Title

Abstract

We analyzed the effects of plowing on root systems and root lodging of maize (Zea mays L.) in comparison with rotary tilling in upland fields converted from paddy fields in Gleysol. The percentage of soil water potential more than-3.1 kPa before the 6th leaf stage tended to be smaller following plowing than rotary tilling; and drainage was improved with plowing. Soil temperature at depths of 5 and 10 cm during the growing season was similar between the tillage treatments. Dry weight and leaf area index did not differ much between tillage treatments. Root length density and root weight density did not differ much between the tillage treatments, but root length and the percentage of root length at a depth of 0-5 cm tended to be higher with plowing than with rotary tilling, and the root depth index, which indicates the mean root depth, tended to be smaller with plowing than with rotary tilling. Although traits of root lodging (culm length, ear height, horizontal pulling resistance (HPR), and HPR-value) did not differ much between the tillage treatments, and root lodging status was lower with plowing than with rotary tilling. These results indicate that the root systems of maize in upland fields converted from paddy fields in Gleysol were shallower with plowing than with rotary tilling, and root lodging was alleviated by plowing. Plowing is expected to reduce lodging effects in maize grown in upland fields converted from paddy fields.

Analysis of the shallow root system of maize grown by plowing upland fields converted from paddy fields: effects of soil hardness and fertilization

“…Previous reports (Shinoto et al, 2019a(Shinoto et al, , 2018a indicate that the root system is shallower in PT than in RT under fertilized conditions. Furthermore, soil hardness at soil depths of 5-20 cm is higher in PT than in RT, and a higher proportion of fertilizer is distributed in the surface layer in PT than in RT (Shinoto et al, 2018b).…”

“…In upland fields converted from paddy fields, growth, grain yield, and nitrogen absorption of maize are not significantly different between rotary tilling and plowing tillage; however, the root system of maize does differ between plowing tillage and rotary tilling (Shinoto et al, 2018a(Shinoto et al, , 2017(Shinoto et al, , 2018b). The root system at maturity or at the milk stage tends to be shallower with plowing tillage than with rotary tilling (Shinoto et al, 2019a(Shinoto et al, , 2018a. Others have also reported that the root system of maize becomes shallower in untilled or shallowly cultivated soils because the root length in the surface layers is longer (Ball-Coelho et al, 1998;Barber, 1971;Bauder et al, 1985).…”