Revista de la Facultad de Ciencias Agrarias
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Use of anti drift nozzles in control of perennial weeds in vineyard nurseries
Get PDFTable grapes are the most widespread fruit species in Chile, requiring a large amount of agrochemical products. Due to this large requirement, agrochemicals such as herbicides need to be applied precisely and in an environmentally safe manner in order to achieve the desired target. Weeds are a limiting factor in vine nurseries, where Cyperus rotundus, Sorghum halepense, and Cynodon dactylon are the hardest species to control. In this case, application though nozzles is of vital importance for a correct herbicide distribution and dosage over the target. However, the use of herbicides in vine nurseries has not been widely practiced and literature on the subject is very scarce. In this project, a comparative study between conventional extended range flat spray (XR) and drift effect nozzles (TT turbo teejet; DG drift guard; AI air injection) was conducted. Weed control with glyphosate and phytotoxicity in Vitis vinifera cv. Thompson Seedless self-rooted nursery plants were evaluated, under wind drift conditions of 5.8 km h-1. This wind drift and the low angle of elevation of the nozzle (35 cm) caused the herbicide to reach the vine, generating the same visual plant toxicity damage regardless of the nozzle type used, with an increasing damage from day 7 to 28 after application (DAA). A gradual decrease was observed from 36 DAA onwards. Although no differences between the nozzles with respect to drift damage were detected, the use of the DG nozzle resulted in a lower percentage of sprouting weeds. This may be due to the DG nozzle having significantly reduced drift compared to conventional or standard nozzles, and, in turn, generating smaller droplets than AI, favoring their retention on the leaves.
Highlights
At wind drift conditions of 5.8 km h-1 and a lowering elevation of the nozzle (35 cm), generating the same visual plant toxicity damage regardless of the nozzle type used.
DG nozzle having significantly reduced drift compared to conventional or standard nozzles, and, in turn, generating smaller droplets than AI, favoring their retention on the leaves.
Regrowth of C. dactylon, the nozzles with bigger drops (DG y AI) achieved better coverage and thus obtained a better control of this weed. While for S. halepense y C. rotundus, the nozzles with median sized drops (DG y TT) achieved minor regrowth, as they were not too small for bad coverage and not too big to drip through vertical leaves.Table grapes are the most widespread fruit species in Chile, requiring a large amount of agrochemical products. Due to this large requirement, agrochemicals such as herbicides need to be applied precisely and in an environmentally safe manner in order to achieve the desired target. Weeds are a limiting factor in vine nurseries, where Cyperus rotundus, Sorghum halepense, and Cynodon dactylon are the hardest species to control. In this case, application though nozzles is of vital importance for a correct herbicide distribution and dosage over the target. However, the use of herbicides in vine nurseries has not been widely practiced and literature on the subject is very scarce. In this project, a comparative study between conventional extended range flat spray (XR) and drift effect nozzles (TT turbo teejet; DG drift guard; AI air injection) was conducted. Weed control with glyphosate and phytotoxicity in Vitis vinifera cv. Thompson Seedless self-rooted nursery plants were evaluated, under wind drift conditions of 5.8 km h-1. This wind drift and the low angle of elevation of the nozzle (35 cm) caused the herbicide to reach the vine, generating the same visual plant toxicity damage regardless of the nozzle type used, with an increasing damage from day 7 to 28 after application (DAA). A gradual decrease was observed from 36 DAA onwards. Although no differences between the nozzles with respect to drift damage were detected, the use of the DG nozzle resulted in a lower percentage of sprouting weeds. This may be due to the DG nozzle having significantly reduced drift compared to conventional or standard nozzles, and, in turn, generating smaller droplets than AI, favoring their retention on the leaves.
Highlights
At wind drift conditions of 5.8 km h-1 and a lowering elevation of the nozzle (35 cm), generating the same visual plant toxicity damage regardless of the nozzle type used.
DG nozzle having significantly reduced drift compared to conventional or standard nozzles, and, in turn, generating smaller droplets than AI, favoring their retention on the leaves.
