USCID fourth international conference

Presented at the Role of irrigation and drainage in a sustainable future: USCID fourth international conference on irrigation and drainage on October 3-6, 2007 in Sacramento, California.Includes bibliographical references.The bean culture is part of crop rotation used by irrigators from the southwestern region of the state of São Paulo, who perform the no-tillage soil management as a form of sustainable soil use. The effect of this conservationist practice on soil compaction, root development and bean culture production components in relation to the conventional management was the objective of this work. The experiment was conducted at the Buriti-Mirim Farm, Angatuba, SP, Brazil, using an 18ha area irrigated through center pivot system divided into two types of soil managements: conventional management and no-tillage management. Crop production components, soil cone index and root development components (distribution in the soil profile, length, surface, diameter and dry matter) were evaluated. Although the no-tillage management had presented lower compaction at the most superficial layers and more uniform root distribution in the soil profile, the managements evaluated were not significantly different in relation to crop productivity

Germination performance of grain sorghum hybrid seeds treated with bioregulator under water deficit

Water stress can reduce the speed and percentage of germination, damaging the development of seedlings. Thus it is necessary to find alternatives they can mitigate these effects. The plant growth regulators has been heavily used in agricultural production and can proporcionarum increase in the growth and development of plants. Thus, the objective of this study was to evaluate the germination performance of seeds of two hybrids of sorghum under simulated water stress, treated with plant growth regulator. The experimental design was completely randomized in a factorial 2 x 4, establishing itself as factors, two seed treatments (with and without plant growth regulator) and four water potential (0, -0.4, -0.8, -1.2 MPa) with four replications, separately for single hybrid grain sorghum: 1G100 and 1G233. Germination, the first count of germination, shoot and root length and dry matter of shoot and root were evaluated. Data were subjected to analysis of variance and means compared by Tukey test at 5% probability and regression analysis. The osmotic potential reduction to the level of -1.2 MPa reduced seed quality, however the application of plant growth regulator did not improve seed quality before the water stress. The plant growth regulator increased root length, dry weight of shoot and root of sorghum seedlings grow 1G233, in the absence of water deficit.Water stress can reduce seed germination speed and percentage, harming the development of seedlings. Thus, it is necessary to find alternatives that can mitigate these effects. Bioregulators have been intensively used in agricultural production and can provide increase in plant growth and development. Therefore, the aim of this work was to evaluate the germination performance of seeds of two grain sorghum hybrids under simulated water deficit treated with bioregulator. The experimental design was completely randomized in a 2 x 4 factorial scheme, with the following factors: two seed treatments (with and without bioregulator) and four osmotic potentials (0; -0.4; -0.8 and -1.2 MPa), with four replicates, separately for the following grain sorghum hybrids: 1G100 and 1G233. Germination, first germination count, shoot and root length and shoot and root dry matter were evaluated. Data obtained were submitted to analysis of variance and means were compared by the Tukey test at 5% probability and regression analysis. The reduction of the osmotic potential to the level of -1.2 MPa reduced the physiological quality of seeds; however, bioregulator application did not result in better seed quality under water stress. Bioregulator Stimulate® increased root length and shoot dry matter of seedlings of grain sorghum cultivar 1G233 in the absence of water deficit

EXTREME EVENTS OF PRECIPITATION AND OCCURRENCES OF FLOODING, RUNOFF AND INUNDATION IN THE METROPOLITAN REGION OF CURITIBA, BRAZIL

Extreme precipitation events cause severe damage in both urban and rural areas. The objective of this work was to analyze rainfall variability, understand the dynamics of extreme precipitation events and to find out the occurrence of floods, runoff and inundation in the Metropolitan Region of Curitiba (MRC). Data from 39 rainfall stations distributed in the MRC area were used, as well as data by municipality of occurrence of flooding, runoff or inundation, from 1976 to 2018. Extreme precipitation events were identified in all months, most frequently in the summer. Totaling 48 decrees of emergency or public calamity and 397,516 people affected by one of the three socioenvironmental disasters.Extreme precipitation events cause severe damage in both urban and rural areas. The objective of this work was to analyze rainfall variability, understand the dynamics of extreme precipitation events and to find out the occurrence of floods, runoff and inundation in the Metropolitan Region of Curitiba (MRC). Data from 39 rainfall stations distributed in the MRC area were used, as well as data by municipality of occurrence of flooding, runoff or inundation, from 1976 to 2018. Extreme precipitation events were identified in all months, most frequently in the summer. Totaling 48 decrees of emergency or public calamity and 397,516 people affected by one of the three socioenvironmental disasters

