Main content area

Impact of composted dairy manure on pH management and physical properties of soilless substrate

Jeong, Ka Yeon, Nelson, P.V., Frantz, J., Brinton, W.
Acta horticulturae 2011 no.891 pp. 173
soilless culture, soilless media, composted manure, physical properties, pH, dairy manure, peat, dolomitic limestone, perlite, pot culture, Chrysanthemum, fertilizer rates, irrigation, buffering capacity, bulk density, leaves, potassium, copper, iron, manganese, calcium, magnesium, nitrogen, phosphorus, boron, zinc, plant growth
Dairy cow manure compost (DMC) was evaluated as a soilless substrate substitute for dolomitic limestone and peat moss in two experiments. The objectives were 1) to quantify the impact of DMC on substrate pH establishment and stabilization throughout crop time and 2) to test the effect of DMC on physical properties of substrate. Peat moss plus DMC (at 5 to 30% by volume) was held constant at 75% volume and perlite at 25% without limestone. Two additional control treatments of 75% sphagnum peat moss and 25% perlite were formulated with and without agricultural dolomitic limestone. Pot chrysanthemum ‘Kory’ plants were transplanted into 16.5-cm diameter (1.4 L) plastic pots and fertilized at each irrigation with 17N-2.2P-14.1K neutral fertilizer. Additions of 0 to 30% DMC resulted in initial substrate pH levels of 3.1 to 6.5. Although pH declined during plant production, the decline was similar in the agricultural limestone and the 20 to 30% DMC treatments that had similar initial pH levels. Thus, pH buffering capacity of DMC was similar to the limestone. The initial EC levels for all substrates were within the acceptable range for seedlings and bedding plants. Magnitude of shrinkage did not relate to addition of DMC and was of little commercial significance. Irrespective of time in the cropping cycle, DMC resulted in increased dry bulk density (Db), decreased total porosity (TP) and container capacity (CC), and little effect on air space (AS). AS levels were in a good range of 15% and above for the 7.6 cm tall test cylinders. End of crop tissue analysis indicated that DMC resulted in higher leaf concentrations of potassium, sulfur, copper, iron, and manganese, lower, but adequate, calcium and magnesium, and similar nitrogen, phosphorus, boron, and zinc concentrations. Maximum plant growth (dry weight) occurred with 15% DMC in Experiment 1 and with 10% DMC in Experiment 2. All limestone and a portion of peat moss were effectively replaced with DMC.