Enhancing pedotransfer functions with environmental data for estimating bulk density and effective cation exchange capacity in a data‐sparse situation

Soil bulk density (BD) and effective cation exchange capacity (ECEC) are among the most important soil properties required for crop growth and environmental management. This study aimed to explore the combination of soil and environmental data in developing pedotransfer functions (PTFs) for BD and ECEC. Multiple linear regression (MLR) and random forest model (RFM) were employed in developing PTFs using three different data sets: soil data (PTF‐1), environmental data (PTF‐2) and the combination of soil and environmental data (PTF‐3). In developing the PTFs, three depth increments were also considered: all depth, topsoil (<0.40 m) and subsoil (>0.40 m). Results showed that PTF‐3 (R²; 0.29–0.69) outperformed both PTF‐1 (R²; 0.11–0.18) and PTF‐2 (R²; 0.22–0.59) in BD estimation. However, for ECEC estimation, PTF‐3 (R²; 0.61–0.86) performed comparably as PTF‐1 (R²; 0.58–0.76) with both PTFs out‐performing PTF‐2 (R²; 0.30–0.71). Also, grouping of data into different soil depth increments improves the estimation of BD with PTFs (especially PTF‐2 and PTF‐3) performing better at subsoils than topsoils. Generally, the most important predictors of BD are sand, silt, elevation, rainfall, temperature for estimation at topsoil while EVI, elevation, temperature and clay are the most important BD predictors in the subsoil. Also, clay, sand, pH, rainfall and SOC are the most important predictors of ECEC in the topsoil while pH, sand, clay, temperature and rainfall are the most important predictors of ECEC in the subsoil. Findings are important for overcoming the challenges of building national soil databases for large‐scale modelling in most data‐sparse countries, especially in the sub‐Saharan Africa (SSA).     

Preliminary evaluation of pineapple mixed-cropping systems for protecting reclaimed gulleys in the tropics: An experiment in Southeast Nigeria

This paper reports on research into the effectiveness of pineapple monocropping or intercropping systems (with cowpeas or egusi-melon) for reestablishing vegetative cover to check soil erosion on a reclaimed gulley in the tropical rainforest of southeastern Nigeria. High-density pineapple planting, intercropped with egusi-melon, was found to promote rapid vegetative cover, checked soil loss, improved soil structural stability and produced a high crop yield. Soil loss was moderate in pineapple plots intercropped with cowpeas and least in pineapple plots intercropped with egusi-melon. Increasing pineapple density enhanced the field establishment of cowpea and egusi-melon respectively.     

Identification and phylogenetic analysis of Babesia parasites in domestic dogs in Nigeria

The present study examined the presence of Babesia parasites in 104 domestic dogs in Nigeria. Sequentially, Babesia parasites infecting domestic dogs underwent genetic and phylogenetic analyses. The results of nested PCR based on the Piroplasmida 18S rRNA gene illustrated that 13.5% (14/104) of the samples were positive. The obtained positive samples determined the nucleotide sequences of the 18S rRNA genes. In the genetic and phylogenetic analyses, four of five nucleotide sequences were similar to Babesia canis rossi, and one sample exhibited a close similarity to a Babesia sp. isolated from a raccoon in Hokkaido, Japan. The present study revealed the widespread presence of B. canis rossi among domestic dogs in Nigeria.     

Response of soil properties and yam yield to Chromolaena odorata (Asteraceae) and Tithonia diversifolia (Asteraceae) mulches

Plant materials differ in their chemical composition, rate of decomposition and suitability as mulch materials. Experiments were conducted during 2006–2007 and 2007–2008 cropping seasons for early yam cultivation at Owo in the forest–savanna transition zone of southwest Nigeria to study the effect of Chromolaena odorata and Tithonia diversifolia mulches applied at 0.0, 5.0, 7.5, 10.0 and 12.5 t ha^?1 on soil chemical properties, leaf nutrient composition, growth and tuber yield of white yam (Dioscorea rotundata Poir). Both C. odorata and T. diversifolia mulches reduced soil bulk density and temperature; increased concentrations of soil organic matter (SOM), total N, available P, exchangeable K, Ca and Mg, leaf N, P, K, Ca and Mg; enhanced growth and yield of yam compared with control. The values of SOM, total N and available P and leaf N and P concentrations increased with increasing mulch rate. C. odorata mulch and T. diversifolia mulch applied at 10.0 and 7.5 t ha^?1, respectively, was found to be suitable for yam production. T. diversifolia mulch compared with C. odorata mulch produced higher values of soil chemical properties, leaf nutrient concentrations, growth and yield of yam. T. diversifolia mulch produced 19% and 18% higher tuber yield compared with C. odorata mulch during 2006–2007 and 2007–2008 cropping seasons, respectively.     

