Yield response factor (Ky) and initial growth in black pepper in a tropical environment

Black pepper is widely produced in Brazil, though there are few studies related to its water requirements and the effects of water deficit (WD) applied under tropical conditions. The growth, sensitivity to WD, and first-year productivity of irrigated plants from the Bragantina cultivar were evaluated, employing an irrigation system with automatic management. The plants were cultivated in plastic pots installed in the field for 391 days using emitters with different flow rates (2.2 [T1], 3.3 [T2], 4.3 [T3], and 5.3 L h­1 [T4 ­ control]). Fresh weight of the leaves, stems, and shoots, and dry weight of the leaves, stem, roots, and shoots as well as the total dry weight of the plant, were evaluated. Productivity was determined by evaluating the grains and spikes from a single harvest. Yield results and the actual versus maximum evapotranspiration rate for the entire growing season was used for calculating the Ky coefficient. Despite 1,346 mm of rainfall, the irrigation system was activated 165 times, distributing a mean volume of 19.0 (T1), 28.5 (T2), 37.1 (T3), and 45.8 L per plant (control). All traits were negatively affected by the WD, and the Ky values obtained (from 1.72 to 2.96) indicate the high sensitivity of black pepper to WD. In general, the spikes produced with at least 81 % of the crop water demand were larger and more numerous than those subjected to inferior treatments. WD occurring during the flowering stage severely hampers the size, weight, and quality of the spikes and grains of black pepper.(AU)

Growth of black pepper plantlets under different substrates and irrigation levels

Optimization of the use of water and the possibility of using residues as substrate in the black pepper production chain can yield economic and environmental benefits. The objective of this study was to evaluate the biometric and physiological traits of black pepper plantlets (Piper nigrum L.), cv. Bragantina, at different irrigation levels and soilless substrates. Plantlets were grown for 120 days on three substrates [biosolid + crushed coconut fiber (3:1, by volume); biosolid + granitic rock powder (3:1, by volume); and biosolid + crushed coconut fiber + granitic rock powder (2:1:1, by volume)] and at five irrigation levels [36 % (very low); 55 % (low); 85 % (moderate); 100 % (well-irrigated); and 126 % of the reference irrigation level (over-irrigated)]. The biometric traits evaluated increased as the irrigation levels increased, with the exception of root dry mass, which was not influenced by this factor, nor water use efficiency, which decreased as the irrigation levels increased. In general, plants grown with a mixture of the three wastes (biosolid + crushed coconut fiber + granitic rock powder) exhibited higher values for biometric variables and chlorophyll content when they were moderately, well or over-irrigated, in comparison with the other two substrates. It was possible to achieve the plantlet commercial standard using this three waste mixture and the moderate irrigation level.

Growth of black pepper plantlets under different substrates and irrigation levels

Optimization of the use of water and the possibility of using residues as substrate in the black pepper production chain can yield economic and environmental benefits. The objective of this study was to evaluate the biometric and physiological traits of black pepper plantlets (Piper nigrum L.), cv. Bragantina, at different irrigation levels and soilless substrates. Plantlets were grown for 120 days on three substrates [biosolid + crushed coconut fiber (3:1, by volume); biosolid + granitic rock powder (3:1, by volume); and biosolid + crushed coconut fiber + granitic rock powder (2:1:1, by volume)] and at five irrigation levels [36 % (very low); 55 % (low); 85 % (moderate); 100 % (well-irrigated); and 126 % of the reference irrigation level (over-irrigated)]. The biometric traits evaluated increased as the irrigation levels increased, with the exception of root dry mass, which was not influenced by this factor, nor water use efficiency, which decreased as the irrigation levels increased. In general, plants grown with a mixture of the three wastes (biosolid + crushed coconut fiber + granitic rock powder) exhibited higher values for biometric variables and chlorophyll content when they were moderately, well or over-irrigated, in comparison with the other two substrates. It was possible to achieve the plantlet commercial standard using this three waste mixture and the moderate irrigation level.(AU)

Growth of black pepper plantlets under different substrates and irrigation levels