PLUVIOMETRIC VARIABILITY AND EXTREME PRECIPITATION AND DROUGHTS EVENTS IN THE CENTRAL NORTH MESOREGION OF PARANÁ

Extreme precipitation events cause severe damage in both urban and rural areas. The purpose of this work was to analyze rainfall variability and detect the extremes of precipitation and droughts occurrences and relate them to ENSO phenomena in the Central North Mesoregion of Paraná (MRNCP). We used data from 44 weather stations distributed in the area of the study, from 1976 to 2018. Based on the results, it was identified the precipitation has regional discrepancies, concentrating the highest rainfall in the southern portion. The highest annual precipitation was highly correlated with the periods identified as El Niño, and then in neutrality. There were large occurrences of drought by decent, with emphasis on the winter months, especially in August. High rainfall heights recorded within 24 hours in all regions analyzed, especially in the summer and spring months.Extreme precipitation events cause severe damage in both urban and rural areas. The purpose of this work was to analyze rainfall variability and detect the extremes of precipitation and droughts occurrences and relate them to ENSO phenomena in the Central North Mesoregion of Paraná (MRNCP). We used data from 44 weather stations distributed in the area of the study, from 1976 to 2018. Based on the results, it was identified the precipitation has regional discrepancies, concentrating the highest rainfall in the southern portion. The highest annual precipitation was highly correlated with the periods identified as El Niño, and then in neutrality. There were large occurrences of drought by decent, with emphasis on the winter months, especially in August. High rainfall heights recorded within 24 hours in all regions analyzed, especially in the summer and spring months

Estimativa do molhamento foliar da soja a partir de variáveis meteorológicas

The objective of this work was to determine models for the estimation of leaf wetness percentage at three heights in the soybean (Glycine max) canopy, using meteorological variables from stations installed at the crop site and at an agrometeorological station. The experiment was conducted in three harvest seasons, in an area cropped with soybean, in the municipality of Londrina, in the state of Paraná, Brazil. To collect the meteorological variables, electronic trees were installed at four heights (0.3, 0.6, 0.9, and 1.7 m) in the crop and a station was installed in an agrometeorological station. The data were separated according to days with and without rain, and the analyses of correlation and of simple and multiple regressions were carried out, in order to obtain models with equations for leaf wetness estimation. Most of the equations that did not use the data of the sensors installed at 1.7 m, especially those of the models based on variables only from the agrometeorological station, presented low reliability. The models obtained with meteorological data only from the soybean crop show high reliability and use a lower amount of variables, which makes them a good alternative for wetness estimation. O objetivo deste trabalho foi determinar modelos para estimativa da percentagem de molhamento foliar em três alturas no dossel da soja (Glycine max), a partir de variáveis meteorológicas de estações instaladas na cultura e em posto agrometeorológico. O experimento foi conduzido em três safras agrícolas, em área com cultura de soja, no Município de Londrina, PR. Para a coleta das variáveis meteorológicas, foram instaladas árvores eletrônicas com sensores de molhamento, em quatro alturas (0,3, 0,6, 0,9 e 1,7 m), na cultura e uma estação em posto agrometeorológico. Separaram-se os dados de dias com e sem chuva, e realizaram-se as análises de correlação e de regressões simples e múltipla, para obter modelos com equações de estimativa de molhamento. A maioria das equações que não utilizou os dados dos sensores instalados a 1,7 m, principalmente as dos modelos baseados apenas nas variáveis do posto agrometeorológico, apresentou baixa confiabilidade. Os modelos obtidos a partir de dados meteorológicos unicamente da cultura de soja apresentam alta confiabilidade e utilizam menor quantidade de variáveis, o que os torna boa alternativa para estimativa de molhamento

Nitrogênio, fósforo e potássio liberados pela decomposição da palhada de braquiária para a soja em sucessão

