Viabilidade Econômica de Irrigação

This study aimed to verify the incidence of Fusarium spp. in commercial maize hybrids and irrigation management strategies utilizing center pivot systems. The experiment was carried out during the second season in a randomized block design with a split-plot arrangement with five maize hybrids (2B810, MG580, AS1633, DKB290, and AG8544). The plots were irrigated with five frequencies (1, 2, 3, 4, and 5 days) in one experiment, and five water depths (at 25, 50, 75, 100, and 125% of crop evapotranspiration) in another experiment. Plant height, ear insertion height, moisture at harvest time, yield, and incidence of stalk rot were evaluated. Neither irrigation frequency nor irrigation depth influenced the incidence of disease. The one-day irrigation frequency provided the highest yield for maize hybrids. Hybrid 2B810 showed the highest yield and the lowest incidence of the disease.

One of the main limitations of soybean production is related to water availability and organisms found in the soil. Under the hypothesis that soil moisture may influence the nematode population, this study aimed to verify the occurrence of nematodes associated with different irrigation management in soybean crops. The experiment was carried out in a randomized block design. Treatments consisted of a subplot scheme, with four replications. The plots consisted of ten irrigation managements divided into five irrigation frequencies (1,2,3,4, and 5 days) and five additional water depths (25, 50, 75, 100, and 125% of crop evapotranspiration-Etc). The subplots were composed of four different soybean cultivars (NA 5909 RR, AS 3680 IPRO, and Desafio RR ePower IPRO). The experiment analyzed the variables plant height, first pod insertion, number of plants, moisture, hundred-grain weight, yield, and occurrence of nematode eggs and adults. Nematodes influence all the production components analyzed, affecting mostly the hundred-grain weight, especially the nematode Helicotylenchus sp., although the Meloidogyne sp. population was larger. The phytonematode population reduces with the increase in soil moisture to levels close to the saturation, indirectly influencing the yield increase.

The sizing of mechanized agricultural systems depends on the soil and climatic conditions, the crop and the work regime. The aim of this study was to determine the probabilities of time available during an agricultural year for mechanized spraying and sowing in the northeast region of the State of Mato Grosso do Sul and south of Goiás. The meteorological restrictions imposed as unfavorable hours were: ambient temperature above 32ºC, relative air humidity below 50%, wind velocity above 15 km h-1 and soil volumetric moisture above 39% (humidity equivalent to 90% of the available water capacity for the studied soil). The mathematical models were elaborated for eight years, based on the historical data of the automatic station of the National Institute of Meteorology installed in the region. It was possible to determine the time available for mechanized sowing and agricultural spraying operations. The available times for every ten days of the agricultural year for mechanized spraying and sowing in the study region were determined. The hourly water balance is used for the restrictive study of soil moisture in determining the time available for mechanized operations. A single self-propelled sprayer (30 m bar) and a single seed drill (48 rows) are not sufficient to meet the operational rate in an area of 3,000 ha in the northeast of the state of Mato Grosso do Sul and south of Goiás.

The aim of this study was to evaluate the development of a corn (Zea mays) crop grown in Brazil on a sandy soil, in a Savannah climate, and under center pivot irrigation. A randomized complete block design with four replicates of three irrigation treatments including a rainfed control treatment (I0), a 100% replacement (I1), and a 200% replacement (I2) of crop evapotranspiration (ETc). The grain yield (GY) and the plant characteristics including plant height (PH), corn cob insertion height (CIH), stem diameter (SD), and 100 grain mass (M100) were measured. The grain yield results were (I2) 9,634 kg ha-1 , (I1) 7,680 kg ha-1 , and (I0) 4,229 kg ha-1. All of the plant characteristic variables had higher values for irrigated treatments than for the rainfed treatment. For all except M100, the I2 treatment increased plant characteristic values the most. The I1 just treatment had the highest values for M100. The sandy soil has good drainage and a high soil infiltration rate, so the higher irrigation depth for I2 did not cause water logging and poor aeration in the soil. Maintaining a higher moisture content increased grain yield, but a cost-benefit analysis is needed to assess cost effectiveness from applying more water.

