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  • Author or Editor: J. W. Worthington x
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Abstract

Trickle irrigation studies often require different water application rates. The design and construction of trickle systems for randomized studies can be difficult and expensive if they involve separate timers, solenoids, valves, and/or irrigation lines for each treatment. One possible solution to this problem is to design the system so that only the emitters are used to regulate the flow of water within each test group. Such a system can be controlled by a single timer with only one lateral line needed for each row.

Open Access

Abstract

Southern peas are difficult to shell when harvested as a fresh vegetable. To overcome this, processors resort to a severe high temp - short time storage process. In this study, changes associated with elevated temperatures were determined with 4 cultivars at 4 stages of maturity. Texture studies revealed that firmness increased with maturity. The texture of the cultivars was similar. Seed moisture declined with maturity and at temperatures of 100°F and 110° but increased at 120°. Reducing sugar content was not related to maturity. There was a marked increase in reducing sugar content of peas held at 120° except for the Brown Crowder cv. Maturity and storage significantly interacted with total sugars.

Open Access

Abstract

Peach trees (Prunus persica (L.) Batsch cv. Redglobe) were trickle-irrigated at 3 rates using open pan evaporation as a basis for calculating theoretical irrigation needs from 1973-1976 beginning when trees were 6-years-old. Although above average rainfall was received about 65% of the time, trickle irrigation (1½ times theoretical needs) increased yield per tree, fruit size, number of fruit buds per tree, and trunk diameter over non-irrigated trees. Trickle irrigation at 1½ the calculated rate increased average yield per tree, fruit size, and trunk diameters over trees sprinkle-irrigated once before harvest.

Open Access

Abstract

Mature peach trees [Prunus persica (L.) Batsch] grown in weighing lysi-meters were subjected to soil moisture stress. Evapotranspiration (ET) was not affected by rapid changes in soil moisture until soil matric potential reached -1500 kPa. When the trees reached permanent wilt, there was a sharp decline in water use.

Open Access

Abstract

Two lighting experiments, conducted in the summer of 1967 at Beltsville, Maryland, were designed to evaluate different light sources for tomato color development during ripening. In late winter 1968, additional tests were conducted to determine temperature rise over ambient due to light source.

Open Access

Abstract

Evapotranspiration of two 5-year-old mature trees of peach [Prunus persica (L.) Batsch] was measured in weighing lysimeters. Diurnal water use patterns were conventional. Trees used an average of 136, 114, 96, and 61 liters per day in July, August, September, and October respectively, with an overall daily average of 102 liters. The crop coefficient based on class A pan evaporation declined from 0.98 in early July to 0.40 just before leaf fall and averaged 0.71 for the season. Class A pan evaporation correlated well with evapotranspiration on a weekly average but poorly on a daily basis.

Open Access

Abstract

‘TAMU Denman’ is a new cultivar of peach [Prunus persica (L.) Batsch] developed by the Texas Agricultural Experiment Station for home and commercial orchards in north and central Texas. ‘TAMU Denman’ is a consistently high-yielding, late-blooming cultivar with heavy bud set. These characteristics facilitate commercial production during years when late freezes reduce production from other varieties. It is named for T.E. Denman, Horticulturist at the Texas Agricultural Experiment Station, Stephenville for 31 years.

Open Access

This research was set up to determine the effectiveness of hydrogen cyanamide as a bloom thinner on peaches and apples. When applied at full bloom hydrogen cyanamide at 0.5 to 1% was effective at reducing fruit set on several varieties of peaches and apples in two different years. Yields were not effected when the lower rates were used. These results indicate that hydrogen cyanamide holds potential as a bloom thinner for both stone fruit and apples when used at the proper rates and timing.

Free access

A computer model was used to predict irrigation rates and numbers of emitters or microsprayers required to trickle irrigate Redskin/Nemaguard peach trees. Irrigation rates were 0, 50%, and 100% of the predicted requirement based on a crop coefficient of 50, 80, 100, 80, and 50 percent of pan evaporation for the tree's canopy area for May, June, July, August and Sept. respectively. Full irrigation (100% of predicted) was applied through 6, 8L/hr emitters or one 48L/hr microsprayer. Half the predicted rate was applied through 6, 4L/hr emitters or 1 24L/hr microsprayer. Control trees received no supplemental irrigation. Microsprayers height was adjusted to wet a surface area comparable to the 6 emitters. There was no significant difference in fruit size or yield based on emitter vs microsprayers, but fruit size and total yield was increased in direct proportion to irrigation rate. There was no treatment effect on tree pruning weights. Moisture measurements indicated that trees de-watered the soil efficiently enough that water never moved below the 30 cm level in spite of the fact that up to 260 liters per tree per day were applied in mid-summer.

Free access

The potential for reducing water use of peach [Prunus persica (L.) Batsch] trees with antitranspirants following fruit harvest was investigated using matched peach trees planted in an outdoor twin weighing lysimeter facility. A 10% solution of the antitranspirant Wilt Pruf NCF was applied to one of the two trees on 7 July 1986. Immediately after application, water use of the treated tree was reduced by 40%. One month after treatment, the water use was reduced 30% and, by the termination of the experiment (85 days after treatment), water use was reduced 12% as compared to control. The average reduction in tree water use for the entire period was 30%. Fully expanded, sunlit leaves (nodes 10 to 20 from the terminal end) from the treated tree exhibited the greatest reduction in water loss compared with immature or inner canopy, shaded leaves. Use of the antitranspirant did not prevent the development of water stress once a critical level of soil moisture was reached. The change in tree water use induced by the antitranspirant did not significantly reduce shoot length, new leaf production, or individual leaf size on actively growing, current-season branches. Fruit and leaf bud initiation, as measured the following spring, were not affected: however. flower bud maturation could not be evaluated due to freeze damage. Chemical name used: di-1-p-menthene (Wilt Pruf NCF).

Free access