Regrowth of C. dactylon, the nozzles with bigger drops (DG y AI) achieved better coverage and thus obtained a better control of this weed. While for S. halepense y C. rotundus, the nozzles with median sized drops (DG y TT) achieved minor regrowth, as they were not too small for bad coverage and not too big to drip through vertical leaves
Dissipation of the insecticides pirimiphos-methyl and dichlorvos in stored maize (Zea mays L.) grains
Get PDFThe aim of this work was to analyze the dissipation dynamics of the insecticides pirimiphos- methyl and dichlorvos in maize (Zea mays L.) grains after post-harvest spray applications. The recommendations for their use for Argentina and the Maximum Residue Limits (MRLs) established by local and international pesticide regulations were considered. Supervised experimental trials were conducted in stored maize grains treated with 10 cc.t-1 of pirimiphos-methyl and 20 cc.t-1 of dichlorvos. Samples were monitored 2, 30, 60, 90 and 120 days after application. The pesticides were extracted from the maize grains using the QuEChERS technique and the residues were determined using high-resolution gas chromatography with mass detector. Residue dissipation percentages and daily dissipation rates differed between active ingredients. At 48 hours after application, pirimiphos-methyl residues were 5.1±0.42 µg.g-1, i.e. below the MRLs established by the Argentine Service for Agrifood Health and Quality (10 µg.g-1), the USA (8 µg.g-1) and the Codex Alimentarius (7 µg.g-1), and close to the MRLs established by the EU (5 µg.g-1). Dichlorvos residues reached 2.97±0.27 µg.g-1, and required at least a 90-day withholding period to be lower than the MRLs of the EU.
Highligths
Pirimiphos-methyl residues had high dissipation in stored maize grains.
Dichlorvos insecticides in stored maize required more time withholding period than Pirimiphos-metyl to be lower than de MRLs of the EU.
Organophosphorus insecticide residues were below the MRL of the Codex Alimentarius.The aim of this work was to analyze the dissipation dynamics of the insecticides pirimiphos- methyl and dichlorvos in maize (Zea mays L.) grains after post-harvest spray applications. The recommendations for their use for Argentina and the Maximum Residue Limits (MRLs) established by local and international pesticide regulations were considered. Supervised experimental trials were conducted in stored maize grains treated with 10 cc.t-1 of pirimiphos-methyl and 20 cc.t-1 of dichlorvos. Samples were monitored 2, 30, 60, 90 and 120 days after application. The pesticides were extracted from the maize grains using the QuEChERS technique and the residues were determined using high-resolution gas chromatography with mass detector. Residue dissipation percentages and daily dissipation rates differed between active ingredients. At 48 hours after application, pirimiphos-methyl residues were 5.1±0.42 µg.g-1, i.e. below the MRLs established by the Argentine Service for Agrifood Health and Quality (10 µg.g-1), the USA (8 µg.g-1) and the Codex Alimentarius (7 µg.g-1), and close to the MRLs established by the EU (5 µg.g-1). Dichlorvos residues reached 2.97±0.27 µg.g-1, and required at least a 90-day withholding period to be lower than the MRLs of the EU.
Highligths
Pirimiphos-methyl residues had high dissipation in stored maize grains.
Dichlorvos insecticides in stored maize required more time withholding period than Pirimiphos-metyl to be lower than de MRLs of the EU.
