Seasonal Yield Response Factor for Red Bombay Onion (Allium cepa L.) Variety in Arba Minch, Ethiopia

Background: For better water resources management in the areas of water shortage for crop production, deficit irrigation is very important. The understanding of the yield response factor to water deficit is crucial for efficient irrigation water management. Deficit irrigation for studying yield response factors is always practiced in the way of stressing the demand of the crops. The present study was done for the determination of the seasonal yield response factor of red Bombay onion variety under Arba Minch agro climate condition. Furthermore, it also examined the effect of furrow irrigation systems on the seasonal yield response factor. Methods: The experiment was conducted from August to November 2019. The experiment had six treatments, which were the combination of two furrow irrigation systems and three irrigation levels. Data were collected for soil moisture before and after each irrigation and bulb yield. The seasonal yield response factors were determined through simple linear regressions using SPSS software. Result: When considering the furrow irrigation system as a factor, the seasonal yield response factor for alternate furrow irrigation system was 1.18 while for paired row furrow irrigation system was 1.07. This red Bombay variety of onion clearly shows more sensitive to water stress for alternative furrow irrigation systems than paired row furrow irrigation systems. Therefore, in the area of water shortage paired row furrow irrigation system is better than alternate furrow irrigation system. The seasonal yield response factor as a wall for red Bombay onion variety in Arba Minch agro-ecological condition was 1.12. Therefore, the red Bombay onion variety in Arba Minch agroclimate condition was sensitive to water stress.

The Effects of Different Irrigation Scheduling Approaches on Seed Yield and Water Use Efficiencies of Cotton

This study was conducted in the Aegean region conditions of Turkey in 2020. It was carried out on May-505, a local cotton variety. The study examined the variation of seed yield, water use efficiency (WUE), and irrigation water use efficiency (IWUE) of cotton with different irrigation programs and water levels. The field trial, which was designed as two factors and three replications, was designed according to the randomized complete block trial design. Four different irrigation levels (IL) (100%, 67%, 33%, and 0%) and two different irrigation scheduling approaches (gravimetric and pan evaporation) were investigated in the study. Seasonal water use values in treatments varied between 215 (0%) and 746 (100% - Pan evaporation approach) mm during the production period. The average yield values obtained with irrigation levels, which have essential effects on cotton seed yield, are listed as follows; 2057 kg ha-1 (IL-0%), 3471 kg ha-1 (IL-33%), 3771 kg ha-1 (IL-67%), and 5083 kg ha-1 (IL-100%). It was determined pan evaporation applications performed higher yields than gravimetric applications. WUE values were between 0.63 – 1.04 kg m-3. The gravimetric method’s yield response factor (ky) was 0.73, and the pan evaporation method’s yield response factor (ky) was 0.89. These results show that cotton is tolerant of water stress. In conclusion, although the pan evaporation approach with 100% treatment is suggested for cotton production in the parts of the Aegean region within the semi-arid climate zone, while water resources are sufficient. When the results are evaluated in terms of seed cotton yield for a deficit irrigation strategy, IL-67% treatment with a gravimetric approach can be used.

Actual evapotranspiration and response factors of the cowpea in Amazonian edaphoclimatic conditions

ABSTRACT Due to the sensitivity of the cowpea to water deficit during the dry season in the Amazonian environment, there is a need for studies related to water management and the optimization of annual yield. Thus, the objective was to estimate the crop evapotranspiration (ETc) and the actual evapotranspiration (ETr), whilst also evaluating the effect of different irrigation depths on the yield response factor (Ky) and dry biomass (Kss) of the cowpea cultivar BR3-Tracuateua under edaphoclimatic conditions in the Amazon region. The experiment was carried out in randomized blocks, with six replicates and four treatments: T1 (100% ETc), T2 (50% ETc), T3 (25% ETc), and T4 (0% ETc), commencing in the reproductive phase with a drip irrigation system. The total evapotranspiration recorded for the cowpea cultivar BR3-Tracuateua across the four treatments was 337.5, 284.35, 258.62, and 219.82 mm with an average consumption of 4.6, 3.90, 3.54, and 3.01 mm d-1 for T1, T2, T3, and T4, respectively. The emergence phase showed evaporation rate of 5.19 mm d-1 and the reproductive, vegetative, and senescence ETc phases showed evaporation of 4.87, 4.84, and 3.32 mm d-1, respectively. The flowering stage had the greatest water demand (5.88 mm d-1). There was a significant difference in the crop yield among all treatments, with decreases of 18.91, 33.12 and 57.17% for T2, T3 and T4 in the grain yield, with a Ky of 1.48, and Kss of 2.03, 1.08, and 0.87 for the flowering, grain filling, and physiological maturation stages, respectively.

