Supplemental irrigation using brackish water on maize in tropical semi-arid regions of Brazil: yield and economic analysis

ABSTRACT: Supplemental irrigation during dry spells could reduce maize yield losses in tropical semi-arid regions, notably in small farms. However, good quality water reserves are not sufficient to meet the demands of farming communities. Consequently, our objective was to evaluate the productivity and profitability of maize under different simulated rainfall scenarios, with and without supplemental irrigation (SI) with brackish water. The field experiments were carried out during the cropping seasons of 2018 and 2019 on Ultisol. The experiment followed a randomized block design in the split-plot scheme with four replicates. The plots were formed by simulating the water supply in the soil corresponding to four water scenarios (rainy, normal, drought and severe drought), and the sub-plots with or without SI with brackish water (Electrical conductivity of 4.5 dS m1). Mean yields of green maize ears were 13,083, 11,532, 10,358 and 9,609 kg ha1 for rainy, normal, drought and severe drought scenarios, as supplemented with brackish water. For the same treatments without SI the values were 11,394, 7,896, 3,913 and 1,374 kg ha1, respectively. Data on farmer's income showed that under normal, drought and severe drought supplementation with brackish water becomes economically advantageous from 0.9, 1.0 and 2.4 ha, respectively, while maize cultivation without SI is not advantageous under the last two scenarios. For severe drought conditions, however, SI using brackish water reduced commercial yield by 27 % with negative effects on the farmers profitability. In this case, it is necessary to use water with either lower salinity or select salt tolerant crops.

Supplemental irrigation using brackish water on maize in tropical semi-arid regions of Brazil: yield and economic analysis

Supplemental irrigation during dry spells could reduce maize yield losses in tropical semi-arid regions, notably in small farms. However, good quality water reserves are not sufficient to meet the demands of farming communities. Consequently, our objective was to evaluate the productivity and profitability of maize under different simulated rainfall scenarios, with and without supplemental irrigation (SI) with brackish water. The field experiments were carried out during the cropping seasons of 2018 and 2019 on Ultisol. The experiment followed a randomized block design in the split-plot scheme with four replicates. The plots were formed by simulating the water supply in the soil corresponding to four water scenarios (rainy, normal, drought and severe drought), and the sub-plots with or without SI with brackish water (Electrical conductivity of 4.5 dS m−1). Mean yields of green maize ears were 13,083, 11,532, 10,358 and 9,609 kg ha−1 for rainy, normal, drought and severe drought scenarios, as supplemented with brackish water. For the same treatments without SI the values were 11,394, 7,896, 3,913 and 1,374 kg ha−1, respectively. Data on farmer's income showed that under normal, drought and severe drought supplementation with brackish water becomes economically advantageous from 0.9, 1.0 and 2.4 ha, respectively, while maize cultivation without SI is not advantageous under the last two scenarios. For severe drought conditions, however, SI using brackish water reduced commercial yield by 27 % with negative effects on the farmers’ profitability. In this case, it is necessary to use water with either lower salinity or select salt tolerant crops.

Supplemental irrigation using brackish water on maize in tropical semi-arid regions of Brazil: yield and economic analysis

Supplemental irrigation during dry spells could reduce maize yield losses in tropical semi-arid regions, notably in small farms. However, good quality water reserves are not sufficient to meet the demands of farming communities. Consequently, our objective was to evaluate the productivity and profitability of maize under different simulated rainfall scenarios, with and without supplemental irrigation (SI) with brackish water. The field experiments were carried out during the cropping seasons of 2018 and 2019 on Ultisol. The experiment followed a randomized block design in the split-plot scheme with four replicates. The plots were formed by simulating the water supply in the soil corresponding to four water scenarios (rainy, normal, drought and severe drought), and the sub-plots with or without SI with brackish water (Electrical conductivity of 4.5 dS m−1). Mean yields of green maize ears were 13,083, 11,532, 10,358 and 9,609 kg ha−1 for rainy, normal, drought and severe drought scenarios, as supplemented with brackish water. For the same treatments without SI the values were 11,394, 7,896, 3,913 and 1,374 kg ha−1, respectively. Data on farmer's income showed that under normal, drought and severe drought supplementation with brackish water becomes economically advantageous from 0.9, 1.0 and 2.4 ha, respectively, while maize cultivation without SI is not advantageous under the last two scenarios. For severe drought conditions, however, SI using brackish water reduced commercial yield by 27 % with negative effects on the farmers profitability. In this case, it is necessary to use water with either lower salinity or select salt tolerant crops.(AU)

