cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.7514204
title: BIOMASS AND NUTRIENT CYCLING BY COVER CROPS IN BRAZILIAN CERRADO IN THE STATE OF PIAUI

description: ABSTRACT Research on the performance of cover crops in crop systems of annual crops in the Brazilian state of Piauí contributes to increases in yield, greater efficiency of fertilizers and mitigation of environmental impacts. The aim of this study was to evaluate the performance of cover crops in terms of biomass production and the accumulation and release of nutrients during the crop season (November to April) in an oxisol in the Brazilian Cerrado in the state of Piauí that was submitted to different crop production systems including soybeans, maize and upland rice. The experiment was established during the 2010/11 and 2011/12 crop years in the rural area near the municipality of Bom Jesus, Piauí. The experimental design was a randomized block in a split-plot array. Different soil management systems (conventional and no-till) were evaluated in the main plots. Different crop production systems consisting of cover crops sown in the off-season (April to November), and annual crops sown during the crop season (November to April) were implemented in the subplots. The crop production systems that included Urochloa ruziziensis and Pennisetum glaucum overseeded on soybeans and Urochloa ruziziensis simultaneously intercropped with maize stood out in terms of biomass production and the accumulation and release of nutrients. Yields of maize and upland rice declined when sown under newly implemented no-till soil management.
DOI: 10.6084/m9.figshare.7514204.v1
title: BIOMASS AND NUTRIENT CYCLING BY COVER CROPS IN BRAZILIAN CERRADO IN THE STATE OF PIAUI

description: ABSTRACT Research on the performance of cover crops in crop systems of annual crops in the Brazilian state of Piauí contributes to increases in yield, greater efficiency of fertilizers and mitigation of environmental impacts. The aim of this study was to evaluate the performance of cover crops in terms of biomass production and the accumulation and release of nutrients during the crop season (November to April) in an oxisol in the Brazilian Cerrado in the state of Piauí that was submitted to different crop production systems including soybeans, maize and upland rice. The experiment was established during the 2010/11 and 2011/12 crop years in the rural area near the municipality of Bom Jesus, Piauí. The experimental design was a randomized block in a split-plot array. Different soil management systems (conventional and no-till) were evaluated in the main plots. Different crop production systems consisting of cover crops sown in the off-season (April to November), and annual crops sown during the crop season (November to April) were implemented in the subplots. The crop production systems that included Urochloa ruziziensis and Pennisetum glaucum overseeded on soybeans and Urochloa ruziziensis simultaneously intercropped with maize stood out in terms of biomass production and the accumulation and release of nutrients. Yields of maize and upland rice declined when sown under newly implemented no-till soil management.
DOI: 10.6084/m9.figshare.7507898
title: ORGANIC MATTER LABILE FRACTIONS AND CARBON STOCKS IN A TYPIC QUARTZIPSAMMENT CULTIVATED WITH SUGARCANE HARVESTED WITHOUT BURNING

description: ABSTRACT The permanence of sugarcane straw on the soil surface, in systems without the pre-harvest straw burning practice, directly affects the soil organic matter dynamics. The objective of this work was to evaluate the changes in total organic carbon (TOC), carbon in the light organic matter (CLOM) and particulate organic carbon (POC), and their carbon stocks in a typic Quartzipsamment cultivated for nine years with sugarcane crops, which were conducted without the pre-harvest straw burning practice, in Paraipaba, State of Ceará, Brazil. Disturbed and undisturbed soil samples were collected at depths of 0.0-0.025, 0.025-0.05, 0.05-0.10, 0.10-0.20 and 0.20-0.30 m, in the sugarcane crop area and in an adjacent native forest area, in order to quantify the TOC, CLOM and POC, as well as the carbon stocks accumulated in the layer 0.0-0.30 m related to these fractions (TOCSt, CLOMSt and POCSt). TOC content changes after nine years of sugarcane crops, conducted without pre-harvest straw burning, were found only in the layers 0.10-0.20 and 0.20-0.30 m. The CLOM varied only in the layer 0.025-0.05 m. The POC content changes were more noticeable than the changes in TOC and CMOL. The CLOM of the sugarcane crop area presented high similarity with TOC, which may affect their quantification in studies related to the soil organic matter dynamics. The sugarcane crop increased the TOCSt, POCSt and CLOMSt in the layer 0.0-0.30 m, compared with the adjacent native forest area.
DOI: 10.6084/m9.figshare.7507898.v1
title: ORGANIC MATTER LABILE FRACTIONS AND CARBON STOCKS IN A TYPIC QUARTZIPSAMMENT CULTIVATED WITH SUGARCANE HARVESTED WITHOUT BURNING

