Soil-plant simulation models have been ever more used as predictive tools to evaluate productivity and environmental impacts of agriculture practices. The aims of this work were to evaluate the STICS model’s capacity of simulate the emissions of nitrous oxide (N2O) under different management systems. And, to predict, by applying the calibrated and validated STICS model, the N2O emissions, under different management systems, in the edaphoclimatic conditions of the Brazilian Cerrado. The study was conducted in a long-term experiment at Embrapa Cerrados, located in Planaltina/DF, Brazil. The experiment started in 1995. The following land use systems were evaluated: CT - conventional tillage with disc harrow, and biannual grass/legume rotation; NT1 - No-tillage, with biannual crop rotation – soybean/sorghum; NT2 - No-tillage, with biannual crop rotation – maize/pigeon pea.Closed static chambers and gas sample analysis by gas chromatography were used to measure N2O fluxes. The model was calibrated with the data measured in the CT and NT1 treatments. The attributes used in the calibration were: growth, development and yield of crops and N2O fluxes. To test the model, data from the NT2 treatment was used. Data for all treatments were collected at the same time. After calibration and validation, the STICS model was used to predict the effects of soil management systems, conventional (CT) and no-tillage (NT) on greenhouse gas emissions and on grain and biomass crops production. The simulation was made for the period from 2021 to 2070. The STICS model performed well at simulation of the following parameters: N2O emissions, soil water dynamics, soil temperature; and leaf area, aerial biomass and grain yield of soybean and maize. The performance of the model was good for the conventional soil management system as well as in the no-tillage system. Based on the predicted increase in temperature for the period 2021–2070, we can conclude from the data generated through the STICS model that there is strong evidence that grain yield and total aerial biomass of plants will decrease. The data show that there is a rising tendency in N2O emissions over the simulated period. This is expected to occur for the two soil management systems studied (NT and CT). We believe this increase in emissions along the years is related to temperature increase and to the reduction of crop cycle.

O fenômeno El Niño Oscilação Sul (ENOS) pode modificar as interações entre variáveis meteorológicas e produção das culturas agrícolas. Avaliar essas modificações por meio de modelos de simulação do crescimento das plantas permite realizar experimentos virtuais que representam diferentes condições de manejo das culturas em curto espaço de tempo. Esse trabalho objetivou investigar a existência de efeito do ENOS, medido pelo indicador Índice Oceânico Niño-(ION), sobre a produtividade da soja (Glycine max L.). A produção foi estimada pelo modelo STICS (Simulateur mulTIdisciplinaire pour les Culture Standard), que simula os processos no sistema solo-planta-atmosfera, calibrado para a cultura da soja nas condições de cultivo da Embrapa Cerrados, em Planaltina, DF. O STICS simulou a produtividade da soja semeada em cada um dos 12 decêndios entre o início de setembro e o final de dezembro, sob as condições de precipitação observadas na estação meteorológica da Embrapa Cerrados, durante 47 anos, de 1974 a 2021. Com base no ION, os mesmos 47 anos foram agrupados em 5 classes do fenômeno ENOS. Calculadas as médias de produtividade em cada decêndio, para cada classe, houve significativo efeito negativo dos anos de El Niño sobre a produtividade da soja nas semeaduras de setembro e outubro.

