Niche processes and conservation implications of fish community assembly in a rice irrigation system

2015 ◽  
Vol 25 (3) ◽  
pp. 322-335 ◽  
Author(s):  
Mitsuru Ohira ◽  
Hiroshi Tsunoda ◽  
Kazuya Nishida ◽  
Yoshito Mitsuo ◽  
Yutaro Senga
1993 ◽  
Vol 27 (4) ◽  
pp. 227-236 ◽  
Author(s):  
Oswaldo Paulo Forattini ◽  
Iná Kakitani ◽  
Eduardo Massad ◽  
Daniel Marucci

A relation between a rice irrigation system and mosquito breeding was established in a study undertaken at the Ribeira Valley Experimental Station, from January through December 1992. Flooding favoured Anopheles (Nyssorhynchus) and Culex (Melanoconion) species, while empty paddies condition were propitious to Aedes scapularis and Culex (Culex) species. Compared with a more primitive area of the same region, several species showed high a degree of adaptation to the anthropic environment. Among them, Anopheles albitarsis, a potential malaria vector that breeds in the irrigation system, has shown immature stage production thirteen times higher than at the natural breeding sites. In addition, Ae. scapularis, An. oswaldoi, Cx. bastagarius, and Cx. chidesteri presented high levels of synanthropy.


1993 ◽  
Vol 36 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Elizabeth M. Strange ◽  
Peter B. Moyle ◽  
Theodore C. Foin

1993 ◽  
Vol 27 (5) ◽  
pp. 313-325 ◽  
Author(s):  
Oswaldo Paulo Forattini ◽  
Iná Kakitani ◽  
Eduardo Massad ◽  
Daniel Marucci

A study of adult Culicidae ecology was carried out from January 1992 through January 1993 at the rice irrigation system of the Ribeira Valley Experimental Station. The adaptation of Anopheles albitarsis to the anthropic environment became evident through the adult collections made at its various habitats represented by the irrigation system and the edge of the residual pond, as well as at those made within the local patchy residual woods. Other potential disease vectors were prevalent in the irrigated system too. There were Aedes scapularis, Culex nigripalpus and Cx. ribeirensis that were collected at various habitats. Remarkable differences among their prevalences were obtained such as between the natural forest and anthropic environments. In the former An. albitarsis was practically non-existent, thus suggesting that it might be considered as eusynathropic. As the populations of other species seemed to increase in the anthropic environment, they may be regarded as hemisynanthropes. Observations suggest the hypothesis that the development of irrigated land may be a factor in the emergence of An. albitarsis, and some other species, as well as the possibility of an increase in the transmission of mosquito-borne diseases such as malaria.


2013 ◽  
Vol 251 ◽  
pp. 32-43 ◽  
Author(s):  
Henrique C. Giacomini ◽  
Donald L. DeAngelis ◽  
Joel C. Trexler ◽  
Miguel Petrere

2017 ◽  
Vol 31 (2) ◽  
pp. 330-340 ◽  
Author(s):  
Fabio Schreiber ◽  
Ananda Scherner ◽  
Joseph H. Massey ◽  
Renato Zanella ◽  
Luis A. Avila

Information on the dissipation of clomazone, imazapyr, and imazapic in paddy water under different irrigation system is not available in the literature. The objective of this study was to investigate the effect of two irrigation systems (intermittent (IF) and continuous (CF) flood) on the dissipation of clomazone, imazapyr, and imazapic in paddy water. Imazapic was the least persistent herbicide in paddy water, with DT50-values of approximately 3 and 5d under CF and IF, respectively. Imazapyr required a two-fold increase in time to reach its half-life in water in contrast to imazapic, with DT50-values of approximately 6 and 11d under CF and IF, respectively. Clomazone showed the highest DT50-values, varying between 7 to 21d under CF and IF, respectively. Imazapyr and imazapic dissipation was faster under CF, while clomazone was not affected. This investigation found that the dissipation behaviors of herbicides vary under different rice irrigation regimes. Thus changes in irrigation management, as will be required to produce more rice grain with less water to avoid future scarcity, should consider impacts of flood management on herbicide persistence and environmental behavior.


Author(s):  
V. O. Ushkarenko ◽  
K. V. Dudchenko

Relevance of research. The most common irrigation regime for rise in the world is constant flooding. Soils of rice crop rotation undergo significant changes during the construction of rice irrigation systems, and during their operation. This leads to the formation of so-called "rice soils" that is the result of the transformation of full-profile soils, which were partially or completely disturbed when planning and building rice checks. Keeping the water layer in the field for 4-5 months leads to irreversible changes in the morphological, physical and chemical soil properties. Therefore, it is relevant to determine the indicators of the soil cover, taking into account the features of the soils of rice crop rotations, in order to prevent the development of degradation processes and increase the productivity of rice crop rotation. The purpose of the study is to determine the main indicators of soil cover of rice crop rotation and their testing on a rice irrigation system with an area of ​​190 hectares. Methods and methods of research. During the study the following methods were used: field method - to study the basic soil properties; laboratory one - to study of physical and chemical, ameliorative, agrochemical soil properties and chemical composition of irrigation, subsoil, drainage and waste water; mathematical and statistical, comparative and retrospective - to evaluate the study results of the basic soil fertility indices. The research was carried out in the area of a rice irrigation system with 8-field crop rotation, where the proportion of rice does not exceed 50%. Rice was grown in accordance with the technology of rice growing, taking into account environmental protection requirements. For the companion crops, commonly used cultivation technologies were used. The system has been operated in a project mode for 50 years. The soil cover of the investigated system is represented by dark chestnut alkalized (72.9 hectares), meadow solonetz(18.9 hectares) and meadow chestnut alkalized (75.8 hectare) soil types. Research results. On the basis of analysis of retrospective data of monitoring study of  the main indicators of agro-amelioration status of soils under rice crop rotation, the indicators of soil condition for the main soil types of rice irrigation systems were determined: groundwater level, groundwater mineralization, content of light-soluble salts in arable layer, chlorine ions content in soil-water extract, toxic salt content, soil salt balance, humus content, the content of easily hydrolyzed nitrogen compounds, the density of upper humus layer, the content of air-dry aggregates, content of water-stable aggregates. Conclusions. The approbation of the developed soil condition indicators on the rice irrigation system of the Rice Institute of the National Academy of Agrarian Sciences was carried out, which enabled to identify the main problems and specify the ways to overcome them. In the areas with meadow chestnut alkalized and meadow solonetzsoil types, it is necessary to increase their drainage capacity, namely to repair drainage networks. In the whole area of the investigated rice irrigation system, it is necessary to increase the proportion of perennial legumes and fallow land in the crop rotation, to do soil slitting or other types of mechanical soil treatments to improve its structural and aggregate composition, in particular, the content of air-dry soil aggregates in size of 0.25-10,00 mm and water-stable soil aggregates larger than 25 mm.


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