description: ABSTRACT The permanence of sugarcane straw on the soil surface, in systems without the pre-harvest straw burning practice, directly affects the soil organic matter dynamics. The objective of this work was to evaluate the changes in total organic carbon (TOC), carbon in the light organic matter (CLOM) and particulate organic carbon (POC), and their carbon stocks in a typic Quartzipsamment cultivated for nine years with sugarcane crops, which were conducted without the pre-harvest straw burning practice, in Paraipaba, State of Ceará, Brazil. Disturbed and undisturbed soil samples were collected at depths of 0.0-0.025, 0.025-0.05, 0.05-0.10, 0.10-0.20 and 0.20-0.30 m, in the sugarcane crop area and in an adjacent native forest area, in order to quantify the TOC, CLOM and POC, as well as the carbon stocks accumulated in the layer 0.0-0.30 m related to these fractions (TOCSt, CLOMSt and POCSt). TOC content changes after nine years of sugarcane crops, conducted without pre-harvest straw burning, were found only in the layers 0.10-0.20 and 0.20-0.30 m. The CLOM varied only in the layer 0.025-0.05 m. The POC content changes were more noticeable than the changes in TOC and CMOL. The CLOM of the sugarcane crop area presented high similarity with TOC, which may affect their quantification in studies related to the soil organic matter dynamics. The sugarcane crop increased the TOCSt, POCSt and CLOMSt in the layer 0.0-0.30 m, compared with the adjacent native forest area.
DOI: 10.6084/m9.figshare.7510445
title: SELECTIVITY OF INSECTICIDES USED IN PEACH FARMING TO LARVAE OF Chrysoperla externa (NEUROPTERA: CHRYSOPIDAE) IN SEMI-FIELD CONDITIONS

description: ABSTRACT The selectivity of five insecticides, regularly used in peach farming, was assessed for larvae of the predator Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) by means of bioassay in semi-field conditions. The bioassay was based on the counting of captured larvae after release in peach trees treated with the insecticides (% of active ingredient in spray liquid): deltamethrin (0.001), fenthion (0.050), phosmet (0.100), lufenuron (0.005) and malathion (0.200). Bait-cards with eggs of Anagasta kuehniella (Zeller) (Lepidoptera: Pyralidae) were used to capture larvae from treated plants; five of them were fixed in plant canopy and five others left on the soil around stem. A protective barrier made up of galvanized steel sheet was used for each plant to avoid loss of larvae. The number of larvae feeding on the bait-cards was measured for four days. According to the number of captured larvae, each insecticide effect was estimated and classified into toxicity categories as stated by the International Organization for Biological and Integrated Control of Noxious Animals and Plants (IOBC). Based on observations, the insect growth regulator lufenuron was harmless, while the neurotoxins deltamethrin and malathion were slightly harmful; and lastly, fenthion and phosmet were moderately harmful to C. externa larvae in semi-field conditions. Thus, lufenuron should be recommended for integrated pest management, since it would preserve this predator species in peach orchards.
DOI: 10.6084/m9.figshare.7510445.v1
title: SELECTIVITY OF INSECTICIDES USED IN PEACH FARMING TO LARVAE OF Chrysoperla externa (NEUROPTERA: CHRYSOPIDAE) IN SEMI-FIELD CONDITIONS