Organophosphorus insecticide residues were below the MRL of the Codex Alimentarius
Factors that affect the success of artificial insemination in cattle of small farmers in one region in Chile: Factores que afectan la inseminación artificial en ganado bovino de pequeños productores en Chile
No full textThis study analyzes different factors that affect the success of artificial insemination (AI) of cows of small farmers inserted in a program of productive and genetic improvement in one region in Chile. The success of AI was modeled as a function of different biological, environmental and social factors recorded by the program, using logistic regression. The outcome for this model was the gestational status of the inseminated cow, diagnosed by ultrasound as non-pregnant or pregnant. Predictors of interest were: smallholder's gender, province where the smallholder was located, smallholder's number of cows, inseminator's years of experience, insemination type (estrus detected or at fixed time), cow's age in years, cow's body condition, cow's ordinal number of births, cow's biotype (dairy or beef) and bull's biotype (dairy or beef). All predictors were evaluated for unconditional associations with the outcome (gestational status). When analyzing the results, the province, the number of cows the owner had, the experience of inseminators and the type of insemination were associated with the success of pregnancy. It is important to stimulate the implementation of these types of programs to help contribute to the improvement of the livelihood of small farmers who depend on low-input systems.
Highlights
Program of Productive and Genetic Improvement of the Cattle of the O'Higgins Region in Central Chile
Artificial insemination success modeled as a function of different biological, environmental, and social factors recorded by the program using logistic regression
The model output was the gestational status of the inseminated cows as diagnosed by ultrasound.
All predictors were evaluated for unconditional associations with the outcome.
The province, the number of cows in the herd, the experience of the inseminators, and the type of insemination were associated with the success of the pregnancy.This study analyzes different factors that affect the success of artificial insemination (AI) of cows of small farmers inserted in a program of productive and genetic improvement in one region in Chile. The success of AI was modeled as a function of different biological, environmental and social factors recorded by the program, using logistic regression. The outcome for this model was the gestational status of the inseminated cow, diagnosed by ultrasound as non-pregnant or pregnant. Predictors of interest were: smallholder's gender, province where the smallholder was located, smallholder's number of cows, inseminator's years of experience, insemination type (estrus detected or at fixed time), cow's age in years, cow's body condition, cow's ordinal number of births, cow's biotype (dairy or beef) and bull's biotype (dairy or beef). All predictors were evaluated for unconditional associations with the outcome (gestational status). When analyzing the results, the province, the number of cows the owner had, the experience of inseminators and the type of insemination were associated with the success of pregnancy. It is important to stimulate the implementation of these types of programs to help contribute to the improvement of the livelihood of small farmers who depend on low-input systems.
Highlights
Program of Productive and Genetic Improvement of the Cattle of the O'Higgins Region in Central Chile
Artificial insemination success modeled as a function of different biological, environmental, and social factors recorded by the program using logistic regression
The model output was the gestational status of the inseminated cows as diagnosed by ultrasound.
All predictors were evaluated for unconditional associations with the outcome.
The province, the number of cows in the herd, the experience of the inseminators, and the type of insemination were associated with the success of the pregnancy
Agro-economic viability from two croppings of broadleaf vegetables intercropped with beet fertilized with roostertree in different population densities
Get PDFThe objective of this study was to evaluate the sustainability and agro-economic viability from two croppings of coriander (C) and two of arugula (A) intercropped with beet (B) as a function of roostertree amounts added to the soil in different population densities. The experimental design was a randomized complete block, with treatments arranged in a 4 x 4 factorial scheme with four replications. The treatments resulted from the combination of four amounts of roostertree biomass (6, 19, 32 and 45 t ha-1 on dry basis) with four population densities of coriander, beet and arugula (20C-50B-20A%, 30C-50B-30A%, 40C-50B-40A% and 50C-50B-50A% of the recommended densities in their single crops). The maximum agronomic efficiency of the polyculture of coriander, beet and arugula was obtained with the density of 40C-50B-40A in the amount of 19 t ha-1 roostertree biomass incorporated into the soil. The highest profitability of the polyculture was obtained with the density of 20C-50B-20A (%) in the amount of 45 t ha-1 of this green manure. High agro-economic efficiency can be obtained by cultivating the polyculture of coriander, beet and arugula when well-managed the factors of production, fertilization with roostertree and population densities.
Highlights
There are agro-economic efficiency and sustainability in the polyculture of coriander-beet-arugula.
Population density is an important production factor for obtaining of agro-economic returns.
