Vegetable Amaranth Research Articles

Producing Horticultural Crops Using Hydroponic Tobacco Transplant Systems

Intensive, deep-batch, hydroponic systems that use float beds (FBs) are used extensively by the tobacco industry to produce transplants. FBs and a modified FB system with separate drying and flooding stages called ebb-and-flood (EF) beds were used to grow 12 diverse horticultural crops to maturity. Beds were filled with 570 L of water with 114 mg·L−1 N and 143 mg·L−1 K or 66 mg·L−1 N and 83 mg·L−1 K in 1994 and 1995, respectively. The EF beds were flooded for 6 hours, then drained for a 6-hour dry stage each 12 hours in 1994, and flooded for 1 hour and dried for 5 hours each 6-hour period in 1995 from May through August. Although both systems were suitable for producing Chinese water spinach (Ipomoea aquatica Forssk.—see footnote in Table 1), vegetable amaranth (Amaranthus tricolor L.), zinnia (Zinnia elegans Jacq.), and sweet basil (Ocimum basilicum L.), the EF system provided greater control over water availability and higher oxygen concentration in the root zone.

PHOTOSYNTHETIC RATES AND YIELD COMPONENTS OF EIGHT VEGETABLE AMARANTHUS GENOTYPES

Over 2 years, eight vegetable amaranth (Amaranthus spp.) genotypes were grown in a yield trial. Data on yield and gas exchange rates were obtained. On 16 July 1993 and 27 June 1994, all genotypes (Hinchoy VL & GL, RRC numbers 389, 701, 843, 1034, 1186, & PI349553) were planted in a randomized complete-block design with four replications. Plants were harvested ≈44 days after planting. Net photosynthesis (Pn), transpiration (E), green yield (GYLD), and leaf fresh weight (LFW) are discussed. Significant variation (P < 0.01) existed across and within years for all treatments. Higher GYLD and LFW were found in 1994, and Pn and E were higher in 1993. Over both years, GYLDs were highest for RRC 843 (10.4 Mg·ha–1) and RRC 1034 (l0.0 Mg·ha–1); RRC 1034 had the highest LFW (64.4 g/plant). The highest E rate (8.9 mmol·m–2·s–1 was in RRC 843 and RRC 1034. Genotype RRC 843 showed highest Pn (27.5 μmol CO2/m2 per second). In general, RRC 843 and RRC 1034 outperformed other genotypes.

VEGETATIVE GROWTH OF VEGETABLE AMARANTH AS AFFECTED BY NITROGEN FERTILIZATION

Influences of nitrogen (N) rate were evaluated on vegetable amaranth. Amaranthus tricolor, grown at uniform populations over two year. The main objective was to determine an optimum level of N fertilization for successful production in middle Georgia. In 1992 and 1993 accession `RRC 241' was planted in randomized complete block design on June 19 and 23, respectively. Four N rates, equally split were evaluated: 0, 45, 90, and 135 kg ha-1. First of the applications were 18 and 13 days post planting for 1992 and 1993, and again when plants were 5 weeks old. Plants were harvested 48 days after planting with green yield, leaf fresh weight. and stem fresh weight collected in both years and leaf area for 1993. In years 1992 and 1993 green yields were 5.3 and 6.5, 10.7 and 9.0. 13.2 and 12.1, and 13.5 and 14.0 Mg ha-1. respectively for the 0, 45, 90, and 135 rates. In both years vegetative components showed significant regression for all treatments. Vegetative response (R2) for green yield in 1992 and 1993 was quadratic (85%) and linear (73%), leaf fresh weight in both years was cubic (63% and 48%), while stem fresh weight response was linear (29%) and cubic (72%). During 1993 leaf area was linear (58%). Non-significance predominantly occurred between the two higher rates for each year and when combined. indicating that 90 kg N ha-1 should provide optimal production of amaranth for the middle Georgia region.

115 EFFECT OF NITROGEN SOURCE AND LEVEL ON VEGETABLE AMARANTH

On 3 Aug. 1993, 20-day-old `Hinn Choy' plants (Amaranthus tricolor L.) were-planted on 15 × 15 cm spacings in 4-row beds at 1.3 m row spacings in a Leadvale silt loam soil. Nitrogen sources of NH4, NO3 and NH4 NO3 were used at rates of 0, 100 and 200 kg/ha, and were split-applied at and 1 week after transplanting. All treatments received both supplemental K and P at the rate of 90 kg/ha at planting. Plants were harvested 31 days after transplanting. Plants given the NH, source were taller, and were higher in yield, leaf chlorophyll, total carotenoids and Mn (dry wt basis) than were plants given other N-sources. NO3-N fertilizer increased leaf Fe and Cu, and residual soil K and NO3, but reduced Mn levels. Leaf blade Ca was highest when NH4NO3 fertilizer was used. Increasing N-rates decreased both soil pH linearly and leaf blade Ca but linearly increased soil EC, NO3, and S and leaf blade N, K, S, P, NO3, Fe, chlorophyll and carotenoids.