FUNÇÃO DE PRODUÇÃO DO GIRASSOL SUBMETIDO A DIFERENTES LÂMINAS DE IRRIGAÇÃO

FUNÇÃO DE PRODUÇÃO DO GIRASSOL SUBMETIDO A DIFERENTES LÂMINAS DE IRRIGAÇÃO LAUREANA APARECIDA COIMBRA PELEGRINI1; MÁRIO SÉRGIO PAIVA DE ARAÚJO2; CLAUDINEI MARTINS GUIMARÃES3; ELIAS FERNANDES DE SOUSA4 E DANIEL FONSECA DE CARVALHO5. 1 Laboratório de Engenharia Agrícola, Centro de Ciências e Tecnologias Agropecuárias, Universidade Estadual do Norte Fluminense Darcy Ribeiro-UENF, Av. Alberto Lamego, 2000 - Parque Califórnia, CEP: 28013-602, Campos dos Goytacazes, RJ, Brasil. E-mail: [email protected]. 2 Laboratório de Engenharia Agrícola, Centro de Ciências e Tecnologias Agropecuárias, Universidade Estadual do Norte Fluminense Darcy Ribeiro-UENF, Av. Alberto Lamego, 2000 - Parque Califórnia, CEP: 28013-602, Campos dos Goytacazes, RJ, Brasil. E-mail: [email protected]. 3 Laboratório de Engenharia Agrícola, Centro de Ciências e Tecnologias Agropecuárias, Universidade Estadual do Norte Fluminense Darcy Ribeiro-UENF, Av. Alberto Lamego, 2000 - Parque Califórnia, CEP: 28013-602, Campos dos Goytacazes, RJ, Brasil. E-mail: [email protected]. 4 Laboratório de Engenharia Agrícola, Centro de Ciências e Tecnologias Agropecuárias, Universidade Estadual do Norte Fluminense Darcy Ribeiro-UENF, Av. Alberto Lamego, 2000 - Parque Califórnia, CEP: 28013-602, Campos dos Goytacazes, RJ, Brasil. E-mail: [email protected]. 5 Instituto de Tecnologia, Departamento de Engenharia, Universidade Federal Rural do Rio de Janeiro, Rodovia BR-465, km 7, CEP: 23897000, Seropédica, RJ, Brasil. E-mail: [email protected]. 1 RESUMO Objetivou-se com esse estudo avaliar os efeitos de diferentes lâminas de irrigação no cultivo de duas variedades de girassol na região Norte Fluminense, RJ, possibilitando a estimativa do fator de resposta ao rendimento da cultura Ky. Irrigou-se com método de “Single Point”, com um aspersor do tipo canhão instalado no centro da área plantada, dividindo a área molhada em quatro quadrantes (blocos) e sete anéis (tratamentos) concêntricos ao aspersor, sendo um dos anéis (anel 3) utilizado como referência para o manejo das irrigações. Foram avaliadas produtividade, altura de planta, área foliar, matéria seca e queda dos rendimentos relativos. A análise estatística foi realizada por regressão linear e quadrática. Os híbridos Helio 358 e Helio 251 apresentaram uma relação positiva com a lâmina de irrigação, sendo recomendado o cultivo com as lâminas de 200 e 316 mm, respectivamente. A irrigação do girassol no período de outono-inverno da região Norte Fluminense, RJ, é fundamental para a obtenção de melhores produtividades, tendo em vista a sensibilidade ao déficit hídrico apresentada pela cultura (Ky = 1,2) e pelo reduzido volume de chuvas normalmente esperado nessa época do ano. Palavras–chave: Helianthus annus L., “single point”, produtividade, coeficiente de resposta, déficit hídrico. PELEGRINI, L. A. C., ARAÚJO, M. S. P. de, GUIMARÃES, C. M., SOUSA, E. F. de, CARVALHO, D. F. de FUNCTION OF SUNFLOWER PRODUCTION UNDER DIFFERENT IRRIGATION DEPTHS 2 ABSTRACT The aim of this study was to evaluate the effects of different irrigation depths on the cultivation of two varieties of sunflower in Rio de Janeiro state’s North region, making it possible to estimate the crop yield response factor (Ky). “Single Point” irrigation method was used, with a cannon sprinkler installed in the center of the planted area, dividing the wet area into four quadrants (blocks) and seven rings (treatmets) concentric to the sprinkler, with one of the rings (ring 3) used as a reference for irrigation management. Yield, plant height, leaf area, dry matter and drop in relative yields were evaluated. Statistical analysis was performed using linear and quadratic regression. The hybrids Helio 358 and Helio 251 showed a positive relationship with the irrigation depth, and the 200 and 316 mm depths are recommended for cultivation, respectively. Irrigation of sunflowers in the autumn-winter period of Rio de Janeiro state’s North region, is essential for obtaining better yields, in view of the sensitivity to the water deficit presented by the crop (Ky = 1.2) and the low volume of rainfall normally expected at this time of year. Keywords: Helianthus annus L., “single point”, productivity, response coefficient, water deficit.

