Effect of water management and nitrogen rates on iron concentration and yield in lowland rice

摘要

In order to attain self-sufficiency of rice in Nigeria, production could be increased to feed the growing population. Water for irrigation is becoming scarce; iron toxicity is a major constraint in the production of lowland rice under waterlogged conditions. Loss of nitrogen through denitrification and leaching also mitigate against sustainable irrigated rice production in Bida area. A field trial was conducted in 2009 and 2010 to evaluate water and nitrogen management on concentration of iron as it affects yield of lowland rice in the NCRI research fields in Bida,Niger State. The results obtained show that there were significant differences in plant height, panicles number, straw and grain yield when compared with the control (farmers practice). There were no significant differences in grain yield between treatments three with values of 3.05 t ha-1 and four with 2.80 t ha-1. Yields generally increased with increasing levels of nitrogen and declined from 80 kg ha-1. Nitrogen use efficiency increased with increasing levels of nitrogen rates and was 4.78 kg at 80 kg N ha-1.There were also significant differences in plant tissue iron content but no significant differences in grain iron content. Iron concentration was higher in the control than treatments with higher levels of nitrogen as shown by iron toxicity score. Irrigation water was applied at soil moisture tension of -30 KPa. The total water applied was 1348 mm including rainfall and crop water use for the control that had flooding till harvest. The treatment that was drained four times at intervals saved 143 mm and water use efficiency was 4.78 kg mm-1.Appropriate water and nitrogen management could reduce the intensity of iron in rice to enhance sustainable yield increases of paddy rice in the lowland soils of Bida area.