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71.
A long-term experiment of minimal and zero tillages was carried out on the sandy loam soil from 1985~1996. The results showed that the yields of minimal tillaged rice and wheat were similar to those by conventional tillage. Zero-tillaged wheat yield increased by 5.3% on average, while the zero-tillaged rice yield reduced by 2. 2%. The yields under long-term minimal and zero tillages showed no obvious temporal trend. After five years of the experiment, the soil organic matter contents were in steady state under different tillages, but its distributions in soil layers were different markedly and the richness in upper layer was observed under minimal and zero tillages, with the richness coefficients of 1. 1140 and 1. 1608, on 7-year average ,respectively. The bulk densities among different tillages were insignificantly different in soil layers of 0~7cm and 14~21cm. In the soil layer of 7~14cm,the bulk densities under conventional, minimal and zero tillages were 1.348,1.412 and 1. 410 g/cm3 respectively, minimal and zero tillages resulted in obvious increases in the bulk density. 相似文献
72.
本文通过体外消化来模拟消化系统以研究乳及发酵乳对FeCl3中铁的化学状态及透析率的影响,结果表明,在消化过程中乳及发醇乳可促进铁的溶解、以及Fe3 的还原和铁的透析,这一作用与样品的pH元失,认为是消化过程中产生的氨基酸和肽起了作用。研究还发现,原乳先加铁盐再送行发酵所产生的作用要较发醇后再加铁盐的作用大,认为发醇乳对铁化学状态及透析率的影响具有时间效应。此外,有乳存在的各试验组其Fe3 透析率较可溶性铁的透析率与对照组差异更大。 相似文献
73.
Effect of culture system on the nutrition and growth performance of Pacific white shrimp Litopenaeus vannamei (Boone) fed different diets 总被引:2,自引:0,他引:2
A.G.J. TACON J.J. CODY L.D. CONQUEST S. DIVAKARAN I.P. FORSTER & O.E. DECAMP 《Aquaculture Nutrition》2002,8(2):121-137
Two 8-week feeding trials were conducted with juvenile Pacific white shrimp, Litopenaeus vannamei (Boone) to compare the growth and performance of animals fed a series of experimental and commercial pelleted shrimp and fish feeds and dietary feeding regimes within an indoor running-water culture system and an outdoor zero-water-exchange culture system. The best overall shrimp growth performance was observed for animals fed the experimental shrimp diet and all-day feeding regime under outdoor zero-water-exchange culture conditions. Final body weight and average weekly growth rate under these conditions were 2.8 and 3.4 times greater, respectively, than animals of similar size fed with the same diet under indoor running-water culture conditions. Although direct comparison between indoor and outdoor culture systems is difficult because of the lower indoor water temperatures, and consequently lower mean daily feed intake of animals, it is believed that the higher growth and feed performance of animals reared under outdoor `green-water' culture conditions was primarily due to their ability to obtain additional nutrients from food organisms endogenously produced within the zero-water-exchange culture system. The most promising features of zero-water-exchange culture systems are that they offer increased biosecurity, reduced feed costs and water use for the farmer, and by doing so provide a potential avenue of moving the shrimp culture industry along a path of greater sustainability and environmental compatibility. 相似文献
74.
LIU Zheng-li SUN Shi-xian CHENG Ru-hong HUANG Wen-sheng LIU Jun-xin QU Zhu-feng XIA Xue-yan SHI Zhi-gang 《中国农业科学(英文版)》2006,5(7):558-562
Super Early Maturation No.2 is a new foxtail millet germplasm developed by using the targeted-character-gene-bank-breeding method. It has several outstanding characteristics. (1) Super early maturity. It can normally mature in Bashang, Hebei Province, China, where the altitude is around 1 400 meters, and it needs 1650°C of effective accumulated temperature in the growing period. (2) Millet is rich in iron. The iron content of the millet of Super Early Maturation No.2 is 54.10 mg kg−1, which is 62.0% higher than the average iron content of the foxtail millet varieties in China. (3) High crude fat content. Its crude fat content is 6.24%, which is 54.1% higher than the average content of foxtail millet varieties in China. (4) High crude protein content. The average of the crude protein content of all the foxtail millet varieties in China is 12.71%, only 5% varieties surpass 14%, however, the crude protein content of Super Early Maturation No.2 is 14.36%, which is rare in improved varieties of foxtail millet in China. (5) Overall characteristics are good. 相似文献
75.
选用1日龄艾维茵肉仔鸡504只 ,随机分为9组 ,每组4个重复 ,每重复14只鸡 ,公母各半 ,采用3×3(Fe×VA)完全随机试验设计 ,研究了日粮添加不同水平Fe(0、30、60mg/kg)和VA(750、1500、2700IU/kg)对肉仔鸡不同生长阶段 (0~4周龄和5~7周龄 )肝脏、心脏、脾脏、胰脏、肾脏、肌肉、胫骨、羽毛等组织铁含量影响。结果表明 :在日粮铁的影响下 ,肉仔鸡体内各组织铁含量顺序依次为 :(前期 :肝脏>肾脏>脾>心脏>胫骨>毛>胰脏>肌肉 ;后期 :肝脏>脾>肾脏>心脏>胫骨>羽毛>胰脏>肌肉 ) ;日粮铁添加水平对前期肝脏、心脏、肾脏、胰脏、羽毛等组织铁含量影响显著 (P<0.01) ,60mgFe/kg 组这些组织铁含量最高 ;对后期肝脏、心脏、脾脏、胰脏、肌肉、胫骨、羽毛等组织的铁含量影响显著 (P<0.01) ,60mgFe/kg组肝脏与心脏组织铁含量最高 ,30mgFe/kg 组脾脏、肌肉、胫骨等组织铁含量最高 ,0mgFe/kg 组胰脏、羽毛等组织铁含量最高 ;肾脏、胰脏、羽毛、肌肉、胫骨在不同生长阶段沉积铁能力不同。日粮铁对不同生长阶段各组织铁含量的影响存在差异。VA影响机体内铁的分布 ,日粮VA添加水平对前期肾脏、肌肉、羽毛等组织铁含量影响显著 (P<0.01) ,对后期肝脏、肾脏、胰脏、肌肉、胫骨、羽毛等组织铁含量影响显著 (P<0.01)。VA对前后 相似文献
76.