description: ABSTRACT The selectivity of five insecticides, regularly used in peach farming, was assessed for larvae of the predator Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) by means of bioassay in semi-field conditions. The bioassay was based on the counting of captured larvae after release in peach trees treated with the insecticides (% of active ingredient in spray liquid): deltamethrin (0.001), fenthion (0.050), phosmet (0.100), lufenuron (0.005) and malathion (0.200). Bait-cards with eggs of Anagasta kuehniella (Zeller) (Lepidoptera: Pyralidae) were used to capture larvae from treated plants; five of them were fixed in plant canopy and five others left on the soil around stem. A protective barrier made up of galvanized steel sheet was used for each plant to avoid loss of larvae. The number of larvae feeding on the bait-cards was measured for four days. According to the number of captured larvae, each insecticide effect was estimated and classified into toxicity categories as stated by the International Organization for Biological and Integrated Control of Noxious Animals and Plants (IOBC). Based on observations, the insect growth regulator lufenuron was harmless, while the neurotoxins deltamethrin and malathion were slightly harmful; and lastly, fenthion and phosmet were moderately harmful to C. externa larvae in semi-field conditions. Thus, lufenuron should be recommended for integrated pest management, since it would preserve this predator species in peach orchards.
DOI: 10.6084/m9.figshare.7516865
title: GROWTH AND REGROWTH OF NEEM AFTER CUTTING IN SALINE - SODIC SOIL TREATED WITH ORGANIC INPUTS

description: ABSTRACT Soil salinity and sodicity are global problems since both promote the physical, chemical and biological degradation of soil, jeopardising the productive capacity of agricultural fields. Inorganic correctives or organic inputs are applied as an attempt to reduce the problem, alongside the use of salt -tolerant plants. This study aimed at evaluating the effects of organic inputs on the growth of neem (Azadirachta indica) strains in saline-sodic soil after cutting. Treatments were arranged in a randomised block design, with four replicates in a 3 × 5 factorial. Organic inputs - bovine manure, common bovine biofertilizer (equal parts of water and fresh bovine manure) and chemically enriched biofertilizer (common biofertilizer components combined with plaster, sugarcane molasses and cow’s milk) - were applied only once, after soil washing, two days prior to seeding, at the levels of 0, 3, 6, 9 and 12% of the substrate volume. Except effects on the stem diameter, the most efficient input was bovine manure, with strong effects on the height increase and biomass yield of neem plants after cutting, especially in treatments at a level greater than 6%. The organic inputs, despite increasing the soil salinity and sodicity in the interval between washing and cutting, stimulated biometric growth and biomass formation in saline-sodic soil.
DOI: 10.6084/m9.figshare.7516865.v1
title: GROWTH AND REGROWTH OF NEEM AFTER CUTTING IN SALINE - SODIC SOIL TREATED WITH ORGANIC INPUTS

description: ABSTRACT Soil salinity and sodicity are global problems since both promote the physical, chemical and biological degradation of soil, jeopardising the productive capacity of agricultural fields. Inorganic correctives or organic inputs are applied as an attempt to reduce the problem, alongside the use of salt -tolerant plants. This study aimed at evaluating the effects of organic inputs on the growth of neem (Azadirachta indica) strains in saline-sodic soil after cutting. Treatments were arranged in a randomised block design, with four replicates in a 3 × 5 factorial. Organic inputs - bovine manure, common bovine biofertilizer (equal parts of water and fresh bovine manure) and chemically enriched biofertilizer (common biofertilizer components combined with plaster, sugarcane molasses and cow’s milk) - were applied only once, after soil washing, two days prior to seeding, at the levels of 0, 3, 6, 9 and 12% of the substrate volume. Except effects on the stem diameter, the most efficient input was bovine manure, with strong effects on the height increase and biomass yield of neem plants after cutting, especially in treatments at a level greater than 6%. The organic inputs, despite increasing the soil salinity and sodicity in the interval between washing and cutting, stimulated biometric growth and biomass formation in saline-sodic soil.
DOI: 10.6084/m9.figshare.7510907
title: EFFECT OF NITROGEN FERTILIZATION ON YIELD AND QUALITY OF WATERMELON, CV. TOP GUN

description: ABSTRACT Nitrogen (N) is the second most important nutrient required by watermelons that can limit their growth and affect fruit quality when deficient. We evaluated the soil (N-nitrate) and foliar N contents and soluble-solid content of the watermelon 'Top Gun' in Brazil at six rates of N fertilization (0, 50, 100, 150, 200 and 250 kg ha-1). N-nitrate and foliar N levels increased linearly with rate. Number of total and marketable fruit, weight of total and marketable fruit and total and marketable yields varied quadratically with rate. N rates of 187 and 184 kg ha-1 produced the highest total and marketable yields, respectively. The rate of N fertilization did not significantly affect total-solid content.
DOI: 10.6084/m9.figshare.7516412
title: EFFECT OF BIOFERTILIZATION ON YELLOW PASSION FRUIT PRODUCTION AND FRUIT QUALITY