Appropriate management in the coriander-beet-arugula fertilization with roostertree can provide economic revenues.The objective of this study was to evaluate the sustainability and agro-economic viability from two croppings of coriander (C) and two of arugula (A) intercropped with beet (B) as a function of roostertree amounts added to the soil in different population densities. The experimental design was a randomized complete block, with treatments arranged in a 4 x 4 factorial scheme with four replications. The treatments resulted from the combination of four amounts of roostertree biomass (6, 19, 32 and 45 t ha-1 on dry basis) with four population densities of coriander, beet and arugula (20C-50B-20A%, 30C-50B-30A%, 40C-50B-40A% and 50C-50B-50A% of the recommended densities in their single crops). The maximum agronomic efficiency of the polyculture of coriander, beet and arugula was obtained with the density of 40C-50B-40A in the amount of 19 t ha-1 roostertree biomass incorporated into the soil. The highest profitability of the polyculture was obtained with the density of 20C-50B-20A (%) in the amount of 45 t ha-1 of this green manure. High agro-economic efficiency can be obtained by cultivating the polyculture of coriander, beet and arugula when well-managed the factors of production, fertilization with roostertree and population densities.
Highlights
There are agro-economic efficiency and sustainability in the polyculture of coriander-beet-arugula.
Population density is an important production factor for obtaining of agro-economic returns.
Appropriate management in the coriander-beet-arugula fertilization with roostertree can provide economic revenues
Cadmium phytotoxicity: issues, progress, environmental concerns and future perspectives
Get PDFCadmium, a high toxicity element, is a potential threat to plant and human health, and a dangerous pollutant in the environment. Uptake and accumulation by crops represent the main entry pathway for potentially health-threatening toxic metals into human and animal food. Crops and other plants take up Cd from the soil or water and may distribute it in their roots and shoots. Soil and/or water are usually contaminated with Cd through natural sources, industrial effluent, and anthropogenic activities. In this review, the sources of Cd contamination, evaluation of the phytotoxic effects on plants, and mode of action of Cd toxicity, were summarized. Plant defensive strategies upon excess Cd are also considered in this review. Cd-induced effects include oxidative stress, disintegration of the photosynthetic apparatus, reduction in gas exchange parameters, nutrient imbalance, and subcellular organelle degradation. In addition, Cd severely impairs biomolecules such as DNA, protein, and lipids. Although plants are sessile in nature, they are equipped with certain mechanisms to cope with unfavorable conditions. These mechanisms include synthesis of metal-helating proteins, expression of enzymatic and non-enzymatic antioxidants, organic acids, and plant root–mycorrhiza association. The built-in system of plant tolerance to Cd can be further enhanced by the application of exogenous organic and inorganic metal sources. This review will broaden the knowledge about the Cd accumulation in plants and the responses to metal exposure, as well as our understanding of metal tolerance and overcoming this serious issue for sustainable agriculture and human health worldwide.
Highlights
Cd accumulation has harmful effects in an organism.
Cd has been listed 7th out of 275 compounds in the priority list of hazardous materials.
Cd remains in the soil for 15–1100 years.
Plants usually imply certain strategies to overcome Cd toxicity.
Plants built-in systems can be enhanced to overwhelmed this problem.Cadmium, a high toxicity element, is a potential threat to plant and human health, and a dangerous pollutant in the environment. Uptake and accumulation by crops represent the main entry pathway for potentially health-threatening toxic metals into human and animal food. Crops and other plants take up Cd from the soil or water and may distribute it in their roots and shoots. Soil and/or water are usually contaminated with Cd through natural sources, industrial effluent, and anthropogenic activities. In this review, the sources of Cd contamination, evaluation of the phytotoxic effects on plants, and mode of action of Cd toxicity, were summarized. Plant defensive strategies upon excess Cd are also considered in this review. Cd-induced effects include oxidative stress, disintegration of the photosynthetic apparatus, reduction in gas exchange parameters, nutrient imbalance, and subcellular organelle degradation. In addition, Cd severely impairs biomolecules such as DNA, protein, and lipids. Although plants are sessile in nature, they are equipped with certain mechanisms to cope with unfavorable conditions. These mechanisms include synthesis of metal-helating proteins, expression of enzymatic and non-enzymatic antioxidants, organic acids, and plant root–mycorrhiza association. The built-in system of plant tolerance to Cd can be further enhanced by the application of exogenous organic and inorganic metal sources. This review will broaden the knowledge about the Cd accumulation in plants and the responses to metal exposure, as well as our understanding of metal tolerance and overcoming this serious issue for sustainable agriculture and human health worldwide.
