scholarly journals Effect of soil-water tension on herbaceous cotton yield

1999 ◽  
Vol 34 (10) ◽  
pp. 1905-1911 ◽  
Author(s):  
Francisco Assis de Oliveira ◽  
Tarcísio Gomes da Silva Campos ◽  
Bernardete Campos Oliveira

A field experiment was conducted during two years, 1990/91, in an alluvial soil, in the State of Paraíba, Brazil, to study the effect of the levels of soil-water tension, 50, 100, 200, 300, 400 and 600 kPa, at 20 cm depth, on upland cotton (Gossypium hirsutum L.r. latifolium Hutch, cv. CNPA-6H) yield. The experimental design was a complete randomized block with six treatments and four repetitions. There was an effect of the treatments on plant height, leaf area index and cotton yield, but the precocity index was not modified. Water should be applied when the soil-water tension, measured at 20 cm depth, reaches values around 200 kPa. There was a quadratic (R² = 0.893**) response of cotton yields to soil water tension, with the maximum when water was applied at 52% of soil water depletion.

2018 ◽  
Vol 17 (2) ◽  
pp. 190
Author(s):  
IGNACIO ASPIAZÚ ◽  
FERNANDO GOMES DA SILVA ◽  
RENATO MENDES OLIVEIRA ◽  
KAREN MARCELLE DE JESUS SILVA ◽  
SILVÂNIO RODRIGUES DOS SANTOS ◽  
...  

  RESUMO O objetivo deste trabalho foi determinar em campo a tensão de água do solo adequada para o reinício da irrigação do milho verde no semiárido. O experimento constou de seis valores de tensão matricial da água do solo (20 kPa, 40 kPa, 60 kPa, 80 kPa, 100 kPa e 120 kPa) testadas em uma cultivar de milho, o hibrido duplo AG 1051. O experimento foi instalado no período de inverno de 2013, nos meses de agosto a novembro, num delineamento experimental de blocos casualizados (DBC), com quatro repetições, conduzidos na fazenda experimental da Embrapa Milho e Sorgo em Nova Porteirinha, MG. Foram avaliadas as variáveis: produtividade de espigas sem palha (t ha-1), número de espigas totais e comerciais por hectare, comprimento de espigas com palha e sem palha e diâmetro de espigas comerciais. Dentre os resultados pode-se constatar que os maiores valores para as variáveis de morfologia e de produtividade foram obtidos quando a irrigação foi efetuada com tensão próxima de 50 kPa, tornando-a a tensão mais adequada para o uso racional da água no manejo da irrigação do milho verde.Palavras-chave: Zea mays L., déficit hídrico, manejo da irrigação, resistência elétrica. SOIL WATER TENSION FOR REWATERING GREEN CORN IN THE SEMIARID  ABSTRACT _ The objective of this work was to determine the adequate water tension for rewatering green corn at field conditions in the semiarid. The experiment consisted of six values of matric soil water tension (20 kPa, 40 kPa, 60 kPa, 80 kPa, 100 kPa and 120 kPa) and one maize cultivar, the double hybrid AG1051. The experiment was installed in the 2013 winter season, from August to November, in a randomized blocks design (DBC), with four replicates, and conducted at the experimental farm belonging to Embrapa Maize and Sorghum in Nova Porteirinha, MG. Morphological parameters were evaluated such as plant height, leaf area index and dry mass, and also the yield parameters such as weight of spikes with straw and without straw (t ha-1), number of total and commercial spikes per hectare, diameter of commercial spikes and length of commercial spikes with and without straw. The highest values for the morphology and productivity variables were obtained when irrigation was carried out with a tension close to 50 kPa, which proved to be the most suitable tension for the rational use of water in the irrigation management of green corn.Keywords: Zea mays L., water deficit, irrigation management, electrical resistance.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 498a-498
Author(s):  
Matthew W. Fidelibus ◽  
Chris A. Martin

Sugar and starch concentrations in leaves and roots of Citrus volkameriana Tan and Pasq were measured in response to irrigation frequency and AMF inoculum. Non-mycorrhizal seedlings were treated with a soil inoculum from one of five different communities of AMF; two AMF communities from Arizona citrus orchard soils, and three communities from undisturbed desert soils. Plants were assigned to frequent (soil water tension > –0.01 MPa) or infrequent (soil water tension > –0.06 MPa) irrigation cycles and were container-grown in a glasshouse for 4 months before tissues were analyzed. Fungal inoculum source did not affect shoot or root carbohydrate levels. Plants grown under high irrigation frequency had increased leaf and root starch levels and increased root sugar levels compared with those under low irrigation frequencies. High irrigation frequency also increased shoot mass.