In Brazil, the common bean crop has representative agricultural exploitation, not only because of its production economic value, but also because there is a large cultivation area. This research aimed to investigate the direct and indirect relationship of morphological components on grain yield in common bean plants. This study was carried out in a Quartzarenic Neosol in the municipality of Cassilândia, Mato Grosso do Sul State, Brazil, in the agricultural year of 2016/2017. The evaluated traits were: grains yield (GY) with its primary components; mass of one hundred grains (HG); number of grains per plant (GP); number of grains per pod (GPP); dry weight of aerial parts (DWA); number of pod per plant (PP); plant dry mass (DM); plant high (PH); and stem diameter (SD). Initially, the Pearson’s correlation among these traits was estimated and the correlation network was used to graphically express the obtained results. Analysis of these data through the statistical techniques of multicollinearity diagnosis followed by path analysis enabled to verify that the number of pod per plant, the mass of one hundred grains, and the number of grains per plant, among the primary components of grain yield, are the traits of greater potential to select and identify superior genotypes for grain productivity yield, and that dry matter and stem diameter traits showed a negative correlation with grain yield in common bean grains. © 2018, Universidade Federal de Uberlandia. All rights reserved.

With the hypothesis that irrigation can influence the maize lodging, the objective was to evaluate the effect of water depth and plant population on the performance of hybrids of this crop. The experiment was conducted in a field equipped with center pivot irrigation, in a randomized complete block design in a split-plot arrangement, with 6 irrigation levels (plots), 2 hybrids (subplots), 3 plant densities (sub-subplots) with 4 replications. Irrigation levels evaluated were a 0 (control treatment), 25, 50, 75, 100 and 125% of crop evapotranspiration (ETc). The evaluated hybrids were Dow 2B810 PW and MORGAN MG 652 PW, in plant densities of 56, 67 and 78 thousand plants per hectare, with 0.45 m spacing between rows. Maize productivity varies with the irrigation depth, reaching the highest values in the region, with 73% of the ETc. Irrigation also influences total plant height (TPH), as well as first ear insertion height (EIH), however, it shows no influence on plant lodging (LOD). Higher plant densities contribute to higher lodging rates, but it is more strongly related to the resistance characteristic of each hybrid. Performance de híbridos de milho submetidos a aplicação de diferentes lâminas de irrigação em pivô central Resumo: Com a hipótese de que a irrigação pode influenciar no acamamento do milho, objetivou-se avaliar o efeito das lâminas de irrigação e da população de plantas na performance de híbridos desta cultura. O experimento foi conduzido em área de Pivô Central, com delineamento experimental em blocos casualizados em esquema de parcelas sub-subdivididas sendo, 6 níveis de irrigação (parcelas), 2 híbridos (subparcelas), 3 populações (sub-subparcelas), com 4 repetições. Os níveis de irrigação foram 0 (tratamento controle), 25, 50, 75, 100 e 125 % da evapotranspiração da cultura (ETc). Os híbridos avaliados foram, Dow 2B810 PW e MORGAN MG 652 PW, nas populações de 56, 67 e 78 mil plantas por hectare, com espaçamento entre linhas de 0,45 metros. A irrigação influencia a produtividade do milho, alcançando os maiores valores, na região de estudo, com 73% da reposição da ETc. A irrigação também influencia na altura total de plantas (ALT), bem como na altura de inserção da primeira espiga (AES), porém, não mostra influência alguma sobre o acamamento de plantas (ACM). Maiores populações de milho contribuem para maiores índices de acamamento de plantas, mas este fator está mais fortemente relacionado à resistência característica de cada híbrido.

