engleski

Role of maize (Zea mays L.) hybrid in overcoming of acid soil stress

Maize is most spread crop on our arable lands. In the 30-year period (1960-1989) in Croatia, mean harvested area of maize was 509 thousands ha. Contriibution of the eastern Croatia (granary of country) in state territory is about 20%, but about 40% of country maize harvested area (and about 50% of total maize yield) is situated in this region. Degree of weather conditions favorability and soil characteristics are main factors of maize grain yield fluctuations. Soil acidity is certainly one of the most damaging soil conditions affecting the growth of the most crops. Choice of suitable maize hybrids plays an important role in yield formation, especially under stress, including less favorable soil characteristics. For this reason, we tested response of ten maize hybrids on normal and stress soil conditions. Five recognized and five experimental (exp.) maize hybrids (Table 2) of Osijek Agricultural Institute were grown in the 1997 growing season on two soils of the western Slavonia (Viroviticko-Podravska county) soils as follows: aluvial soil (normal fertility, pH in KCl=6.92) and stagnosol (reduced fertility, pH in KCl=4.06). The field experiments were conducted in four replications (experimental plot: two 10-m long rows = 14.35m2). Maize was sown in term April 28 and it was harvested at October 10, 1997. Grain yields were calculated on realized plant density and 14% moisture basis. In general, the growing season of 1997 was favorable for maize growing in Croatia, especially concerning rainfall distribution and temperature regime. For this reason, response of maize to soil stress was very low, because grain yields on the acid soil was only for 7% lower (mean 12.36 t ha-1) in comparison with the neutral soil (13.31 t ha-1). Also, percent of plant density realization was 83% and 88%, while grain moisture at harvest 27.6% and 31.2%, for acid soil and neutral soil, respectively (averages of ten hybrids). The highest yield differences were found among tested hybrids: from 9.87 to 15.83 t ha-1. OsSK373exp and OsSK554 hybrids (mean yield 15.04 t ha-1) yielded considerably more than OsSK332 and OsSK382 hybrids (mean 10.33 t ha-1). Also, differences were found among yields of same hybrids on two tested soils. For example, yields of four hybrids (OsSK373exp, Os382, OsSK427exp and OsSK445) were from 13% to 19% higher on neutral soil than on acid soil (means: 13.43 and 11.59 t ha-1, respectively), while yields of three hybrids (OsSK552, OsSK554 and OsSK426exp) were similar on both soil types (means: 13.59 and 13.68 t ha-1, respectively). In general, according from USA Corn Belt experiences drought accompanying with high air-temperatures at critical growth stages (July and August) is main responsible factor of low maize yields, under dry farming system growing, and our findings are also similar. Mean annually maize grain yields in the 10-year period (1980-1989, Statistical year books) in Croatia ranged from 3.92 to 5.33 t ha-1. These difference are mainly influenced by weather characteristics. However, soil properties are also considerable factor influencing maize yields: mean 6.85 t ha-1 in Vukovar municipality (prevailing of the most fertile soils of country) and mean 4.97 t ha-1 in Podravska Slatina municipality (prevailing of acid soils) for tested 10-year period. Although choice of maize hybrid is important factor of yield, especially under soil stress, favorable weather characteristics - rainfall quantities and their distribution, as well as temperature regime - can considerably to alleviate stress condition. Similar investigations could be contribution to better balance between plants and their soil environment.

Corn; Hybrid; Acid soil

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