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  • Author or Editor: D. R. Earhart x
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Abstract

Concentration of endogenous ethylene was higher in Ag+-treated cuttings of sweet potato (Ipomoea batatas Lam.) than in the control or in cuttings subjected to 48°C for 2 minutes. When leaf tissue was dipped in 0, 125, 250, or 500 mg/liter Ag+, endogenous ethylene was increased by the 250 and 500 mg/liter treatments. When equal concentrations of NO3– were applied to cuttings as KNO3, Ca(N)O3)2, or AgNO3, only AgNO3 increased the endogenous ethylene content.

Open Access

Abstract

The lower 15 cm (4 nodes) of vine tip cuttings of sweet potato (Ipomoea batatas (L.) Lam. cv Jewel) were planted in blasting sand and immersed in a full strength Hoagland’s nutrient solution to a height of either 5 or 15 cm. More roots were initiated at the two lower nodes and roots were more numerous and larger by 6-12 weeks in the 5 cm immersion level while at the 15 cm level more roots originated at the upper nodes. Endogenous ethylene (C2H4) increased in the stems of plants immersed to a height of 15 cm.

Open Access

Abstract

The ‘Topaz’ (Fig. 1) sweet potato [Ipomoea batatas (L.) Lam.], developed by the Texas Agricultural Experiment Station, combines high yield good sprout production, and excellent baking and canning quality.

Open Access

Abstract

Ethylene (C2H4) was higher in the internal atmosphere of crown gall infected rose bushes than in healthy plants. C2H4 was higher in the crown and root tissues than in the top of normal as well as crown gall infected plants.

Open Access

Response of triploid watermelon [Citrullus lanatus (Thunb.) cv. Tiffany] to fertilizer source (FS) [poultry litter (PL) vs. commercial fertilizer (CF)1, black plastic mulch (BPM), and spunbonded floating row cover (SFC) was evaluated in 1990 on an East Texas Fuquay-Darco sandy loam soil. Plant growth and percent soluble solids were equated by FS. Vine fresh weight, number and total melon weight per plot, average melon weight, and percent soluble solids were increased 27%, 29%, 45%, 24%, and 17%, respectively, by BPM when compared to no mulch treatment. BPM + SFC treatment decreased vine fresh weight but increased total melon number which in turn increased plot weight. PL increased plant P, K, and Mg 16%, 12%, and 24%, respectively, when compared to CF. Plant Ca was increased 21% by CF. Plant N, P, Ca, and Mg were increased 18%, 16%, 22%, and 15% by the use of BPM. A reduction in plant N was found when SFC was used alone and with treatments lacking BPM or BPM + SFC. Mean soil temperature was increased on the average 2°C at 10 cm depth by BPM when compared to all other treatments. Mean 24 hr air temperature 2 cm above BP and bare ground under SFC was increased 5°C above ambient.

Free access

When poultry litter (PL) is applied to meet the nitrogen (N) needed for plant growth, phosphorus (P) can accumulate, leading to non-point source pollution of surface water. This study was conducted at Overton, Texas on a Bowie fine sandy loam (fine-loamy, siliceous, thermic, Plinthic Paleudults) to investigate the use of warm- and cool-season forage legumes in rotational cropping systems to remove excess P. Cropping systems were: spring legume—fall vegetable (SL-FV), spring vegetable—fall legume (SV-FL), and spring vegetable-fall vegetable (SV-FV). Warm- and cool-season legumes were Iron and Clay cowpea and crimson clover, respectively. Poultry litter rates were 0, 1X, 2X, 4X, and commercial blend (CB) as subplots. Fertility treatments were applied to vegetable plots only. The crop, IX PL and CB rate for each season were: spring 1995—watermelon, 2.2 t·ha-1, 48.8N—12.2P—28K kg·ha-1; fall 1995—turnip, 8.3 t·ha-1, 89.6N—24.4P—28K kg·ha-1; spring 1996—tomato, 6.7 t·ha-1, 100.9N—17.1P—78.5K kg·ha-1. Soil P increased at all depths sampled (0-15, 15-30, and 30-45 cm) as PL rate increased. Residual P from CB was equal to the control. Through spring 1996, soil P concentration in the surface 0-15 cm was increased by all systems. System SV-FL reduced P accumulation by 35.6 mg·kg-1 when compared to SL-FV and 44.7 mg·kg-1 when compared to SV-FV. Residual P continued to increase as PL rate increased. Rate of increase was reduced by a system of SV-FL.

