Assessment of Environment-friendly Usage of Spent Wash and its Nutritional Potential for Sugarcane Production

ABSTRACT

Excessive and inappropriate use of fertilizers is a key factor of low sugarcane yield and degradation of soil. A two-year (2013–14 and 2014–15) field study was conducted to assess the impact of combined application of organic and inorganic fertilizers on sugarcane at research farm of Shakarganj Sugar Research Institute, Jhang, Pakistan. Experiment was conducted under randomized complete block design with three replications. Treatments were used as control (no exogenous application), spent wash (160 t ha⁻¹), (nitrogen, phosphorus and potassium) NPK (168:112:112 kg ha⁻¹), spent wash (120 t ha⁻¹) + NPK (42:28:28 kg ha⁻¹), spent wash (80 t ha⁻¹) + NPK (84:56:56 kg ha⁻¹), spent wash (40 t ha⁻¹) + NPK (126:84:84 kg ha⁻¹), and spent wash (160 t ha⁻¹) + NPK (42:28:28 kg ha⁻¹). Application of spent wash @ 80 t ha⁻¹ + NPK @ 84:56:56 kg ha⁻¹ resulted maximum crop growth rate (11.35 g m⁻² d⁻¹), leaf area index (7.78), and net assimilation rate (2.53 g m⁻² d⁻¹). Maximum number of millable canes (14), weight per stripped cane (0.90 kg), stripped cane yield (117.60 t ha⁻¹) and unstripped cane yield (141.25 t ha⁻¹) were observed with spent wash @ 80 t ha⁻¹ + NPK @ 84:56:56 kg ha⁻¹, followed by sole fertilizer application @ 168:112:112 kg NPK ha⁻¹ and spent wash @160 t ha⁻¹ + NPK @ 42:28:28 kg ha⁻¹. Similar trend was observed regarding quality parameters. The maximum benefit–cost ratio (1.80) was achieved with integrated application of spent wash @ 80 t ha⁻¹ + NPK @ 84:56:56 kg ha⁻¹.

KEYWORDS:

• Sugarcane
• spent wash
• NPK
• cane yield
• sugar recovery
• economic analysis