Effect of plant density on grain yield and moisture content in maize hybrids

Abstract

A two-year trial (2002-2003) was conducted in order to study the effect of plant density (30,000, 40,000, 50,000 and 60,000 plants ha-1) and vegetation length (ZPSC 434, ZPSC 680 and ZPSC 735) of hybrids on grain yield and humidity content in corn grain. A field microexperiment was used under the agro ecological conditions of northern Šumadija (Radmilovac) on the trial plots of the Faculty of Agriculture, Belgrade University. Experiments were conducted on the leached chernozem soil type using a split-plot design in three replications. In the first trial year and under favorable weather conditions average yields amounted to 9.39 t ha-1. In the second trial year characterized by unfavorable humid weather conditions the yield achieved was substantially lower amounting to 6.80 t ha-1. On average for hybrids and trial years the smallest average corn grain yield containing 14% humidity was achieved with the smallest plant density (30,000 plants ha-1) amounting to 6.99 t/ha. Increasing plant density by 10, 20 and 30 thousand plants per hectare tended to raise yield by 0.90, 1.58 and 1.94 t ha-1, i.e. by 12.9 22.6 and 27.8% respectively. The highest average yields for average plant density was achieved using the hybrid ZP 434 (8.47 t ha-1), followed by ZP 680 (8.05 t ha-1) whereas the lowest yield was achieved using the hybrid ZP 735 (7.77 t ha-1). In the first trial year increasing plant density tended to raise humidity content in hybrid corn grain. The increase amounted to 3.8 to 8.0 points at 40,000 plants, i.e. 60,000 plants ha-1, respectively compared with the smallest plant density (30,000 plants ha-1). In the second trial year, humidity content in the grain varied irregularly. Considering the 2-year average, the lowest humidity content in the grain was registered using the hybrid ZP 434, amounting to 18.5%. The reason for this being a shorter vegetation period of ZP 434 compared with the other two hybrids tested.

U dvogodišnjem periodu (2002-2003) vršena su ispitivanja uticaja gustine useva (30.000, 40.000, 50.000 i 60.000 biljaka po hektaru) i hibrida različite dužine vegetacionog perioda (ZPSC 434, ZPSC 680 i ZPSC 735) na prinos zrna i sadržaj vlage u zrnu kukuruza. Ispitivanja su obavljena putem poljskih mikroogleda u agroekološkim uslovima severne Šumadije (Radmilovac) na oglednom imanju Poljoprivrednog fakulteta Univerziteta u Beogradu. Ogledi su izvedeni na zemljištu tipa degradirani černozem, metodom razdeljenih parcela (split-plot) u tri ponavljanja. U meteorološki povoljnijoj, prvoj godini, prosečan prinos je iznosio 9,39 t/ha, dok je u drugoj godini, koja se karakterisala pre svega, nepovoljnijim uslovima vlažnosti, prinos bio znatno niži i iznosio je 6,80 t/ha. U proseku za hibride i godine ispitivanja, najniži prosečan prinos zrna kukuruza sa 14% vlage je ostvaren pri najmanjoj gustini useva (30.000 biljaka/ha) i iznosio je 6,99 t/ha. Sa povećanjem gustine useva za 10, 20 i 30 hiljada biljaka po hektaru prinos se povećavao za 0,90, 1,58 i 1,94 t/ha, odnosno za 12,9, 22,6 i 27,8%. Najviši prosečan prinos, u proseku za gustine useva, ostvaren je kod hibrida ZP 434 (8,47 t/ha), zatim ZP 680 (8,05 t/ha), a najniži kod hibrida ZP 735 (7,77 t/ha). Sadržaj vlage u zrnu hibrida kukuruza se, u prvoj godini, povećavao sa povećanjem gustine useva kukuruza. To povećanje je, u odnosu na najmanju gustinu (30.000 biljaka/ha), iznosilo od 3,8 do 8,0 indeksnih poena pri gustini od 40.000 odnosno 60.000 biljaka po hektaru. U drugoj godini sadržaj vlage u zrnu je nepravilno varirao. U dvogodišnjem proseku, najmanji sadržaj vlage u zrnu utvrđen je kod hibrida ZP 434 i iznosio je 18,5%. Ovo je svakako, neposredna posledica i okolnosti da je hibrid ZP 434 kraćeg vegetacionog perioda u odnosu na preostala dva hibrida zastupljena u našim istraživanjima.