使各关键控制点处于人为控制之下.实现了斑点叉尾鮰人工繁殖按无公害化、规范化、标准化生产.     

Species richness and guild composition in rubber plantations compared to secondary forest on Hainan Island, China

Currently, the one of great threats to tropical biodiversity is the conversion of natural ecosystems to agriculture, and this threat is particularly critical on Hainan, the largest tropical island in China and a global biodiversity hotspot. Rubber (Hevea brasiliensis) has been planted on Hainan since the 1950s, resulting in extensive replacement of native forest, and the rate of this transformation has increased with latex prices since the 1990s. Rubber plantations now cover ca. 506,680 ha on Hainan and reach ca 1,000 m in elevation. To investigate the effect of this land-use change, we compared avian communities between a rubber plantation and a native secondary semi-deciduous monsoon forest. We found that species richness was higher in the native forest than in rubber, and that community composition differed greatly between the two habitats. No strict frugivores were recorded in rubber and no granivores in semi-deciduous monsoon forest. In both richness and abundance, more nectarivores and fewer insectivores occurred in rubber than in the native forest. Some common forest species, as well as protected species, were found only in native forest, including Hainan Partridge (Arborophila ardens), Red Junglefowl (Gallus gallus), Emerald Dove (Chalcophaps indica), Black-browed Barbet (Megalaima oorti), Blue-rumped Pitta (Pitta soror), Puff-throated Bulbul (Alophoixus pallidus), and Chestnut Bulbul (Hemixos castanonotus). Although ten babbler species were found in the native forest, only two were in rubber. Among the species missing in rubber was the endemic Hainan species Grey Laughingthrush (Garrulax maesi). Its endangerment through habitat conversion is of particular conservation concern.