| incorporation of different n sources and light response curves of nitrogenase and photosynthesis by cyanobacterial blooms from rice fields. | in this work, we estimate the contributions of the different sources of n incorporated by two n(2)-fixing cyanobacterial blooms (anabaena sp. and microchaete sp.) in the rice fields of valencia (spain) during the crop cycles of 1999 and 2000, and evaluate the response of nitrogenase and c assimilation activities to changing irradiances. our results show that, far from the generally assumed idea that the largest part of the n incorporated by n(2)-fixing cyanobacterial blooms in rice fields comes ... | 2006 | 16596437 |
| epiphytic cyanobacteria on chara vulgaris are the main contributors to n(2) fixation in rice fields. | the distribution of nitrogenase activity in the rice-soil system and the possible contribution of epiphytic cyanobacteria on rice plants and other macrophytes to this activity were studied in two locations in the rice fields of valencia, spain, in two consecutive crop seasons. the largest proportion of photodependent n(2) fixation was associated with the macrophyte chara vulgaris in both years and at both locations. the nitrogen fixation rate associated with chara always represented more than 45 ... | 2004 | 15345425 |
| characteristics of rice straw and sewage sludge as composting materials in valencia (spain). | this work supports the idea that composting can be useful for minimizing the rice straw and sewage sludge environmental impact. several physical, chemical and microbiological properties of these raw materials were analyzed. the characteristics of the rice straw were complementary to those of the sewage sludge for the application of composting. the c/n ratios suitable for a rapid increased in microbial activity were the lowest (17-24). a temperature of 62 degrees c during 48 h removed pathogenic ... | 2004 | 15207303 |
| botanical identification of several echinochloa biotypes collected in spanish rice fields with control failures of cyhalofop-butyl. | there is some disagreement about the species that constitute echinochloa. correct identification is agronomically and economically important because echinochloa spp. are aggressive invaders and difficult to control. the identification of echinochloa spp. is complicated because of the morphological diversity shown by the genus. this work was initiated because of the differential response to cyhalofop-butyl treatment shown by some populations of echinochloa spp. four biotypes were selected for bot ... | 2003 | 15149139 |
| direct and indirect exogenous contamination by pesticides of rice-farming soils in a mediterranean wetland. | it is known that the sources of soil contamination can be endogenous or exogenous and that exogenous contamination may be direct or indirect. in this work, an environmental pesticide fate study was conducted in soil profiles collected from 23 rice field sites in an important mediterranean wetland (albufera natural park, valencia, spain) from april 1996 to november 1997. temporal and spatial distribution of 44 pesticide residues in an alluvial mediterranean soil (gleyic-calcaric fluvisol, fluvaqu ... | 2003 | 12520386 |
| work, rice and malaria in valencia in the xviiith century. | this study, prepared with documentary sources from archives, focuses on one of the most serious health problems in spain in the age of enlightenment; that is, the pernicious endemics of malaria in the humid mediterranean zones. based on material from the general archives of simancas, the author studies the health polemic between the partisans and detractors of rice cultivation in the swampy bogs of the turia and júcar river areas. to these considerations on valencia's agricultural expansion in t ... | 1994 | 11639839 |