Variations in Soil Physical Properties in a Cleared Forestland Continuously Cultivated for Seven Years in Eastern Nsukka,Nigeria

In this study, soil physical properties were evaluated in the top 40 cm of cleared forestland that had been subjected to continuous cultivation for 7 years to ascertain selected crop or crop combinations that influenced the soil physical properties the most. There was no significant effect of crop treatment on particle‐size distributions over 6 years of cultivation. In year 7, clay values were significantly (p = 0.05) greater in plots grown with solely cassava (SC) and solely maize (SM) than in the plots grown with solely pigeon pea (SP). The soil depth effects over the 7 years were significant on the clay content. The mean values of bulk density, pore‐size distribution, and hydraulic conductivity obtained from each plot fluctuated over the years. The bulk density values in 1998 ranged from 1.29 to 1.43 g cm³, but from 1999 to 2004, the range was from 1.12 to 1.40 g cm³. Thus, bulk density generally decreased when compared with their respective values in 1998. The greatest decrease of ≈ 22% was in 2000. More than 70% of the macroporosity values were significantly less than their respective values in 1998. The greatest decease of 72% was obtained from SM plots in 2001. All the microporosity were significantly more than the 1998 values. All the increases were >100% of the original values. These increases were reflected in the variations of total and saturated hydraulic conductivity (Ks) values. However, in 2004, Ks values decreased in the plots grown to C + P, SP, and SM. Generally, the C + M + P mixture appeared to be the most consistent in improving micro‐ and total porosities and Ks among the crop treatments.     

Information and Training Needs of Non-Timber Forest Products' Operators in Southern Nigeria

Abstract

This study examined the training needs of non-timber forest products' (NTFP) operators in Southern Nigeria. One hundred-fifty forest operators in Ondo State, Nigeria were sampled using structured questionnaire. Data collected was analyzed using percentages, mean, Chi-square test, and Pearson Product Moment Correlation. The results revealed that majority of the forest operators in Southern Nigeria are middle-aged women with low level of education. The need for training is high and significant (P < 0.05), and there is a positive relationship between training/ information received and the operators's productivity.     

Vegetation and its relation to soil nutrient and salinity in the Calabar mangrove swamp,Nigeria

The study examines vegetation – environment relationships. Vegetation measurements included species frequency, density, diameter and tree height, while environmental measurements were soil particle size distribution, acid properties (pH, Al, SO₄), nutrient cations (Ca, Na, Mg, K), organic carbon, nitrogen, phosphorus and chloride content. Nypa fruticans was the dominant species in the A stratum (> 3 m tall) while Rhizophora mangle was dominant in the B stratum (1–3 m tall). The C stratum (< 1 m tall) was dominated by mangrove, Nypa and Raphia saplings. Silt was dominant and the most variable particle size fraction. A principal components analysis of the soil data indicated the first three dominant components influencing the vegetation were salinity, nutrient and soil texture. Tree height and density correlated highly with the salinity and soil texture gradients (P < 0.01), while basal area correlated with salinity and nutrient gradients (P < 0.01). While Avicannia africana in the A stratum was influenced largely by the salinity and soil texture gradients. Nypa fruticans in the B stratum was influenced by salinity and nutrients.     

Evaluation of yield stability of cowpea under sole and intercrop management in Nigeria

Summary Nine cowpea (Vigna unguiculata (L.) Walp.) breeding lines were grown in 13 experiments under sole crop and intercrop management, with and without insecticide application, in Nigeria. Cowpea was intercropped with cassava (Manihot esculenta Cranz), maize (Zea mays L.) and maize-cassava in the forest zone and with sorghum (Sorghum bicolor Moench.) and millet (Pennisetum glaucum (L.) R.Br.) in the savanna zone. Line by cropping system interactions were significant in 5 of 13 experiments and line by insecticide treatment interactions were significant in 2 of 13 experiments. Cowpea yield was severely depressed in intercropped plots and in plots to which no insecticide was applied. Among-environment variation in cowpea yield was greater when no insecticide was applied. Within each management treatment, the yield performance and stability of the cowpea lines was examined. Stability was assessed both by examining among-environment coefficients of variation and by regression analysis. Several of the breeding lines evaluated appeared promising under different levels of management and in a diversity of environments.     

Traditional soil and land appraisal on fadama lands in northeast Nigeria

Abstract. As part of a study of recession farming on the 'fadama' lands on a segment of the Komadugu-Yobe floodplain, a survey was carried out to investigate the local farmers' perception of soil types and management practices. The farmers are clearly aware of the differences in soil type on the fadama and they possess unique skills in managing their farm lands. The farmers classify fadama soils for recession farming by assessing soil texture and soil drainage conditions by feel and observation. Integrating such local knowledge into soil surveys will lead to better practical definition of mapping units and give soil names that have more meaning for the farmers.     

从尼日利亚进境的芋头中截获最短尾短体线虫

广东检验检疫技术中心植检实验室于2008年4月从尼日利亚进境的芋头中分离到数条短体线虫,经纯培养、形态观察、测量,以及对rDNA-ITS、D2D3区序列的扩增、克隆、测序分析,鉴定为最短尾短体线虫(Pratylenchus brachyurus(Godfrey,1929)Filipjev & Schuurmans Stekhoven,1941)。该线虫在国内局部分布,属于检疫性线虫,在系统内首次截获。