Citrus Carbohydrate Levels were Related to Irrigation Frequency but Not Arbuscular Mycorrhizal Fungal (AMF) Inoculum

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.

2020 ◽  
Vol 8 (2) ◽  
pp. 574
Author(s):  
Helane Cristina Aguiar Santos ◽  
Joaquim Alves De Lima Junior ◽  
William Lee Carrera De Aviz ◽  
Deiviane De Souza Barral ◽  
Renan De Souza ◽  
...  

Considering the lack of technical information on the water depth and nitrogen fertilization via fertigation in bell pepper cultivation, this work aimed to provide management data for its production in the northern region of Brazil. The experiment was carried out in a greenhouse at FEIGA / UFRA, with a 1.0 x 0.50 m spacing, in a randomized block design, with a 5 x 4 factorial scheme, with three replications. The treatments consisted of five water tensions in the soil (15, 25, 35, 45 and 65 kPa) and four nitrogen doses (0, 135, 265 and 395 kg.ha-1). There was no interaction between the factors of water tension in the soil and nitrogen doses for any of the variables analyzed. Height of plants, fresh shoot mass and dry shoot mass showed significant differences only for nitrogen doses. Predawn potential, showed significant difference for soil water tensions and nitrogen doses. Ahead of the conditions under which this work was carried out and the results obtained for the variables analyzed for the bell pepper cultivation in a protected environment, we found that the soil water tension of 15 kPa and the nitrogen dose of 265 kg.ha-1 were ideal for the crop.


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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