International Journal of Agricultural Policy and Research
Vol.4 (10), pp. 202-216, October, 2016
Available online at https://www.journalissues.org/IJAPR/
Article 16/ID/JPR069/15/ pages
Author(s) agree that this article remain permanently open access under the terms of the Creative Commons Attribution License 4.0 International License.
Original Research Article
Water productivity and radiation use efficiency of soybeans under water conservation practices in Ile-Ife, Nigeria
Omotayo B. Adeboye*1, Bart Schultz2, Kenneth O. Adekalu1 and Krishna Prasad3
1Department of Agricultural and Environmental Engineering, Obafemi Awolowo University, Ile-Ife, Nigeria
2Chairgroup, Land and Water Development, UNESCO-IHE Institute For Water Education,Delft, the Netherlands.
3Irrigation and Water Resources Consultant, Lalitpur, Nepal
* Corresponding Author Email: adeboyeomotayo(at)yahoo.com
Increasing water productivity and radiation use efficiencies (RUE) of Soybeans are very important in order to improve its production at field level. In this study, we investigated the productivity of Soybeans under the conventional (NC) and six water conservation practices: Tied ridge, Mulch, Soil bund , Tied ridge plus soil bund , Tied ridge plus mulch (TRML) and Mulch plus Soil bund arranged in a randomised complete block design. The objective of the study was to determine the effects of soil water storage (SWS) on land and water productivity and radiation use efficiency (RUE) of the crop and model the relationship between seed yield, total intercepted photosynthetically active radiation (TIPAR) or RUE. The RUE was determined by the linear relationship between dry matter and TIPAR. Average TIPAR ranged from 231 MJ m-2 for TR to 247 MJ m-2 for BD while for SWS, it ranged ranged from 485 mm for NC to 517 mm for TRML. Average seasonal RUEs ranged from 1.32 ± 0.19 g MJ-1 for TR and 1.92 ± 0.01 g MJ-1 intercepted photosynthetically active radiation (IPAR) for ML. Water conservation practices did not affect RUE of the crop. Seed yield was significantly correlated with IPAR (r2 = 0.61, p = 0.02) unlike with crop water use (r2 = 0.26; p = 0.36), RUE (r2 = 0.07; p = 0.36) and SWS (r2 = 0.03; p = 0.26). However, conservation practices increased seed yield by 24.2 to 44.3%. Water productivity (WPseed) increased by 14 to 41.8% and was strongly correlated to IPAR (r2 = 0.71) than with WPbiomass (r2 = 0.53) which increased by 7.8 to 28.3% under water conservation practices. However, WPbiomass and seed yield were not significantly related to RUE. It is hereby concluded that water conservation practices increased the seed yield and water productivity for seed and biomass but did not significantly affect the RUE of the crop. These findings will provide useful information for the development of water and radiation driven models for the production of Soybeans under rainfed conditions.
Key words: Soybean, water conservation practice, radiation use efficiency, yield, crop water productivity