With the hypothesis that irrigation can influence the maize lodging, the objective was to evaluate the effect of water depth and plant population on the performance of hybrids of this crop. The experiment was conducted in a field equipped with center pivot irrigation, in a randomized complete block design in a split-plot arrangement, with 6 irrigation levels (plots), 2 hybrids (subplots), 3 plant densities (sub-subplots) with 4 replications. Irrigation levels evaluated were a 0 (control treatment), 25, 50, 75, 100 and 125% of crop evapotranspiration (ETc). The evaluated hybrids were Dow 2B810 PW and MORGAN MG 652 PW, in plant densities of 56, 67 and 78 thousand plants per hectare, with 0.45 m spacing between rows. Maize productivity varies with the irrigation depth, reaching the highest values in the region, with 73% of the ETc. Irrigation also influences total plant height (TPH), as well as first ear insertion height (EIH), however, it shows no influence on plant lodging (LOD). Higher plant densities contribute to higher lodging rates, but it is more strongly related to the resistance characteristic of each hybrid. Performance de híbridos de milho submetidos a aplicação de diferentes lâminas de irrigação em pivô central Resumo: Com a hipótese de que a irrigação pode influenciar no acamamento do milho, objetivou-se avaliar o efeito das lâminas de irrigação e da população de plantas na performance de híbridos desta cultura. O experimento foi conduzido em área de Pivô Central, com delineamento experimental em blocos casualizados em esquema de parcelas sub-subdivididas sendo, 6 níveis de irrigação (parcelas), 2 híbridos (subparcelas), 3 populações (sub-subparcelas), com 4 repetições. Os níveis de irrigação foram 0 (tratamento controle), 25, 50, 75, 100 e 125 % da evapotranspiração da cultura (ETc). Os híbridos avaliados foram, Dow 2B810 PW e MORGAN MG 652 PW, nas populações de 56, 67 e 78 mil plantas por hectare, com espaçamento entre linhas de 0,45 metros. A irrigação influencia a produtividade do milho, alcançando os maiores valores, na região de estudo, com 73% da reposição da ETc. A irrigação também influencia na altura total de plantas (ALT), bem como na altura de inserção da primeira espiga (AES), porém, não mostra influência alguma sobre o acamamento de plantas (ACM). Maiores populações de milho contribuem para maiores índices de acamamento de plantas, mas este fator está mais fortemente relacionado à resistência característica de cada híbrido. Palavras chaves: Zea mays, irrigação, acamamento. 162 Gava et al.

Reductions in soybean yields are mainly linked to the occurrence of dry spells, which are becoming more frequent due to climate change. Thus, the aim of this study was to evaluate soybean cultivars irrigated with different water depths under center pivot. The experiment was conducted during the 2014/15 growing season, under center-pivot irrigation in Chapadão do Sul, MS, Brazil. The design was a randomized block in split plot with four replicates, where plots consisted of 4 water depths (0, 50, 75 and 100% of crop evapotranspiration -ETc) and the subplots of 6 soybean cultivars (NA 5909 RR, DM 5958 IPRO, Anta 82 RR, M 7110 IPRO, Desafio RR, M 7739 IPRO). The cultivar Desafio RR was the one that best responded to irrigation, increasing yield to 6174 kg ha⁻¹ against 3798 kg ha⁻¹ under rainfed condition. The highest yield under rainfed condition was obtained by the cultivar NA 5909 RR, reaching 4806 kg ha-1. This shows that some cultivars can respond positively to irrigation, resulting in increased yield, depending on the genetic characteristics of each one. © 2018, Departamento de Engenharia Agricola - UFCG/Cnpq. All Rights Resreved.

The performance of surface drainage practices and mulching was evaluated in a low land area in Northern Paraná, Brazil. Before and after rice crop, drainage rates were compared for treatments with and without mole drains, and discharge and clogging of the mole drains were also determined. Under beans, the effects of mole drains and bedding on soil drainage, together with the effect of mulching on soil moisture retention, were evaluated. The results indicated that mole drains were more efficient if constructed under lower soil moisture, however, their longevity was less than one year. During bean cultivation, mole drains and mulching maintained soil water table deeper and lower soil water tension, but these effects occurred in layers deeper than the root zone (15 cm), resulting in low crop yield.

Áreas irrigadas requerem cultivo intensivo para maximizar o uso da terra e do sistema de irrigação. A cultura do arroz, devido a resposta à suplementação hídrica, elevado potencial produtivo e compatibilidade fitotécnica com outras culturas, tem elevado potencial para uso em sucessão de cultivos nas áreas irrigadas por aspersão no norte do Paraná. Com o objetivo de se determinar o potencial produtivo, o requerimento hídrico e a duração do ciclo fenológico do arroz, duas cultivares de sequeiro (IAPAR 9 e IAPAR 64) foram semeadas em duas épocas (5 de outubro e 1º de dezembro) e submetidas a três regimes hídricos (irrigação a tensões de 25 e 70 kPa e sem irrigação) em Londrina, PR. A produtividade foi elevada na semeadura de outubro (5400 a 6000 kg ha-1) e menor na de dezembro (1600 a 4800 kg ha-1) devido à baixa temperatura no final do ciclo, principalmente para a cultivar de ciclo tardio (IAPAR 64); não houve diferença significativa entre os tratamentos irrigados mas a deficiência hídrica decresceu a produção do tratamento sem irrigação, em cerca de 50%, e atrasou a floração. Concluiu-se, então, que o arroz constitui uma alternativa promissora para sucessão de culturas em projetos de irrigação na região.