ABSTRACT Optimization of the use of water and the possibility of using residues as substrate in the black pepper production chain can yield economic and environmental benefits. The objective of this study was to evaluate the biometric and physiological traits of black pepper plantlets (Piper nigrum L.), cv. Bragantina, at different irrigation levels and soilless substrates. Plantlets were grown for 120 days on three substrates [biosolid + crushed coconut fiber (3:1, by volume); biosolid + granitic rock powder (3:1, by volume); and biosolid + crushed coconut fiber + granitic rock powder (2:1:1, by volume)] and at five irrigation levels [36 % (very low); 55 % (low); 85 % (moderate); 100 % (well-irrigated); and 126 % of the reference irrigation level (over-irrigated)]. The biometric traits evaluated increased as the irrigation levels increased, with the exception of root dry mass, which was not influenced by this factor, nor water use efficiency, which decreased as the irrigation levels increased. In general, plants grown with a mixture of the three wastes (biosolid + crushed coconut fiber + granitic rock powder) exhibited higher values for biometric variables and chlorophyll content when they were moderately, well or over-irrigated, in comparison with the other two substrates. It was possible to achieve the plantlet commercial standard using this three waste mixture and the moderate irrigation level.

Automation of lettuce seedlings irrigation with sensors deployed in the substrate or at the atmosphere

Seedling production is an important step in the lettuce production system. However, there is a tendency to apply excessive irrigation at this stage. The aim of this study was to test the use of the Simplified Irrigation Controller (SIC) under two conditions: first, with the sensor installed in the substrate (measuring the soil water tension) and second, in the atmosphere (“atmospheric” - responding to vapor demand in the atmosphere) to control the irrigation of lettuce seedlings. The performance of the SIC was evaluated by monitoring plant traits. The lettuce seeds of the Regina cultivar were sown in styrofoam trays with commercial organic substrate. Both experiments were conducted under greenhouse conditions and evaluated under different SIC activation tensions. Shoot fresh weight and dry weight, height, number of leaves, leaf length, leaf area, water use efficiency (WUE) (ratio between the dry mass of plant produced by the volume of water applied), chlorophyll content, stomatal conductance and chlorophyll a fluorescence were assessed. In the experiment with the substrate sensor, the tension of 11.5 kPa caused death in 94 % of the seedlings and was disregarded in the statistical analysis. All biometric and physiological traits evaluated decreased as the SIC tensions increased. Thus, tensions of 4.0 (substrate sensor) and 3.5 kPa (atmospheric sensor) showed greater potential for producing vigorous seedlings, with WUE average values of 1.86 and 1.37 g L−1, respectively. Cultivation of lettuce seedlings proved viable under both conditions when the SIC was used, with the emergence of a number of practical advantages of the atmospheric sensor over the substrate one.

Automation of lettuce seedlings irrigation with sensors deployed in the substrate or at the atmosphere

Seedling production is an important step in the lettuce production system. However, there is a tendency to apply excessive irrigation at this stage. The aim of this study was to test the use of the Simplified Irrigation Controller (SIC) under two conditions: first, with the sensor installed in the substrate (measuring the soil water tension) and second, in the atmosphere (“atmospheric” - responding to vapor demand in the atmosphere) to control the irrigation of lettuce seedlings. The performance of the SIC was evaluated by monitoring plant traits. The lettuce seeds of the Regina cultivar were sown in styrofoam trays with commercial organic substrate. Both experiments were conducted under greenhouse conditions and evaluated under different SIC activation tensions. Shoot fresh weight and dry weight, height, number of leaves, leaf length, leaf area, water use efficiency (WUE) (ratio between the dry mass of plant produced by the volume of water applied), chlorophyll content, stomatal conductance and chlorophyll a fluorescence were assessed. In the experiment with the substrate sensor, the tension of 11.5 kPa caused death in 94 % of the seedlings and was disregarded in the statistical analysis. All biometric and physiological traits evaluated decreased as the SIC tensions increased. Thus, tensions of 4.0 (substrate sensor) and 3.5 kPa (atmospheric sensor) showed greater potential for producing vigorous seedlings, with WUE average values of 1.86 and 1.37 g L−1, respectively. Cultivation of lettuce seedlings proved viable under both conditions when the SIC was used, with the emergence of a number of practical advantages of the atmospheric sensor over the substrate one.(AU)

