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Martins T.,State University of Ponta Grossa | Saab S.C.,State University of Ponta Grossa | Milori D.M.B.P.,EMBRAPA - Empresa Brasileira de Pesquisa Agropecuaria | Brinatti A.M.,State University of Ponta Grossa | And 3 more authors.
Soil and Tillage Research | Year: 2011

In this work is presented the use of the C/N ratio and the Laser Induced Fluorescence (LIF) spectroscopy for determining the humification of soil organic matter (SOM) in an Oxisol under three different long-term tillage managements (no-tillage (NT), reduced tillage (RT) and conventional tillage (CT)). Humification of SOM was evaluated in the soil and its fractions (clay. < 2. μm, silt 2-20. μm, sand 20-1000. μm). The obtained results show that lower SOM humification was observed in soil under NT, mainly at the surface (0-5. cm). In CT, SOM humification values maintained constant for all investigated depths (0-5, 5-10, 10-15 and 15-20. cm). Also, clay was the soil fraction that exhibited the lesser humification of SOM. Based on the obtained results it can be said that NT favors the accumulation of SOM on its surface, increasing aggregate stability and presenting samples with lower humification indexes. These results indicate a larger availability of nutrients for the plants in this management. © 2010 Elsevier B.V. Source


de Moraes Sa J.C.,State University of Ponta Grossa | Seguy L.,CIRAD - Agricultural Research for Development | Tivet F.,CIRAD - Agricultural Research for Development | Lal R.,Ohio State University | And 8 more authors.
Land Degradation and Development | Year: 2015

The continuous use of plowing for grain production has been the principal cause of soil degradation. This project was formulated on the hypothesis that the intensification of cropping systems by increasing biomass-C input and its biodiversity under no-till (NT) drives soil restoration of degraded agro-ecosystem. The present study conducted at subtropical [Ponta Grossa (PG) site] and tropical regions [Lucas do Rio Verde, MT (LRV) site] in Brazil aimed to (i) assess the impact of the continuous plow-based conventional tillage (CT) on soil organic carbon (SOC) stock vis-à-vis native vegetation (NV) as baseline; (ii) compare SOC balance among CT, NT cropping systems, and NV; and (iii) evaluate the redistribution of SOC stock in soil profile in relation to soil resilience. The continuous CT decreased the SOC stock by 0·58 and 0·67MgCha-1y-1 in the 0- to 20-cm depth at the PG and LRV sites, respectively, and the rate of SOC sequestration was 0·59 for the PG site and ranged from 0·48 to 1·30MgCha-1y-1 for the LRV site. The fraction of C input by crop residues converted into SOC stock was ~14·2% at the PG site and ~20·5% at the LRV site. The SOC resilience index ranged from 0·29 to 0·79, and it increased with the increase in the C input among the NT systems and the SOC sequestration rates at the LRV site. These data support the hypothesis that NT cropping systems with high C input have a large potential to reverse the process of soil degradation and SOC decline. © 2015 John Wiley & Sons, Ltd. Source


Balota E.L.,Agricultural Research Institute of Parana IAPAR | Machineski O.,Agricultural Research Institute of Parana IAPAR | Truber P.V.,Agricultural Research Institute of Parana IAPAR | Scherer A.,Agricultural Research Institute of Parana IAPAR | de Souza F.S.,Filadelfia University
Brazilian Journal of Plant Physiology | Year: 2011

The physic nut (Jatropha curcas L.) is a perennial tree that occurs naturally in the tropical and subtropical regions of Brazil. Fruits of physic nut present an oil content of 28% on a dry weight basis. Although the plant has adapted to diverse soil conditions such as low fertility, the correction of soil acidity and the addition of fertilizer are essential for highly productive plants. Thus, the response of the physic nut to different soil phosphorus levels (P) and arbuscular mycorrhizal fungi (AMF) inoculation must be characterized. Hence, the objective of the present study was to evaluate the response of physic nut seedlings to arbuscular mycorrhizal fungi (AMF) inoculation at different levels of soil P. Experiment was carried out in a greenhouse encompassing AMF treatments (inoculation with Gigaspora margarita or Glomus clarum, and the non inoculated controls), and phosphorus treatments (0, 25, 50, 100, 200 and 400 mg kg -1 added to soil). At low soil P levels, arbuscular mycorrhizal fungi inoculation had a significant positive effect on plant growth, shoot and root dry matter content, plant height, number of leaves, total leaf area, leaf area per leaf and the Dickson quality index. The root:shoot ratio and the leaf area ratio were also affected by mycorrhizal inoculation and the level of P addition. Physic nut plants exhibited high mycorrhizal dependency at soil P additions up to 50 mg kg -1. Source


Shigueoka L.H.,Agricultural Research Institute of Parana IAPAR | Shigueoka L.H.,State University Londrina | Sera G.H.,Agricultural Research Institute of Parana IAPAR | Sera T.,Agricultural Research Institute of Parana IAPAR | And 8 more authors.
Crop Breeding and Applied Biotechnology | Year: 2014

The aim of this study was to select high-yielding coffee progenies with resistance to coffee leaf rust for the State of Paraná (Brazil). Field experiments in a randomized block design were carried out in Itaguajé and Congonhinhas. Yield, vegetative vigor and rust resistance of nine progenies of Arabic coffee and three check cultivars were evaluated. Many genotypes derived from "Sarchimor" and "Catucaí" were susceptible. Three coffee genotypes of Sarchimor germplasm and the F6 generation of genotype "Catuaí x (Catuaí x BA-10 coffee)" were selected to advance generations and are promising to become new cultivars for being higher-yielding than 'IAPAR 59' and 'Tupi IAC 1669-33' and having a large number of plants with complete rust resistance. Source

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