Highlights
Cd accumulation has harmful effects in an organism.
Cd has been listed 7th out of 275 compounds in the priority list of hazardous materials.
Cd remains in the soil for 15–1100 years.
Plants usually imply certain strategies to overcome Cd toxicity.
Plants built-in systems can be enhanced to overwhelmed this problem
Fungal diversity and Fusarium oxysporum pathogenicity associated with coffee corky-root disease in Mexico
Get PDFThe disease known as coffee corky-roots associated to the infection by the root-knot nematode Meloidogyne paranaensis is an important issue for coffee crop in several countries. In Mexico, particularly in the Veracruz state, considerable loses are recorded annually in Coffea arabica plantations by corky-root disease. Previous studies have revealed the presence of fungi in coffee corky-root tissues. However, these fungi have not been yet identified. This work aimed to identify at species level the fungi associated to the coffee corky-root symptoms and determine their pathogenicity on coffee plants. Coffee roots with corky-root symptoms were collected in eight sites distributed through the major coffee growing region of Veracruz. Observations of inside cortical root tissues under scanning electron microscope revealed abundant mycelium and conidia incorky-root samples in contrast with absence of any fungi development in healthy roots. Forty-nine fungi strains from internal corky-root tissue were isolated and identified at species level by ITS sequences. Fusarium oxysporum was the most frequent species and the only present in all of the corky-root samples. These strains were selected for the pathogenicity test. All F. oxysporum strains colonized the vascular system of coffee plants although none caused wilting symptoms.
Highlights
Fusarium oxysporum is a major fungus associated with coffee corky-root disease.
None of the oxysporum strains inoculated into the roots of coffee plants caused vascular withering symptoms
In the tissues damaged by coffee corky-root disease interact nematodes, fungi and bacteria.The disease known as coffee corky-roots associated to the infection by the root-knot nematode Meloidogyne paranaensis is an important issue for coffee crop in several countries. In Mexico, particularly in the Veracruz state, considerable loses are recorded annually in Coffea arabica plantations by corky-root disease. Previous studies have revealed the presence of fungi in coffee corky-root tissues. However, these fungi have not been yet identified. This work aimed to identify at species level the fungi associated to the coffee corky-root symptoms and determine their pathogenicity on coffee plants. Coffee roots with corky-root symptoms were collected in eight sites distributed through the major coffee growing region of Veracruz. Observations of inside cortical root tissues under scanning electron microscope revealed abundant mycelium and conidia incorky-root samples in contrast with absence of any fungi development in healthy roots. Forty-nine fungi strains from internal corky-root tissue were isolated and identified at species level by ITS sequences. Fusarium oxysporum was the most frequent species and the only present in all of the corky-root samples. These strains were selected for the pathogenicity test. All F. oxysporum strains colonized the vascular system of coffee plants although none caused wilting symptoms.
Highlights
Fusarium oxysporum is a major fungus associated with coffee corky-root disease.