An accurate estimation of crop yield under climate change scenarios is essential to quantify our ability to feed a growing population and develop agronomic adaptations to meet future food demand. A coordinated evaluation of yield simulations from process-based eco-physiological models for climate change impact assessment is still missing for soybean, the most widely grown grain legume and the main source of protein in our food chain. In this first soybean multi-model study, we used ten prominent models capable of simulating soybean yield under varying temperature and atmospheric CO2 concentration [CO2] to quantify the uncertainty in soybean yield simulations in response to these factors. Models were first parametrized with high quality measured data from five contrasting environments. We found considerable variability among models in simulated yield responses to increasing temperature and [CO2]. For example, under a + 3 degrees C temperature rise in our coolest location in Argentina, some models simulated that yield would reduce as much as 24%, while others simulated yield increases up to 29%. In our warmest location in Brazil, the models simulated a yield reduction ranging from a 38% decrease under + 3 degrees C temperature rise to no effect on yield. Similarly, when increasing [CO2] from 360 to 540 ppm, the models simulated a yield increase that ranged from 6% to 31%. Model calibration did not reduce variability across models but had an unexpected effect on modifying yield responses to temperature for some of the models. The high uncertainty in model responses indicates the limited applicability of individual models for climate change food projections. However, the ensemble mean of simulations across models was an effective tool to reduce the high uncertainty in soybean yield simulations associated with individual models and their parametrization. Ensemble mean yield responses to temperature and [CO2] were similar to those reported from the literature. Our study is the first demonstration of the benefits achieved from using an ensemble of grain legume models for climate change food projections, and highlights that further soybean model development with experiments under elevated [CO2] and temperature is needed to reduce the uncertainty from the individual models.

Population dynamics studies make it possible to predict the response of species to seasonal and inter‐annual climatic phenomena in hypothetical scenarios of climatic abnormality. However, long‐term studies on the temporal distribution and abundances of species are still scarce in the literature, including for species of agricultural importance. The present study aimed to bridge this gap through monthly collection events of species of cutworms (species of Agrotis and Feltia ) across eight crop seasons (from July 2012 to June 2020) in the Brazilian Savanna (Cerrado). This biome is characterised by an irregular distribution of rainfall during a normal year, including two well‐defined periods of dry and rainy seasons. Only five species of cutworms were recorded: Agrotis ipsilon , Agrotis canities , Feltia repleta , Feltia submontana and Feltia subterranea , all widely distributed across South America. Except for F. submontana , occurring only in the autumn, other species occurred nearly year‐round, with distinct peaks of abundance in the dry season (April to October), supporting the hypothesis that species of Agrotina are well adapted to dry environments. The association of cutworms with dry environments was recovered for multivoltine, abundant species, such as A. ipsilon and F. subterranea , as for univoltine species, such as F. submontana . Across eight crop seasons, the abundance of all species decreased, coinciding with a high intensity El Niño effect. However, the effect itself was not found to be significant to predict the temporal distribution and abundances of cutworms and the causes of population decrease from 2014 to 2015 crop season remain to be explained. After the temporal autocorrelation effects were removed, it was revealed that the abundance of cutworms tends to be larger in crop seasons with less precipitation. Thus, this variable can be used to predict outbreaks of cutworms in the Cerrado. Some species of cutworms deserve special concern due to their frequency, seasonality and higher abundances in the Cerrado during the dry season. Their adaptability to adverse conditions may increase their spatio‐temporal distribution in Brazil and the frequency of outbreaks in a scenario of climate change, with the continuing reduction of rainfall in central and southeastern Brazil.

Abstract: Mocis latipes (Guenée, 1852) (Lepidoptera: Erebidae) has been recognized as a major owlet caterpillar associated to the herbivory of gramineaceous plants across the American continent. During outbreaks, the caterpillars are capable of completely consuming preferred hosts (grasses) and, when these hosts are destroyed, they can move to adjacent non-grass plants and cause similar damage. Meteorological variable such as temperature and humidity are described as factors that affect the development and abundance of M. latipes. This paper aimed to describe and compare the spatial and temporal distribution of M. latipes in different locations in Brazil and to evaluate the influence of meteorological variables on the temporal range. A total of 12 locations were evaluated, in each collection point light traps were installed near cultivated areas. In order to understand the influence of meteorological variables on the abundance of M. latipes, the data were analyzed using a Generalized Linear Model according to Poisson regression. A linear regression was also used to verify the relation between the abundance and the latitude. A total of 1,985 moths were collected. The highest collections were in Amazon and Cerrado biomes. Results show that abundance was inversely related to increasing latitude and Poisson regression analysis indicated that the main meteorological variables were significantly related to abundance at each site. This study shows that due to the high preference for gramineas and the high temperature requirements (30°C), M. latipes is an important species in hot regions and regions with hight humidity. Furthurmore, even in higher latitudes, in subtropical areas, during summer months, populations can Rapidly growth being able to cause economic damages.

