Tillage effects on soil physical condition and root growth associated with sugarcane water availability

We hypothesized that in-row deep tillage (DT) may improve crop resilience during dry spells through change in the soil physical/hydraulic properties, in root system development and yield. The objective of this study was to gain insight into the influence of this management on soil physical properties and root growth associated with sugarcane water availability. A three-year experiment on a sandy-clay haplustox was used for the assessment of water retention, bulk density, porosity, pressure head, temperature and plant response (yield and root system). Soil carbon stocks were also assessed in the soil profile. The treatments compared of conventional tillage (CT), which consisted of a 0.3 m ploughing followed by two disking graders with 20" discs and one light disking leveler grade, and DT, a subsoiler rod (0.8 m deep) with a rotary hoe with 16 knives to raise crop seedbed in rows. Our results reveal that DT resulted in lower bulk density and higher total porosity values than CT in most cases for the surface soil layers. Moreover, while the soil water relations did not show significant difference for total water availability, the soil water pressure head monitoring indicated a trend of more negative values under CT management, i.e., a drier condition. Additionally, DT resulted in better root system development referring to root density and root length density. However, DT resulted in lower sugarcane yield. The experiment was carried out under rainfed conditions, but rainfall distribution did not limit sugarcane production. Therefore, under the mild water stress conditions as observed in this study, the observed root biomass increase did not favor sugarcane yield187110118CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP404245/2013-7; 407258/2013-22016/09133-