MESCH / Department of Hydrology and Water Resources

Orientador: Morel de Passos e Carvalho / Banca: João Antonio da Costa Andrade / Banca: Gener Tadeu Pereira / Resumo: O milho é um dos cereais mais cultivados e consumidos no mundo. Para silagem é a forrageira de melhor qualidade, muito utilizada na alimentação bovina. Por apresentar sistema radicular com alto potencial de desenvolvimento, os atributos físicos do solo são de extrema importância à sua produtividade, uma vez que, em condições adversas, podem dificultar a penetração das raízes e, conseqüentemente, limitar o adequado aproveitamento dos nutrientes e da água disponível. No ano agrícola de 2005, na Fazenda Bonança (Agropecuária Dahma), município de Pereira Barreto (SP), Brasil (20o40'12'' latitude S; 51o01'50'' longitude W), foram analisadas a produtividade de forragem do milho safrinha outonal (MSF), no sistema plantio direto irrigado, as densidades da partícula (DP) e do solo (DS), as porosidades totais determinada (PT) e calculada (PTc), os teores de areia (AR), silte (SI) e de argila (AR) de um Latossolo Vermelho Distrófico (Acrustox Háplico) local, nas profundidades 1 (0-0,10 m), 2 (0,10-0,20 m) e 3 (0,20-0,30 m). O objetivo foi estudar a variabilidade e as correlações lineares e espaciais entre os atributos da planta e do solo, visando selecionar um indicador da qualidade física do solo de boa representatividade para a produtividade da forragem. Foi instalada a malha geoestatística para a coleta dos dados do solo e da planta, contendo 125 pontos amostrais, numa área de 2500 m2 e declive homogêneo de 0,025 m/m. No geral, os atributos estudados, além de não terem revelado distribuição aleatória, apresentaram variabilidade entre média e baixa. Seguiram padrões espaciais claramente definidos, com alcances da dependência espacial entre 6,8 e 46,8 metros. Assim, o maior alcance que poderá assegurar extrema semelhança em magnitude para qualquer atributo estudado, e que poderá alimentar os pacotes ...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Corn is one of cereals most cropped and consumed in the world. At silage is the best green crop, very employed in the bovine nutrition. Once it has roots with high growth capability, the soil physical attributes are very important to his productivity, so that, in adverse conditions, they can inhibit the roots penetration, and thus restrict the suitable absorption of plant nutrients and available water. The forage productivity of autumnal corn (FP) in no-tillage and irrigated, and the particle (PD) and bulk (BD) densities, the determined (TPd) and computed (TPc) total porosities, the contents of sand (SA), silt (SI), and clay (CL) soil attributes, in depths 1 (0-0,10 m), 2 (0,10-0,20 m), and 3 (0,20-0,30 m), in a Haplic Acrustox of Bonança Farm (Dahma Agricultural Company) in Pereira Barreto County, Sao Paulo State, Brazil (20o40'12'' latitude S; 51o01'50'' longitude W), were analyzed in the agricultural year of 2005. The purpose was to study the variability and linear spatial correlations among the attributes (plant and soil), aiming to select an index of soil physical quality with good capacity to represent the forage productivity. A grid geostatistical to collect soil and plant data was installed, with one hundred and twenty five sample points, in a area of 2500 m2, with homogeneous slope steepness of 0.025 m/m. Yonder not changed randomly, the studied attributes showed median to low variability, with excellent spatial performances, and ranges between 6.8 and 46.8 meters. Therefore, the farthermost range at to guarantee high similitude in size, at every-one soil researched attribute, and however it will be used in the computational software of precision agriculture, must be of 46.8 meters. The FP will be estimated through equation of multiple linear regression, from the TPd1 and TPd2 attributes. The Core Method must determine the TP advantageous. Although the ...(Complete abstract click electronic access below) / Mestre

The transition of natural landscapes to intensive agricultural uses has resulted in severe loss of soil organic carbon (SOC), increased CO₂ emissions, river depletion, and groundwater overdraft. Despite negative documented effects of agricultural land use (i.e., soil erosion, nutrient runoff) on critical natural resources (i.e., water, soil), food production must increase to meet the demands of a rising human population. Given the environmental and agricultural productivity concerns of intensely managed soils, it is critical to implement conservation practices that mitigate the negative effects of crop production and enhance environmental integrity. In the Mississippi Alluvial Valley (MAV) region of Mississippi, USA, the adoption of cover crop (CC) and no-tillage (NT) management practices has been low because of a lack of research specific to the regional nuances. Therefore, this study assessed the long-term soil physiochemical and biological responses from integrating CC and NT management to agricultural soils of the region. Research plots were established in a split-block design with two tillage treatments: NT and reduced tillage (RT) and three CC treatments: no cover (NC), rye (RY) and a rye+clover (RC) mix. Soil samples were taken during the growing season of 2019 and 2020. Bulk density was found to be significantly lower in NT plots and aggregate stability was greatest in plots with a single CC species. Moisture retention increased in NT.. Soil organic carbon was greater in NT and CC treatments and there was no difference in CO₂ flux. Bacterial abundance had a positive effect on SOC but a negative effect on CO₂. The rate of proportional change and pattern of variability in C pools suggested loss of SOC in reduced tillage (RT) treatments. Microbial abundance, functional genes and enzyme activity was greater in NT with CC, but diversity was greater in RT. No-tillage practices lower diversity and influence long-term community changes while CC practices enact a seasonal response to environmental conditions. I conclude that in heavy clay soils of the mid-South region of the MAV, RT with a CC is optimal for soil health traits associated with crop sustainability, however the management will still contribute to increased CO₂ emissions.