The first detection of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) in Brazil pointed to a gloomy future for South American agriculture in the 2012/2013 harvest, and insecticide sales increased exponentially during 2013 and 2014. However, after this outbreak, the population of this insect returned to manageable levels. This study documents data on H. armigera moth collection using light traps during the outbreak in two locations: (a) western region of the state of Bahia, including population levels of H. armigera and main noctuid pests during the big outbreak (February and March 2013); (b) Federal District, including monthly data for five growing seasons (July 2012–June 2017). During the outbreak, an average of 527.3 moths were collected per trap (cotton crop, March) in the western region of Bahia each night, while the maximum average in the Federal District was 75.4 moths (January). The number of moths decreased in the following growing seasons, and in October 2016, the maximum number was 2.8 moths per trap. Aspects related to the variations of H. armigera and Helicoverpa zea (Boddie) populations, including the study of phenology and relationship with climatic factors and Oceanic Niño Index, were analyzed and discussed. All aspects are approached to contribute to the management of lepidopteran pests, especially H. armigera, in the productive systems of the Brazilian Cerrado.

Conservation agriculture (CA) is recognized as a promising crop management strategy for sustainable agricultural intensification. The objective of this study was to evaluate CA cropping systems for rainfed maize as an alternative to the traditional tillage-based cropping systems (CT) in the context of family farms, using a multi-criteria model that represents the point of view of farmers. Farmers considered several aspects for evaluating the cropping systems, thatwere systematized in the model through five criteria (with sub-criteria): (a) costs; (b) yield; (c) labour; (d) human health and environment; and (e) production risks. CA did not differ from CT for the ‘costs’ criterion but was superior for the ‘yield’ and ‘labour’ criteria. In contrast, CT obtained better ratings for the criteria ‘human health and environment’ and ‘production risks’. Considering all criteria, CA was better appraised than CT. However, a new local policy measure that subsidizes the hiring of mechanized tillage services overturns this outcome, indicating the importance of exogenous factors. Overall, the participatory processes in building the model allowed us to better understand the reasons of adoption or non-adoption of CA by small-scale farmers in the tropics.

Abstract Relay intercropping of maize with fodder crops is a promising option for sustainable intensification of dairy small-scale farms in the Cerrado of Brazil. Twenty-six intercropping trials were conducted on farmers’ fields with the following experimental treatments: sole maize crop cropping (MS), maize-Brachiaria intercropping (MB) and maize-pigeon pea intercropping (MP). The trials were managed by the farmers, i.e. choice of conventional tillage (CT) versus no-tillage (NT), sowing dates, fertilization and weed control. Maize grain yield varied strongly across the farmer fields, from 100 to 5900 kg ha−1 in the MS treatment, 500 to 6900 kg ha−1 in MP and 300 to 5500 kg ha−1 in MB. Intercropping did not significantly affect maize grain yields under NT, but yields were reduced under CT in one out of two seasons. Maize yields in the intercropped systems were also higher under NT than CT. Total biomass productivity was significantly higher in the maize-fodder than in the sole maize system. An increased interval between sowing of maize and fodder crop significantly reduced the fodder crop biomass. Relay intercropping, especially in combination with NT, is a promising option if crop calendars and fertilization are properly managed by farmers to reduce interspecific competition between the maize and fodder crop.

