Manurial amendments and source of water for supplemental irrigation of sawah-rice system influenced soil quality and rice yield

Abstract

Soil and water management research on adapting the promising sawah ecotechnology for lowland rice farming in West Africa has largely focused on the abundant inland valleys; floodplains which too represent a huge agricultural resource in the region have not been so involved. Sawah refers to a bunded, puddled and leveled basin for rice, with water inlets and outlets for irrigation and drainage, respectively. In conventional sawah, soil fertility is augmented using mineral fertilizers, with an option to harness lowland water resources for use in small-scale irrigation to create the so-called sawah typologies. In this study, we evaluated the effects of three manurial amendments (rice husk, rice-husk ash and poultry droppings, each at 10 t ha–1) and NPK 20:10:10 at 400 kg ha–1 interacting with source of water (spring or pond) used for supplemental irrigation of three sawah typologies in a floodplain in southeastern Nigeria. Plots amended with poultry droppings and supplemented with spring water recorded the overall best performance of the sawah-rice system; the control being the unamended non-supplemented (solely rainfed) plots recorded the worst. Rice-husk ash and rice husk enhanced soil pH and soil organic carbon, respectively. The three sawah typologies showed a consistent trend thus spring-supplemented ≥ pond-supplemented ≥ non-supplemented sawah. Rice grain yield was influenced by soil total nitrogen and the sum of the three plant-nutrient basic cations (K+ , Ca2+ and Mg2+), with the influence of K+ alone being the greatest. To enhance rice performance including grain yields in floodplain sawah, farmers should utilise poultry droppings as soil manure and spring water for supplemental irrigation.

Capability groupings of some nun river floodplain soils of Bayelsa State, Southern Nigeria

“…Agricultural potentials of alluvial soils have not been fully exploited due to insufficient data on their physical and chemical properties and concomitant changes they undergo under intensive cultivation (Effiong and Ibia, 2009;Ukaegbu et al, 2015;Ukabiala et al, 2021). Floodplains are about the most fertile lowland resources used mostly for rice production as well as dry season vegetable farming, and they can be highly responsive to management (Nnadi et al, 2021). In Bayelsa State of Nigeria occurs a vast land space of floodplain soils with high agricultural potentials but current information on their characteristics, capabilities and suitability are inadequate (Dickson et al, 2020).…”

Hydrochemical characteristics and suitability of Kanzenze River for irrigation of akagera upper catchment in Rwanda

“…The increasing request for high-quality water for irrigation in Rwanda in the last years has led to the use of poor-quality water for irrigation mainly in farmland. The use of low-quality water could cause a decline in crop productivity (Nwite et al, 2017;Abdel-Fattah et al, 2020;Nnadi et al, 2021). The current study indicated that the water of the Kanzenze River was classified as moderate for salinity and acidic hazard.…”

Soil properties affecting soil organic carbon stock of different land use types in two agro-ecological zones of Nigeria

“…Lowest mean SOC was observed on A -LU3 at Ado-Ekiti. This may be attributed to frequent wetting-drying cycles in waterlogged soils which facilitates SOC decomposition, thus lowering of its content in the soil (Nwite et al, 2017;Nnadi et al, 2021). At the two sites, the range of mean SOM among the LUTs and across the four soil depths ranged between 0.60 and 1.56% and 0.59 and 1.59% respectively.…”