O cultivo do milheto com água salobra e adubação orgânica altera as características do solo / Pearl millet cultivation with brackish water and organic fertilizer alters soil properties

Regiões semiáridas são caracterizadas pela elevada evapotranspiração e baixa precipitação pluvial, favorecendo o acúmulo de sais quando irrigado com água salobra. Objetivou se avaliar o efeito do cultivo de milheto com níveis de água salobra e fertilização orgânica nas propriedades químicas e físicas do solo. Adotou-se o delineamento de blocos ao acaso, com arranjo fatorial, em parcelas subdivididas, com três repetições. As parcelas foram constituídas por quatro lâminas de irrigação (25, 50, 75 e 100% da evapotranspiração da cultura) e as subparcelas foram compostas por quatro níveis de fertilização orgânica (0; 15; 30 e 45 Mg ha-1). No final do ciclo de produção do milheto, o solo foi coletado nas camadas de 0-0.20 e 0.20-0.40 m, para aspectos físicos (densidade do solo, densidade de partículas e porosidade) e químicos (CE, pH, K, Na, Ca, Mg, H + Al, SB, CTC, V). Não houve interação entre a água salobra e a fertilização orgânica nas propriedades químicas do solo. A água salobra reduziu o potássio na camada de 0,20-0,.40 m. Observou-se efeito linear negativo para densidade na camada 0,20 - 0,40 m sob níveis de fertilização orgânica. Níveis de água salobra e fertilizante orgânico no cultivo do milheto não altera as propriedades químicas e físicas do solo na camada de 0-0,20 m. Porém, o uso de água salobra reduz a concentração de potássio no solo e a aplicação de fertilização orgânica reduz a densidade do solo na camada de 0.20-0,40 m.

Semi-arid regions are characterized by high evapotranspiration and low rainfall, favoring the accumulation of salts when irrigated with brackish water. The aim of this study was to evaluate the effect of pearl millet cultivation with brackish water levels and fertilized with organic fertilizer on the chemical and physical properties of the soil. A split plot randomized block design was adopted, in a factorial arrangement, with three repetitions. Plots consisted of four irrigation levels (25, 50, 75 and 100% crop evapotranspiration) and subplots consisted of four levels of organic fertilizer (0; 15; 30 and 45 Mg ha-¹). At the end of the pearl millet production cycle, soil was collected from layers 0-0.20 m and 0.20-0.40 m, for physical (soil bulk density, particle density and porosity) and chemical (EC, pH, K, Na, Ca, Mg, H + Al, SB, CEC, V) properties. There was no effect of interaction of brackish water levels and organic fertilizer levels on soil chemical properties. Brackish water reduced potassium on layer 0.20-0.40 m. A negative linear effect was found for density in the 0.20-0.40 m layer under different levels of organic fertilizer. Brackish water levels and organic fertilizer levels in the cultivation of pearl millet does not alter soil chemical and physical properties at the 0-0.20 m layer. However, the use of brackish water reduces the concentration of potassium in the soil and the application of organic fertilizer reduces soil density at the 0.20-0.40 m layer.

Pearl millet cultivation with brackish water and organic fertilizer alters soil properties / O cultivo do milheto com água salobra e adubação orgânica altera as características do solo

