scholarly journals EFFECT OF CONTINUOUS VS PERIODIC pH ADJUSTMENT ON GROWTH OF `GEORGIA JET' AND `T1-155' SWEET POTATO CULTIVARS GROWN USING THE NUTRIENT FILM TECHNIQUE (NFT)

HortScience ◽  
1990 ◽  
Vol 25 (8) ◽  
pp. 864c-864 ◽  
Author(s):  
Edwin Martinez ◽  
Conrad Bonsi ◽  
Phili p Loretan ◽  
Walter Hill ◽  
Desmond Mortley ◽  
...  

Sweet potato, selected as a potential food source for future long-term manned space missions, is being evaluated for NASA's Controlled Ecological Life Support Systems (CELSS) program. Greenhouse experiments were conducted to determine the effects of two pH treatments on the growth and storage root yield of `T1-155' and `Georgia Jet ' sweet potato cultivars. Vine cuttings of these cultivars were grown in a specially designed Tuskegee University NFT system. Plants were subjected to a continuous pH treatment in which the nutrient solution pH was maintained at 5.00 ± 0.10 throughout the growth period, and a periodic pH treatment in which the nutrient solution pH was adjusted to 6.00 at biweekly changeover intervals and when reservoirs were refilled with deionized water between biweekly changeovers. Results showed that for both cultivars the treatment with periodic pH adjustment had significantly higher storage root yield than treatment with continuous pH adjustment. This experiment is being repeated.

HortScience ◽  
1995 ◽  
Vol 30 (3) ◽  
pp. 429c-429
Author(s):  
Jennifer L. Seminara ◽  
Desmond G. Mortley ◽  
Philip A. Loretan ◽  
Beverly Smith

Two trials were conducted to determine the effect of duration of storing vine cuttings on yield of sweetpotatoes grown under greenhouse conditions in nutrient film technique. TI-155 sweetpotato [Ipomoea batatas (L). Lam.] vine cuttings with leaves removed were stored at room temperature in an open basket for 0, 3, 5, and 7 days before planting in a complete randomized design with two replications. A modified half Hoagland's nutrient solution was used. Nutrient solution pH was maintained between 5.5 and 6.0 and changed every 2 weeks. Salinity, electrical conductivity, and solution temperature were monitored at regular intervals. Results show a trend toward increased percent dry matter as storage duration increased. Storing vine cuttings for 5 days produced the highest yield of storage root fresh and dry weights. Foliage fresh and dry weights were not influenced by preplanting treatments.


2021 ◽  
Vol 22 (9) ◽  
pp. 4826
Author(s):  
Yang Gao ◽  
Zhonghou Tang ◽  
Houqiang Xia ◽  
Minfei Sheng ◽  
Ming Liu ◽  
...  

A field experiment was established to study sweet potato growth, starch dynamic accumulation, key enzymes and gene transcription in the sucrose-to-starch conversion and their relationships under six K2O rates using Ningzishu 1 (sensitive to low-K) and Xushu 32 (tolerant to low-K). The results indicated that K application significantly improved the biomass accumulation of plant and storage root, although treatments at high levels of K, i.e., 300–375 kg K2O ha−1, significantly decreased plant biomass and storage root yield. Compared with the no-K treatment, K application enhanced the biomass accumulation of plant and storage root by 3–47% and 13–45%, respectively, through promoting the biomass accumulation rate. Additionally, K application also enhanced the photosynthetic capacity of sweet potato. In this study, low stomatal conductance and net photosynthetic rate (Pn) accompanied with decreased intercellular CO2 concentration were observed in the no-K treatment at 35 DAT, indicating that Pn was reduced mainly due to stomatal limitation; at 55 DAT, reduced Pn in the no-K treatment was caused by non-stomatal factors. Compared with the no-K treatment, the content of sucrose, amylose and amylopectin decreased by 9–34%, 9–23% and 6–19%, respectively, but starch accumulation increased by 11–21% under K supply. The activities of sucrose synthetase (SuSy), adenosine-diphosphate-glucose pyrophosphorylase (AGPase), starch synthase (SSS) and the transcription of Susy, AGP, SSS34 and SSS67 were enhanced by K application and had positive relationships with starch accumulation. Therefore, K application promoted starch accumulation and storage root yield through regulating the activities and genes transcription of SuSy, AGPase and SSS in the sucrose-to-starch conversion.


