18% to 27% ( Sacks and Francis, 2001 ). The majority of the variability was the result of unknown causes or interactions between variables (25% to 50%). We postulated that location differences are closely tied to soil properties and soil fertility
Alba A. Clivati McIntyre, David M. Francis, Timothy K. Hartz, and Christopher Gunter
Stephanie Wedryk, Joel Felix, Doug Doohan, and John Cardina
mechanical techniques that aid in building soil fertility and suppressing weeds with the potential to enhance yields in the first organic year ( Hanson et al., 2004 ). Compost applications during transition to organic vegetable production and after transition
M. Lenny Wells
, humid conditions and an average of >30 inches of rainfall per year. Regional conditions can have a significant effect on crop management practices, tree nutritional status, and orchard soil fertility, all of which affect crop production. As a result, it
Charles L. Rohwer and Vincent A. Fritz
. Reported impacts of transplant solution P on yield are minimal or variable in high-P-fertility soils or P-fertilized soils ( Arnold, 1953 ; Grubinger et al., 1993 ). The objective of this study was to evaluate the ability of black plastic mulch, P- and N
Gail S. Lee and Tina G. Teague
In soils that can range in pH from the low 4's to 7, depending on the location and liming history, deficiency of Zn, B, and Mo coupled with the soil acidity complex of Mn toxicity had been previously identified as severe limiting factors in producing quality Brassica crops. Fertility studies on fall and spring planted Brassicas focused on the effect of including/not including micronutrients during various phases of growth when NPK preplant fertilizer was reduced. Differential responses to reduction in preplant NPK and applications of micronutrients was found to be dependent on planting time (fall or spring), species of Brassica planted and cultivar. Nutrient uptake in leaf blades and petioles was followed. In broccoli timing of micronutrient applications significantly affected the harvest period length. Broccoli final yields of the B, Zn and Mg treatments were found to contribute ≈75% to 80% of the final yield of a full range micronutrient solution.
C. Stevens, V. A. Khan, J. Y. Lu, A. Y. Tang, and A. E. Hiltbold
Partial steam and chemical sterilization of soil rich in organic matter increased the soil nutrients, little information exists with regard to the effect of soil solarization (SS) in this regard. A study was established to determine the effects of SS in combination with wheat residue and subsequent crop residue on increased growth response (IGR) of cole crops and soil fertility for two years. SS for 90 days increased K+, P, Ca++ and Mg++ 3 times more within five months after SS. The SS effect released higher levels of total N in the soil. However, increase levels of N was lower than that required for maximum IGR of collard. The IGR of cole crops without fertilizers was higher in SS plots as compared to bare soil. The IGR of collard was evident almost two years after SS.
Monica Ozores-Hampton, Phillip A. Stansly, and Thomas A. Obreza
Methyl bromide will be unavailable to conventional vegetable growers in the year 2005, and it cannot be used by organic growers. Chemical alternatives are more expensive and may also be subject to future restrictions. Non-chemical alternatives like solarization and organic amendments are as yet largely unproven but do offer promise of sustainable solutions free of government regulation. The objective of this study was to evaluate the effects of soil-incorporated biosolids and soil solarization on plant growth, yield, and soil fertility. Main plots were a biosolids soil amendment (37 Mg·ha-1 and a non-amended control. Treated main plots had received some type of organic amendment for the previous 6 years. Sub-plots were fumigated with methyl bromide as they had been for 6 years, or non-fumigated. Non-fumigated plots were further split into solarized and non-solarized plots. Bell pepper (Capsicum annuum `X 3R Aladdin') was grown for 8 months. Nitrogen fertilization was reduced to 50% of the recommended rate in the biosolids plots due to expected N mineralization from the biosolids amendment. Plant biomass was higher in the biosolids plots compared with the non-amended plots but there were no differences in marketable pepper yields between biosolids and non-biosolids plots. Plants grown in solarized soil produced lower plant biomass and yields than the methyl bromide and non-fumigated treatments. Soil pH and Mehlich 1-extractable P, K, Ca, Mg, Zn, Mn, Fe, and Cu were higher in biosolids plots than in non-amended control plots. Soil organic matter concentration was 3-fold higher where biosolids were applied compared with non-amended soil. The results suggest that regular organic amendment applications to a sandy Florida soil can increase plant growth and produce similar yields with less inorganic nutrients than are applied in a standard fertilization program. However, methyl bromide and non-fumigated treatments produced higher yields than soil solarization.
Xinhua Yin, Janet Turner, Clark Seavert, Roberto Nunez-Elisea, and Helen Cahn
Theinfluences of a synthetic fabric cover in the row area of sweet cherry trees on soil fertility and plant nutrition are largely unknown. A field trial has been conducted on young `Regina' sweet cherry on a sandy loam soil at the Mid-Columbia Agricultural Research and Extension Center, Hood River, Ore., since 2001. The difference in soil NO - 3, P, K, Ca, Mg, S, B, Zn, Mn, Cu, pH, or organic matter was nonsignificant between the covered and non-covered treatments in any year. Leaf N content was 11% to 16% greater with the covered treatment compared with the non-covered treatment in 2002 and 2003, but leaf N was similar for the two treatments in 2001. Leaf P content was similar for the two treatments in 2001, but was about 36% less with the covered treatment than the non-covered treatment in 2002 and 2003. Leaf Ca content was decreased by 11% to 17% due to a synthetic fabric cover in 2002 and 2003. Leaf Mg content was 13% to 24% less with the covered treatment than the non-covered treatment in 2002 and 2003. However, the decreased leaf P, Ca, and Mg contents with the covered trees were due to the dilute effects of increased tree growth. The effects of a fabric cover on leaf K, S, B, Zn, Mn, and Cu contents were primarily nonsignificant. Our results suggest that although nutrient availability in the soil is not reduced by a wide synthetic fabric cover, higher rates of fertilizers may be needed for the covered sweet cherry trees due to the elevated tree growth and fruit production from a long-term perspective.
Ian Merwin, Michael Biltonen, and John A. Ray
Three orchard groundcover management systems (GMSs) were established in a newly planted apple (Malus domestica cvs. Liberty, Nova Easygro, and NY84828-12 on Malling 9 rootstock) orchard on a silty-clay loam soil (Aeric Ochraqualf). The GMSs were applied in 2-m-wide strips within tree rows as follows: 1) a 6-cm-thick mulch layer of composed manure, straw, sawdust, and vegetable plant wastes applied in May 1992 and 1994; 2) a “green manure” cover crop of canola (Brassica campestris cv. Humus) seeded in mid-August each year and tilled under the following May; and 3) Post-emergence applications of N-(phosphonomethyl) glycine (glyphosate) herbicide (2.0 kg a.i./ha) in mid-May and July each year. After 3 years of GMS treatments, apple tree growth and trunk cross-sectional area were similar in all three systems. Fruit yield and yield efficiency were greater in glyphosate and compost than in canola GMSs, and `Liberty' was the most productive cultivar. Topsoil N, P, K, Ca, Mg, Zn, and organic matter content were all substantially greater in the compost GMS. Leaf N, K, and P concentrations were consistently greater in trees in compost plots; leaf Ca, Mg, Cu, and Zn concentrations were lower in compost GMS. Weed growth was rank and difficult to control in the compost mulch, but this GMS substantially enhanced orchard soil fertility.
T.R. Konsler and J.E. Shelton
Abbreviations: RN, root nutrient; RW, root weight; SF, soil fertility. 1 Professor Emeritus, Dept. of Horticultural Science. 2 Associate Professor, Dept. of Soil Science. Paper no. 12055 of the Journal Series of the North Carolina Agricultural