The objective of this work was to determine the nitrogen, phosphorus, and potassium released by N-fertilized Urochloa brizantha straw, desiccated before sowing of no-tillage soybean (Glycine max) in succession. The pasture was grown in three paddocks, each fertilized with one N rate (0, 150, or 300 kg ha-1), and assessed at two desiccation periods (60 or 15 days before soybean sowing), in four replicates. Nitrogen fertilization of U. brizantha pasture increases N and K cycling and the release of these nutrients to the subsequent soybean crop. The quantity of K released by U. brizantha straw fertilized with 150 or 300 kg ha-1 N (about 80 kg ha-1 K) offsets that contained in an export of up to 4 Mg ha-1 soybean grains, assuming zero K losses in the system. An early desiccation of the U. brizantha pasture does not improve K uptake by the soybean crop, since 50% of the nutrient is released in the first 20 days after desiccation. The dynamics of P release from U. brizantha straw (about 6 to 10 kg ha-1 during the soybean crop) is not influenced by N fertilization and the time of pasture desiccation.O objetivo deste trabalho foi avaliar o nitrogênio, o fósforo e o potássio liberados pela palha de pastagem de Urochloa brizantha adubadada com N, dessecada antes da semeadura da soja (Glycine max) em sucessão, no sistema plantio direto. A pastagem foi cultivada em três piquetes, cada um fertilizado com uma dose de N (0, 150 ou 300 kg ha-1), e avaliada em dois períodos de dessecação (60 ou 15 dias antes da semeadura da soja), com quatro repetições. A adubação nitrogenada na pastagem de U. brizantha aumenta a ciclagem de N e K e a liberação destes nutrientes à soja em sucessão. A quantidade de K liberada pela palha de U. brizantha adubada com 150 ou 300 kg ha-1 de N (aproximadamente 80 kg ha-1 de K) atende a exportação de até 4 Mg ha-1 de grãos de soja, ao se considerar a ausência de perdas de K no sistema. A dessecação antecipada de pastagem de U. brizantha não favorece o aproveitamento de K pela cultura da soja, já que 50% do nutriente é liberado nos 20 primeiros dias após a dessecação. A dinâmica de liberação de P pela palha de U. brizantha (de 6 a 10 kg ha-1 durante a cultura da soja) não é influenciada pela adubação nitrogenada e pela época de dessecação

DINÂMICA DA COBERTURA DO SOLO POR PLANTAS E NDVI DE CULTIVARES DE SOJA EM DIFERENTES ARRANJOS ESPACIAIS DE PLANTAS

A densidade de semeadura e o espaçamento entre as fileiras podem influenciar no crescimento e desenvolvimento das culturas. O objetivo do trabalho foi avaliar a dinâmica do crescimento de duas cultivares de soja com tipo de crescimento indeterminado, em diferentes arranjos espaciais de plantas, compostos por espaçamentos entre fileiras e densidades de semeadura. O experimento foi conduzido nas safras 2013/14 e 2014/15 com delineamento experimental em blocos completos casualizados, esquema fatorial 2 x 4 x 3, com três repetições. Os tratamentos constituíram-se da combinação de duas cultivares: BRS 359 RR e BMX Potência RR, de quatro espaçamentos entre fileiras: 20 cm (reduzido); 20/80 cm (fileira dupla); 50 cm (usual) e 50 x 50 cm (cruzado) e três densidades de semeadura: 150, 300 e 450 mil sementes viáveis ha-1. Foram avaliados o índice de vegetação por diferença normalizada (NDVI) e a porcentagem da cobertura do solo pelo dossel. O NDVI e a porcentagem de cobertura do solo pelo dossel de cultivares modernas de soja, com tipo de crescimento indeterminado, são mais afetados pelos espaçamentos entre fileiras no início do ciclo de desenvolvimento, mas na fase de enchimento de grãos as diferenças são menores. A densidade de 150 mil sementes viáveis ha-1 ocasiona menor NDVI e cobertura do dossel no início do ciclo, entretanto no final do ciclo essa diferença se dissipa e todas as densidades apresentam pleno fechamento do dossel