1990 ◽  
Vol 115 (5) ◽  
pp. 712-714 ◽  
Author(s):  
Doyle A. Smittle ◽  
Melvin R. Hall ◽  
James R. Stansell

Sweetpotatoes [Ipomoea batatas (L.) Lam cv. Georgia Jet] were grown on two soil types in drainage lysimeters under controlled soil water regimes during 1982 and 1983. Water regimes consisted of irrigating the sweetpotatoes throughout growth when soil water tension at 23 cm exceeded 25, 50, or 100 kPa or by allowing a 100-kPa water stress before root enlargement, during early root enlargement, or throughout root enlargement. Water use and marketable yields were greater when sweetpotatoes were grown on a Tifton loamy sand (fine loamy, siliceous, thermic, Plinthitic Paleudult) than when grown on a Bonifay sand (loamy, siliceous, thermic, Grossarenic, Plinthitic Paleudult). Water use, marketable yield, and yield of U.S. #1 grade roots generally decreased when soil water tensions exceeded 25 kPa before irrigation, although soil water stress of 100 kPa during storage root development did not significantly affect yield. Regression equations are provided to describe the relationships of water use to plant age and to compute daily evapotranspiration: pan evaporation ratios (crop factors) for sweetpotatoes irrigated at 25, 50, and 100 kPa of soil water tension.


Nativa ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 415
Author(s):  
Morgana Scaramussa Gonçalves ◽  
Wilian Rodrigues Ribeiro ◽  
Edvaldo Fialho Dos Reis ◽  
Antônio Carlos Cóser

A irrigação é usada para conter os efeitos da sazonalidade de produção garantindo maior intensificação dos sistemas de produção a pasto, assim, contribuindo para o aumento da produção e do valor bromatológico das gramíneas. Dessa forma, objetivou-se com esse trabalho avaliar o valor bromatológico de gramíneas tropicais cultivadas em condições de ambiente protegido, submetidas a diferentes tensões de água no solo. Foram realizados três experimentos com as gramíneas Mombaça, Marandu e Tifton 85, onde cada qual, foi conduzida em um esquema de parcelas subdivididas, tendo nas parcelas os níveis do fator tensão de água no solo (20, 40, 50, 60 e 70 kPa) e nas subparcelas níveis 1º, 2º e 3º do fator corte, em um delineamento inteiramente casualizado com cinco repetições. Nas tensões de água no solo de 20 (Mombaça) e 50 kPa (Marandu e Tifton 85) as gramíneas expressaram seu máximo de valor nutritivo. Os maiores teores de PB foram obtidos nas gramíneas Mombaça e Tifton 85. Para as variáveis FDN e FDA o fator tensão de água no solo não foi significativo.Palavras-chave: proteína bruta, fibra, irrigação, forrageiras. BROMATOLOGY OF TROPICAL GRASSES UNDER DIFFERENT SOIL WATER TENSIONS IN PROTECTED ENVIRONMENT ABSTRACT:The irrigation is used to contain the effects of seasonality of production, ensuring a greater intensification of pasture production systems, thus contributing to the increase of production and the bromatological value of grasses. Thus, the objective of this work was to evaluate the nutritive value of tropical grasses grown under protected environment conditions, subject to different soil water stresses. Three experiments, using Mombasa, Marandu and Tifton 85 grasses under a protected environment were carried out and each one was conducted in a subdivided plots scheme, with the levels of soil water tension factor (20, 40, 50, 60 and 70 kPa) and in the subplots levels 1, 2 and 3 of the cut factor, in a completely randomized design with five replicationss. At soil water stresses of 20 (Mombasa) and 50 kPa (Marandu and Tifton 85) the grasses expressed their maximum nutritive value. The highest CP levels were obtained in the Mombasa and Tifton 85 grasses. For the NDF and ADF variables, the soil water stress factor was not significant.Keywords: crude protein, fiber, irrigation, forages.


Author(s):  
A. Wahab ◽  
H. Talleyrand ◽  
M. A. Lugo-López

Grain and stover yields of RS 671 grain sorghum were measured at Barranquitas in an Oxisol and at Corozal in an Ultisol. Measurements were made of weather factors, soil moisture content and tension, plant growth, water deficits and rooting depths. At each site a plot was irrigated as often as necessary to maintain a soil water tension of less than 1 bar. Nonirrigated plots at Corozal were watered whenever necessary to prevent plants from wilting permanently. During a prolonged drought and at grain filling, sorghum extracted water in the Oxisol to a depth of 120 cm. Plants became water stressed after the soil water tension at a depth of 90 cm reached 15 bars. In the Ultisol, sorghum plants were unable to effectively extract available soil moisture at depths below 45 cm. Both plant growth and grain yield were greater in the Oxisol than in the Ultisol. The relative soil compaction of the Ultisol was greater than that of the Oxisol.


Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2761
Author(s):  
Misheck Musokwa ◽  
Paramu L. Mafongoya ◽  
Paxie W. Chirwa

Maize production under smallholder systems in South Africa (RSA) depends on rainfall. Incidences of dry spells throughout the growing season have affected maize yields negatively. The study examined water distribution and water use efficiency (WUE) of maize rotated with two-year pigeonpea fallows as compared to continuous maize without fertilizer. A randomized complete block design, replicated three times, was used with four treatments, which included continuous unfertilized maize, natural fallow-maize, pigeonpea + grass-pigeonpea-maize, and two-year pigeonpea fallow-maize. Soil water mark sensors were installed 0.2; 0.5; and 1.2 m on each plot to monitor soil water tension (kPa). Soil samples were analyzed using pressure plates to determine water retention curves which were used to convert soil water tension to volumetric water content. Maize rotated with two-year pigeonpea fallows had higher dry matter yield (11,661 kg ha−1) and WUE (20.78 kg mm−1) than continuous maize (5314 kg ha−1 and 9.48 kg mm−1). In this era of water scarcity and drought incidences caused by climate change, maize rotated with pigeonpea fallows is recommended among smallholder farmers in RSA because of its higher WUE, hence food security will be guaranteed.


2019 ◽  
Vol 22 (1) ◽  
pp. 73-81
Author(s):  
S Parveen ◽  
E Humphreys ◽  
M Ahmed

Decreasing availability and increasing costs of water and labour are driving researchers and farmers to find management strategies that increase input water productivity and reduce labour requirement in rice production. Wet seeding instead of transplanting greatly reduces the labour requirement for crop establishment, whereas use of alternate wetting and drying (AWD) instead of continuous flooding reduces irrigation input. However, the safe threshold for irrigating wet seeded rice (WSR), and how this varies with growth stage, has not been established. Therefore, a greenhouse experiment was conducted to determine the effects of different degrees of irrigation threshold during different crop growth stages on crop performance of WSR. This was done in greenhouse experiment in the 2011 wet season at the International Rice Research Institute, Los Baños, Philippines. In the experiments, water stresses were applied by withholding irrigation until soil water tension increased to 10, 20 or 40 kPa at 10 cm below the soil surface. Soil water tension was measured using 30 cm long gauge tensiometer installed with the center of the ceramic cup. The stresses were applied during three crop stages: 3-leaf (3L) to panicle initiation (PI), PI to flowering (FL), and FL to physiological maturity (PM). The experiment was also included a continuously flooded (CF) treatment. Stress during 3L to PI increased the time to PI (by 2 to 4 days) but reduced the duration of grain filling by 3 to 5 days, the larger values with 20 and 40 kPa thresholds. There was no effect of stress thresholds of 10 to 40 kPa during PI-FL on crop duration. Stress during grain filling reduced the duration of grain filling by 6 days for all thresholds. Stresses of 20 and 40 kPa during 3L to PI reduced green leaf and tiller density at PI, but this effect disappeared with the imposition of CF after PI. There were consistent trends for lower final biomass as the level of water deficit stress increased, and imposition of stresses of 20 and 40 kPa at any or all three stages significantly reduced biomass compared with CF. These results suggest that, for shortening the ripening period, water stress may be imposed as 10 to 20 kPa during FL to PM. Bangladesh Rice j. 2018, 22(1): 73-81


1979 ◽  
Vol 59 (3) ◽  
pp. 301-311 ◽  
Author(s):  
C. L. PAUL ◽  
J. DE VRIES

Cone penetration resistance (an index of soil strength) was found to be linearly dependent upon soil water tension within a limited range of tensions close to saturation. This relationship was established with data collected from three soil types in farmers’ fields located in the Lower Fraser Valley of British Columbia during late winter and spring over a 2-yr period. For the mineral soils the slope of the relationship was predicted quite well by a theoretically-based equation. The slope could not be predicted for an organic soil. Solution of the equation required a number of simplifying assumptions and direct measurement of the angle of shearing resistance, [Formula: see text]. This equation was integrated and the constant of integration, the value of which depended upon the particular depth intervals at which measurements of cone penetration were made, was replaced by the intercept from the empirical strength-tension relationship. In this way, a semi-empirical model was developed for the prediction of soil strength from soil water tension, or vice versa, for the mineral soils. Prediction for the organic soil could be carried out with the empirical relationship.


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