The impact of long-term reduced primary soil tillage on maize (Zea mays L.) productivity

Abstract

A long-term field experiment (since 1988) was carried out at the Experimental Station of the Aleksandras Stulginskis University (ASU, 54° 52′ N, 23° 49′ E) in the conditions of transitional maritime-climate. Research data from the 2010-2012 experimental period are presented. The soil of the experimental site is silty light loam Endohypogleyic-Eutric Planosol (PLe-gln-w). Average annual temperature is 6.2°C. The aim of the experiment was to establish the influence of reduced primary autumn soil tillage on maize productivity. The treatments of the experiment were: 1) conventionally (22-25 cm) ploughed by a mouldboard plough, 2) shallowly (12-15 cm) ploughed by a mouldboard plough, 3) deeply (25-30 cm) tilled by a chisel cultivator, 4) shallowly (10-12 cm) tilled by a disc harrow, 5) no-till. The experimental results showed that all primary soil tillage methods (except for chiselling) normally had insignificant effect on maize biometric parameters. Deep chiselling had consistent negative influence on the biometric parameters of maize canopy, while no no-till effect was insignificantly positive. Maize crop biometric parameters partially depended on weed infestation at the beginning and the end of maize vegetation. In two out of three experimental years, maize crop density at the beginning and end of vegetation did not differ significantly in differently tilled plots. A relationship was found between the number of annual as well as total number of weeds and crop density at the beginning of vegetation (r = -0.926** and -0.948**). Crop density at the beginning of vegetation had significant positive effect on most maize productivity parameters. Reduced soil tillage from shallow ploughing to no-till had total positive effect on maize productivity in 2011 only because of the lower weed infestation. Relationships were established between weed infestation and maize crop productivity parameters (correlation coefficients from -0.394 to -0.965**). Productivity parameters were influenced by biometric parameters too (correlation coefficients from 0.713** to 0.920**).