None of the oxysporum strains inoculated into the roots of coffee plants caused vascular withering symptoms
In the tissues damaged by coffee corky-root disease interact nematodes, fungi and bacteria
Characterization of Fusarium spp., A Phytopathogen of avocado (Persea americana Miller var. drymifolia (Schltdl. and Cham.)) in Michoacán, México
Get PDFAvocado has great socioeconomic importance in Mexico because of the benefits it generates for the production chain participants and the significant foreign exchange earnings engendered by the export of its fruit. However, this crop has phytosanitary problems, caused mainly by fungi, among which the genus Fusarium stands out. The objective of this study was to characterize Fusarium species that caused root rot in avocado trees in Michoacan, Mexico. In 19 isolates of Fusarium spp., polymerase chain reactions (PCR) with primers coding for elongation factor and calmodulin genes were performed. These sequences were compared in homology using BLAST analysis and aligned in MEGA 6.0. Cladograms were created based on maximum verisimilitude. The pathogenicity of the isolates was evaluated based on their virulence and severity in the avocado plants. Morphological and molecular analyses showed that 15 isolates belonged to F. oxysporum Schl and four to F. solani Mart. All isolates were pathogenic, with virulence ranging from 16 to 56 days. All isolates produced root rot and yellowing of leaves, with 63% producing wilting and 16% producing apical necrosis, the latter being the most severe.
Highlights
From: Fusarium spp. is reported in avocado in Michoacán, México.
With the morphological and molecular methods, two species of the gender Fusarium; F. oxysporum and solani, were identified in avocado crops.
The species found in avocado can cause death of nursery seedlings and trees of various ages due to the destruction of their root system.
The gender Fusarium is found in all the crops in Michoacán, México, considerably decreasing the production for the damage inflicted in the root, causing significant losses in the production of its fruit.Avocado has great socioeconomic importance in Mexico because of the benefits it generates for the production chain participants and the significant foreign exchange earnings engendered by the export of its fruit. However, this crop has phytosanitary problems, caused mainly by fungi, among which the genus Fusarium stands out. The objective of this study was to characterize Fusarium species that caused root rot in avocado trees in Michoacan, Mexico. In 19 isolates of Fusarium spp., polymerase chain reactions (PCR) with primers coding for elongation factor and calmodulin genes were performed. These sequences were compared in homology using BLAST analysis and aligned in MEGA 6.0. Cladograms were created based on maximum verisimilitude. The pathogenicity of the isolates was evaluated based on their virulence and severity in the avocado plants. Morphological and molecular analyses showed that 15 isolates belonged to F. oxysporum Schl and four to F. solani Mart. All isolates were pathogenic, with virulence ranging from 16 to 56 days. All isolates produced root rot and yellowing of leaves, with 63% producing wilting and 16% producing apical necrosis, the latter being the most severe.
Highlights
From: Fusarium spp. is reported in avocado in Michoacán, México.
With the morphological and molecular methods, two species of the gender Fusarium; F. oxysporum and solani, were identified in avocado crops.
The species found in avocado can cause death of nursery seedlings and trees of various ages due to the destruction of their root system.
The gender Fusarium is found in all the crops in Michoacán, México, considerably decreasing the production for the damage inflicted in the root, causing significant losses in the production of its fruit
Effects of hydropriming on maize seeds (Zea mays L) and the growth, development, and yield of crops
No full textSeed germination is a process that involves several phases, beginning with the uptake of water by dry seeds and ending with emergence. Based on current knowledge, several methodologies have been developed to manipulate this process in order to produce beneficial effects on crops. The hydropriming of maize seeds is one technique that has been used to lower the in-field germination time. The objective of the present study was to measure the effect of different hydropriming times on maize seeds and the subsequent growth, development, and yield of plants. The results demonstrated that seeds hydropriming for 12 and 18 hours germinated more rapidly in comparison with the control and 36-hour treatment. Yield was also affected as a function of the imbibition time. The generated data