No abstract

Soils of Khana Local Government Area of Rivers State, Southern Nigeria were evaluated using semi detailed soil survey for citrus cultivation. The purpose of this research was to evaluate the suitability of soils of the study area for the cultivation of citrus. The total land area covers 49,631.54 ha and was delineated into eight mapping units based on the soil types. One pedon each was dug in each mapping unit and described using the FAO system. The nonparametric method of soil suitability evaluation was used. Four soil orders, majorly Inceptisols/Cambisols, Entosols/Arenosols, Ultisols/Acrisols, and Alfisols/Lixisols, were identified in the area. The results showed that land requirements/characteristics such as climate (mean annual rainfall), wetness (depth to water table) and fertility made the land marginally suitable (S3) to not suitable (N) for citrus cultivation across the eight pedons. The three limitations for citrus cultivation in the area are climate (annual rainfall), wetness (depth to the water table) and fertility (low status of NPK and pH). The land is potentially suitable for citrus cultivation but currently marginally and not suitable due to these three limitations.

No abstract

A 200 hectare parcel of land in Edo state of Nigeria was evaluated for its suitability for rice cultivation, under three land utilization types (LUT) :(i) Rain-fed upland,(ii) Natural flood and (iii) Irrigated rice cultivation.. Six soil mapping units were established and appropriate guidelines specific for each LUT was followed in establishing the suitability of the land for rice cultivation. The suitability of each soil for each of the different land utilization types was ranked relative to the other soils and the rankings were compared using the Spearman's ranking correlation coefficient. The results showed that Rain-fed upland rice can only be practiced in 40 hectares (19.5 %) of the area, at a marginal class of suitability, Irrigation can be practiced in at least 160 ha and Natural floods in 189 ha (94.5 %). With a correlation coefficient of 0.96 between Irrigated and Natural flood methods, it means that either of them can be practiced but because their seasons are different, one can be made to follow the other in practice-Irrigation to follow Natural floods.

Some soils of coastal plain sands in South Southern Nigeria were assessed for oil palm and coconut cultivation. This research was carried out to evaluate the soils of the study area using rigid grid soil survey methodology at detailed scale. The study area (128.11 ha) was delineated into four soil mapping units based on soil type. A pedon was sunk in each mapping unit and described according to FAO. Three soil orders, including Entisols (Ahiara), Inceptisols (Kulfo) and Ultisols (Orlu), were identified. Parametric and limitation methods of land suitability evaluation were used. Major limitations to assessment were climate (mean annual temperatures) and soil physical properties (texture/structure). Aggregate suitability rating (both actual and potential) showed that Ultisols (pedons 3 and 4, covering 56.73 ha) was moderately suitable (S2) for coconut and marginally suitable (S3) for oil palm, Inceptisols (pedon 2, covering 54.25 ha) was marginally suitable (S3) for coconut but not suitable (NS) for oil palm, and Entisols (Pedon 1covering 17.13 ha) was not suitable (NS) for any of the crops. Thus, area with Entisols should not be used for cultivation of any of the crops due to major limitation in texture. Moreover, both assessment approaches captured the major limitations. Therefore, the use of any of the approaches employed in this study and for these crops becomes a matter of choice as both of them showed no major differences in the application of their procedures.