description: ABSTRACT This study aimed at evaluating the effects of bovine biofertilizer on passion fruit production and fruit quality. We carried out an experiment in the city of Nova Floresta, Paraíba State, Brazil. It was carried out in a randomized block design with three replications and three plants per plot. We adopted a 3 x 5 factorial scheme, which evaluated three passion fruit genotypes and five cattle biofertilizer doses. The assessed genotypes consisted of a local one (Guinezinho - LG) and two hybrids (BRS Gigante Amarelo - GA and BRS Sol do Cerrado - SC). We applied five rates of cattle biofertilizer (B) monthly at a constant volume of 5 L plant-1, after diluting in irrigation water (W) at an electrical conductivity of 1.4 dS m-1. The evaluated rates were 0% (100% irrigation water - 0B + 5W), 10% (1B + 9W), 20% (2B + 8W), 30% (3B + 7W) and 40% (4B + 6W). Every week, we sampled, counted and weighed fruit to gather data on fruit number per plant, pant production, and yield. At peak production, we also sampled two fruit randomly from each plot floor area. These fruits were used for determinations of the average mass in fruit, peel and pulp (seeds + juice), peel thickness, fruit diameter and length, pulp yield, soluble solid content, titratable acidity, vitamin C, pH and pulp electrical conductivity. As a result, we observed that the biofertilizer did not compromise both LG and GA production capacity. Overall, the biofertilizer doses provided quality characteristics superior to those required by the fruit market.
DOI: 10.6084/m9.figshare.7516412.v1
title: EFFECT OF BIOFERTILIZATION ON YELLOW PASSION FRUIT PRODUCTION AND FRUIT QUALITY

description: ABSTRACT This study aimed at evaluating the effects of bovine biofertilizer on passion fruit production and fruit quality. We carried out an experiment in the city of Nova Floresta, Paraíba State, Brazil. It was carried out in a randomized block design with three replications and three plants per plot. We adopted a 3 x 5 factorial scheme, which evaluated three passion fruit genotypes and five cattle biofertilizer doses. The assessed genotypes consisted of a local one (Guinezinho - LG) and two hybrids (BRS Gigante Amarelo - GA and BRS Sol do Cerrado - SC). We applied five rates of cattle biofertilizer (B) monthly at a constant volume of 5 L plant-1, after diluting in irrigation water (W) at an electrical conductivity of 1.4 dS m-1. The evaluated rates were 0% (100% irrigation water - 0B + 5W), 10% (1B + 9W), 20% (2B + 8W), 30% (3B + 7W) and 40% (4B + 6W). Every week, we sampled, counted and weighed fruit to gather data on fruit number per plant, pant production, and yield. At peak production, we also sampled two fruit randomly from each plot floor area. These fruits were used for determinations of the average mass in fruit, peel and pulp (seeds + juice), peel thickness, fruit diameter and length, pulp yield, soluble solid content, titratable acidity, vitamin C, pH and pulp electrical conductivity. As a result, we observed that the biofertilizer did not compromise both LG and GA production capacity. Overall, the biofertilizer doses provided quality characteristics superior to those required by the fruit market.
DOI: 10.6084/m9.figshare.7518212.v1
title: WATER DEMAND, CROP COEFFICIENT AND UNCOUPLING FACTOR OF COWPEA IN THE EASTERN AMAZON

description: ABSTRACT Cowpea has great socioeconomic importance in the northeastern part of Pará state. However, in order to provide suitable irrigation management during the dry period this region requires solid information regarding water demand by regional crops. This research aims to determine the water demand, the crop coefficient (Kc) and the uncoupling factor during the different development stages of cowpea in the northeast of Pará. The crop evapotranspiration (ETc) was measured by drainage lysimeters. This information was coupled to the reference evapotranspiration (ETo) to obtain the crop coefficients, which were used to adjust the model function of accumulated degree-days and the leaf area index (LAI). The uncoupling factor was estimated to indicate the factors that control evapotranspiration. The ETc values reached a cumulative total of 267.73 mm ± 10.21 mm during the cowpea cycle. The average value of the uncoupling factor was 0.66. This indicates that the cowpea crop does not fully uncouple from the atmosphere underneath the climatic conditions in northeast Pará. The cowpea Kc values presented averages of 0.8, 1.4 and 0.8 in the vegetative phase, reproductive phase and final stage, respectively. The Gaussian model showed an excellent fit for the estimation of Kc values based on accumulated degree days and the LAI. These amounts differ from others found in the literature. Therefore, it reinforces the necessity for an assessment of crop coefficients under local conditions and for the employment of more precise methods.
DOI: 10.6084/m9.figshare.7518212
title: WATER DEMAND, CROP COEFFICIENT AND UNCOUPLING FACTOR OF COWPEA IN THE EASTERN AMAZON

