Improving bud sprouting, growth and yield of winter initiated sugarcane ratoon through tillage cum organic mediated rhizospheric modulation in Udic ustochrept under subtropical Indian condition
Abstract Field experiment was conducted during 2007–2010 at research farm of Indian Institute of Sugarcane ( Saccharum officinarum ) Research, Lucknow. The findings of the investigation revealed that tillage operation performed by Ratoon Management Device (RMD) involving earthing-up from both the sides of sugarcane stubble protects the subterranean buds from cold injury and provides congenial rhizospheric environment for survival and sprouting of buds. Tillage through RMD superimposed with composted trash regulates the soil microbial activities (ex situ soil respiration – 29.52 mg CO 2 -C kg −1  soil day −1 and soil microbial biomass carbon (SMBC) – 187.3 mg C microb  kg −1  soil day −1 ). These in turn enhance the sprouting of stubble buds which otherwise fail to sprout under the influence of extremely low temperature. The tillage cum organic treatments creates congenial soil–water–air relations which produce viable and vigorous sprouts. Translated into practice, it means that the fact ‘Tillage is manure’ is quite pertinent in winter initiated sugarcane ratoon as mechanical manipulations of soil (tillage) at its optimum moisture level creates favourable physical environment (soil tilth) in root zone (bulk density – 1.35 Mg m −3 at 0–15 cm soil depth and infiltration rate – 5.5 mm h −1 ). Addition of organics further provides congenial substrate/s to soil microbiota and enhances their metabolic activities which along with new activated roots maintain better soil–water–air relations and enhancing their sprouting in cold conditions. This ensures synchronized, early formed adequate number of millable canes (135,000 ha −1 ), consequently resulting in higher ratoon cane (94.1 Mg ha −1 ) and sugar yields (8.75 Mg ha −1 ). The tillage cum organic technology is of immense significance to cane growers by increasing sugar yield in early crushing season from ratoon.