FERTILIZER LEVELS MAXIMIZING YIELDS AND ECONOMIC RETURNS FROM VEGETABLE AMARANTH IN THE MIDSOUTH.

In an Arkansas mineral soil with pH of 5.7 and testing 59, 14, and 84 kg/ha of N, P and K, respectively, two cultivars of vegetable amaranth (Amaranthus tricolor L.), `Hinn Choy' and `RC 241' were grown in a fertilizer (3N × 3K × 4P) field experiment. Fertilizer P accounted for 90% of leaf fw yield variations, followed by K, 3%; and N, 2%. Multiple regression equations summarize the yield responses: Yhc = .528 + .00658 N + .146 P − .0000293 N2 − .001537 P2 + .0001351 N*P + .0001854 P*K, R2 = .964 Yrc = .63 + .2085 P − .001349 P2 + .0003497 P*K, R2 = .954 where Y = mt/ha, N, P, K = kg/ha of N, P and K. Fertilizer levels maximizing yields, and optimum levels under varying fertilizer cost/crop price situations were estimated using the derivatives and cost/price ratios. In RC estimated Pmax = 101 kg and estimated Popt = 93 kg at $1.33/kg P and $66/mt of crop.

711 (PS 6) EFFECT OF NITROGEN FERTILIZATION ON GROWTH AND YIELD OF AMARANTH

This study was conducted to establish the optimum level of N fertilization for the production of vegetable amaranth, Amaranthus tricolor, in middle Georgia. The soil fertilization treatments consisted of 0, 45, 90 and 135 kg N ha-1, applied in two equal doses, first at 18 days after planting and again when plants were 5 weeks old. Accession RRC 241 was planted on 19 June in randomized complete block design with four replications. The crop was harvested 48 days after planting and data on leaf number, leaf fresh weight, stem fresh weight, and green yield were collected. Green yield for treatments 0, 45, 90 and 135 kg N ha-1 were 5.3, 10.7, 13.2 and 13.5 Mg ha-1, respectively. Regression of N fertilization on all vegetative components were significant. A linear response was seen for stem fresh weight, a quadratic response for green yield and cubic responses for leaf number and leaf fresh weight. The R2 values for leaf number, leaf fresh weight, stem fresh weight, and green yield were 0.61, 0.63, 0.29 and 0.85, respectively. The results indicate that 90 kg N ha-1 of fertilization should provide optimal vegetative growth in amaranth.

VEGETABLE AMARANTH PERFORMANCE AT DIFFERENT SOIL MOISTURE LEVELS

The effects of differing soil moisture levels on the vegetative components of vegetable amaranth, Amaranthus tricolor RRC no. 241, were evaluated. A completely randomized design with 10 replications and 4 treatments (3,6,13, & 18% soil moisture) was followed. Leaf, stem, plant, root fresh weight and leaf area (LFW, SFW, PFW, RFW, and LA, respectively)—were recorded 48 days after planting. For each of the vegetative components the only significant difference (P ≤ 0.05) occurred between 3% versus 6-18% soil moistures, with moisture level of 6-18% showing no significant variation among themselves. The mean ranges for LFW (28.3-32.7 g), STW (6.9-9.2 g), PFW (41.3-48.2 g), RFW (8.6-12.8 g), and LA (1049-1222 cm2) across 6-18% soil moisture were approximately four times greater than the vegetative components of 3% soil moisture. From these preliminary results, it appears that vegetable amaranth has the ability to grow and perform well over a 6-18% soil moisture range, indicating an ability to better adjust and adapt to changing soil moisture environments.

FATE OF NITROGEN FERTILIZERS AS AFFECTED BY RATE AND SOURCE ON AMARANTH.

Amaranth (Amaranthus sp.) is a vegetable crop with grains and leaves high in protein, especially, lysine and the sulfur-containing amino acids which are limiting in many vegetables and grains. These nutritional qualities and the ease of growth make it a suitable alternate crop for limited resource farmers. A study was conducted to determine the effect of nitrogen sources and fertilization rates on amaranth production in Alabama and other Southeastern States. The experiment was set up as a complete randomized block design in Norfolk sandy loam (Fine silicoeus, thermic, Typic Paleudult). Four nitrogen sources (urea, sodium nitrate, ammonium sulfate, and ammonium nitrate) were used at three different levels (0, 40, and 80 Kg/ha) one week after transplanting. Sources of nitrogen did not have any significant effect on both fresh and dry vegetable yield (p 0.05). However, fertilization brought significant increases in both yield and total nitrogen content of vegetable amaranth (p 0.05).

