Effects of different soil management practices on total P and Olsen-P sediment loss: A field rainfall simulation study

Field rainfall simulations were conducted in 2002 and 2005 to study the effects of different soil management practices on the total phosphorous (TP) and Olsen-P losses by soil erosion and redistribution along a 15 m long slope in Luoyang, Henan province, China. Field plots were set up in 2001 and included the following soil management practices: subsoiling with mulch (SSM), no-till with mulch (NTM), reduced tillage (RT), and a conventional tillage control (CT). The results showed that there were no significant differences in TP and Olsen-P content in the sediment load between different plots after 6 years uniform tillage practices. The enrichment of TP and Olsen-P at the lower slope showed a clear redistribution along the slope. Effects of tillage practices on the temporal pattern of the enrichment ratio (ER) of TP and Olsen-P was not uniform. ER_TP values were initially high and diminished after a short period of time and leveled to the end of the rainfall test in CT and RT plots, but remained ≥ 1. The ER of Olsen-P at the end of rainfall simulation showed a significant difference when compared to the initial stage, 0.78 to 1.60, respectively. However, the temporal loss rate of TP and Olsen-P showed a similar pattern because it was more depending on the sediment loss rate than on the concentration in the sediment. SSM resulted in 96% less TP and Olsen-P erosion loss compared to CT in 2002. Also, SSM showed the highest reduction in TP and Olsen-P loss after 4 years consistent practice. RT reduced TP and Olsen-P loss by 30%, although the runoff reduction was not significant. NTM was the best alternative with respect to TP and Olsen-P conservation, when considering its lower operational costs.     

前期不同水分状况对土壤氧化亚氮排放的影响

田间采集的新鲜土壤样品分别在室温下风干(土样D)和淹水(土样S)保存110d后,将二者的含水量分别调至20%、40%、60%、80%、100%持水量(WHC,Water Holding Capacity),在25℃下培育138h,设置不通和通入10%(v/v)乙炔的处理。结果显示,在20%～80%WHC下培育时,土样S的氧化亚氮(N2O)排放量为土样D的2.48倍～6.36倍(p<0.01),而在100%WHC水分含量下培育时,土样S的N2O排放量仅为土样D的19%(p<0.01),通入乙炔不但未使土样D的N2O排放量增加,反而显著减少。通入乙炔的处理,培养结束后硝态氮的含量增加。随培育水分含量的升高,土样S和土样D的二氧化碳排放量增大。供试土样可能存在异养硝化作用。前期水分的差异显著影响土壤N2O排放量,故在田间测定土壤N2O排放量时,要考虑土壤前期水分的差异。     

优质晚籼稻产量因素分析及育种应用探讨

对62份优质晚籼稻新品系产量因素进行相关分析和通径分析．结果表明：各产量因素与产量均呈正相关,其中穴穗数、结实率和穗长与产量的相关达极显著或显著水平;对产量的净贡献率大小依次为穴穗数(39．2％)、结实率(24．58％)、每穗总粒数(17．8％)、千粒重(15．37％)。株高和穗长作用极微弱且为负值。各产量因素问相互制约,相互促进。根据研究结果和育种实践,认为优质晚籼稻高产育种的主攻方向是提高穴穗数、结实率和总粒数;高产(产量在550kg／667m^2以上)结构模式应该是有效穗21—23万穗／667m^2,每穗总粒数160—175粒,结实率85％-90％,千粒重25—28g.     

Gluten Enhances Cooking,Textural, and Sensory Properties of Oat Noodles

Whole grain oats are widely regarded as conferring significant health benefits. Composite flour of whole grain oat flour, wheat flour, and tapioca starch in the ratio 1:1:0.16 was formulated to make oat noodles with the addition of gluten at various levels. The influence of gluten on pasting and gelling properties of composite flour, and on cooking, textural, and sensory properties of salted oat noodles was evaluated. Addition of gluten decreased the paste viscosity, reduced hardness and springiness of gel, reduced cooking yield, cooking loss, and broken ratio during cooking, and increased the tensile strength and firmness of cooked noodles. Scanning electron microscopy showed that gluten tightened the network of protein in the noodles by forming oriented fibrils. Addition of gluten had little effect on the color of raw and cooked oat noodles, which were somewhat yellow. Sensory evaluation indicated that addition of gluten could enhance the overall acceptability of cooked oat noodles. This study may stimulate further interest in using functional whole grain cereal ingredients in developing healthy staple foods.     

植酸酶酶活测定时需要了解的问题

尽管饲料工业中应用淀粉酶已经多年．但畜禽饲料中植酸酶的广泛使用却是前所未有的。植酸酶的广泛应用带来了新挑战．那就是在植酸酶活力的表达和测定方法上还未能形成统一的规定。     

血红素补铁剂对断奶仔猪生长和抗病性能的影响

铁是动物必需的微量元素之一．在猪体内可以作为氧和二氧化碳的载体。参与氧的运输、交换、组织呼吸过程。饲料中缺铁将影响动物机体代谢．仔猪出现贫血症状。严重者3-4周龄死亡。畜牧生产中通常在饲料中补铁或给初生2～3日龄的仔猪注射铁剂．但由于大多数无机补铁剂吸收差．同时还容易与饲料中其他必需微量元素产生拮抗．影响矿物质营养元素的吸收平衡,因此开发新型有机补铁剂有着重要的意义。     

鹅GHR基因荧光定量PCR险测方法的建立

采用PCR方法克隆了鹅生长激素受体(GHR)基因,构建了重组质粒pMD-18T-GHR,并将其作为标准阳性模板.通过对反应条件进行优化,以定量的10倍系列稀释的质粒pMD-18T-GHR为标准品进行荧光定量PCR扩增,建立了检测GHR的荧光定量PCR方法.结果显示,该方法构建的标准曲线线性关系良好,建立的GHR基因荧光定量PCR检测方法灵敏度高、特异性强(可以检测出低于10个拷贝/μL的样品),准确可靠.籽鹅和莱茵鹅GHRmRNA出壳到90日龄生长过程中肝脏中的表达量不同,30日龄不同组织表达量各有变化特点.     

中国农业的优良传统与农业循环经济的发展

本文通过对中国古代重农思想、农学思想以及地力常新、精耕细作和农牧结合等优良传统的阐述,提出大力发展农业循环经济,促进“生产发展”的基本思路、基本原则和发展建议。     

借鉴台湾经验 发展福建休闲农业的思考

休闲农业在台湾发展较早,现已取得了良好的社会、经济和生态效益,是台湾农业转型的新走向。本文介绍了台湾休闲农业特色,分析了福建发展休闲农业基础,提出借鉴台湾经验,发展福建休闲农业的策略。