allowed for an optimal soaking time of 22.12 hours to be determined, resulting in an estimated yield of 16.6 t per hectare.Seed germination is a process that involves several phases, beginning with the uptake of water by dry seeds and ending with emergence. Based on current knowledge, several methodologies have been developed to manipulate this process in order to produce beneficial effects on crops. The hydropriming of maize seeds is one technique that has been used to lower the in-field germination time. The objective of the present study was to measure the effect of different hydropriming times on maize seeds and the subsequent growth, development, and yield of plants. The results demonstrated that seeds hydropriming for 12 and 18 hours germinated more rapidly in comparison with the control and 36-hour treatment. Yield was also affected as a function of the imbibition time. The generated data allowed for an optimal soaking time of 22.12 hours to be determined, resulting in an estimated yield of 16.6 t per hectare
Power and draft required by chisel plow on soils worked in no-tillage in the Argentinean flat Pampas: Power and draft required by chisel plow on soils worked in no-tillage
No full textThe no-tillage systems production in Argentina requires high traffic intensities, for example 50 to 65 Mg km ha. Due to these traffic intensities applied continuously and successively, the soils are compacted. An of the techniques commonly utilized for management of topsoil and subsoil compaction is the chiseling. The objective of this work were: a) to evaluate the effect of vertical tillage on the physical properties of an Typic Argiudol soil from northeastern Rolling Pampa Region at Argentina and b) to quantify the power required by a chisel plow working in one and two depth layers on a soil under no-tillage. Three treatments were applied: T1) control plot (unloosened soil), T2) loosened with one chisel plow pass at 0.25 m deep range, and T3) loosened with two chisel passes, the first at 0.15m and the second at 0.25m. The following variables were measured: cone Index (CI), soil water content, (SWC), tractor slip (TS) and power and draft force (PD). The main results and conlusions showed: a) The CI values on the two deep tillage treatments was statistically different (P < 0.01) from that on the control plot up tu 300 mm and b) the chisel plow working in two depth range (T3) can significantly increase the specific resistance and drawbar power. This means that vertical tillage carried out in two chisel passe (T3) produced, from an energy point of view, less efficiency than (T2).
Highlights
The chisel plow working in two depth ranges could significantly increase the specific resistance and total drawbar power.
According to the resuslts obtained, shape, width, rake angle and spacing of an individual soil cutting tool strongly influenced in the implement draft.
After vertical tillage was applied, soil physical parameters measured on topsoil and subsoil resulted in soil physical conditions that would be suitable for crop development.The no-tillage systems production in Argentina requires high traffic intensities, for example 50 to 65 Mg km ha. Due to these traffic intensities applied continuously and successively, the soils are compacted. An of the techniques commonly utilized for management of topsoil and subsoil compaction is the chiseling. The objective of this work were: a) to evaluate the effect of vertical tillage on the physical properties of an Typic Argiudol soil from northeastern Rolling Pampa Region at Argentina and b) to quantify the power required by a chisel plow working in one and two depth layers on a soil under no-tillage. Three treatments were applied: T1) control plot (unloosened soil), T2) loosened with one chisel plow pass at 0.25 m deep range, and T3) loosened with two chisel passes, the first at 0.15m and the second at 0.25m. The following variables were measured: cone Index (CI), soil water content, (SWC), tractor slip (TS) and power and draft force (PD). The main results and conlusions showed: a) The CI values on the two deep tillage treatments was statistically different (P < 0.01) from that on the control plot up tu 300 mm and b) the chisel plow working in two depth range (T3) can significantly increase the specific resistance and drawbar power. This means that vertical tillage carried out in two chisel passe (T3) produced, from an energy point of view, less efficiency than (T2).
Highlights
The chisel plow working in two depth ranges could significantly increase the specific resistance and total drawbar power.
According to the resuslts obtained, shape, width, rake angle and spacing of an individual soil cutting tool strongly influenced in the implement draft.