description: ABSTRACT Cowpea has great socioeconomic importance in the northeastern part of Pará state. However, in order to provide suitable irrigation management during the dry period this region requires solid information regarding water demand by regional crops. This research aims to determine the water demand, the crop coefficient (Kc) and the uncoupling factor during the different development stages of cowpea in the northeast of Pará. The crop evapotranspiration (ETc) was measured by drainage lysimeters. This information was coupled to the reference evapotranspiration (ETo) to obtain the crop coefficients, which were used to adjust the model function of accumulated degree-days and the leaf area index (LAI). The uncoupling factor was estimated to indicate the factors that control evapotranspiration. The ETc values reached a cumulative total of 267.73 mm ± 10.21 mm during the cowpea cycle. The average value of the uncoupling factor was 0.66. This indicates that the cowpea crop does not fully uncouple from the atmosphere underneath the climatic conditions in northeast Pará. The cowpea Kc values presented averages of 0.8, 1.4 and 0.8 in the vegetative phase, reproductive phase and final stage, respectively. The Gaussian model showed an excellent fit for the estimation of Kc values based on accumulated degree days and the LAI. These amounts differ from others found in the literature. Therefore, it reinforces the necessity for an assessment of crop coefficients under local conditions and for the employment of more precise methods.
DOI: 10.6084/m9.figshare.7506272.v1
title: MECHANISMS CONTROLLING SURFACE WATER QUALITY IN THE COBRAS RIVER SUB-BASIN, NORTHEASTERN BRAZIL

description: ABSTRACT Stream water quality is dependent on many factors, including the source and quantity of the streamflow and the types of geology and soil along the path of the stream. This study aims to evaluate the origin and the mechanisms controlling the input of ions that effect surface water quality in the sub -basin of the Rio das Cobras, Rio Grande do Norte state, Northeastern Brazil. Thirteen ponds were identified for study: three in the main river and ten in the tributaries between, thus covering the whole area and lithology of the sub -basin. The samples were collected at two different times (late dry and rainy periods) in the hydrological years 2009 and 2010, equating to total of four collection times. We analyzed the spatial and seasonal behavior of water quality in the sub-basin, using Piper diagrams, and analyzed the source of the ions using Guibbs diagram and molar ratios. With respect to ions, we found that water predominate in 82% sodium and 76% bicarbonate water (cations and anions, respectively). The main salinity control mechanism was related to the interaction of the colloidal particles (minerals and organic sediment) with the ions dissolved in water. Based on the analysis of nitrates and nitrites there was no evidence of contamination from anthropogenic sources.
DOI: 10.6084/m9.figshare.7506272
title: MECHANISMS CONTROLLING SURFACE WATER QUALITY IN THE COBRAS RIVER SUB-BASIN, NORTHEASTERN BRAZIL

description: ABSTRACT Stream water quality is dependent on many factors, including the source and quantity of the streamflow and the types of geology and soil along the path of the stream. This study aims to evaluate the origin and the mechanisms controlling the input of ions that effect surface water quality in the sub -basin of the Rio das Cobras, Rio Grande do Norte state, Northeastern Brazil. Thirteen ponds were identified for study: three in the main river and ten in the tributaries between, thus covering the whole area and lithology of the sub -basin. The samples were collected at two different times (late dry and rainy periods) in the hydrological years 2009 and 2010, equating to total of four collection times. We analyzed the spatial and seasonal behavior of water quality in the sub-basin, using Piper diagrams, and analyzed the source of the ions using Guibbs diagram and molar ratios. With respect to ions, we found that water predominate in 82% sodium and 76% bicarbonate water (cations and anions, respectively). The main salinity control mechanism was related to the interaction of the colloidal particles (minerals and organic sediment) with the ions dissolved in water. Based on the analysis of nitrates and nitrites there was no evidence of contamination from anthropogenic sources.