The Dynamic Yield Response Factor of Alfalfa Improves the Accuracy of Dual Crop Coefficient Approach under Water and Salt Stress

The accurate quantification of crop water use or evapotranspiration (ET) under water and salt stress is needed for efficient water management and precision irrigation in water scarce regions. However, few studies were examined on alfalfa water use and its components under water and salt stress. We carried out two field experiments to quantify alfalfa water use through setting up different water and salt gradients, including two irrigation levels (full and deficit irrigation) and four soil salinity levels (0, 2‰, 4‰ and 6‰ salt of mass ratio) in an arid region of Northwest China. Electrical conductivity of soil saturation extract (ECe), soil water content (SWC), leaf area index (LAI) and soil evaporation (E) were measured. The SIMDualKc model, which uses the FAO56 dual Kc approach, was calibrated and validated using measured SWC and E. Model results show a good agreement between observed and simulated SWC and E without stress. The depletion fraction for no stress (p) and the percent yield reduction per unit increase in soil salinity (b) were 0.50 and 6.0%/(dS m−1), respectively, slightly lower than those of FAO-56 (0.55 and 7.3%/(dS m−1)). The difference indicates that alfalfa has a lower capacity of water use but a greater tolerance to salt stress after soil salinity reached its sensitivity threshold in the arid region. The model performed a reduced accuracy under water and salt stress and the differences tended to increase as stress increased, which was partly attributed to constant yield response factor (Ky) under different soil water and salt stress. The key parameter Ky dynamically increased with the increased degree of stress. Compared to constant Ky, the simulations of SWC and E showed improved accuracy with dynamic Ky. These results suggested that the response and acclimation of alfalfa to stress might be incorporated into the dual Kc model through the diversity of Ky.

Estimation of Yield Response Factor for Each Growth Stage under Local Conditions Using AquaCrop-OS

We propose a methodology to estimate the yield response factor (i.e., the slope of the water-yield function) under local conditions for a given crop, weather, sowing date, and management at each growth stage using AquaCrop-OS. The methodology was applied to three crops (maize, sugar beet, and wheat) and four soil types (clay loam, loam, silty clay loam, and silty loam), considering three levels of bulk density: low, medium, and high. Yields are estimated for different weather and management scenarios using a problem-specific algorithm for optimal irrigation scheduling with limited water supply (GET-OPTIS). Our results show a good agreement between benchmarking (mathematical approach) and benchmark (estimated by AquaCrop-OS) using the Normalised Root Mean Square Error (NRMSE), allowing us to estimate reliable yield response factors ( K y ) under local conditions and to dispose of the typical simple mathematical approach, which estimates the yield reduction as a result of water scarcity at each growth stage.