From the Proceedings of the 1974 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 19-20, 1974, Flagstaff, Arizona / Reliable information on soil-water status is required in order to make accurate water balance studies of watersheds, to determine the survival probabilities of various types of vegetation between rainfalls in low rainfall areas, and to determine the susceptibility of the uppermost soil to wind erosion. Simple solarimeters may help to accomplish this objective. Bare soil albedo was a linear function of the water content of a very thin surface layer of soil, and albedo correlated well with water contents of thicker soil layers. In addition, albedo measurements could be used to delineate the 3 classical stages of soil drying. Albedo may also be used to differentiate between the initial potential rate phase of evaporation following an application of water, and the succeeding falling rate phase. Results of applying this technique to a field of Avondale clay loam indicate that 20% to 25% of the water applied by either irrigation or rain will be lost by stage 1 potential evaporation, independent of seasonal variations in evaporative demand. Presently the techniques developed are applicable only to bare soil surfaces.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-04-23T15:55:11Z No. of bitstreams: 1 SARA REGINA MIRANDA RUFINO - TESE PPGEP 2014..pdf: 3286437 bytes, checksum: cfafef220e2b9de314c5df81f2286b36 (MD5) / Made available in DSpace on 2018-04-23T15:55:11Z (GMT). No. of bitstreams: 1 SARA REGINA MIRANDA RUFINO - TESE PPGEP 2014..pdf: 3286437 bytes, checksum: cfafef220e2b9de314c5df81f2286b36 (MD5) Previous issue date: 2014-08-28 / A agricultura familiar, com base agroecológica, tem estimulado mudanças significativas na vida de famílias de agricultores familiares, seja no manejo do solo, na relação com o meio ambiente, hábitos alimentares, segurança alimentar, ou mesmo autonomia produtiva. Nesta perspectiva, avaliar a qualidade do solo dentro de sistemas em transição agroecológica (convencional para agroecológico), pode proporcionar melhor compreensão sobre seus efeitos deste sistema de cultivo do solo. Na busca da sustentabilidade de sistemas agrícolas o uso de indicadores no monitoramento das condições do solo constitui-se numa importante ferramenta para a tomada de decisões na condução das produções. O objetivo deste trabalho foi comparar propriedades físicas, químicas, bioquímicas, microbiológicas e termogravimétricas de solos de mesorregiões do agreste da Paraíba em transição agroecológica. O presente estudo foi desenvolvido na Mesorregião do Agreste-Brejo da Paraíba. Foram coletados solos em propriedades de agricultores familiares sob sistema de cultivo agroecológico e convencional, os quais foram submetidos a diferentes indicadores de sustentabilidade do solo. Os indicadores químicos nitrogênio, matéria orgânica leve, carbono orgânico total e matéria orgânica, apresentaram maior correlação e sensibilidade quanto a sua utilização de indicadores da qualidade de solos em transição agroecológica. A termogravimetria apresentou potencialidade na identificação dos solos com relação ao teor de matéria orgânica de solo agrícola. / A family farm with agroecological base, has spurred significant changes in the lives of farming families, either in soil management in relation to the environment, eating habits, food security, or even productive autonomy. In this perspective, assessing soil quality within systems (for conventional agroecological) agroecological transition may provide better understanding of the effects of this system of cultivation. In search of the sustainability of agricultural systems, using indicators in the monitoring of soil conditions constitutes an important tool for decision making in the conduct of productions. The objective of this study was to compare physical, chemical, biochemical, microbiological and thermogravimetric soils of the rough mesoregions of Paraíba in agroecological transition properties. This study was developed in Meso - Heath of the Wasteland Paraíba. Soil samples were collected on properties of farmers in agro-ecological and conventional cropping system, which were subjected to different indicators of soil sustainability. Chemical indicators nitrogen, light organic matter, total organic carbon and organic matter showed higher correlation and sensitivity as the use of soil quality indicators in agro-ecological transition. Thermogravimetry showed potential in the identification of soils in relation to organic matter content of agricultural soil.