不同气候年型与土壤类型下春小麦高产高效栽培技术体系模拟研究

为了对春小麦高产高效栽培技术体系进行模拟,采用五元二次正交旋转回归设计,以基本苗(X1)、基氮(X2)、基磷(X3)、追氮(X4)与灌水次数(X5)5个因子作为决策变量,籽粒产量为目标函数,以田间试验资料为基础,建立了不同年型与土壤类型下春小麦产量的多元回归数学模型。通过对模型的分析,获得了不同年型、不同土壤类型下春小麦产量优化(500kg/666.7m2)与经济最佳栽培技术体系,对显著影响产量的两因子交互效应进行了分析,体现了根据不同条件采用变量栽培管理措施的理念。

Evaluation of the Production, Quality of Three Cultivars of Rhodes Grass （Chloris Gayana） and Viability of Seeds, Introduced in the Pampas

This paper describes how a research was carried out about Chloris gayana Kunth. The objective of the work was to agronomical characterize the best sowing date, establishment efficiency, first year management, persistence strategies, biomass production and seeds. The parameter evaluated was： morphological, quality and production of seeds of three commercial cultivars （Santana, Finecut and Recleimer）. Trial duration is December 2012 to December 2016 （33o S, 61o W） Argentina. Design three random blocks with three repetitions, plot 5 × 5 meter. The results were analyzed by ANOVA （Analysis of Variance）, and there was used Tukey Test （p 〈 0.05） for comparison of averages, to determine significant differences between the different ones that will be sown. It was determined that the ends of spring dates ensure better establishment. Although the data of morphology of the first year （length of pod, length of blade and number of leaves/plant） presented differences between the cv, they did not mark a tendency that ensures the best development of one. Recleimer with 598 and 1,026 accumulated degree days present the highest values in both measurements. The accumulation of biomass over the years shows that commercial cv show a very similar performance （12,000 kg DM （Dry Matter） per hectare per year）. The annual accumulation of DM would not vary significantly as monthly cuts are applied during the growing season or total accumulation without cuts would be allowed. In relation to quality parameters （gross protein, neutral detergent fiber and acid detergent fiber）, Recleimer has the lowest values. Santana and Finecut were best in quality. Production of the seed was highest in May for all cvs. However, viability was limited in all date but Finecut and Recleimer showed best performance. As expected, in the megathermal species, seed production being one of the critical points.

Annual Variations of Biogenic Element Contents of Manila Clam(Ruditapes philippinarum) Bottom-Cultivated in Jiaozhou Bay, China

Manila clam （Ruditapes philippinarum） was monthly sampled from its benthic aquaculture area in Jiaozhou Bay from May 2009 to June 2010.The annual variations of major elemental composition,organic content,fatness and element ratio of Manila clam were examined.The element removal effect of clam farming in Jiaozhou Bay was analyzed based on natural mortality and clam harvest.The results indicated that the variation trend of carbon content in shell （Cshell） was similar to that in clam （Cclam）.Such a variation was higher in summer and autumn than in other seasons,which ranged from 9.10±0.13 to 10.38 ± 0.09 mmol g^-1 and from 11.28 ±0.29 to 12.36±0.06 mmol g 1,respectively.Carbon content of flesh （Cflnesh） showed an opposite variation trend to that of shell in most months,varying from 29.42 ± 0.05 to 33.64 ± 0.62 mmol g^-1.Nitrogen content of shell （Nshell） and flesh （Nflesh） changed seasonally,which was relatively low in spring and summer.Nshell and Nflesh varied from 0.07 ±0.009 to 0.14±0.009 mmol g^-1 and from 5.46 ± 0.12 to 7.39 ± 0.43 mmol g^-1,respectively.Total nitrogen content of clam ranged from 0.50 ± 0.003 to 0.76 ± 0.10 mmol g^-1 with a falling tend except for a high value in March 2010.Phosphorus content of clam （Nclam） fluctuated largely,while phosphorus content of shell （Pshell） was less varied than that of flesh （Pflesh）.Pshell varied from 0.006±0.001 to 0.016±0.001 mmol g^-1; while Pflesh fluctuated between 0.058±0.017 and 0.293±0.029mmolg^-1.Pclam ranged from 0.015±0.002 to 0.041 ±0.006mmolg^-1.Carbon and nitrogen content were slightly affected by shell length,width or height.Elemental contents were closely related to the reproduction cycle.The removal amounts of carbon,nitrogen and phosphorus from clam harvest and natural death in Jiaozhou Bay were 2.92× 10^4t,1420t and 145 t,respectively.The nutrient removal may aid to reduce the concentrations of nitrogen and phosphorus,the main causes of eutrophication,and to maintain the ecosystem health of Jiaozhou Bay.

Chemical Quality of Landrace Varieties Cultivated in Traditional Communities in the State of Maranhao, Brazil

The aim of this study was to analyze the chemical composition of landrace seeds of rice, maize and cassava grown in traditional communities in file state of Maranchao. The sample collection was based on file description of the farmers for identification of varieties of plants, based on protein content, lipids, carbohydrates and mineral through Association of Official Analytical Chemists （AOAC） methods. Landrace seeds of nine maize cultivars, 13 rice and 40 cassava, with differences in centesimal composition in all varieties were analyzed. For maize landrace seeds file lipid values, carbohydrates and ash are in the average for the species. The protein contents and ash to file surveyed rice varieties were high, while the levels of lipids and carbohydrates are within average in relation to conventional varieties. The results obtained for cassava showed high percentages of protein, with a significant level for the feeding of the people of the community who consume their byproducts. Thus, differences in file chemical composition of file varieties studied showed file interference of genotype, management and environmental factors in their chemical and physiological quality, reinforcing file importance of file study of creole varieties for the development of new germplasm and for file guarantee of food sovereignty of traditional communities.