Evaluation of soil water percolation under different irrigation practices, antecedent moisture and groundwater depths in paddy fields

2017 ◽  
Vol 192 ◽  
pp. 149-158 ◽  
Author(s):  
Baoli Xu ◽  
Dongguo Shao ◽  
Xuezhi Tan ◽  
Xia Yang ◽  
Wenquan Gu ◽  
...  
1991 ◽  
Vol 122 (1-4) ◽  
pp. 141-159 ◽  
Author(s):  
Holger Johnsson ◽  
Lars-Christer Lundin

2012 ◽  
Vol 5 (3) ◽  
pp. 676 ◽  
Author(s):  
Paulo Roberto Megma Francisco ◽  
Iêde De Brito Chaves ◽  
Eduardo Rodrigues Viana de Lima ◽  
Maria Marle Bandeira ◽  
Bernardo Barbosa da Silva

O estado da Paraíba tem como característica climática marcante as irregularidades, tanto espacial quanto temporal do seu regime de chuvas, uma vez que, 86,6% do seu território faz parte da região semiárida brasileira. A cobertura vegetal de caatinga, já bastante impactada pela ação antrópica, apresenta diferentes feições relacionadas aos fatores edafoclimáticos, dentre estes, a precipitação, que influenciada pelo relevo, tende a aumentar com a altitude dentro dos diferentes espaços hidrogeográficos. Quanto menor a precipitação, maior a aridez e a irregularidade da distribuição das chuvas. No período seco, a maioria das plantas da caatinga perde a folhagem, recompondo-se rapidamente, logo que inicia um novo período de chuva. Este trabalho teve como objetivo analisar a influência da umidade antecedente em imagem orbital de média resolução espacial e utilizada para mapeamento da vegetação de caatinga através do Índice de Vegetação de Diferença Normalizada e o Índice de Biomassa da Vegetação Lenhosa. Concluiu-se que com a utilização de imagem de média resolução espacial a classificação em 9 classes foi satisfatória na separação das fisionomias existentes na região estudada; que a análise da diferença espectral pode contribuir no monitoramento; que houve influência da umidade antecedente nas respostas espectrais; que a biomassa da vegetação de caatinga está relacionada à disponibilidade de água no solo; e com o uso de geotecnologia pode-se chegar a resultados satisfatórios.Palavras - chave: Semiárido, índice de vegetação, sensoriamento remoto. Mapping of Caatinga with Use of Geotechnology and Analysis of Antecedent Humidity in Hydrographic Basin ABSTRACTThe state of Paraíba is characterized by striking climatic irregularities, both its spatial and temporal rainfall, since 86.6% of its territory is part of the Brazilian semiarid region. The vegetation of caatinga, enough already impacted by human activity, has different features related to soil and climatic factors, among these, the precipitation, which influenced by the relief, tends to increase with altitude within the different spaces hidrogeografic. The lower rainfall, increased aridity and the irregularity of rainfall distribution. In the dry season, most plants of the caatinga lose foliage, recovering quickly, as soon as you start a new period of rain. Generally, the quantity and persistence of hardwood biomass from caatinga vegetation is related to soil water availability. This study aimed to analyze the influence of antecedent moisture on multispectral image captured by the sensor and medium resolution satellite used for mapping of caatinga vegetation using NDVI and IBVL. It was concluded by this study that the use of medium-resolution image, the classification in nine classes was satisfactory in the separation the physiognomies in the region studied, which of the difference spectral analysis can help in monitoring and there was no influence of antecedent humidity on spectral responses, that biomass of caatinga vegetation is related to soil water availability, and the use of geotechnology can be reached satisfactory results.Keywords: Semiarid, vegetation index, remote sensing.


2018 ◽  
Vol 11 (1) ◽  
pp. 157 ◽  
Author(s):  
Yunjiang Zuo ◽  
Yuedong Guo ◽  
Changchun Song ◽  
Shaofei Jin ◽  
Tianhua Qiao

Water and heat transport is the focus of hydrological research in seasonal frost areas. Considering Sanjiang Plain as the study area, this study explored the influence of land use change on soil water and heat transport and the future trend of surface water and heat transport. The effects of land use change on soil water and heat transport were revealed using observation data from the Sanjiang Mire Wetland Experimental Station of the Chinese Academy of Sciences from the period of May 2016 to May 2017. The analysis found evident changes in the water and heat status of different land use types. During conversion from uplands to paddy fields, the surface soil moisture content increased, evapotranspiration increased by approximately 20%, surface infiltration decreased by about 50%, and surface heat flux increased. In a future climate change scenario, the change trend of soil water and heat condition was roughly consistent with the present situation, and the proportion of evapotranspiration of upland and paddy fields in precipitation decreased to 40% and 55%, respectively. These results can provide a theoretical basis for the rational utilization of land and water resources in Sanjiang Plain.


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