2018 ◽  
Vol 3 (1) ◽  
pp. 644-651
Author(s):  
A.O. Adekiya ◽  
C.M. Aboyeji ◽  
T.M. Agbede ◽  
O. Dunsin ◽  
O.T.V. Adebiyi

Abstract Micro-nutrients especially zinc can not only increase the yield of sweet potato but can also improve the quality of tubers. Hence, experiments were carried out in 2015 and 2016 cropping seasons to determine the impact of various levels of ZnSO4 fertilizer on soil chemical properties, foliage and storage root yields and proximate qualities of sweet potato (Ipomoea batatas L.). The experiments consisted of 5 levels (0, 5, 10, 15 and 20 kg ha-1) of ZnSO4 fertilizer. These were arranged in a randomized complete block design and replicated three times. ZnSO4 increased (with the exception of P) soil chemical properties compared with the control. N, K, Ca, Mg and Zn were increased up to the 20 kg ha-1 ZnSO4 level in both years. ZnSO4 reduced P concentrations in soil as the level increased. For sweet potato performance, 5 kg ha-1 ZnSO4 fertilizer had the highest values of foliage yield (vine length and vine weight) and storage root yield. Using the mean of the two years and compared with the control, ZnSO4 fertilizer at 5 kg ha-1 increased storage root yield of sweet potato by 17.4%. On fitting the mean storage root yield data of the two years with a cubic equation, the optimum rate of Zn for sweet potato was found to be 3.9 kg ha-1 to achieve the maximum sweet potato yield. In this study, relative to the control, ZnSO4 fertilizer increased moisture and decreased the fibre contents of sweet potato. There were no consistent patterns of variation between the 5, 10, 15 and 20 kg ha-1 ZnSO4 treatments for proximate qualities except that the highest values of fat, protein, carbohydrate and ash was at 5 kg ha-1 ZnSO4.


2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Josabeth Navarro ◽  
Jahdiel Salazar ◽  
James Jihoon Kang ◽  
Jason Parsons ◽  
Chu-Lin Cheng ◽  
...  

South Texas is located in a subtropical semiarid climate, and due to high temperature and irregular precipitation, farmers opt to leave their fields fallow during the summer months jeopardizing overall soil health. We evaluated whether sweet potato (Ipomoea batatas) cultivation coupled with drip irrigation could restore soil biological activities compared with bare fallow. Additionally, because sweet potatoes have high demand of soil nutrients, especially potassium (K), we evaluated the nutrient supply of locally sourced soil amendments. Sweet potato was cultivated during summer 2018 in McAllen, Texas, under control (no fertilizer), NPK (synthetic fertilizer), RC (yard-waste compost), and AC (compost produced under an enhanced composting process), and biochar (gasified walnut shell at 900°C), each with three replicates. Soil amendments were applied at different amounts to result in a rate of 80 kg K ha−1. Soil biological indicators were microbial biomass phosphorous, phosphatase activity, and the rate of fluorescein diacetate hydrolysis (FDA). Available nitrogen, phosphorus, potassium, and sodium were also quantified. Aboveground biomass and storage root yield estimated sweet potato’s agronomic performance. Cultivation and irrigation stimulated soil enzyme activities and microbial biomass-phosphorous. Sweet potato yields were the highest in NPK treatment but still 2.8 times lower than variety’s potential yield. Storage root yield was inversely related to aboveground biomass, suggesting that growing conditions benefited the production of shoot versus roots. Both biochar and AC treatments stimulated FDA rates and K availability. Soil pH and sodium concentration increased in all treatments over the growing season, possibly due to river-sourced irrigation water. Together, these findings show that crop cultivation promoted soil biological activities and the maintenance of nutrient cycling, compared to bare-fallow conditions. For a better agronomic performance of sweet potato, it would be necessary to identify management practices that minimize increase in soil pH and salinity.


HortScience ◽  
1994 ◽  
Vol 29 (7) ◽  
pp. 731d-731
Author(s):  
A.A. Trotman ◽  
P.P. David ◽  
D.G. Mortley ◽  
G.W. Carver