Agriculture is an activity of risk and uncertainty. Agricultural Climate Risk Zoning (ZARC) indicates what, where and when to plant to escape climate events. The objective of this work was to compare two methodologies for agricultural climate risk zoning of soybean (Glycine max (L) Merrill) in the Cerrado Biome. The Water Requirement Satisfaction Index (WRSI) was used considering the phenological phases critical to water deficit: Phase I (germination and emergence) and Phase III (flowering and grain filling). In the first approach, phase III was considered. In the second approach, phases I and III were considered. The SARRAZON program was used to simulate water balance. The low climate risk zone corresponded to WRSI > 0.50 in phase I; and WRSI > 0.65 in phase III. For comparison purposes, the sowing time, percentage of risk areas and number of recommended municipalities were considered. In the second methodology, the low risk zones were smaller. Soybean has been recommended in soils with the highest available water capacity. The high-risk areas were in the transition between the Caatinga and Pantanal biomes. This study guides soy agroclimatic risk and subsidizes public policies in the Cerrado.

A agricultura é uma atividade de risco e incerteza. O Zoneamento Agrícola de Risco Climático (ZARC) indica o que, onde e quando plantar para fugir dos eventos climáticos. O objetivo do trabalho foi comparar duas metodologias para o zoneamento agrícola de risco climático da soja (Glycine max (L) Merrill) no Bioma Cerrado. Utilizou-se o Índice de Satisfação da Necessidade de Água (ISNA) considerando às fases fenológicas críticas ao déficit hídrico: Fase I (germinação e emergência) e Fase III (floração e enchimento de grãos). Na primeira abordagem considerou-se a fase III. Na segunda abordagem consideraram-se as fases I e III. Utilizou-se o programa SARRAZON para a simulação do balanço hídrico. A zona de baixo risco climático correspondeu ao ISNA > 0,50 na fase I; e, o ISNA> 0,65 na fase III. Para fins de comparação considerou-se a época de semeadura, porcentagem das áreas de risco e quantidade de municípios recomendados. Na segunda metodologia, as zonas de baixo risco foram menores. A soja foi recomendada em solos com maior capacidade de água disponível. As áreas de alto risco situaram-se na transição entre os biomas Caatinga e Pantanal. Esse estudo orienta o risco agroclimático da soja e subsidia políticas públicas no Cerrado. Palavras-chave: agroclimatologia; gestão ambiental; política agrícola; planejamento ambiental. CLIMATIC RISK ZONING METHODOLOGIES FOR SOYBEAN CULTIVATION IN THE CERRADO BIOME ABSTRACT: Agriculture is an activity of risk and uncertainty. Agricultural Climate Risk Zoning (ZARC) indicates what, where and when to plant to escape climate events. The objective of this work was to compare two methodologies for agricultural climate risk zoning of soybean (Glycine max (L) Merrill) in the Cerrado Biome. The Water Requirement Satisfaction Index (WRSI) was used considering the phenological phases critical to water deficit: Phase I (germination and emergence) and Phase III (flowering and grain filling). In the first approach, phase III was considered. In the second approach, phases I and III were considered. The SARRAZON program was used to simulate water balance. The low climate risk zone corresponded to WRSI > 0.50 in phase I; and WRSI > 0.65 in phase III. For comparison purposes, the sowing time, percentage of risk areas and number of recommended municipalities were considered. In the second methodology, the low risk zones were smaller. Soybean has been recommended in soils with the highest available water capacity. The high-risk areas were in the transition between the Caatinga and Pantanal biomes. This study guides soy agroclimatic risk and subsidizes public policies in the Cerrado. Keywords: agroclimatology; environmental management; agricultural policy; environmental planning.