Semi-arid regions are characterized by high evapotranspiration and low rainfall, favoring the accumulation of salts when irrigated with brackish water. The aim of this study was to evaluate the effect of pearl millet cultivation with brackish water levels and fertilized with organic fertilizer on the chemical and physical properties of the soil. A split plot randomized block design was adopted, in a factorial arrangement, with three repetitions. Plots consisted of four irrigation levels (25, 50, 75 and 100% crop evapotranspiration) and subplots consisted of four levels of organic fertilizer (0; 15; 30 and 45 Mg ha-1). At the end of the pearl millet production cycle, soil was collected from layers 0-0.20 m and 0.20-0.40 m, for physical (soil bulk density, particle density and porosity) and chemical (EC, pH, K, Na, Ca, Mg, H + Al, SB, CEC, V) properties. There was no effect of interaction of brackish water levels and organic fertilizer levels on soil chemical properties. Brackish water reduced potassium on layer 0.20-0.40 m. A negative linear effect was found for density in the 0.20-0.40 m layer under different levels of organic fertilizer. Brackish water levels and organic fertilizer levels in the cultivation of pearl millet does not alter soil chemical and physical properties at the 0-0.20 m layer. However, the use of brackish water reduces the concentration of potassium in the soil and the application of organic fertilizer reduces soil density at the 0.20-0.40 m layer.

Regiões semiáridas são caracterizadas pela elevada evapotranspiração e baixa precipitação pluvial, favorecendo o acúmulo de sais quando irrigado com água salobra. Objetivouse avaliar o efeito do cultivo de milheto com níveis de água salobra e fertilização orgânica nas propriedades químicas e físicas do solo. Adotou-se o delineamento de blocos ao acaso, com arranjo fatorial, em parcelas subdivididas, com três repetições. As parcelas foram constituídas por quatro lâminas de irrigação (25, 50, 75 e 100% da evapotranspiração da cultura) e as subparcelas foram compostas por quatro níveis de fertilização orgânica (0; 15; 30 e 45 Mg ha-1). No final do ciclo de produção do milheto, o solo foi coletado nas camadas de 0-0.20 e 0.20-0.40 m, para aspectos físicos (densidade do solo, densidade de partículas e porosidade) e químicos (CE, pH, K, Na, Ca, Mg, H + Al, SB, CTC, V). Não houve interação entre a água salobra e a fertilização orgânica nas propriedades químicas do solo. A água salobra reduziu o potássio na camada de 0,20-0,.40 m. Observou-se efeito linear negativo para densidade na camada 0,20 - 0,40 m sob níveis de fertilização orgânica. Níveis de água salobra e fertilizante orgânico no cultivo do milheto não altera as propriedades químicas e físicas do solo na camada de 0-0,20 m. Porém, o uso de água salobra reduz a concentração de potássio no solo e a aplicação de fertilização orgânica reduz a densidade do solo na camada de 0.20-0,40 m.

Estratégias de uso de lâminas de água salobra e níveis de matéria orgânica em sistemas biossalinos de produção de palma forrageira com cortes sucessivos a cada seis meses

Objetivou-se avaliar a morfologia, produtividade, composição química-bromatológica e mineral da palma forrageira cv. Orelha de Elefante Mexicana em sistemas biossalinos, recebendo diferentes lâminas de água salobra (L0 0,0%; L1 12,5%; L2 25,0%; L3 37,5% e L4 50,0% da Evapotranspiração - ETo) e cargas de matéria orgânica (0, 15, 30, 45 t ha-1). O delineamento foi em blocos casualizados, em arranjo fatorial 5 x 4, cinco parcelas (níveis lâminas de água - LA) e quatro subparcelas (doses de matéria orgânica - MO). As variáveis produtivas, produção de matéria verde (PMV) com valor de 156.234,7, 29.576 e 48.260,5 t ha-1, primeiro, segundo e terceiro corte, respectivamente, produção de matéria seca (PMS)com valor de 10.684,6, 2.287,8 t ha-1, e3.381,2 t ha-1primeiro, segundo e terceiro corte, respectivamente, acúmulo de água (AA) com valor de 145.550, 26.606,8 e 44.879,3 m3 ha-1 primeiro, segundo e terceiro corte, respectivamente, eficiência no uso da água (EUA)com valor de 29,2, 14,0 e 25,7 kg/MS ha-1 mm-1, primeiro segundo e terceiro corte, respectivamente e de crescimento, altura da planta (AP), largura da planta (LP), número de cladódios totais (NCT), número de cladódios de 1ª ordem (NC1), comprimento do cladódio mãe (CCM), largura do cladódio mãe (LCM), espessura do cladódio mãe (ECM), perímetro do cladódio mãe (PCM), comprimento de cladódio de 1ª ordem (CC1), largura de cladódio de 1ª ordem (LC1), espessura de cladódios 1ª ordem (EC1) e perímetro de cladódio de 1ª ordem (PC1) foram significantes sob o efeito da MO em todos os corte, com exceção do PCM do primeiro corte e LC1 e EC1 do terceiro corte. Para LA o CCM do primeiro corte e LP e CC1 do segundo corte foram significativos. Exceto a matéria seca (MS) e matéria mineral (MM) todos os outros componentes químicos, proteína bruta (PB), fibra em detergente neutro (FDN), fibra em detergente ácido (FDA), extrato etéreo (EE), lignina (LIG) e digestibilidade in vitro da matéria seca (DIVMS) apresentaram interação LA x MO (P<0,05). Nos elementos minerais o nitrogênio (N) e sódio (Na) mostraram interação LA x MO significativa no primeiro corte. No segundo corte N e cálcio (Ca) e no terceiro corte N, fósforo (P) e Ca apresentaram interação LA x MO. O aumento da matéria orgânica nos sistemas de produção biossalinos incrementou a produtividade de biomassa forrageira em todas três fases de cortes. Enquanto a lâmina de irrigação influencia positivamente na produção quando o déficit hídrico via precipitação foi mais acentuado. A combinação lâmina e matéria orgânica influencia a composição bromatológica da palma.