G. Velu K. N. Rai V. Muralidharan V. N. Kulkarni T. Longvah T. S. Raveendran 《Plant Breeding》2007,126(2):182-185
Development of crop cultivars with elevated levels of micronutrients is being increasingly recognized as one of the approaches to provide sustainable solutions to various health problems associated with micronutrient malnutrition, especially in developing countries. To assess the prospects of this approach in pearl millet (Pennisetum glaucum), a diverse range of genetic materials, consisting of 40 hybrid parents, 30 each of population progenies and improved populations, and 20 germplasm accessions, was analysed for grain iron (Fe) and zinc (Zn) content, deficiencies of which adversely affect human health. Based on the mean performance in two seasons at ICRISAT, Patancheru, India, large variability among the entries was found, both for Fe (30.1–75.7 mg/kg on dry weight basis) and Zn (24.5–64.8 mg/kg). The highest levels of grain Fe and Zn were observed in well‐adapted commercial varieties and their progenies, and in the parental lines of hybrids, which were either entirely based on iniari germplasm, or had large components of it in their parentage. There were indications of large within‐population genetic variability for both Fe and Zn. The correlation between Fe and Zn content was positive and highly significant (r = 0.84; P < 0.01). These results indicate that there are good prospects of simultaneous selection for both micronutrients, and that selection within populations, especially those with the predominantly iniari germplasm, is likely to provide good opportunities for developing pearl millet varieties and hybrid parents with significantly improved grain Fe and Zn content in pearl millet. 相似文献
77.
Coke oven waste water is respectively pretreated by blast furnace sludge method and blast furnace sludge plus iron scrap method, the effects of pH and the quantity of materials and treatment time on the removal efficiency of COD are analyzed. The results indicate that blast furnace sludge plus iron scrap method is superior to blast furnace sludge method .The treatment time and pH can greatly affect on the removal efficiency of COD using blast furnace sludge plus iron scrap method. The treatment time after 30 minutes and pH have no remarkable effects the removal efficiency of COD using blast furnace sludge method. The removal efficiency of COD increases with the increase of blast furnace sludge and iron scrap, but the increase rate decreases gradually. 相似文献
78.
钙盐诱导下土壤锰和铁的释放及其对胡椒的生物有效性 总被引:9,自引:7,他引:9
Releases of manganese and iron ions from an albic soil (Albic-Udic Luvisol), a yellow-red soil (Hap-Udic Ferrisol) and a yellow-brown soil (Arp-Udic Luvisol) induced by calcium salt addition and their bioavailability to pepper (Capsicum frutescens L.) were studied in a pot experiment. Addition of Ca(NO3)2 decreased soil pH and increased both exchangeable and DTPA (diethylenetriamine pentaacetic acid)-extractable Mn and Fe in soils. Meanwhile, total Mn accumulation in the shoots of Capsicum frutescens L. on the salt-treated soils increased significantly (P< 0.01) compared with the control, suggesting that salt addition to soil induced Mn toxicity in Capsicum frutescens L. Although exchangeable and DTPA-extractable Fe increased also in the salt-treated soils, Fe uptake by the shoots of Capsicum frutescens L. decreased. The effect of added salts in soils on dry matter weight of pepper varied with the soil characteristics, showing different buffer capacities of the soils for salt toxicity in an order of yellow-brown soil > albic soil > yellow-red soil. Fe/Mn ratio in shoots of Capsicum frutescens L. decreased with increasing salt addition for all the soils, which was ascribed to the antagonistic effect of Mn on Fe accumulation. The ratio of Fe/Mn in the tissue was a better indicator of the appearance of Mn toxicity symptoms than Mn concentration alone. 相似文献
79.
干湿交替对作物根际特征及铁膜形成的影响研究进展 总被引:4,自引:0,他引:4
铁膜普遍存在于水生植物的根系表面,根际周围Fe~(2+)的浓度和根系氧化力决定了根表铁膜的数量。干湿交替是农业生产中常用的灌溉技术。在干湿交替过程中,水分和氧气含量的变化导致根际土壤发生一系列物理、化学和生物学变化,从而对根表铁膜的形成产生影响。本文综述了干湿交替过程对根际特征变化的影响,分析了根表铁膜的形成条件、化学组成与空间结构和根表铁膜的形成过程,并在此基础上探讨了干湿交替对铁膜形成的影响以及干湿交替诱导铁膜形成的可能机制。最后对干湿交替诱导铁膜形成的研究方法与应用前景进行了展望。 相似文献
80.