The owlet moths (Lepidoptera: Noctuidae)Anicla infecta (Ochsenheimer 1816), Elaphria agrotina (Guenee 1852) and Spodoptera frugiperda (J.E. Smith 1797) occur in the entire American continent. These polyphagous moths have a preference for grasses, and have different biological habits. In this study, the populations of these three species were evaluated monthly with light traps in the Brazilian Savannah, ranging a span of four crop seasons (from July, 2013 to June, 2017). The population data were analyzed and correlated with the meteorological variables: maximum temperature, minimum temperature, relative humidity and precipitation. A total of 4719 individuals were collected in the following percentages: A. infecta (n = 459; 9.73%), E. agrotina (n =1809; 38.33%) and S. frugiperda (n = 2451; (51.94%). The abundance of all species went down from the first crop season (2013/2014) to the third (2015/2016). In the fourth crop season (2016/2017), the populations of A. infecta and E. agrotina stabilized, but the abundance of S. frugiperda experienced further decrease. The numbers of individuals of three species declined when precipitation was much above (crop season 2014/2015) and below (crop season 2015/2016) than expected by the climatological normal. There were significant, but different degrees of correlation, between the meteorological factors and the ONI index (Oceanic Nino Index - indicator for monitoring El Nino-Southern Oscillation or "ENSO") with respect to monthly population variations. The results are discussed in accordance with principles of the Integrated Pest Management (IPM) in mind, given the continental distribution and agricultural importance of the three owlet moth species studied. (C) 2019 Published by Elsevier Editora Ltda. on behalf of Sociedade Brasileira de Entomologia.

This work aimed to determine the agricultural productivity and the technological quality of the juice of the sugarcane varieties, which were submitted to different hydrological regimes. The experimental design was made in randomized blocks with three repetitions in subdivided plots, with three varieties: RB855156, RB835486 and RB867515 (plot), and seven hydrological regimes corresponding to 0, 7, 17, 36, 46, 75 and 100% of ETc (subplot). The following production characteristics were evaluated: length of internode (LI), stem weight (SW), number of tillers per hectare and productivity; and technological components of the juice: degrees Brix of the juice, Pol of the juice (sucrose levels), purity (PTY), RS (amount of reducing sugars of the juice), RSC (reducing sugars of the sugarcane plant), fibers, Pol of the sugarcane plant (CPP), total retrievable sugars (TRS) and the value of the sugarcane megagram (Mg). The maximum productivity of sugarcane was 182.31 Mg ha(-1), which was registered with irrigation equivalent to 69.01% of ETc. The sugarcane cultivated with irrigation equivalent to 75% of ETc did not provide significant difference for the industrial quality of varieties tested in relation to the non-irrigated cultivation (0% of ETc). There was no significant difference for the values of reducing sugars (RS), the reducing sugars of the sugarcane plant (RSC) and the juice purity (PTY) among varieties.

O presente trabalho teve como objetivo determinar a produtividade agrícola e a qualidade tecnológica do caldo das variedades da cana-de-açúcar, submetidas a diferentes regimes hídricos. O delineamento experimental foi em blocos ao acaso com três repetições em parcelas subdivididas, com três variedades RB855156, RB835486 e RB867515 (parcela), e sete regimes hídricos correspondendo a 0, 7, 17, 36, 46, 75 e 100% da ETc (subparcela). Foram avaliadas as características de produção: comprimento do entrenó (CE), peso do colmo (PC), número de perfilhos por hectare e produtividade; e tecnológicos do caldo: ºBrix do caldo, Pol do caldo (Teor de sacarose), pureza (PZA), AR (teor de açúcares redutores do caldo), ARC (açúcares redutores da cana), fibras, Pol da cana (PCC), açúcares totais recuperáveis (ATR) e o valor da megagrama da cana (VMgC). O máximo de produtividade da cana-de-açúcar foi de 182,31 Mg ha-1 registrado com irrigação equivalente a 69,01% da ETc; A cana-de-açúcar cultivada com irrigação equivalente a 75% da ETc não proporcionou diferença significativa para a qualidade industrial das variedades testadas em relação ao cultivo em sequeiro (0% da ETc). Não houve diferença significativa para os valores do teor de açúcares redutores (AR), açúcares redutores da cana (ARC) e a pureza do caldo (PZA) entre as variedades. Palavras-chave: Saccharum spp., estresse hídrico, níveis de irrigação. PRODUCTIVITY AND QUALITY OF THIRD RATOON SUGARCANE VARIETIES UNDER VARIABLE HYDROLOGICAL REGIME ABSTRACT This work aimed to determine the agricultural productivity and the technological quality of the juice of the sugarcane varieties, which were submitted to different hydrological regimes. The experimental design was made in randomized blocks with three repetitions in subdivided plots, with three varieties: RB855156, RB835486 and RB867515 (plot), and seven hydrological regimes corresponding to 0, 7, 17, 36, 46, 75 and 100% of ETc (subplot). The following production characteristics were evaluated: length of internode (LI), stem weight (SW), number of tillers per hectare and productivity; and technological components of the juice: ºBrix of the juice, Pol of the juice (sucrose levels), purity (PTY), RS (amount of reducing sugars of the juice), RSC (reducing sugars of the sugarcane plant), fibers, Pol of the sugarcane plant (CPP), total retrievable sugars (TRS) and the value of the sugarcane megagram (Mg). The maximum productivity of sugarcane was 182.31 Mg ha-1, which was registered with irrigation equivalent to 69.01% of ETc. The sugarcane cultivated with irrigation equivalent to 75% of ETc did not provide significant difference for the industrial quality of varieties tested in relation to the non-irrigated cultivation (0% of ETc). There was no significant difference for the values of reducing sugars (RS), the reducing sugars of the sugarcane plant (RSC) and the juice purity (PTY) among varieties. Keywords: Saccharum spp., water stress, levels of irrigation. DOI: http://dx.doi.org/10.14583/2318-7670.v04n01a08