The objective was to evaluate the morphology, productivity, chemical-composition and mineral composition of forage palm cv. Mexican Elephant Ear in biosaline systems, receiving different depths of brackish water (L0 0.0%; L1 12.5%; L2 25.0%; L3 37.5% and L4 50.0% of Evapotranspiration - ETo) and loads of organic matter (0, 15, 30, 45 t ha-1). The design was in randomized blocks, in a 5 x 4 factorial arrangement, five plots (water depths levels - WD) and four subplots (organic matter doses - OM). The productive variables, of green matter production (GMP) with a value of 156,234.7, 29,576 and 48,260.5 t ha-1, first, second and third cut, respectively, dry matter production (DMP) with a value of 10,684.6 , 2,287.8, and 3,381.2 t ha-1 first, second and third cut, respectively, water accumulation (WA) with a value of 145,550, 26,606.8 and 44,879.3 m3 ha-1 first, second and third cut, respectively, and water use efficiency (WUE) with a value of 29.2, 14.0 and 25.7 kg / DM ha-1 mm-1, first second and third cut, respectively and growth , plant height (PH), plant width (PW), number of total cladodes (NCT), number of 1st order cladodes (NC1), length of the mother cladode (LMC), width of the mother cladode (WMC), thickness mother cladode (TMC), mother cladode perimeter (MCP), 1st order cladode length (CL1), 1st order cladode width (CW1), 1st order cladode thickness (CT1) and 1st order cladode perimeter (CP1) were significant under the effect of OM in all sections, except for the CPM of the first section and CL1 and CT1 of the third section.For SW, the LMC of the first cut and PW and CL1 of the second cut were significant (P <0.05). Except for dry matter (DM) and mineral matter (MM) all other chemical components, crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), ether extract (EE), lignin (LIG) and in vitro dry matter digestibility (IVDMD) showed SW x Om interaction (P <0.05). In the mineral elements, nitrogen (N) and sodium (Na) showed significant SW x OM interaction (P <0.05) in the first cut. In the second cut N and calcium (Ca) and in the third cut N, phosphorus (P) and Ca showed LA x OM interaction. The increase in organic matter in the biossaline production systems increases the productivity of forage biomass in all three cutting phases. While the irrigation depth influenced positively when the water deficit via precipitation was more pronounced. The combination of blade and organic matter influenced the composition of the cactus.

