Utjecaj razmaka cijevne drenaže na prinos ratarskih kultura na hidromelioriranom tlu

The research objective was to investigate the effect of different drainpipe spacing variants on the yield of field crops grown on hydroameliorated soil and to determine, applying the analysis of variance, the significance of the difference in yields between the tested variants. Investigations were carried out on hydroameliorated Gleyic Podzoluvisol on the experimental amelioration field Jelenščak-Kutina (central Sava valley) in the 1990-1993 and 1995-1999 periods. Four different variants of drainpipe spacing were tested in the trial (15 m, 20 m, 25 m and 30 m) in four replications. The same crop was grown and the same agricultural practices applied at the same time in all trial variants and in all trial years. During the research period, maize was grown in five years, winter wheat in three and oats in one year. Yields of the same crops differed per years and per different drainpipe spacing due to different factors, such as the genetic characteristics of the cultivars, or hybrids, different quantities and distribution of precipitation during the trial years, soil moisture before drilling, number of plants per unit area, total fertilizer applied and top-dressing pattern in the growing season, as well as the time of harvest. The highest maize yield was achieved in 1991 and ranged from 88.00 dt/ha (15 m spacing) to 71.74 t/ha (30 m). The lowest maize yield was recorded in 1996 - from 58.20 dt/ha (15 m) to 43.48 dt/ha (30 m). The highest wheat yield was achieved in 1991 - from 57.96 dt/ha (15 m) to 52.35 dt/ha (30 m), and the lowest in 1998 - from 38.88 dt/ha (20 m) to 30.88 dt/ha (30 m). Oats yield ranged from 42.19 dt/ha (15 m) to 37.59 t/ha (30 m). Analysis of variance, done separately for each trial year, rendered highly significant differences (p<0.01) between yields of particular crops in dependence on the drainpipe spacing in six trial years (1990, 1991, 1992, 1996, 1997 and 1998). Significant differences (p<0.05) between yields were recorded in 1999, while the 1993 and 1995 differences between yields, depending on the drainpipe spacing, were not significant. In the agroecological conditions of the central Sava valley, satisfactory yields can be obtained with the drainpipe spacing of 15 m. Drainpipe spacing of 20 m, supplemented by repeated vertical deep loosening of soil, may give satisfactory results in years when the drainage system is adequately maintained.Cilj istraživanja bio je ispitati utjecaj različitih razmaka cijevne drenaže na prinos ratarskih kultura na hidromelioriranom tlu i utvrditi analizom varijance opravdanost razlike u visini prinosa između testiranih varijanata. Istraživanja su provedena u razdoblju od 1990-1993. i od 1995-1999. god. Na melioracijskom pokusnom polju “Jelenščak”-Kutina ( srednja Posavina), na hidromelioriranom tlu Gleyic Podzoluvisol. U pokusu su bile testirane četiri varijante razmaka cijevne drenaže:15 m, 20 m, 25 m i 30 m, postavljene u četiri ponavljanja. Tijekom svake godine istraživanja na svim varijantama razmaka cijevne drenaže uzgajana je ista kultura i bili su primijenjeni jednaki agrotehnički zahvati i rokovi njihovih izvođenja. Tijekom istraživanja kukuruz je bio uzgajan pet godina, ozima pšenica tri i zob u jednoj godini. Prinos istih kultura bio je različit po godinama istraživanja i po različitim razmacima cijevne drenaže, što je prouzročeno različitim čimbenicima, kao što su: genetske značajke kultivara, odnosno hibrida, različita količina i raspored oborina tijekom godina istraživanja, vlažnost tla pred početak sjetve, broj biljaka na jedinicu površine, ukupna količina gnojiva i raspored prihrane usjeva u vrijeme vegetacije te vrijeme žetve-berbe usjeva. Tako je prinos kukuruza bio najviši u 1991. god. i kretao se od 88.00 dt/ha (za razmak od 15 m) do 71.74 t/ha (30 m). Najniži prinos kukuruza utvrđen je 1996. u visini od 58.20 dt/ha (15 m) do 43.48 dt/ha (30 m). Najviši prinos pšenice utvrđen je 1991. u visini od 57.96 dt/ha (15 m) do 52.35 dt/ha (30 m), a najniži 1998. od 38.88 dt/ha (20 m) do 30.88 dt/ha (30 m). Prinos zobi bio je od 42.19 dt/ha (15 m) do 37.59 t/ha (30 m). Analizom varijance posebno za svaku godinu istraživanja utvrđene su visoko signifikantne razlike (p<0.01) između prinosa pojedine kulture ovisno o razmaku cijevne drenaže u šest godina ispitivanja (1990, 1991, 1992,1996, 1997 i 1998). Signifikantne razlike (p