About 70% of Brazil's farm output is produced in the Cerrado region. The main crops grown are maize, soybean, sugarcane and cotton. The climate is sub-humid tropical, typical of the rather moister savanna regions of the world. Climate model predictions (Torres and Marengo, 2013) suggest that the Cerrado will experience a temperature increase of between 2 °C and 4 °C by the end of the century. Model projections for future rainfall under high emission scenarios indicate a decrease of 20% to 40% of current values. Changes in the distribution of rainfall throughout the year are also expected. These climate changes may have a severe impact on the agricultural sector. There is an urgent need to quantify more securely the risks and uncertainties involved in the effects of climate change on crop production. The objective of this study is to assess the impact of climate change on maize yields in the Cerrado.

About 70% of Brazil's farm output is produced in the Cerrado region. The climate is sub-humid tropical, typical of the rather moister savanna regions of the world. Climate changes will have a severe impact on the agricultural sector in this region. A temperature increase of between 2 °C and 4 °C by the end of the century has been predicted. Model projections for future rainfall under high emission scenarios suggest a decrease of 20% to 40% of current values. The objective of this study is to assess the impact of climate change on maize yields in the Cerrado. To do so, we used the crop growth model STICS that was calibrated and tested against crop and soil data from an agronomic field trial at the experimental station of Embrapa Cerrados. The simulations covered present climate (1961-1990) and projections for the IPCC A1B emission scenario (2011-2050, 2051-2100). Climate change projections were generated using the Eta CCS regional climate model nested in the global model HadAM3P. Two systems were simulated: maize under conventional tillage and under no-tillage. We simulated water-limited yields for a typical local maize cultivar for 12 sowing dates and for two soil types, representing a scenario of low and high plant-available soil water storage capacity. STICS satisfactorily reproduced the growth and development of maize and the soil water dynamics of the experiment. Crop yields were highest under no-tillage. This cropping system uses most efficiently the seasonal rainfall as a result of reduced surface water run-off and soil evaporation, and also presents the greatest year-to-year yield stability. Future higher temperatures cause a significant decrease in the growing period of maize (an average of 20 days) leading to lower total biomass and grain production. Due to future decreased rainfall and increased risk of longer dry spells the sowing windows for optimal yields become smaller, especially under the conventional tillage system. (Texte integral)

