CHARACTERIZATION AND SUITABILITY RATING OF SOME SELECTED WETLAND SOILS FOR RAINFED RICE PRODUCTION IN KWANDE LOCAL GOVERNMENT AREA, BENUE STATE
Authors: Kyat, M. M  , Idoga,  , S. O. I Abagyeh , Ugese, F  
Published: May 2023

This study was carried out to characterize and determine the suitability of selected soils of Kwande for rainfed rice production. The study area was Adagi, Ikyurav-ya Council Ward, Kwande Local Government Area of Benue State (05º35' and 05º47' N and longitudes and 07º55' and 07º39' E). The soils were characterized, classified and mapped out according to their morphological, physical and chemical properties. They were also mapped according to their topographic positions in relation to the level of soil moisture. Six varieties of rice (Faro 62, Faro 61, Faro 57, Faro 44, OM2386 and a local {Gborogidi}) were tested across three topographic positions. Field trials were carried out on three slope levels (middle, lower and toe) with the view to compare the performance among six varieties of rice and to ascertain the best variety for each of the slope levels. The study revealed that the soils were deep (107 – 167 cm), somewhat poorly drained, having 40.80 % to 76.80 % of sand, 08.00 % to 29.00 % of silt and 12.20 % to 40.92 % of clay. Unit I soils occupied the middle slope and were well drained while the other units were somewhat poorly drained as a result of their topographical positions and their texture and structure (moderate to strong sub-angular blocky). The soils in the study area were structurally strong coarse subangular blocky to strong fine subangular blocky in most of the horizons. The soils were rated as strongly acid to slightly alkaline in reaction ranging from 4.5 – 7.5. The soils had low organic carbon (0.17 to 2.51 gkg-1), very low total nitrogen (0.03 – 0.11 gkg-1), very low available P (2.31 to 5.90 mgkg-1), low to medium exchangeable bases (2.50 – 3.20 cmolkg1), low CEC (5.80 to 8.10 cmolkg-1) and high to very high base saturation (78.77 to 91.60 %). Based on these properties, the major soils of the three topographic positions namely; middle slope (unit I), profile 1 was classified as Typic Plinthustalf/Plinthic Lixisols (Arenic) while profile 2 was classified as Aquic Haplustept/Haplic Cambisol (Greyic); unit II profiles 3 and 5 were classified as Aquic Eutrudept/ Endogleyic Cambisol (Greyic) while profile 4 was qualified as Fluventic Haplustept/Haplic Cambisol (Greyic). The soil unit III was classified as Aquic Eutrudept/Endogleyic Cambisol (Greyic)). Soils of Unit I were well drained with low-water holding capacity and were strongly acid and being rated as marginally suitable (S3) while soil units II and III were rated as highly suitable (S1) for rainfed rice production as a result of their high-water holding capacity, low lying and tolerable soil reaction (high pH). Six (6) rice varieties were used as test crop. The rice yield results showed a positive correlation between the suitability classes and the actual yield. From the experiment, the rice yielded far better in the lower and toe slopes in soil Units II and III and were rated highly suitable (S1)than soil Unit I which was rated as marginally suitable (S3). The yields of soil unit II were statistically higher (5.39 t/ha) while the middle slope (unit I) was significantly lower (2.66 t/ha). Among the varieties, the yields were statistically higher in the following order: Faro 44> FARO 57> OM6328> FARO 62> FARO 61 and > Local. FARO 44 from the results seems to have scale neutrality, having the highest yield in all topographic positions, hence they are highly recommended as the best variety among the common varieties in the community. FARO 57 and OM6328 varieties are also highly recommended since they were not statistically different in yield with the other best variety. Considering the low chemical fertility status of the soil in the study area, appropriate fertilizers (250 kg of NPK 20:10:10) are recommended to make up the deficiency. The lower and toe slope positions are better topographic positions and are recommended for lowland rice than the middle slope.