After vertical tillage was applied, soil physical parameters measured on topsoil and subsoil resulted in soil physical conditions that would be suitable for crop development
Effects of 20 years of parceling on the condition of communal rangeland on a Mexican ejido
Get PDFThis study evaluated the current condition of rangeland on 18 out of 62 plots created in 1993 by parceling the communal rangeland of the El Castañón ejido (Catorce, San Luis Potosí, México). Six plots located in three different rangeland sites were analyzed: two, visually characterized as ‘good’, two as ‘poor’, and two as ‘intermediate’. The density and volumetric biomass of the preponderant perennial species were estimated after grouping them by vital form and forage value. The current state of soil cover was assessed using Canfield’s line intercept method. Estimates of the variables of vegetation structure and soil cover on the plots were then subjected to multivariate analysis (DECORANA). The hypothesis established that the concepts of site and condition of rangeland, developed for climatic grasslands in the USA, are valid for multi-stratified rangelands in the scrublands of the potosino highland. The three sites of rangeland and the visual assessments of their condition were confirmed by the results of the analyses of vegetation and soil cover. After prioritizing 17 characteristics of the 18 plots, we confirmed that the variables density and biomass by groups of species with distinct forage value, and the ratio of bare soil to ground covered with vegetation and mulch, generated adequate evaluations of the condition of these rangelands. The studied plots showed important differences in rangeland condition, after 20 years of parceling and individual exploitation.
Higlights
The grazing lands in the Mexican ejidos are communal, without clear rules that determine the adequate amount of livestock that can graze a given area, hence there are abuse and deterioration of up to 95% of these lands.
The ejido "El Castañón y Anexos" was the first in the Potosino highlands that took advantage of the amendment to article 27 of the Constitution in 1993, to parcel out common use areas and manage them individually since then.
Three rangeland sites were recognized and in each of them two parcels with better condition, two with worst condition, and two with intermediate condition, were evaluated, for a total of 18 studied parcels, out of the 62 resulting from the parcel out process.
The used combination of vegetation and soil cover variables, were adequate to verify visual gradients from good to fair, and from fair to poor condition, which may allow their application in the evaluation of the condition of rangelands under similar ecological conditions.
The results obtained after the parcel out process of the communal rangelands of the "El Castañón y Anexos" ejido, may be the basis to stop and reverse the generalized desertification of the grazing lands under social usufruct.This study evaluated the current condition of rangeland on 18 out of 62 plots created in 1993 by parceling the communal rangeland of the El Castañón ejido (Catorce, San Luis Potosí, México). Six plots located in three different rangeland sites were analyzed: two, visually characterized as ‘good’, two as ‘poor’, and two as ‘intermediate’. The density and volumetric biomass of the preponderant perennial species were estimated after grouping them by vital form and forage value. The current state of soil cover was assessed using Canfield’s line intercept method. Estimates of the variables of vegetation structure and soil cover on the plots were then subjected to multivariate analysis (DECORANA). The hypothesis established that the concepts of site and condition of rangeland, developed for climatic grasslands in the USA, are valid for multi-stratified rangelands in the scrublands of the potosino highland. The three sites of rangeland and the visual assessments of their condition were confirmed by the results of the analyses of vegetation and soil cover. After prioritizing 17 characteristics of the 18 plots, we confirmed that the variables density and biomass by groups of species with distinct forage value, and the ratio of bare soil to ground covered with vegetation and mulch, generated adequate evaluations of the condition of these rangelands. The studied plots showed important differences in rangeland condition, after 20 years of parceling and individual exploitation.
Higlights
The grazing lands in the Mexican ejidos are communal, without clear rules that determine the adequate amount of livestock that can graze a given area, hence there are abuse and deterioration of up to 95% of these lands.
The ejido "El Castañón y Anexos" was the first in the Potosino highlands that took advantage of the amendment to article 27 of the Constitution in 1993, to parcel out common use areas and manage them individually since then.
Three rangeland sites were recognized and in each of them two parcels with better condition, two with worst condition, and two with intermediate condition, were evaluated, for a total of 18 studied parcels, out of the 62 resulting from the parcel out process.
The used combination of vegetation and soil cover variables, were adequate to verify visual gradients from good to fair, and from fair to poor condition, which may allow their application in the evaluation of the condition of rangelands under similar ecological conditions.
The results obtained after the parcel out process of the communal rangelands of the "El Castañón y Anexos" ejido, may be the basis to stop and reverse the generalized desertification of the grazing lands under social usufruct