stimulated farmers to accept organic farming as an alternative. Sales of organic products. G.K. Panicker and C.A. Sims. Alcorn State University, Mississippi. USA.
Effect of Worm Castings, Cow Manure, and Forest Waste on Yield and Fruit Quality of Organic Blueberries Grown on a Heavy Soil G.K. Panicker and C.A. Sims Alcorn State University, Mississippi USA J.L. Silva and F.B. Matta Mississippi State University Mississippi USA
J.M. Spiers USDA-ARS Thad Cochran Southern Horticultural Laboratory Mississippi USA
Keywords: rabbiteye blueberry, organic manures, anthocyanins, nitrate-N, biomass development, pine needle, pine bark Abstract Blueberries are one of the richest sources of antioxidant phytochemicals, having a high level of anthocyanins. Anthocyanins are phenolic compounds that posses antioxidant activities. Rabbiteye blueberry (Vaccinium ashei Reade var. Tifblue) was grown on Memphis Silt Loam soil (Typic Hapludalf, silty, mixed, thermic). Two organic manure treatments (worm castings and cow manure) were applied in basins around each plant. The control treatment received regular inorganic fertilizer. All treatments received pine bark and pine needle uniformly, and no chemicals were applied to control pests, diseases, and weeds. Percent canopy cover, canopy width and height, stem diameter, and yield were significantly higher in organic plants treated with worm castings. There was no significant difference in size, diameter, degree Brix, and vitamin C of the fruit, but the content of total anthocyanins was higher in fruit treated with worm castings. There was no difference in microbial load and no pathogens were found in the fruit. Concentrations of nitrate-N and P were higher in surface soils treated with organic manures, but there was no trend in N or P enrichment in lower layers of the soil. The leaching of N and P into subsurface layers from inorganic fertilizer was highly significant. Blueberry can be grown successfully on heavy soils with forest waste that can maintain soil acidity and worm castings increases yield and fruit quality of this crop. INTRODUCTION Blueberries are in the family Eracaceae and genus Vaccinium which contains about 400 species of shrubs, woody vines and small trees (Vander Kloet, 1988). The blueberries are in Cyanococcus which includes lowbush (Vaccinium angustifolium Ait), highbush (Vaccinium corymbosum L.), and rabbiteye (Vaccinium ashei Reade). Among the rabbiteye cultivars, ‘Tifblue’ dominates in production and occupies 40% of the rabbiteye hectarage in the US (Moore, 1993). They are shallow-rooted crops grown on soils characterized by good aeration and drainage (Eck and Childers, 1966) and hence, can not grow on heavy soils. The maximum yield recorded by the Tifblue variety on a light soil in Mississippi, after five year growth period, is 12,000 kg ha-1 (Spiers et al., 1985). Memphis silt loam is a heavy soil which has a bulk density of 1.6 with 4% sand, 68% silt, 27% clay, and less than 1% organic matter (Panicker and Tiwari, 1994). Blueberries are one of the richest sources of phytochemicals of the fresh fruits and vegetables (Prior, 1998). Flavonoids in blueberries act as an anti-adhesion, blocking the binding of Eschericia coli to the urinary tract wall and thereby reducing infection (Kalt and Dufous, 1997). Increased concerns over the last several decades on environmental quality have stimulated farmers to accept organic farming as an alternative. Sales of organic products Proc. IInd IS on Human Health Effects of F&V Ed.: B. Patil Acta Hort. 841, ISHS 2009
581
reached US $8 billion in the USA in 2001, continuing a 20% annual growth rate (Dimitri and Greene, 2002). Groundwater and surface water supplies are threatened with contamination. Crop nutrients from agricultural fertilizers are the most serious and widespread source of excess N and P (National Research Council, 1993). The objectives of this research were to evaluate the effect of worm castings, cow manure and forest waste on (a) yield and fruit quality of Rabbiteye blueberry, and (b) physico-chemical changes and ground water quality in a heavy soil. MATERIALS AND METHODS Rows were opened with a mould-board plow on a heavy soil, Memphis silt loam, and pine bark was mixed with the soil with a rotary tiller to increase soil organic matter and moisture retention, improve soil structure, and decrease soil bulk density. One-yearold bare-rooted plants were raised at a spacing of 1.47 m x 3.52 m in March, 2002, and pine needle was applied over the rows as mulch. Based on soil and manure tests for nutrient requirements, organic and inorganic manures were applied in basins around each plant in a completely randomized design for five years (Table 1) by strictly following the federal regulations on animal waste application (Federal Register, 