O incremento de produtividade, bem como as vantagens indiretas da irrigação, podem viabilizar esta prática mesmo em regiões com boas incidências de chuva.

Foi possível aumentar a produtividade, aumentando a população de plantas acima do recomendado pelos detentores das sementes, para as condições e épocas analisadas.

Com a irrigação é possível aumentar a produtividade da soja em mais de 60% em relação ao sequeiro, mesmo em regiões com boa incidência de chuvas, devido a ocorrência de veranicos.

Planting density can influence the competitiveness among plants mainly by water, nutrients and solar radiation, directly affecting yield. The purpose of this study was to evaluate the productivity of different soybean cultivars at different planting populations under irrigated and rainfed conditions. The experiment was conducted during the 2014/15 growing season, under center pivot irrigation in Chapadão do Sul – MS, Brazil. The experimental design was randomized complete block design with split-plot, as follows: Irrigated and Rainfed (plots) x Six cultivars (subplots) x Three Plant Populations (sub-subplots) with 4 replications. The irrigation management was realized by Penman-Monteith-FAO method. The cultivars used were: NA 5909 RR, DM 5958 IPRO, Anta 82 RR, M 7110 IPRO, Desafio RR and M 7739 IPRO. Populations indicated by the holders of the seeds were tested, and also population 20% above and 20% below with the hypothesis that in different humidity conditions, different cultivars may have different answers depending on their populations. In rainfed condition productivity and mass of one hundred grains were influenced by water deficit. Cultivar Desafio RR presented the best performance under irrigation, with productivity of 6174 kg ha−1.

This study was conducted at the Agronomic Institute of Parana (IAPAR), Londrina, Parana state (latitude 23° 18' S, longitude 51° 09' W, average elevation of 585 m). Londrina's climate in Köppen's classification is Cfa type, that is, humid subtropical climate with rain in all seasons and droughts in winter. Soil water evaporation (E) was determined for different soil mulching cover fractions. The treatments were applied on 2.66 m 2 x 1.3 m deep weighing lysimeters for the determination of E by mass difference with an accuracy of 0.01 milimeter in 1 h intervals. Evaporation was determined for different mulching fractions using the average amount of wheat straw produced in that region of 5 ton.ha -1 distributed onto 25, 50, 75 and 100% of the soil surface. In the first cycle (28 October to 27 November, 2008), the reductions of E in treatments with 25, 50, 75 and 100% mulching cover in relation to the not-mulched soil were 15, 17, 20 and 30%, while in the second cycle (19 January to 16 February, 2009), the reduction were 15, 30, 45 and 60%, respectively.

Although the vinasse is rich in nutrients and able to replace conventional fertilizer, the application areas need to be topped with nitrogen, which is made with urea application by using larger cover manpower and equipment. But the application of nitrogen can be accomplished using the already existing system of fertigation, simply add the same one premix tank and pump insertion in the line. Treatments consisted of a witness, and three doses of vinasse application, corresponding to 150, 300 and 450 m3 ha-1 with the addition of urea solution equivalent to 200 kg ha-1 in each treatment, 150, 300 and 450 m3 ha -1 of vinasse with applications of 200 kg ha-1 urea applied by the conventional method for coverage, groove depth of 0.15 m, according to production units in the region. The aim of this study was to compare the effect of nitrogen, inserting into the line of stillage fertigation, with the system of conventional application of urea by coverage, in three doses of application in the cane sugar culture. The results indicate that dissolved urea may be applied through the fertigation system that does not result in a reduction or increase in income, but there will be less use of machinery and manpower, reducing production costs and impacts on the environment.