SOIL pH AND MOISTURE EFFECTS ON VEGETABLE AMARANTH PRODUCTION

The effect of soil moisture and pH levels on the vegetative growth of amaranth were studied in the greenhouse during 1990-91. Three soil pH levels: 4.5, 5.3, and 6.4 and four soil water levels: 3, 6, 12 and 18% (w/w) comprised the treatments of the two studies. The plants grown in pH 6.4 were significantly taller and had greater leaf area than plants grown in pH 5.3 or 4.7 soil. There was a significant decrease in all above ground plant parts with each increase in soil acidity. The top fresh weight of plants grown in 5.6 and 4.7 pH soil were 27% and 73% lower, respectively, than plant grown in 6.4 pH soil. Plant grown in 3% soil water had significantly lower leaf, stem and root fresh weights than other soil water levels. There was no significant difference in the performance of plants grown in 6, 12 or 18% soil water, suggesting that amaranth plant is adapted to a wide range of soil moisture conditions.

Nutritional and antinutritional composition of vegetable and grain amaranth leaves

AbstractThe foliage of 61 accessionso f amaranthus comparising both the grain and vegetable types referable to 10 species were evaluated for carotenoid, protein, nitrate, odxalate and moisture contents (fresh weight). Carotenoid varied from 90 to 200 mg kg−1 in vegetable types and from 60 to 200 mg kg−1 in the leaves of grain types. Variation for leaf protein was found to be 14‐30, 15‐43 g kg−1; nitrate 1.8.‐8.8, 4.1‐9.2 g kg−1; oxalate 5.1‐19.2, 3‐16.5 g kg−1; and moisture 780‐860, 750‐840 g kg−1 in vegetable and grain types, respectively. Analysis of the amino acid composition of leaf protein of some high carotenoid lines revealed a well balanced composition with high lysine (40‐56 g kg−1). variation of all the five parameters (carotenoid, protein, nitrate, oxalate and moisture) with respect tot he leaf position in vegetable type (4‐ and 8‐week‐old plants) and with respect to age (‐ to 4‐month‐old plants) in grain types was also studied.

VEGETABLE AND GRAIN AMARANTH SEED YIELD AND QUALITY AFFECTED BY APPLIED NITROGEN

Twenty-one day old seedlings of a vegetable amaranth (RCC 241, Amaranthus tricolor) and a grain amaranth (K343, A. hybridus × A. hvpocondriacus) were transplanted on July 28, 1989. Equal applications of NH4N O3 were made on July 28 and August 25 to give total N rates of 0, 60, 120 and 240 kg/ha. Accessions were harvested on Oct. 18 and 14, respectively. Increasing N, induced a quadratic response in plant dry wt, seed wt/plant and seed size fractions in both amaranth types. Seed size fractions as a percent of the total seed, plant height and seed to plant dry weight ratio were not affected by increased N. Seed protein increased linearly whereas seed nitrate increased quadratically with increasing N application. Higher N rates increased residual soil NO3, NR4 and electrolytes and decreased pH. Decreasing soil pH appeared to reduce soil K and Cu but increase Fe and Mn availability. The effect of N rate on seed germination was inconclusive, but the larger seed size was higher in germination. There were differences among species in most responses tested. These data suggest that N applications be tailored to the season growing length required by the respective species/cultivar.

VEGETABLE AND GRAIN AMARANTH SEED YIELD AND QUALITY AFFECTED BY APPLIED NITROGEN

Twenty-one day old seedlings of a vegetable amaranth (RCC 241, Amaranthus tricolor) and a grain amaranth (K343, A. hybridus × A. hvpocondriacus) were transplanted on July 28, 1989. Equal applications of NH4N O3 were made on July 28 and August 25 to give total N rates of 0, 60, 120 and 240 kg/ha. Accessions were harvested on Oct. 18 and 14, respectively. Increasing N, induced a quadratic response in plant dry wt, seed wt/plant and seed size fractions in both amaranth types. Seed size fractions as a percent of the total seed, plant height and seed to plant dry weight ratio were not affected by increased N. Seed protein increased linearly whereas seed nitrate increased quadratically with increasing N application. Higher N rates increased residual soil NO3, NR4 and electrolytes and decreased pH. Decreasing soil pH appeared to reduce soil K and Cu but increase Fe and Mn availability. The effect of N rate on seed germination was inconclusive, but the larger seed size was higher in germination. There were differences among species in most responses tested. These data suggest that N applications be tailored to the season growing length required by the respective species/cultivar.

