Soil organic matter and NPK status as influenced by integrated use of green manure, crop residues, cane trash and urea N in sugarcane-based crop sequences

Yadav, R.L.

Soil organic matter and NPK status as influenced by integrated use of green manure, crop residues, cane trash and urea N in sugarcane-based crop sequences

1995

Yadav, R.L.

A field experiment was conducted at Lucknow (26.5 degrees N, 80.5 degrees E, 120 m above mean sea level), India, during 1992-1995 to compare biomass productivity and crop yields in Sesbania aculeata (as green manure)-sugarcane-ratoon and rice-sugarcane-ratoon rotations at 0, 150 and 300 kg ha-1 N through urea to sugarcane, and 0, 75, 150 and 225 kg N ha-1 applied to the subsequent ratoon crop with and without trash mulch. The Sesbania-sugarcane-ratoon rotation added 14.48 t ha-1 biomass to the soil compared with 4.81 t ha-1 by the rice-sugarcane-ratoon rotation because Sesbania yielded a significantly greater biomass (11.12 t ha-1) than did the residual rootmass of rice (1.68 t ha-1) and sugarcane (2.64-3.83 t ha-1). Soil organic carbon, however, tended to decline after green manuring with Sesbania but gradually increased after incorporation of rice-root residues. Trash mulching of the ratoon crop upgraded the level of soil organic carbon and mineral-N status compared to no mulching. Sugarcane yields were significantly higher in the rice-sugarcane-ratoon rotation than in the Sesbania-sugarcane-ratoon rotation. A multiple linear regression model; Y=8.075+0.675 (PN) -22.45(OC)+0.671(P); R2=0.965, showed that cane yields (Y) were influenced significantly by N uptake (PN), soil organic carbon (OC) and available P (P) status.

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