Response of Sorghum-groundnut to Row Arrangement and Orientation under Nominal Nitrogen Management

摘要

Aim: A study was conducted in eastern Uganda to rationalise sorghum-groundnut mixtures through manipulation of row arrangement and orientation, under nominal N management. Study Design: Treatments included row arrangements, viz . alternating 1:1 (single rows) and staggered 2:2 (double rows); row orientation viz . north-south and east-west; and N application, viz . 0 and 40 kg ha-1. Treatments were laid down in a randomized complete block design, in a split-split plot arrangement. Nitrogen rate was the main plot, row orientation as subplot and row arrangement as sub-subplot. Place and Duration of Study: The study was conducted in eastern Uganda for two cropping seasons (2010b-2011a). Methodology: Sorghum (Sekedo variety) and groundnut Red beauty variety ( Emoit ), were the component intercrops. Measurements included plant height, grain yield, solar radiation interception and intercropping financial advantage. Light interception was determined using a digital Lux light sensor (Lutron Model: Lx-101). The light available to the under storey intercrop was computed as a fraction to the total available (ambient) PAR. The data collected were analysed using GenStat software Version 11, and significant treatment means were separated using LSD at 5% probability level. Results: Staggered double rows gave better groundnut grain yield irrespective of row orientation and N regime. The E-W row orientation resulted in a greater groundnut yield by up to 50%, than those facing N-S. Sorghum yield, however, was slightly increased by N rate, but not by row orientation and arrangement. Groundnut rows oriented E-W intercepted more solar radiation than those in the N-S direction, in both alternate single and double row arrangements. Conclusion: The staggered double rows, oriented east-west and subjected to application of 40 N kg ha-1 is technically and financially the superior management option for sorghum production in eastern Uganda.