because both soils received abundant amounts of organic materials from the compost and organic fertilizer ( Table 1 ). Conventional onion growers believe that composted animal manure application is as important as chemical fertilizers for improving soil
Jongtae Lee, Sunkyoung Hwang, Seongtae Lee, Injong Ha, Haejun Hwang, Sangdae Lee, and Juyeon Kim
nutrient removal by a crop provides useful information for sustainable soil fertility management. In sustainable agriculture, nutrient management planning should ideally provide, over the long-term, a balance between nutrient inputs and outputs. In the
Yuan Li, Arend-Jan Both, Christian A. Wyenandt, Edward F. Durner, and Joseph R. Heckman
soil fertility management and optimized plant nutrition ( Datnoff et al., 2007 ). In particular, the application of Si as part of a fertilization strategy has been studied for typical Si accumulator species such as rice ( Oryza sativa ), wheat
David Sotomayor-Ramírez, Miguel Oliveras-Berrocales, and Linda Wessel-Beaver
under an annual rotation common on the south coast of Puerto Rico of ‘Aruba’ pepper [ Capsicum annuum (Seminis, St. Louis, MO)] followed by ‘Tropicuke’ cucumber [ Cucumis sativus (PanDia Seeds, Ojai, CA)] followed by fallow. Table 1. Soil fertility
Paul B. Francis and C. Robert Stark, Jr.
-irrigated plasticulture tomato production research for five seasons before 2007. Prior soil fertility management involved soil sampling in early September and granular fertilizer amendments according to University of Arkansas soil test recommendations. Pelleted
T.K. Hartz, J.P. Mitchell, and C. Giannini
Nitrogen and carbon mineralization rates of 19 manure and compost samples were determined in 1996, with an additional 12 samples evaluated in 1997. These organic amendments were mixed with a soil: sand blend at 2% by dry weight and the amended blends were incubated at constant moisture for 12 (1996) or 24 weeks (1997) at 25 °C. Net N mineralization was measured at 4- (1996) or 8-week (1997) intervals, C mineralization at 4-week intervals in 1997. Pots of the amended blends were also seeded with fescue (Festuca arundinacea Shreb.) and watered, but not fertilized, for 17 (1996) or 18 weeks (1997); N phytoavailability was estimated from fescue biomass N and mineral N in pot leachate. An average of 16%, 7%, and 1% of organic N was mineralized in 12 weeks of incubation in 1996, and an average of 15%, 6%, and 2% in 24 weeks of incubation in 1997, in manure, manure compost, and plant residue compost, respectively. Overall, N recovery in the fescue assay averaged 11%, 6%, and 2% of total amendment N for manure, manure compost, and plant residue compost, respectively. Mineralization of manure C averaged 35% of initial C content in 24 weeks, while compost C mineralization averaged only 14%. Within 4 (compost) or 16 weeks (manure), the rate of mineralization of amendment C had declined to a level similar to that of the soil organic C.
Bielinski M. Santos
Selecting the “right” nutrient rate for fertilization programs is one of the most important decisions growers face. On one hand, increasing fertilizer prices and environmental concerns have increased the awareness of accurately managing fertilization programs, thus reducing fertilizer amounts during cropping seasons. By contrast, many growers fear not obtaining the desired crop performance and economic returns, especially when fertilization is assumed as “inexpensive insurance” to improve yields, thus leading to overfertilization. The objective of this paper was to provide general principles for selecting and monitoring the right nutrient rate within the framework of the “4R” nutrient management concept (right rate, right source, right placement, and right timing) to protect environmental quality while maintaining productivity. Some methodologies to determine, apply, and adjust fertilization rates during the growing season were discussed, including in-season monitoring procedures, such as petiole sap testing, plant diagnostic analysis, leaf color evaluation, and plant growth index.
J.T. Baker, D.R. Earhart, M.L. Baker, F.J. Dainello, and V.A. Haby
Triploid watermelon (Citrullus lanatus Thunb.) was grown on the same plots in 1990 and 1991 and fertilized with either poultry litter or commercial fertilizer. Additional treatments included bare soil or plots mulched with black polyethylene, and plots with or without spunbonded fabric row covers over both bare soil and mulch. Watermelon yields were unaffected by fertilizer source in 1990 but were significantly higher for poultry litter than for commercial fertilizer treatment in 1991. Polyethylene mulch significantly increased postharvest soil NO3 and leaf N concentrations in 1990 and increased yield and yield components in both years. There were no beneficial effects of row covers on yield in either year, presumably because no early-season freezes occurred.
T. H. Yeager, R. D. Wright, and M. M. Alley
Multiple branched liners of ‘Helleri’ holly growing in a pine bark medium were fertilized at the beginning of active root growth at 300, 400, 500, or 600 ppm N with a 20N−8.7P−16.7K water soluble fertilizer. One week later, one half of the plants were fertilized again. The treatments were repeated during the next 2 periods of root growth which occurred about 6 weeks apart. The above soluble fertilizer was applied weekly at 300 ppm N to the control plants. Shoot growth of plants fertilized twice at 500 ppm N was comparable to growth of the control plants. Further, these plants received 44% less fertilizer and utilized 17.6% more of the total fertilizer applied. Extract nutrient and soluble salt levels were high during root growth and low during shoot growth except for the control plants, indicating the plant's need for fertilizer predominates during periods of active root growth.
Stuart L. Warren, Thomas J. Monaco, and Walter A. Skroch
Seven vegetation management programs ranging from 100% cover of grass-dominated vegetation to bare soil were created on opposing north and south aspects. Nutrient contents of the herbaceous vegetation and soil were effected significantly by management programs, location in the plot (row and interrow), and time. The presence or absence of vegetation influenced vegetative uptake and leaching losses, resulting in differences among the vegetation management programs. In general, the upper soil (0- to 15-cm depth) with 100% vegetative cover contained more exchangeable Mg and less NO3 and available P than under bare soil. Exchangeable Ca was not affected by the management programs. Differences in growth form (grass or forb), perennial or annual vegetation, and percent bare soil accounted for the majority of differences in the nutrient content of the noncrop vegetation. Aspect did not affect any of the plant and soil parameters measured.