Aluminum Accumulation in Vegetable Amaranth Grown in a Soil with Adjusted pH Values

Abstract Two levels of phosphorus (20 and 80 kg P/ha) and two levels of aluminum (0 and 85 kg Al/ha) were applied to Enders soils of pH 4.4, 6.6, or 7.3. Sixteen-day-old vegetable amaranth (Amaranthus tricolor L.) plants (Rodale Research Center Accession 241) were transplanted 24 July 1986 and harvested 27 days later. Increasing soil pH from 4.4 to 7.3 decreased plant height, fresh weight, leaf area, leaf blade chlorophyll, N, K, Mn, and Zn, but increased Ca, Mg, Al, and Na (dry-weight basis). Supplemental P increased plant height, leaf area, plant dry weight, leaf blade P, K, Ca, Mg, Na, and chlorophyll; decreased Fe, B, Zn, and Al; but had no effect on leaf blade protein. Adding Al to the soil decreased plant height, leaf blade chlorophyll, N, P, and Na, but increased Mn. At the termination of the experiment, exchangeable soil Al was found only in soil at pH 4.4 (1.1 cmol·kg-1). The highest leaf blade Al concentration (2473 mg·kg-1) was found in soil at pH 6.6 that received the low rate of supplemental P. Regardless of soil pH, leaf blade Al was negatively correlated with plant height (r = -0.78), plant dry weight (r = -0.78), available soil P (r = -0.51), and leaf blade P (r = -0.53), but it was positively correlated with Fe (r = 0.98).

Oxalate in vegetable Amaranth (Amaranthus gangeticus). forms, contents, and their possible implications for human health

AbstractForms of oxalate in Amaranthus gangeticus L (a vegetable amaranth) grown in three sites with different soil and climatic factors were identified, and their contents were determined. On average the total oxalate content was 91 g kg−1 on a dry weight basis. This is high when compared with the amounts reported to be a health hazard in other vegetables and forage crops. Two dominant fractions of oxalate in amaranth were isolated: a fraction soluble in boiling water which was predominantly in the form of potassium and magnesium oxalate, and an associated insoluble residue which was predominantly calcium oxalate.Most of the Ca in amaranth is unlikely to be available to the body. A suggestion was made that research on reducing the oxalate content of amaranth should first be directed at soluble oxalates because they can interfere with Ca availability from other food sources.

Photosynthetic characteristics of Amaranthus tricolor, a C4 tropical leafy vegetable

The gas exchange characteristics are reported for Amaranthus tricolor, a C4 vegetable amaranth of southeastern Asia. Maximum photosynthetic capacity was 48.3±1.0 μmol CO2 m(-2) s(-1) and the temperature optimum was 35°C. The calculated intercellular CO2 concentration at this leaf temperature and an incident photon flux (400-700 mm) of 2 mmol m(-2) s(-1) averaged 208±14 μl l(-1), abnormally high for a C4 species. The photosynthetic rate, intercellular CO2 concentration, and leaf conductance all decreased with an increase in water vapor pressure deficit. However, the decrease in leaf conductance which resulted in a decrease in intercellular CO2 concentration accounted for only one fourth of the observed decrease in photosynthetic rate as water vapor pressure deficit was increased. Subsequent measurements indicated that the dependence of net photosynthesis on intercellular CO2 concentration changed with water vapor pressure deficit.

Photosynthetic characteristics of Amaranthus tricolor, a C4 tropical leafy vegetable

The gas exchange characteristics are reported for Amaranthus tricolor, a C4 vegetable amaranth of southeastern Asia. Maximum photosynthetic capacity was 48.3±1.0μmol CO2 m(-2)s(-1) and the temperature optimum was 35°C. The calculated intercellular CO2 concentration at this leaf temperature and an incident photon flux (400-700 mm) of 2 mmol m(-2)s(-1) averaged 208±14 μl l(-1), abnormally high for a C4 species. The photosynthetic rate, intercellular CO2 concentration, and leaf conductance all decreased with an increase in water vapor pressure deficit. However, the decrease in leaf conductance which resulted in a decrease in intercellular CO2 concentration accounted for only one fourth of the observed decrease in photosynthetic rate as water vapor pressure deficit was increased. Subsequent measurements indicated that the depence of net photosynthesis on intercellular CO2 concetration changed with water vapor pressure deficit.

Field Evaluation of Vegetable Amaranth (Amaranthus spp.)

Abstract The horticultural potential of 20 vegetable amaranth (Amaranthus spp.) entries was evaluated in the field at Beltsville, Md., during the summers of 1979 and 1980. Mean fresh yields (leaves and stems) for 5 experiments ranged from 4.0 to 16.5 MT/ha. Yields were highest for A. dubius, intermediate for A. cruentus, and least for A. tricolor. Yield was negatively correlated with leaf:stem ratio (r=−0.56**). Entries with the highest leaf: stem ratios were found within A. tricolor.