Effect of subsurface drip irrigation on onion yield

Subsurface drip system is the latest method of irrigation. The design of subsurface drip system involves consideration of structure and texture of soil, and crop’s root development pattern. A 3-year experiment was conducted on onion (Allium Cepa L., cv. Creole Red) in a sandy loam soil from October to May in 2002–2003, 2003–2004 and 2004–2005 to study the effect of depth of placement of drip lateral and different levels of irrigation on yield. Tests for uniformity of water application through the system were carried out in December of each year. Three different irrigation levels of 60, 80 and 100% of the crop evapotranspiration and six placement depths of the drip laterals (surface (0), 5, 10, 15, 20 and 30 cm) were maintained in the study. Onion yield was significantly affected by the placement depth of the drip lateral. Maximum yield (25.7 t ha⁻¹) was obtained by applying the 60.7 cm of irrigation water and by placing the drip lateral at 10 cm soil depth. Maximum irrigation water use efficiency (IWUE) (0.55 t ha⁻¹ cm⁻¹) was obtained by placing the drip lateral at 10 cm depth. The greater vertical movement of water in the sandy-loam soil took place because of the predominant role of gravity rather than that of the capillary forces. Therefore, placement of drip lateral at shallow depths is recommended in onion crop to get higher yield.     

库尔勒香梨两种树形冠层内果实产量与品质差异性分析

[目的]探明库尔勒香梨不同冠层内果实产量与品质的分布规律及其差异性.[方法]应用树冠分格法,对疏散分层形和开心形树形冠层内不同部位的果实产量与品质进行测定与分析.[结果]疏散分层形和开心形平均每株果实产量分别达到138.5、160.1 kg,在冠层中层与外围开心形产量高于疏散分层形,而上层与下层,中部与内膛均低于疏散分层形,开心形的中层与上层,中层与下层,疏散分层形的内膛与中部,内膛与外围其产量均存在极显著差异,其他部位无显著差异;疏散分层形与开心形的平均单果质量分别达到131.57、145.86 g,果形指数均在1.2左右,冠层不同部位,开心形在萼片脱落、色泽黄绿、有红晕、果面光滑等果实外观品质上所占的百分比分别为16;、21.9;、69;、96.1;,均高于疏散分层形;开心形的果实硬度、可滴定酸、VC、可溶性圆形物、固酸比分别为7.25 kg/cm2、0.946 g/kg、55.7 mg/kg、12.27;、11.48,均优于疏散分层形;垂直部位,两种树形硬度、可滴定酸、VC、可溶性固形物、固酸比等均存在极显著差异,而水平部位差异不明显.[结论]开心形在产量、果实外观品质以及果实内在品质上均优于疏散分层形.     

Economic valuation and conservation: Do people vote for better preservation of Shadegan International Wetland?

Shadegan International Wetland (SIW) is a unique natural ecosystem with great national and international significance, designated under Ramsar Convention. Located in southern part of Iran, this wetland serves many functions. Among them the rich biodiversity, ecological, hydrological, and economic functions are the most important. Despite the great opportunities for sustainable development of this wetland, it is currently under serious threats from a diverse range of non-sustainable activities. Underestimating SIW’s non-market values in development decisions is a major reason for the conversion and excessive depletion of its resources. The aim of this study was therefore to estimate the economic benefit of SIW as a very useful instrument to reflect the values of this unique ecosystem to society members. A choice experiment (CE) survey was undertaken to estimate the value of different nonmarket attributes of SIW. In addition to the overall model, users and nonusers preferences were also estimated. Random parameter logit (RPL) model was employed to derive the marginal value of the respondents for different attributes of the nonmarket values of SIW. Results indicated the respondents’ positive preferences towards better conservation of SIW.     

早春短命植物绵果荠无菌苗组织培养相关因素研究

为建立绵果荠（Lachnoloma lehmannii）无菌苗培养体系,以种子作为试验材料,对不同消毒方法的效果进行了比较,并对影响种子萌发、幼苗生长相关因素进行了探讨。结果表明,1）种子消毒适宜方法为种子流水冲洗1~2 min,70%酒精浸泡1 min,0.1% HgCl2消毒1.5 min;2）光照对种子萌发有促进作用,而幼苗的不同部位对光照有不同响应;3）种子萌发对低温有依赖性,而幼苗生长需要一定的高温;4）适宜激素对种子萌发有促进作用,而幼苗的不同部位对激素有不同反应。因此,绵果荠种子萌发和幼苗生长适合培养体系为把种子消毒后接种无激素的MS,放在变温为15 ℃/5 ℃的光照条件下培养4~5 d,萌发后转至温度为（25±1） ℃的光照条件下培养,发芽率达到90%,比对照高16%,且幼苗长势良好。     

日本大豆引种四川盆地的品质评价研究

将原产于日本的17个大豆种质资源引种至我国四川盆地栽培,并对其引种前后的籽粒品质性状进行分析评价,探究引种大豆在四川盆地的适应性,以期为丰富西南大豆种质资源提供参考。品质性状变异分析结果表明,大豆异黄酮的变异系数大,除苷元外均达到30%以上,而其余性状的变异系数也均大于10%。与引种前相比,各供试大豆的可溶性蛋白含量普遍升高,而脂肪酸、可溶性多糖和异黄酮含量普遍降低。基于引种大豆11个品质性状的主成分聚类分析,将供试的17份种质资源划分为五大类,其中,Ⅰ类大豆为高脂肪酸品种,其生育期适中,亚油酸含量大于55‰,可作为高油脂杂交育种亲本材料加以利用;Ⅲ类大豆为高蛋白型品种,可作为豆制品开发原材料加以利用;Ⅴ类大豆为高异黄酮型品种,可作为功能性成分原料来源加以利用。