Abstract

FLORES-AGUILAR, José de Jesús et al. Effect of organic, inorganic and a combination of fertilizers on alfalfa production and soil chemistry properties. Terra Latinoam [online]. 2012, vol.30, n.3, pp.213-220. ISSN 2395-8030.

The purpose of the present study was to determine the response of alfalfa forage production and soil chemical properties to organic (28 Mg ha-1 of sheep manure), inorganic (0.434 Mg ha-1 of triple superphosphate; Ca(H2PO4)2) and combined (14 Mg ha-1 of sheep manure and 0.217 Mg ha-1 of triple superphosphate) fertilization, in doses of 200 kg ha-1 of phosphorus per year. Fertilization was fractioned into four quarterly applications in a randomized block design, involving five replications and four treatments: T1 = no fertilization was applied (control); T2 = organic fertilization; T3 = inorganic fertilization and T4 = combined fertilization. Annual dry matter production (Mg ha-1) was different (P ≤ 0.05) among treatments, averaging: 19.9±0.062 for control, 28.8±0.090 for organic fertilization, 29.2±0.095 for inorganic fertilization and 32.7±0.108 for combined fertilization. Mean forage production during the four quarters was higher (P ≤ 0.05) with organic, inorganic and combined fertilization than with the control. The efficiency of phosphorus utilization was 23.1% for organic fertilizer, 37% inorganic and 64% for the combined. The ratio of dry matter produced per kilogram of phosphorus applied was 144% with the organic fertilizer, 146% with inorganic and 163% with combined fertilization. The P and pH increased by 1.1 units (from 5.6 to 6.7) and 28 mg L-1 (70 to 98) for the organic fertilizer and 0.8 units (5.6 to 6.4) and 20 mg L-1 (for 70 to 90) for the combined fertilizer. It is concluded that the combined application of fertilizers favored increased alfalfa forage production and improved soil chemical properties throughout the year.

Keywords : phosphorous; sheep manure; triple superphosphate.

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