SOYBEAN BASE FERTILIZATION: CHEMICAL AND MICROBIOLOGICAL SOIL INDICATORS AND CROP YIELD

Recent searches stress that soybean yield might be doubled in Brazilian conditions, so that base fertilization is pivotal, once it might interfere over the chemical and microbiological soil indicators and hence, over the crop grain yield. It was aimed to assess alterations in the chemical and microbiological soil indicators, in the short term, and the soybean biometric and grain yield performance as a function of different fertilizers for base fertilization, in two sowing dates. An experiment comprised of two sowing dates was carried out in 2019/2020 season on a dystroferic Red Latossol, in north Parana state. It were assessed five treatments comprising: 1) control; 2) mineral fertilizer; 3) organomineral fertilizer; 4) mineral fertilizer mixed to granulated gypsum; and 5) slow release mineral fertilizer. Randomized block design with four replicates was the design adopted. It were assessed chemical and microbiological soil indicators; final stand; first pod insertion height; plant height; stem diameter; number of pods per plant; number of grains per plant; number of grains per pod; grain mass per plant; one thousand grain mass and grain yield. There is no base fertilization effect over the chemical soil indicators in the short term, however, there is effect over the microbiological soil indicators. Biometric and grain yield performance are decreased as sowing date is delayed, regardless of the base fertilization employed.Pesquisas recentes apontam que a produtividade da soja pode ser duplicada em condições brasileiras, para tanto, a adubação de base se mostra fundamental, pois pode interferir nos indicadores químicos e microbiológicos do solo e, consequentemente, no rendimento da cultura. Objetivou-se avaliar as alterações nos indicadores químicos e microbiológicos do solo, no curto prazo, e os desempenhos fitométricos e produtivo da soja em função do uso de diferentes fertilizantes na adubação de base, em duas épocas de semeadura. Foi conduzido experimento em duas épocas de semeadura na safra 2019/2020, em um Latossolo Vermelho distroférrico, no norte do estado do Paraná. Foram avaliados cinco tratamentos que consistiram de: 1) controle; 2) fertilizante mineral; 3) fertilizante organomineral; 4) fertilizante mineral em mistura com gesso granulado e 5) fertilizante mineral de liberação lenta. O delineamento experimental foi em blocos ao acaso com quatro repetições. Foram avaliados os indicadores químicos e microbiológicos do solo; estande final; altura de inserção da primeira vagem; altura de planta; diâmetro do caule; número de vagens por planta; número de grãos por planta; número de grãos por vagem; massa de grãos por planta; massa de mil grãos e produtividade. Não há efeito da adubação de base sobre os indicadores químicos do solo no curto prazo, porém, há efeito sobre os indicadores microbiológicos. Os desempenhos fitométricos e produtivo da soja são reduzidos conforme o atraso da semeadura, independentemente do tipo de fertilizante utilizado na adubação de base empregada

Produtividade de soja em consequência do atraso da colheita e de condições ambientais

The objective of this work was to evaluate the effect of harvest delay on grain moisture, thousand grain weight, and soybean productivity, as well as to identify the most important meteorological variables during pre‑harvest and to propose empirical algorithms to estimate soybean yield losses. The experiments were carried out in the municipalities of Castro, in the state of Paraná, and of Itaberá, in the state of São Paulo, Brazil, in the seasons from 2011/2012 to 2013/2014, with the soybean cultivar 'NA5909RG', in seven environments. Treatments consisted of eight harvest times of soybean after phenological stage R8.2. The analysis of group of experiments showed a significant interaction between environments and harvest times. Grain moisture and grain yield are directly affected by the number of days with rainfall equal to or higher than 3 mm. At the R8.2 phenological stage, the highest values of productivity are obtained; however, after this stage, there is a decline of productivity as a consequence of harvest delay. The greatest, accumulated losses of productivity occur in environments with high frequency of rainfall, and high temperature and solar radiation. Two algorithms based on agrometeorological variables are proposed to estimate soybean yield loss.O objetivo deste trabalho foi avaliar o efeito do atraso da colheita sobre umidade dos grãos, massa de mil grãos e produtividade da soja, assim como identificar as variáveis agrometeorológicas mais importantes durante o período pré‑colheita e propor algoritmos empíricos para a estimativa das perdas de produtividade. Os experimentos foram realizados em Castro, PR, e Itaberá, SP, nas safras de 2011/2012 a 2013/2014, da cultivar de soja 'NA5909RG', em sete ambientes. Os tratamentos consistiram de oito momentos de colheita de soja a partir do estádio fenológico R8.2. A análise de grupos de experimentos mostrou interação significativa entre ambientes e momentos de colheita. A umidade e a produção de grãos são influenciadas diretamente pelo número de dias com precipitação pluvial igual ou superior a 3 mm. No estádio fenológico R8.2, são obtidos os maiores valores de produtividade; no entanto, após esse estádio, há declínio da produtividade em consequência do atraso da colheita. As maiores perdas acumuladas de produtividade ocorrem em ambientes com alta frequência de precipitações pluviais e com temperatura e radiação solar global elevadas. Dois algoritmos com base em variáveis agrometeorológicas são propostos para a estimativa da perda de produtividade de soja