2001). Fresh worm castings, produced by wriggler worms on decaying organic materials, was bought from a certified organic company for plant nutrients. It was applied in basins of blueberries as a basal dose before the flowering season. No chemicals were applied for the duration of the experiment. Phenotypic evaluation on biomass development, fruit quality, and soil physico-chemical studies were conducted. Soil core samples, up to a depth of 100 cm, were analyzed for nitrate-N and P movement and water quality. Fresh fruits were analyzed for microbial load, quality, and total anthocyanins, and total phenolics. RESULTS AND DISCUSSION Percent canopy cover, canopy height, stem diameter, fruit weight, and yield were significantly higher in organic plants treated with worm casting (Table 2). Concentrations of nitrate-N and P were higher in the surface soil with organic manures, but there was no trend in enrichment of these elements in the lower layers of soil. The leaching of N and P into subsurface layers from inorganic fertilizer was highly significant (Table 3). The total anthocyanins were similar for all treatments, but tended to be higher for organic treatments (Table 3). Since pine bark and needle were applied uniformly for all treatments, there was no significant difference in soil moisture, pH, and compaction. There was no significant difference in titratable acidity, fruit pH, degree Brix, and canopy width. CONCLUSION The results suggest that blueberries can be grown successfully with pine needle and bark on heavy soils. Worm castings is an excellent organic manure and may improve fruit quality, and controlled application of animal waste on blueberry orchards can be an agronomically and environmentally sound practice. Literature Cited Dimitri, C. and Greene, C. 2002. Recent growth patterns in the U.S. organic food market. USDA-ERS. Agric. Information Bulletin No. AIB777. Washington, DC. Eck, P. and Childers, N.F. 1966. Blueberry Culture. Rutgers University Press, New Brunswick, N.J. p. 132-134. Federal Register. 2001. Regulations on raw animal manure application in agriculture. Federal Register/Vol. 65. No. 246. December 21, 2001/Rules and Regulations, USA. Kalt, W. and Dufour, D. 1997. Health benefits of blueberries. HortTechnology Vol. 7. Moore, J.N. 1993. Blueberry cultivars of North America. HortTechnology 3 (4): 370-374. National Research Council. 1993. Soil and water quality: An agenda for agriculture. National Academy Press, Washington, DC. Panicker, G.K. and Tiwari, S.C. 1994. Effects of pine needle, gypsum, and polymers on 582
soil crusting, seedling emergence, and yield of snap beans. Proceedings of the 52nd Professional Agricultural Workers Conference, Dec. 4-6, 1994. Tuskegee University, USA. p. 251-259 Prior, L.R. 1998. Antioxidant capacity and health benefit of Fruits and Vegetables: Blueberries: the leader of the pack. USDA Human Nutrition Research Center Publication, MA Spiers, J.M., Braswell, J.H. and Hedwood, C.P. Jr. 1985. Establishment and maintenance of Rabbiteye blueberries. MSU Extension Bulletin 941. Vander Kloet, S.P. 1988. The genus Vaccinium in North America Agri. Canada, Ottawa, Publ. 1828: p.201 Tables Table 1. Average nutrient content of treatments (%) and application rates by year. Treatments in Kg ha-1 N P K Pine needle 1.57 0.09 0.41 Pine bark
Ca
Mg
S
1st Yr. 2nd Yr. 3rd Yr. 4th Yr. 5th Yr.
0.42
0.11
0.15
15,680 7,840 7,840
0.68 0.08
0.17
0.55
0.16
0.08
11,200
Worm Castings 1.89 0.47
0.58
5.84
0.33
0.24
….
407
610
813
Cow manure 0.33 0.12
0.23
0.99
0.08
0.05
….
813
1220
1626 1626
NPK
4.00
….
….
…
….
102
204
305
12.0 10.0
…
…
5,000 5,000 …
… 813
305
583
Table 2. Effect of treatments on biomass development, fruit size, and yield (recorded in 2007). Treatments
Stem Canopy Canopy Fruit Fruit Yield Diameter Cover Height Diameter Weight Kg ha-1 (cm) Percent (cm) (cm) (gm) _______________________________________________________________________ Worm Castings Cow Manure
2.66a
72.34a
184.05a
1.41a
1.33a
7989a
1.44b
42.9b
153.03ab
1.23a
1.04b
6347.5b
NPK
1.5b
42.9b
135.55b
1.32a
1.12ab
6651.8b
LSD
0.6911
27.67
43.54
0.2
0.2407
458.77
CV%
23.12
32.81
17.28
9.58
12.93
4.1
Means within a column followed by the same letter are not significantly different (P=0.05)
Table 3. Effect of treatments on anthocyanins and phenolics (mg/100g) in fruits, and nitrate-N and P concentration in soil. ________________________________________________________________________ Treatments Total Total Nitrate-N (mg Kg-1) P (ppm) anthocyanins phenolics 66-100cm depth 66-100cm depth Worm castings 114.08a 284.25a 5.11b 30.84c Cow manure 102.78a 284.05a 5.52b 44.68b NPK 99.20a 280.75a 13.5a 79.4a LSD 37.85 73.17 0.77 3.99 CV% 22.46 16.15 6.01 4.63 Means within a column followed by the same letter are not significantly different (P=0.05)
584
