. Once air capacity decreases and gas exchange is restricted, the physical and chemical properties of soil worsen, which affects the normal growth of the crops, resulting in reduced production ( Nawaz et al., 2013 ). Aeration irrigation is an improvement
Fengyun Zhao, Junli Sun, Songlin Yu, Huaifeng Liu, and Kun Yu
Diana Niñirola, Juan A. Fernández, Encarnación Conesa, Juan A. Martínez, and Catalina Egea-Gilabert
to ensure the functionality of the root, because a lack of oxygen reduces water and mineral uptake by the plant, which may limit growth and, consequently, crop yield ( Tesi et al., 2003a ). To avoid negative repercussions on yield, growers aerate the
Dan Chapman, G.R. McEachern, Laurence Sistrunk, John Lipe, Larry Stein, and J.B. Storey
Five Texas orchards were selected in Spring 1993 in commercial pecan counties for testing three types of soil aeration equipment. Mechanical aeration spikes were either 20 or 46 cm long, and a pneumatic spike was 20 cm long. The mechanical spikes are on a rolling cylinder that can be manufactured in sufficient lengths to fit the tree spacing in different orchards. The pneumatic probe is manually inserted into the soil so that a quick burst of 130-psi air can be delivered to effect soil profile fracturing. The fourth replicated treatment was an nontreated control. There were no differences in trunk diameter increases and yield in 1993 between May-applied replicated treatments. The May treatments and November measurements will continue for two more years to allow for differences in soil aeration to influence growth and yield. Shoot growth measurements will be taken in Spring 1995. Irrigation water has penetrated the soil under aerated trees more readily than in nonaerated controls.
R.G. Linderman and E.A. Davis
and Benson, 2001 ). The use of aerated steam to pasteurize soil or potting mixes to eradicate soilborne pathogens, weed seeds, and insects was pioneered by K.F. Baker (1957) . The principles of treating soil or potting media with heat at temperatures
Bryant C. Scharenbroch
potentially noxious waste products ( Finck, 1982 ). Aerated compost teas are one such organic fertilizer becoming more widely used with the hopes of improving soil quality and managing tree nutrition. Aerated compost tea is made by mixing compost with aerated
Dan Chapman, Laurence Sistrunk, and J. Benton Storey
Objectives of this experiment were: 1) to determine what effect a soil spike aerator had on nut quality and yield, and 2) to determine whether soil compaction influenced nut quality and yield.3) to determine whether tree stress influenced nut quality or yield on pecan trees In 1990, a randomized design was set up in a 33 year old orchard on Westwood silty clay loam with 3 main treatment factors: 1990 nut size (measure of tree stress), aeration, and cultivar. Location for this experiment was the Adriance Orchard on the Texas A&M Plantation - Brazos River flood plain. Nut quality was determined by the % kernel and # nuts/kg. Yield was measured in kg per tree. Results after two years showed that aeration increased the nut size of stressed trees in 1991 and non-stressed trees in 1992 Yield was unaffected by aeration in both years but stressed trees produced lower yields in 1992. Aeration increased nut size, but not significantly from 119 nuts/kg to 111 nuts/kg in 1991. There was a significant increase with aeration in 1992 from 121 nuts/kg to 113 nuts/kg. Yield and % kernel were not significantly different for both years with aeration Stress did not increase % kernel in either 1991 or 1992 but nut size was larger on non-stressed trees for both years. Stressed trees produced fewer nuts per tree in 1992.
Dan Chapman, Laurence Sistrunk, and J. Benton Storey
In 1990, a randomized design was set up in a 33 year old orchard on Westwood silty clay loam with 4 main treatment factors: 1990 nut size, chiseling, aeration, and cultivar. Location for this experiment was the Adriance Orchard on the Texas A&M Plantation – Brazos River flood plain. Nut quality was determined by the % kernel and # nuts / kg. Yield was measured per tree and calculated for g/cm2 cross-sectional trunk area. The soil bulk density for each treatment was 1.53 g/cm3 and found to be statistically uniform at the start of the experiment. Results after one year showed that aeration increased the nut size and % kernel of `Mahan' but not of `Desirable' and `Stuart'. Chiseling increased the yield of `Stuart' and `Desirable' and nut size of all 3 cultivars but not % kernel. Aeration increased the % kernel from a mean 48.6% to 56.8% and nut size from 129 nuts/kg to 102 nuts/kg of the 1990 small-nut-size trees but did not significantly increase nut quality for the 1990 normal-nut-size trees.
Claudia Calonje, Chad Husby, and Michael Calonje
improvement in germination or growth of rare Zamia spp. in containers. Providing the proper balance of aeration, water retention, nutrient-holding capacity, and decomposition rate are among the key factors that must be considered in evaluating a cycad
Chandrappa Gangaiah*, Edward E. Carey, and Ned A. Tisserat
Compost teas, made using an aerated brewing process, have been reported to have potential for controlling a range of plant diseases and improving crop health. Septoria leaf spot of tomato, caused by the fungus Septoria lycopersici, is a common and destructive disease of tomato in Kansas. A field trial was conducted at Wichita, Kansas during Summer 2003 to evaluate the potential of pre-plant compost, and compost tea applied as a foliar spray or through drip fertigation, to control Septoria leaf spot of tomato. The experimental design included three factors: Pre-plant application of 13N-13P-13K or vermicompost; fertigation with CaNO3 or compost tea; and foliar spray with compost tea, fungicide (Dithane) or water. A split plot design was used with fertigation treatments as main plots and the other two factors as sub-plots. There were 3 replications. Tomato cultivar Merced was used and individual plots consisted of 5 plants grown on beds covered with red plastic mulch and supported by stake and weave system. Aerated compost tea was brewed weekly using a vermicompost-based recipe including alfalfa pellets, molasses, humic acid, fish emulsion and yucca extract and applied to plots starting 2 weeks after transplanting. Disease incidence and severity were recorded weekly for 3 weeks following the appearance of disease. Plots were harvested twice weekly and counts of No. 1, No 2 and cull grade tomatoes were recorded. There were no effects of pre-plant or fertigation treatments on Septoria leaf spot disease, but there was a significant effect due to foliar sprays, with mean severity of compost-tea-sprayed plots (26.3%) and fungicide-sprayed plots (31.9%) significantly lower than water-sprayed plots (45.9%) at trial termination.
William J. Carpenter
Priming permits seeds to slowly imbibe water at regulated rates and to begin the initial stages of germination. Hypertonic polyethylene glycol (PEG) 8000 solutions of 1.0 and 1.2 MPa at 15C improved seed germination of dusty miller (Senecio cineraria DC.). At 0.8 MPa, germination was promoted during priming. No differences in rates, span, or total germination were found among seeds primed for 1, 2, or 3 weeks with or without aeration during priming. Germination percentages of primed and nonprimed seeds were similar at 10, 15, 20, and 25C, but 42% to 81% higher for primed seed at 30 or 35C. Priming reduced days to 50% of total germination (T50) 23% to 61%, and germination spans in days 30% to 67%. Primed seeds germinated most rapidly and uniformly at 20 and 25C. No change in total germination, T50, or germination span resulted when moisture contents of primed seeds were lowered to 7.8% or seeds were held at –80C for 7 days. Primed seed performance was unchanged after storage at 5C and 52% RH for 16 weeks.