FATOR DE RESPOSTA PRODUTIVA DE MOMBAÇA E MARANDU AO DÉFICIT HÍDRICO

O objetivo com este estudo foi compreender o efeito da disponibilidade hídrica sobre a produtividade no capim-mombaça [Megathyrsus maximus (Jacq.) B. K. Simon & S. W. L. Jacobs] e capim-marandu [Brachiaria brizantha (Hochst. ex A. Rich.) R. D. Webster], determinando o coeficiente de resposta ao déficit hídrico (ky). O experimento foi avaliado em delineamento de blocos ao acaso, com duas forragens e três repetições. O período experimental correspondeu a doze ciclos de crescimento com intervalos fixos de colheita (28 dias para a estação chuvosa e 42 dias para a estação seca). Os ky foram determinados com base nos dados de produção real e potencial das forrageiras, bem como nos dados de evapotranspiração real e máxima. Para ambas as forragens, o acúmulo de forragem (AF) foi maior no outono e menor no inverno (5310 e 626 kg de matéria seca ha-1, respectivamente). Na média das quatro estações, o AF para capim-marandu foi 21,3% maior que o capim-mombaça (3344 vs. 2756 kg matéria seca ha-1, respectivamente). Para o capim-mombaça, o ky foi de 1,05, indicando sensibilidade média a alta ao déficit hídrico. No entanto, o ky foi de 0,63 para o capim-marandu, o que representa baixa sensibilidade ao déficit de água do solo.Palavras-chave: Brachiaria; coeficiente de sensibilidade; Megathyrsus; tolerância a seca. YIELD RESPONSE FACTOR OF MOMBAÇA GUINEA GRASS AND MARANDU PALISADE GRASS TO WATER DEFICIT ABSTRACT: The objective with this research was to understand the effect of water availability on Mombaça guinea grass [Megathyrsus maximus (Jacq.) B. K. Simon & S. W. L. Jacobs] and Marandu palisade grass [Brachiaria brizantha (Hochst. ex A. Rich.) R. D. Webster] productivity, determining the yield response factor to water deficit (ky). The experiment was evaluated in a randomized block design with two forages and three replicates. The experimental period corresponded to twelve growth cycles with fixed harvest intervals (28 days for the rainy season and 42 days for the dry season). The ky were determinate based on the data of real and potential yield of grasses, as well as the data of real and maximum evapotranspiration. To both grasses, herbage accumulation (HA) was greatest in the autumn and leats in the winter (5310 and 626 kg dry matter ha-1, respectively). On average of the four seasons, the HA for Marandu palisade grass was 21.3% higher than Mombaça guinea grass (3344 vs 2756 kg dry matter ha-1, respectively). For Mombaça guinea grass, ky was 1.05, indicating medium to high sensitivity to water deficit. However, the ky was 0.63 for Marandu palisade grass, which represents low sensitivity to soil water deficit.Keywords: Brachiaria; drought tolerance; Megathyrsus; sensitivity coefficient.

Yield Response Factor to Water (Ky) of FMX 993, FMT 701 and FMX 910 Cotton Varieties in Campo Verde, MT

Production of herbaceous cotton in rainfed is subject to water-deficit risks due to climatic variations, such as precipitation with non-homogeneous spatial-temporal distribution. In this sense, the objective of this study was to evaluate the yield response factor to water of FMX 993, FMT 701 and FMX 910 cotton varieties, in Campo Verde County, Mato Grosso State, Brazil. Real yield data of the 2009/10 and 2010/11 seasons of the three varieties were obtained. Meteorological data were used to estimate the maximum yield and to calculate the daily water balance for each variety and seasons. From these values the yield response factor to water (Ky) was obtained. Ky values ranged from 0 to 0.9, with the lowest and highest values for FMX 910 for the 2009/10 and 2010/11 seasons, respectively. These values obtained from Ky indicate that all varieties studied present increasing tolerance to water-deficit. The FMX 993 variety had a lower variation in Ky values between 0.3 and 0.5 for the 2009/10 and 2010/11 seasons, in that order. Therefore, among the cotton varieties evaluated in this study, recommend FMX 993 for the conditions of Campo Verde County, Mato Grosso State, due to its greater tolerance to the water-deficit.

Effect of Water Stress on the Development of Soybean Crop

The present work had the objective of evaluating the effects of the spatial variability of the main meteorological elements on soybean yield, variety M7739 IPRO from Monsoy, with an early cycle of 105 days, with sowing at the beginning of October and harvesting at the beginning of the month in February, in two agricultural years (2013/14 and 2014/15) at Santa Luzia farm, located in the municipality of Campo Verde - MT (15º42'28 ''S, 55º19'59'' W, 736 m). The meteorological data of the region were obtained through the 9th district of meteorology (9th DISME) of the National Institute of Meteorology - INMET. The coefficient of culture (kc) was defined following the development stages of the culture. The estimates of evapotranspiration (potential and crop) were determined by the water balance method and the sensitivity coefficients (ky) of the soybean crop were estimated by the expression Ky=(1-Yr/Ym)/(1-ETr/ETm), in which ky = yield response factor; Yr = actual yield of the crop; Ym = maximum yield of the crop; ETr = actual evapotranspiration e ETm = maximum evapotranspiration. The values of Ky were all lower than 1, both for the crop cycle in the 2013/14 crop year and for the crop cycle 2014/15, indicating that the soybean crop is adaptable to water deficit.