Liberação de cálcio, magnésio e enxofre da palha de pastagem de braquiária para a soja em sistema de integração lavoura-pecuária

Plant residues that remain in the soil of an integrated crop-livestock system constitute an important reserve of nutrients for crops in succession. The objective of this study was to evaluate the release of calcium (Ca), magnesium (Mg), and sulfur (S) from the decomposition of Urochloa brizantha cv. BRS Piatã pasture grass, fertilized with three different doses of nitrogen (N) and subjected to two different desiccation periods, prior to sowing a soybean crop. The experiment was conducted in Londrina, Paraná, between March 2016 and March 2018. Three different doses of N were applied to a pasture of U. brizantha cv. BRS Piatã (0, 150 and 300 kg N ha-1), forming three distinct paddocks. In each paddock, two different periods (60 and 15 days prior to sowing soybeans) for pasture desiccation were evaluated with four replications. Polynomial regression analysis was performed for the period after desiccation. Ca and S content in the U. brizantha straw did not vary over the course of decomposition, while magnesium content decreased, despite nitrogen fertilization and the desiccation periods. The amount of Ca released from U. brizantha straw by the end of the successive soybean cycle was approximately 15 kg ha-1, despite nitrogen fertilization and the desiccation periods. The amount of Mg released from U. brizantha straw by the end of the successive soybean cycle ranged from 10 to 15 kg ha-1, while the release of greater amounts tended to correspond with the presence of nitrogen fertilization in the pasture grass. The amount of S released from U. brizantha straw by the end of the successive soybean cycle ranged from 4 to 6 kg ha-1, while the release of lesser amounts tended to correspond with the presence of nitrogen fertilization in the pasture grass, despite the desiccation periods.Os resíduos de plantas que permanecem no solo em um sistema de integração lavoura-pecuária constituem em uma importante reserva de nutrientes para a cultura em sucessão. O objetivo do trabalho foi avaliar a liberação de cálcio (Ca), magnésio (Mg) e enxofre (S) de palha de pastagem de Urochloa brizantha cv. BRS Piatã, cultivada em três doses de nitrogênio (N) e submetida a duas épocas de dessecação em relação à semeadura da soja. O experimento foi conduzido em Londrina, Paraná, entre março de 2016 e março de 2018. Foram avaliadas três doses de N na pastagem de U. brizantha cv. BRS Piatã (0; 150 e 300 kg N ha-1), constituindo três piquetes distintos. Em cada piquete foram avaliadas duas épocas de dessecação da pastagem (60 e 15 dias antes da semeadura da soja), com quatro repetições. Os teores de Ca e S na palha de pastagem de U. brizantha não variam com o tempo de decomposição, enquanto os teores de Mg foram reduzidos, independentemente da adubação nitrogenada e da época de dessecação. A quantidade de Ca liberada pela palha de pastagem de U. brizantha até o final do ciclo da soja em sucessão foi de, aproximadamente, 15 kg ha-1, independentemente da adubação nitrogenada e da época de dessecação. A quantidade de Mg liberada pela U. brizantha até o final do ciclo da soja em sucessão variou de 10 a 15 kg ha-1, com tendência de haver maior quantidade liberada na presença de adubação nitrogenada na pastagem. A quantidade de S liberada pela U. brizantha até o final do ciclo da soja em sucessão variou de 4 a 6 kg ha-1, com tendência de haver menor quantidade liberada na presença de adubação nitrogenada na pastagem, independentemente da época de dessecação