Free access

Phosphorus (P) concentration in surface waters from non-point agricultural sources is an increasing resource management concern. This study was conducted at Overton, Texas, on a Bowie fine sandy loam (fine-loamy, siliceous, thermic, Plinthic Paleudults) to evaluate cool-season legumes for P uptake following poultry litter (PL) application rates on spring vegetables. Treatments were PL rate (0, 1X, 2X, 4X) and a commercial blend (CB) for comparison. Cool-season legumes, consisting of crimson clover, berseem clover, hairy vetch, and red clover, were the subplots. The vegetable crop in Spring 1995 was watermelon. The 1X PL rate was 2.2 t·ha-1 and the CB was 44.8N-0P-32.5K kg·ha-1. Dry matter yield was decreased by the 4X PL rate. Plant P concentration increased linearly as PL rate was increased. The greatest P uptake (4.1 kg·ha-1) was at the 2X rate. Hairy vetch had the greatest yield (1,875 kg·ha-1), plant P concentration (0.53%), and P uptake (9.6 kg·ha-1). PL rate increased soil P concentration at all depths. The least amount of P accumulation was from CB and was equal to the control. Hairy vetch appears to have the capability of removing a greater amount of P and reducing soil concentration when compared to the other legume species tested.

Free access

In a field experiment, fertilizer source (poultry litter vs. commercial), plastic mulch, row cover, and fertilizer rate (residual from 1990 study vs. additional) were applied in factorial combinations to determine the effect on vegetative growth and production of triploid watermelons. Litter (3.12 % total N) was re-applied at the rate of 13.2 Mt·ha-1 along with commercial fertilizer (6N-10.5P-20K) at 1.1 Mt·ha-1. Plastic mulch showed the greatest influence on vegetative growth and production variables by increasing vine length 26.1 cm, leaf area 61.8 cm2, yield 4207 kg·ha-1, melon number 741 ·ha-1, and average melon weight 0.8 kg, over unmulched plots. Plastic mulch with or without row cover increased melon number significantly when compared to plots without mulch or row covers. Poultry litter increased vine length, yield, and average melon weight 15.4 cm, 1971 kg·ha-1, and 0.5 kg, respectively, when compared to commercial fertilizer. Poultry litter in combination with row cover increased yield by 3864 kg ·ha-1 over commercial fertilizer with row cover, and approximately 2567 kg·ha-1 over poultry litter and commercial fertilizer without row cover. Additional fertilizer increased average melon weight 1.3 kg.

Free access

A factored experiment was established at the Texas A&M Univ. Research and Extension Center at Overton in Spring 1995. The objective was to investigate the use of warm- and cool-season legume cover crops in vegetable cropping systems for reducing phosphorus (P) accumulation from poultry litter (PL) and commercial blend (CB) fertilizer. PL rates were based on soil test nitrogen (N) requirement of the vegetable crop and percent N content of the litter. This was considered the 1X rate. Fertility treatments were applied to the vegetable crop only. PL was applied at O, 1X, 2X and 4X rates. CB was applied at recommended rates for N, P, and K. The vegetable crops were: Spring 1995—watermelon; Fall 1995—turnip; Spring 1996—tomato; Fall 1996—collard; Spring 1997—squash. The legumes were: spring—Iron and Clay cowpea; fall—crimson clover. Dry-matter yield of cowpeas and clover was not affected by fertility treatment in any of the years studied to date (Spring 1995, 1996, 1997). Plant concentration of P for both cover crops was increased all 3 years as rate increased. PL applied at the 1X rate maintained P levels in the surface 0—15 cm of soil at 60 mg·kg-1 over the five-season study period. CB maintained levels of P equal to the control. A cropping system of spring vegetable—fall legume greatly reduced P accumulation. A reduction in P was also noted from a system of fall vegetable—spring legume, but not as pronounced. The greatest accumulation was with a system of spring vegetable—fall vegetable.

Free access

Abstract

The ‘Cordner’ sweet potato [Ipomoea batatas (L.) Lam.], developed jointly by the Texas Agricultural Experiment Station and Oklahoma State Univ., combines high yield, good sprout production, and excellent baking and canning quality.

Open Access