Automatically controlled deficit irrigation of lettuce in organic potponics

Concerns with water crisis involve all sectors of society and irrigated agriculture remains the main water consumer. This study evaluated an agricultural production system for lettuce cultivation in greenhouse, organic potponics, to economize water and manure use, using a Simplified Irrigation Controller (SIC), based on soil matric potential monitoring. Five irrigation volumes were evaluated in pots with 4.8 L, fertilized with 200 g of vermicompost. One of the volumes was controlled with the SIC. The other volumes represented 130, 80, 60 and 33 % of that controlled by the SIC and all treatments received water at the same time. Shoot fresh weight, head diameter and stomatal conductance (gs) increased linearly with irrigation volumes. For shoot dry weight, number of leaves and water use efficiency (WUE), the regression was quadratic with maximum values at 126, 114 and 83 %, respectively. Leaf relative water content did not show variation among treatments and changes in some fluorescence parameters (Reo/RC, Sm, N and R0) were much more remarkable to drought compared with the FV/ FM ratio, one of the most commonly used stress indicators. The data indicated a tradeoff between WUE and plant growth thus the economic values of water and lettuce should be taken into account to indicate the best SIC irrigation volume. Organic potponics is promising and should be further improved to save on water, labor and fertilizer use.

Automatically controlled deficit irrigation of lettuce in organic potponics

Concerns with water crisis involve all sectors of society and irrigated agriculture remains the main water consumer. This study evaluated an agricultural production system for lettuce cultivation in greenhouse, organic potponics, to economize water and manure use, using a Simplified Irrigation Controller (SIC), based on soil matric potential monitoring. Five irrigation volumes were evaluated in pots with 4.8 L, fertilized with 200 g of vermicompost. One of the volumes was controlled with the SIC. The other volumes represented 130, 80, 60 and 33 % of that controlled by the SIC and all treatments received water at the same time. Shoot fresh weight, head diameter and stomatal conductance (gs) increased linearly with irrigation volumes. For shoot dry weight, number of leaves and water use efficiency (WUE), the regression was quadratic with maximum values at 126, 114 and 83 %, respectively. Leaf relative water content did not show variation among treatments and changes in some fluorescence parameters (Reo/RC, Sm, N and R0) were much more remarkable to drought compared with the FV/ FM ratio, one of the most commonly used stress indicators. The data indicated a tradeoff between WUE and plant growth thus the economic values of water and lettuce should be taken into account to indicate the best SIC irrigation volume. Organic potponics is promising and should be further improved to save on water, labor and fertilizer use.(AU)

Spatial and temporal patterns of soil water content in an agroecological production system

ABSTRACT: Spatial and temporal patterns of soil water content (SWC) can not only improve the understanding of soil water processes but also the water management in the field. The spatial distribution of SWC depends on the spatial variability of soil attributes, vegetation and landscape features. The aim of this study was to evaluate: i) the spatial and temporal variability pattern in an agroecological system; ii) understand the factors affecting the spatial variations of SWC; iii) determine if wet and dry zones conserve their spatial position; iv) evaluate the possibility of using this information to reduce the number of SWC measurements. The experiment was carried out in an area of 2,502 m2, where a regular grid with spacing of 10 m was laid out. At each point, time domain reflectometer sensors were installed at depths of 0.05, 0.15, 0.30 m to monitor the SWC for 18 days in 2014 (Jan, Feb and Mar) and 9 days in 2014/2015 (Dec and Jan). The SWC, at the three soil depths, followed a similar and systematic pattern, being highest in the deepest layers, and exhibited temporal stability. The correlation between SWC and clay content varied both with the depth and the magnitude of SWC. During the wet season it is necessary to intensify the sampling density to estimate the SWC, while during the dry season the Spearman rank correlation remained high indicating the need for a small sampling effort only. The driest zones tend to conserve their spatial position more for a longer period than compared to wettest zones.

Spatial and temporal patterns of soil water content in an agroecological production system

ABSTRACT: Spatial and temporal patterns of soil water content (SWC) can not only improve the understanding of soil water processes but also the water management in the field. The spatial distribution of SWC depends on the spatial variability of soil attributes, vegetation and landscape features. The aim of this study was to evaluate: i) the spatial and temporal variability pattern in an agroecological system; ii) understand the factors affecting the spatial variations of SWC; iii) determine if wet and dry zones conserve their spatial position; iv) evaluate the possibility of using this information to reduce the number of SWC measurements. The experiment was carried out in an area of 2,502 m2, where a regular grid with spacing of 10 m was laid out. At each point, time domain reflectometer sensors were installed at depths of 0.05, 0.15, 0.30 m to monitor the SWC for 18 days in 2014 (Jan, Feb and Mar) and 9 days in 2014/2015 (Dec and Jan). The SWC, at the three soil depths, followed a similar and systematic pattern, being highest in the deepest layers, and exhibited temporal stability. The correlation between SWC and clay content varied both with the depth and the magnitude of SWC. During the wet season it is necessary to intensify the sampling density to estimate the SWC, while during the dry season the Spearman rank correlation remained high indicating the need for a small sampling effort only. The driest zones tend to conserve their spatial position more for a longer period than compared to wettest zones.(AU)

