Biofertilizing efficiency of Sargassum polycystum extract on growth and biochemical composition of Vigna radiata and Vigna mungo

Objective: To evaluate the effect of marine brown alga Sargassum polycystum extract on growth and biochemical parameters of Vigna radiata and Vigna mungo. Methods: Different concentrations of algal extracts (0.5%, 1.0%, 2.0%, 3.0%, 4.0%, and 5.0%) were prepared and applied to the crops at every 10-day intervals under natural conditions. After 30 d, the plants were harvested to evaluate the growth and biochemical parameters. Results: Seaweed liquid fertilizers treated seedlings showed maximum growth in 3.0% concentration when compared to the untreated seedlings. Similarly, biochemical parameters such as photosynthetic pigments, protein, reducing sugar, total sugar and amino acids exhibited increases in 3.0%concentration seaweed extract. Decreases in growth and biochemical parameters were noticed in concentrations higher than 3.0%. Conclusions: Presence of micronutrients and growth regulating substances in the liquid extract help healthier and faster productivity of the crop.

Hydrogeochemical Characteristics and Quality Assessment of Surface Water in an Agricultural Area in Equatorial Africa: The Mungo River Basin, South West Cameroon, Central Africa

The Mungo River and its tributaries represent the major sources of water supply for agriculture and drinking purposes for the Douala city and the south western agricultural region of Cameroon. In this study, the surface water hydrochemistry was investigated at 12 locations to determine the hydrochemical and heavy metals characteristics and to assess the suitability for drinking and irrigational purposes. Results of water samples collected along the main channel and tributaries showed that the major ions were dominated by Ca2+ > Na+ > Mg2+ > K+ > NH4+ and > HCO3- > SO42- > Cl- > F- > PO43- , with concentrations varying between 0 to 60 mg/l. Heavy metal concentrations were relatively weak, dominated by Fe > Mn > As > Cd > Zn > Se. The main hydrochemical facies types revealed primarily 52% Ca-Na-HCO3 and 48% Ca-Mg-HCO3. Base on Gibbs diagram and relative ion ratios, the hydrochemical characteristics are derived from weathering of silicate rocks and atmospheric source. The influence of anthropogenic factors including agro-industrial activities on the hydrochemical characteristics was less marked. The chemical composition of the water samples was compared with the drinking water standards and only the concentration of Fe was above the WHO guide limits in a single sample at Passi. The evaluation of the water quality for irrigation showed that 95% of water samples are suitable for irrigation in almost all soil types. According to the water quality index (HPI, HEI and Cd), this water is considered of excellent quality for consumption. The results provide a preliminary database for sustainable management of water resource in the Mungo River basin.

Lysimeter based crop coefficients for estimation of crop evapotranspiration of black gram (Vigna Mungo L.) in sub-humid region

Black gram is dominant pulse crop of the region.Crop coefficient is an important parameter,which needs to be determined for accurate estimates of the crop water requirement.Crop coefficient,the ratio of potential crop evapotranspiration to reference evapotranspiration,is an important parameter in irrigation planning and management.However,this information is not available for many important crops in the study region.A study was undertaken to develop crop coefficients for black gram crop,and a comparison is made of single and dual crop coefficient approaches to estimate actual crop evapotranspiration under the climatic conditions of Udaipur,India.Crop coefficient was developed from daily measured black gram evapotranspiration(ETBG)data by electronic weighing lysimeter and reference evapotranspiration calculated using standard Penman-Monteith method.The measured values of crop coefficient for the crop were 0.48,1.18 and 0.33 during initial,mid-season and late-season stages.The evaluation of different approaches showed that daily ETBG estimate based on dual crop coefficient method have been found best(SE=0.40,r=0.96).Furthermore,a quadratic curve(second-order polynomial)method were fitted well(SE=0.47,r=0.94)to predict crop coefficient values as function of days after sowing(DAS).These locally developed and evaluated values can be used for proper irrigation planning in water scarcity area of Udaipur and other areas with similar agro-ecological conditions.

低温胁迫下植物体内POD、COD、ATPase同工酶的变化

０～４℃低温对绿豆（武清绿豆）、红豆（京农２号）、黄豆（鲁豆７６０５）三种作物幼苗生长的抑制作用是明显的．这三种作物对低温处理的反应都很敏感．其中绿豆和红豆比黄豆更为敏感．绿豆、红豆、黄豆胚轴中ＰＯＤ、ＣＯＤ、ＡＴＰａｓｅ三种同工酶的变化表明，植物的生长受抑与ＰＯＤ、ＣＯＤ、ＡＴＰａｓｅ同工酶变化相关．

Stochastic Modelling of Actual Black Gram Evapotranspiration

The study was undertaken to develop and evaluate evapotranspiration model for black gram (Vigna Mungo L.) crop under climatic conditions of Udaipur, India. Pan evaporation data for the duration of twenty three years (1978-2001) and measured black gram evapotranspiration data by electronic lysimeter for duration of kharif season of 2001 were used for analysis. Black gram is an important crop of Udaipur region. No sys-tematic study on modelling of black gram evapotranspiration was conducted in past under above said cli-matic conditions. Therefore, stochastic model was developed for the estimation of daily black gram evapotranspiration using 24 years data. Validation of the developed models was done by the comparison of the estimated values with the measured values. The developed stochastic model for black gram evapotran-spiration was found to predict the daily black gram evapotranspiration very accurately.

东海DC-1,DC-2孔古地磁研究

本文报道了东海DC-1,DC-2孔古地磁研究结果,表明DC-l孔26.9m岩芯及DC-2孔61.0m岩芯段均以正极性为主,属布容正极性世 (Brunhcs)。其中DC-l孔18.86-19.18m的反向磁化带(倾角为—49.29°),经^(14)C测年为距今115lO土570a;DC-2孔29.95—30.54m处反向磁化带(倾角为—40.5°),经^(14)C测年为距今10250±lOOa。可与哥德堡事件(Gǒthcnburg)对比。对比地磁年表,DC-2孔37.80—38.0m为反极性事件与蒙哥事件(Mungo event)相当,7l.20—74.44m划为布莱克事件(B1akc event)。据此计算全新世沉积速率为2.12—2.84m/1000a,晚更新世沉积速率为O.65一O.69m/1000a。