Nowadays, in a context of climate change, economical uncertainties and social pressure to mitigate agriculture externalities, farmers have to adopt new cropping systems to achieve a sustainable and cost-effective grain production. Conservation agriculture consists of a range of cropping systems based on a combination of three main principles: (1) soil tillage reduction, (2) soil protection by organic residues and (3) diversification in crop rotation. Conservation agriculture has been promoted as a way to reduce production costs, soil erosion and soil fertility degradation under both tropical and temperate conditions. Conservation agriculture-based cropping systems have diffused widely under Brazilian large-scale farms’ conditions and more recently in Europe in the context of medium-size mechanized farms. Their diffusion, however, is still limited under small-scale non-mechanized farms’ conditions of tropical countries. To assess the advantages and limits of such new cropping systems, this article compares experiences with conservation agriculture from the tropical Cerrado region of Brazil and from temperate conditions of Europe. It focusses on agronomic performances, environmental impacts and economical results. Conservation agriculture systems appear to be interesting options to achieve sustainable and intensive crop production under different agroecological environments because they use efficiently available resources and maintain soil fertility. However, this mostly results from the permanent presence of an organic mulch on the soil surface and the incorporation of cover crops in the rotations. Such modifications require a significant reorganization of the production process at farm level, and when facing technical or socioeconomic constraints, most farmers usually opt for applying only partially the three main principles of conservation agriculture. Investigating more fully the consequences of such partial implementation of conservation agriculture principles on its actual efficiency and assessing the most efficient participatory approaches needed to adapt conservation agriculture principles to local conditions and farming systems are top priorities for future research.

Os agricultores familiares em assentamentos de reforma agraria do Municipio de Unai-MG tem restricoes comuns aos agricultores familiares: a falta de recursos financeiros, a fragilidade das organizacoes sociais, a baixa taxa de escolaridade. Varios problemas foram identificados que afetam os resultados das culturas em geral, e do milho em particular. Entre eles, destacam-se o acesso limitado a maquinas para preparo do solo, as dificuldades para a gestao da fertilidade do solo e o elevado requerimento de trabalho para controle de plantas daninhas. Estes problemas afetam a produtividade do milho e comprometem a valorizacao de fatores escassos como a terra e a mao de obra familiar. Neste contexto, a agricultura de conservacao (AC), com enfase no uso de plantio direto (SPD) com tracao animal e de plantas de cobertura, apresenta-se como uma alternativa promissora para permitir a producao destes agricultores em bases sustentaveis. O objetivo desta publicacao e fornecer informacoes para os tecnicos e agricultores que enfrentam problemas semelhantes para que possam construir sistemas de cultivo com base na AC. Foram desenvolvidos sistemas de cultivo em plantio direto, adaptados as condicoes dos agricultores. Estes sistemas foram avaliados em experimentos e nos estabelecimentos dos agricultores. O SPD mostrou-se promissor para viabilizar tecnica e economicamente a producao de milho nas condicoes da reforma agraria em Unai-MG.

Climatic risk zoning allows the identification of areas of low risk of reduced crop productivity due to climatic events. In Brazil, losses to agriculture due to climate are mainly caused by drought. The objective of this research was to determine areas of low climatic risk for corn and palisade grass cultivated in integrated crop-livestock systems in Sao Paulo state. Corn varieties characterized by a 120-day growing cycle and soil with three different water holding capacities (sandy, medium and clayey soils) were considered. A daily water balance model was used to simulate planting dates between September and December. The water requirement satisfaction index (WRSI) was calculated for critical phenological phases of both cultures (germination, emergence and tillering of palisade grass and flowering and grain filling of corn). The WRSI values, calculated for a minimum frequency of 80%, were located spatially using the SPRING v. 5.1 geographic information system and the most favorable periods for sowing in different areas were determined. The results showed that there are areas of low climatic risk for cultivation of corn and palisade grass in integrated crop-livestock production systems in Sao Paulo state. Although climatic risk in these areas also depends on soil type, the most favorable period for planting is between October and November.