Yield, water use efficiency, and yield response factor in carrot crop under different irrigation depths / Produtividade, eficiência no uso da água e fator de resposta em produção de cenoura sob diferentes lâminas de irrigação

The aim of the present study was to evaluate the effect of different irrigation depths on the yield, water use efficiency (WUE), and yield response factor (Ky) of carrot (cv. 'Brasília') in the edaphoclimatic conditions of Baixada Fluminense, RJ, Brazil. Field trials were conducted in a Red-Yellow Argisol in the 2010-2011period. A randomized block design was used, with 5 treatments (depths) and 4 replicates. Depths were applied by drippers with different flow rates, and the irrigation was managed by time domain reflectometry (TDR) technique. The reference (ETo) and crop (ETc) evapotranspiration depths reached 286.3 and 264.1mm in 2010, and 336.0 and 329.9mm in 2011, respectively. The root yield varied from 30.4 to 68.9t ha-1 as a response to treatments without irrigation and 100% replacement of the soil water depth, respectively. Values for WUE in the carrot crop varied from 15 to 31kg m-3 and the mean Ky value was 0.82. The mean values for Kc were obtained in the initial (0.76), intermediate (1.02), and final (0.96) stages. Carrot crop was influenced by different water depths (treatments) applied, and the highest value for WUE was obtained for 63.4% of soil water replacement.(AU)

O objetivo deste estudo foi avaliar o efeito de diferentes lâminas de irrigação na produtividade, na eficiência de uso da água (EUA) e no coeficiente de resposta de produção (Ky) da cenoura (cv. 'Brasília') ao déficit hídrico do solo, nas condições edafoclimáticas da Baixada Fluminense-RJ. Ensaios de campo foram conduzidos em 2010 e 2011, em um Argissolo Vermelho-Amarelo, usando um delineamento em blocos casualizados, com 5 tratamentos (lâminas) e 4 repetições. As lâminas foram aplicadas por gotejadores com diferentes vazões e o manejo da irrigação foi realizado com a técnica da TDR. As lâminas de evapotranspiração de referência (ETo) e da cultura (ETc) totalizaram 286,3 e 264,1mm, em 2010, e 336,0 e 329,9mm, em 2011, respectivamente. A produtividade de raízes variou de 30,4 a 68,9t ha-1 como resposta aos tratamentos sem irrigação e com 100% de reposição da lâmina de água no solo, respectivamente. Os valores de EUA no cultivo da cenoura variaram de 15 a 31kg m-3 e o Ky médio foi de 0,82. Foram obtidos os valores médios de Kc nas fases inicial (0,76), intermediária (1,02) e final (0,96). A cultura da cenoura foi influenciada pelas diferentes lâminas aplicadas (tratamentos) e a maior EUA foi obtida para o tratamento com reposição de 63,4% da água do solo.(AU)

Onion yield under agroecological farming system using distinct irrigation depths and soil covers / Produtividade de cebola em sistema de cultivo agroecológico sob distintas lâminas de irrigação e coberturas do solo

The present study was carried out in order to evaluate the effects of irrigation depths applied through drip and presence/absence of soil cover in onion yield, under agroecological farming. The experiment was conducted in Seropédica, RJ, Brazil, from May to September 2012. The experimental design was a randomized complete block with split-plot design with 10 treatments and 7 replications, characterized by the presence (+S) and absence (-S) of soil cover and five irrigation depths according to percentages of the crop evapotranspiration (ETc): 0, 22, 45, 75 and 100% (0, 155, 220.6, 320.5 and 372,7mm in +S condition and 0, 145.5, 207.6, 285, 351,4mm in -S condition). The irrigation influenced by second-order polynomial regression the total yield of bulbs, percentage distribution of bulbs in diameter classes and water use efficiency (WUE) in the -S condition, and in the linear regression the WUE in +S condition. The soil cover promoted an increase on the total bulb yield, WUE and the percentage of bulbs classified in classes of greater diameter.(AU)