In a greenhouse study, continuous use of the same plant nutrient solution for hydroponic culture of sweetpotato was investigated to determine the effect on storage root yield, plant growth and nutrient solution composition. Plants were grown for 120 days under continuous flow from a 30.4-liter reservoir. Plant growth was compared when nutrient solution was changed at 14-day intervals and when nutrient solution was not changed but nutrients replenished through addition of a Modified half-Hoagland's (N:K=1:2.4) plant nutrient solution when volume in reservoir was -10 liters. Storage root yield was significantly decreased (181 vs 310.3 g/plant) and foliar biomass was significantly increased (372.4 vs 2% g/plant) when nutrient solution was not changed Nitrate and phosphate concentrations decreased in the plant nutrient over the duration of the experiment while sulfate and chloride concentrations increased. Salinity and electrical conductivity were monitored at 2-day intervals and increased with duration of the crop. Increased foliage production may have been the result of nitrogen replenishment going largely for foliage rather than storage root production. It may be that continuous use of the same plant nutrient solution as practiced in this study, resulted in lowered phosphate and nitrate concentrations that limited uptake of these ions by sweetpotato plants, thus reducing yield


HortScience ◽  
1990 ◽  
Vol 25 (8) ◽  
pp. 857g-857
Author(s):  
Desmond Mortley ◽  
Conrad Bonsi ◽  
Philip Loretan ◽  
Walter Hill ◽  
Carlton Morris

Greenhouse experiments were conducted to evaluate the effects of spacing within and between growth channels on the yield of `TI-1551 sweet potatoes grown hydroponically using the nutrient film technique (NFT). Spacings within channels were 12.7, 17.8 and 25.4 cm whereas between growth channels the spacings were 12.7, 25.4 and 38.1 cm. Vine cuttings (15 cm) placed in each channel (0.15×0.15×1.2 m) were supplied with a modified half-Hoagland solution and grown for 120 days. Storage root number, fresh and dry weights and foliage fresh and dry weights tended to increase as spacing between channels increased. Spacing of plants within channels had no significant effect on any sweet potato growth responses.


HortScience ◽  
1990 ◽  
Vol 25 (8) ◽  
pp. 858g-858
Author(s):  
Desmond Mortley ◽  
Conrad Bonsi ◽  
Philip Loretan ◽  
Walter Hill ◽  
Edwin Martinez

Hydroponic experiments using the nutrient film technique (NFT) were conducted in environmental growth chambers to evaluate the response of two sweet potato cultivars, `Georgia Jet' and `TI-155', to two photoperiod and temperature regimes. Vine cuttings of these cultivars were planted in growth channels supplied with modified half-Hoagland nutrient solution using NFT. Plants were subjected to a 24 h photoperiod or a 12:12 h light:dark photoperiod, a constant temperature of 28C or light:dark temperature of 28/22C. Plants were exposed to irradiance levels of 400 umol m-2 s-1 at canopy level and 70% RH. Storage root fresh and dry weights were increased for both cultivars under the 24 h photoperiod at the 28C constant temperature. `Georgia Jet' storage root numbers were not affected by any treatment while those for `TI-155' were reduced under continuous light for both temperature regimes. Foliage fresh and dry weights were not affected by any treatment.


HortScience ◽  
2009 ◽  
Vol 44 (5) ◽  
pp. 1491-1493 ◽  
Author(s):  
Desmond G. Mortley ◽  
Stephanie Burrell ◽  
Conrad K. Bonsi ◽  
Walter A. Hill ◽  
Carlton E. Morris

Growth chamber experiments were conducted to evaluate the effect of irradiance and daily light period on storage root yield and leaf elemental concentration of two sweetpotato cultivars grown hydroponically by use of the nutrient film technique (NFT). Stem cuttings (15 cm) of cv. Whatley/Loretan and Georgia Jet were grown in NFT channels (0.15 × 0.15 × 1.2 m) in reach-in growth chambers under light period/irradiance combinations of 18 h: 300 μmol·m−2·s−1 or 9 h: 600 μmol·m−2·s−1 photosynthetic photon flux. Temperature was 28/22 °C light/dark with a relative humidity of 70% ± 5%. Storage root and foliage yields were greater in both cultivars exposed to a longer daily light period and lower irradiance. The main effect of cultivar indicated that storage root yield was significantly greater among plants of ‘Whatley/Loretan’ compared with that of ‘Georgia Jet’, whereas foliage yield was similar between cultivars. Leaves of plants grown under longer daily light period and lower irradiance had significantly lower concentrations of all elements, nitrogen, phosphorus, potassium, calcium, magnesium, manganese, iron, calcium, boron, and zinc, except for calcium, manganese, and boron. There were no significant differences in leaf elemental concentration between cultivars. Thus, a longer daily light and lower irradiance enhanced biomass production of sweetpotato but reduced leaf elemental concentration probably because of a “dilution” effect.


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