engleski

Phosphorus as a limiting factor of rural development in Lika region

Grain yields of field crops in mountain Lika- Senj county of Croatia are considerably lower than in lowland area, mainly as affected by soil and climatic limitations. The field experiment with increased rates of P fertilization was conducted at beginning of May 2001. Four rates of ameliorative P fertilization were applied in form of monoammonium phosphate (MAP: 12% N + 52% P2O5) as follows (kg P2O5/ha): a) control, b) a + 500 , c) a + 1000, d) a + 1500 and f) a + 2000. The field experiment was conducted in four replicates (experimental plot of fertilization = 64.26 m2) by three corn hybrids (early maturity groups of hybrids: Alpos, OsSK247 and OsSK332: experimental plot of hybrid = 28.6 m2). Corn was sown in term May 16 and harvested in October 5, 2001. Theoretical plant density (TPD) was 71429 plants/ha (distance in row 20 cm, interrov spacing 70 cm). Corn grain yields were calculated on 90% TPD and 14% grain moisture basis. In general, by phosphorus application, corn grain yields were increased for 30% compared to the control and they were as follows: 6.87, 7.89, 7.81, 8.96 and 9.02 t/ha, for the control, 500, 100, 1500 and 2000 kg P2O5/ha. Depending on the hybrids, grain yields were as follows: 7.65, 8.02 and 8.65 t/ha, for Alpos. OsSK247 and OsSK332, respectively. Response to P fertilization was depended also on the hybrids. For example, OsSK 247 responded by yield increases by application of 2000 kg, while by remaining two tested hybrids the highest yield was found by application 1500 kg P2O5/ /ha. Under environmental conditions of cold climate at Lika region, Alpos should be recommend for matured grain, while OsSK247 and OsSK332 as ensilage corn. By growing of hybrids of the earliest maturity group (for example, Alpos) is possible in cold climate of Lika region to produce matured grain. However, more chances is for successful growing of ensilage corn for need of livestock feeding on own farm. We recommend application of the higher P quantities by fertilization for normalization of corn grain yields on P-deficient soils.

phosphorus deficiency ; corn ; yield ; Lika province ; Croatia

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