Water use, growth and development of sugarcane as affected by a trash mulching

Abstract

Retention of a sugarcane mulch blanket, following green cane harvesting could increase soil water conservation, soil health (organic matter content and micro-organism activity) and soil nutrient status. However, little is known about the effect of such a mulch layer on sugarcane crop growth and development. To study the latter, an experiment was carried out in Komatipoort at the South African Sugarcane Research Institute’s Experimental Station. Row spacing arrangement was either 1.5 m or 1.2 m x 0.6 m tram rows. N14 was planted as a fast canopy growing cultivar and N26 as a slow canopy growing cultivar. Plots were either covered by a mulch layer or left as bare soil. Stalk population, stalk height and radiation interception were measured every second week. Soil temperature readings were logged hourly at a depth of 0.15 m. Preliminary results indicated that early growth and development of sugarcane was delayed under mulch treatments. Stalk length of N26 was reduced more than that of N14. Stalk population of both cultivars were significantly lower under the mulch treatment. Fractional interception of solar radiation was only 50% at 150 days after planting for the mulch treatment, compared to 70% for bare plots. Slow initial growth and delayed canopy development in mulch treatments were associated with low soil temperatures in the period leading up to full canopy closure. Soil temperature in the mulch treatments remained between 3 to 4oC lower than the bare soil treatments. Early indications are that the presence of a mulch layer may reduce early growth and development of sugarcane. Copyright