GENÓTIPOS DE MILHETO IRRIGADOS COM ÁGUA SALINA SOB DIFERENTES NÍVEIS DE GESSO AGRÍCOLA

Objetivou-se avaliar produtividade, características agronômicas e composição bromatológica de genótipos de milheto forrageiro, submetidos a quatro níveis de gesso agrícola, irrigados com água salina em dois ciclos. O estudo foi conduzido em Petrolina PE, com duração de 75 dias para o primeiro ciclo e 65 dias para o segundo. Utilizou-se o delineamento experimental em blocos casualizados dispostos em esquema fatorial 3x4, considerando três genótipos de milheto (IPA BULK 1BF, BRS1501 e ADR 300) e quatro níveis de gesso agrícola (0, 2, 4 e 8 t ha-1), com três repetições, totalizando 36 parcelas. Os genótipos de milheto irrigados com água salina não diferiram entre si para variáveis analisadas: produtividade de matéria verde, produtividade de matéria seca; percentagens de lâmina foliar, colmo e panícula; diâmetro da base do colmo, altura de planta, número de folhas, número de perfilhos, tamanho médio das folhas e teores de matéria seca, proteína bruta, fibra em detergente neutro, fibra em detergente ácido, extrato etéreo, cinzas, lignina, hemicelulose, celulose, digestibilidade e carboidratos totais. Houve diferença entre os cortes, com as maiores produtividades de 40.513,89; 46.819,43; 48.430,55 kg ha-1 na matéria verde para os cultivares BULK 1BF, ADR 300 e BRS 1501 respectivamente e 10.136,57; 11.812,21; 12.070,05 kg ha-1 na matéria seca para as cultivares BULK 1BF, BRS 1501 e ADR 300, no segundo corte. O teor de matéria seca foi de 25,77% no primeiro corte e 25,02% no segundo corte. As porcentagens de lâmina e colmo foram de 21,05; 58,70 e 16,10; 70,00% no primeiro e segundo corte, respectivamente. O segundo corte apresentou menor proporção de panícula com média de 13,4%, enquanto o primeiro corte foi de 20,40%. Houve diferença (P<0,05) para percentual de proteína bruta de 15,90% para o primeiro corte e de 10,42% para o segundo corte. Os níveis de gesso foram significativos para a variável lignina do cultivar BRS 1501. O aumento das doses de gesso representou ganho no tamanho de panícula dos cultivares no segundo corte. O teor de potássio na rebrota foi mais elevado. O cálcio e o enxofre foram mais demandados no primeiro ciclo. O acúmulo de sódio nas plantas, mesmo irrigadas com água salina, não foi tóxico para os cultivares estudados.

The objective was to evaluate productivity, agronomic characteristics and bromatological composition of forage millet genotypes, submitted to four levels of agricultural gypsum irrigated with saline water in two cycles. The study was conducted in Petrolina - PE, with a duration of 75 days for the first cycle and 65 days for the second cycle. The experiment was carried out in a randomized block design with 3x4 factorial, considering three millet genotypes (IPA BULK 1BF, BRS 1501 and ADR 300) and four levels of agricultural gypsum (0, 2, 4 and 8 t ha-1), with three replications, totaling 36 plots. The millet genotypes irrigated with saline water did not differ among the analyzed variables: green matter yield, dry matter yield; percentages of leaf blade, stem and panicle; diameter of the stem base, plant height, number of leaves, number of tillers, average leaf size and dry matter content, crude protein, neutral detergent fiber, acid detergent fiber, ethereal extract, ash, lignin, hemicellulose, cellulose, digestibility and total carbohydrates. There was a difference between the cuts, with the highest yields of 40,513.89; 46,819.43; 48,430.55 kg ha-1 in the green matter for the varieties BULK 1 BF, ADR 300 and BRS 1501 respectively and 10,136.57; 11,812.21; 12,070.05 kg ha-1 in the dry matter for the BULK 1 BF, BRS 1501 and ADR 300 varieties, in the second cut. The dry matter content was 25.77% in the first cut and 25.02% in the second cut. The percentages of blade and stem were 21.05; 58.70 and 16.10; 70.00% in the first and second cut, respectively. The second cut presented a smaller proportion of panicle with a mean of 13.4% while the first cut was of 20.40%. There was a difference (P<0.05) for crude protein percentage of 15.90% for the first cut and 10.42% for the second cut. The gypsum levels were significant for the lignin variable of the BRS 1501 variety. The increase of the doses of gypsum represented a gain in the panicle size of the varieties in the second cut. The potassium content in regrowth was higher. Calcium and sulfur were more in demand in the first cycle. The accumulation of sodium in the plants, even irrigated with saline water, was not toxic to the studied varieties.