O presente estudo teve como objetivo avaliar os efeitos de lâminas de irrigação, aplicadas via gotejamento, e do uso de cobertura morta na produção de cebola em cultivo agroecológico. O experimento foi conduzido em Seropédica, RJ, no período de Maio a Setembro de 2012. O delineamento experimental adotado foi em blocos completos casualizados com parcelas subdivididas, com 10 tratamentos e 7 repetições, caracterizados pela presença (CC) e ausência (SC) de cobertura do solo e por cinco lâminas de irrigação, relativas às porcentagens da evapotranspiração da cultura (ETc): 0, 22, 45, 75 e 100% (0; 155; 220,6; 320,5 e 372,7mm na condição SC e 0; 145,5; 207,6; 285 e 351,4mm na condição CC). A irrigação influenciou, por meio da regressão polinomial de segunda ordem, as variáveis produtividade total de bulbos, distribuição do percentual de bulbos em classes de diâmetro e eficiência do uso da água (EUA) na condição SC e, na regressão linear a EUA, na condição CC. A cobertura morta promoveu um incremento na produtividade total de bulbos, na eficiência do uso da água e no percentual de bulbos enquadrados nas classes de maior diâmetro.(AU)

Irrigação no cultivo orgânico de alface utilizando Irrigás, tanque Classe A e um sistema automático de baixo custo / Irrigation with Irrigás, Class A pan and an low cost controller in the organic cultivation of lettuce

O presente estudo teve como objetivo comparar um sistema automático de baixo custo a outras duas técnicas de manejo (sistema Irrigás e tanque classe A) na cultura da alface (Lactuca sativa L.) com relação à operacionalidade dos sistemas, custo dos equipamentos, lâminas aplicadas e dados de produção da cultura. O cultivo foi desenvolvido num delineamento experimental de blocos ao acaso, com quatro tratamentos casualizados em seis blocos. Os tratamentos foram caracterizados pelo sistema Irrigás, tanque Classe A (TCA) e pelo uso de um acionador automático de baixo custo para irrigação (AAI), em duas tensões de água no solo (9,0kPa e 12,0kPa). Foram avaliados dados de lâmina aplicada, eficiência no uso da água e as variáveis de produção, área foliar, massa fresca e seca da parte aérea, diâmetro e altura da cabeça. Não houve diferença significativa entre os tratamentos para nenhuma das variáveis de produção avaliadas(P>0,05) e as lâminas totais referentes aos diferentes métodos de manejo foram próximas à evapotranspiração de referência (ETo) acumulada no período. A eficiência no uso da água nos tratamentos TCA, AAI/9kPa, Irrigás, AAI/12kPa foi, respectivamente, 241,4; 217,9; 205,5 e 267,1kg ha-1 mm-1, enquanto as produtividades foram respectivamente, 32,80; 28,86; 28,80 e 35,45Mg ha-1. Os resultados obtidos são próximos de valores reportados na literatura, permitindo concluir que as metodologias de manejo avaliadas foram eficientes para o cultivo de alface, e que, dessa forma, a escolha do método dependerá da disponibilidade de mão-de-obra e também do nível de treinamento do agricultor.(AU)

The objective of the present research was to compare an low cost controller with two other techniques of irrigation management, Irrigas system and Class A pan, in the cultive of lettuce (Lactuca sativa L.),concerning operability of systems, equipment costs, applied depths and crop yield data. The cultivation was developed in a randomized complete blocks design with four treatments randomized in six replicates. The treatments were characterized by the system Irrigás, Class A pan (TCA) and the use of automatic irrigation of low cost device (AAI) in two different soil water tensions (9.0kPa and 12.0kPa). Data of irrigation depth, water use efficiency and production variables leaf area, fresh and dry weight of shoots, diameter and height of the head were evaluated. There wasn't significant difference between treatments for any of the production variables evaluated (P>0.05) and total irrigation depths were related to different management practices and close to the evapotranspiration estimated reference (ETo) accumulated in the period. The water use efficiency in treatments TCA, AAI/9kPa, Irrigás, AAI/12kPa were, respectively, 241.4, 217.9, 205.5 and 267.1kg ha-1 mm-1, while the productivities were, respectively, 32.80, 28.86, 28.80 and 35.45Mg ha-1. The results obtained are close to values reported in the literature, allowing to conclude that the evaluated methodologies were efficient for growing lettuce and thus the method chosen would depend on the availability of skilled manpower and also of the level of farmer training.(AU)