The performance and profitability of sweet potato (Ipomoea batatas L.) as influenced by propagule length and application rates of cattle dung in humid ultisols

This study was conducted in 2013 and 2014 at the Teaching and Research Farm of the Faculty of Agriculture, University of Benin, Benin City, Nigeria. The aim of the study was to evaluate the effect of propagule length and cattle dung application rates on the growth, yield and profitability of sweet potato (Ipomea batatas L.) in a humid Ultisols. Treatments consisted of three different propagule lengths of vine cuttings (30, 40 and 50 cm) and three rates (0, 225 and 450 kg N ha−1 ) of cattle dung in a 3 × 3 factorial arrangement fitted into randomized complete block design and replicated three times. The productivity of sweet potato was enhanced by the application of cattle dung and increasing propagule length positively. Growth and yield variables varied significantly with propagule length and cattle dung application. Number of vines, vine girth and number of leaves increased significantly with increase in propagule length. Cattle dung application rates of 225 and 450 kg N ha−1 had statistically at par number of vines, vine girth, vine length, number of nodes and leaves and leaf area index but significantly higher than unfertilized plants. The highest tuber yield of 26.10 and 22.00 t ha−1 was obtained from vine cutting of 40 cm and 20 t ha−1 cattle manure, respectively. The interaction of propagule length and cattle dung application rate on all growth and yield parameters were not significant. Tuber size significantly (P ≤ 0.05) correlated positively with number of leaves (r = 0.351), number of nodes (r = 0.288), number of tubers (r = 0.377), tuber length (r = 0.475). Tuber yield significantly correlated positively with the number of leaves (r = 0.335), number of tubers (r = 0.281), tuber length (r = 0.365) and tuber size (r = 0.652). The appropriate propagule length and cattle dung application rates were 40 cm and 225 kg N ha−1, respectively as they had the highest return per naira invested. Key words: economic analysis, growth variables, organic fertilizer, tuber yiel

Yield and yield components of intercropped dual-purpose lablab and cowpea with maize of contrasting maturities

Intercropping is a way to intensify agricultural land use. Cowpea is an important crop in the traditional farming systems in northern Nigeria because it serves to provide food and feed. Although lablab has potential to function in these ways, it remains an underutilized crop because among other factors, there is dearth of information on its incorporation into the system by way of intercropping it with the major cereal crops. A field trial was conducted at Samaru (11º 11’N, 07º 38’E, 686 m asl) in northern Guinea savannah of Nigeria, to evaluate the relative yield and yield components of dual-purpose lablab and cowpea cultivars when gown sole and when intercropped with maize of contrasting maturities. The experiment was laid out in a split-plot design with four replications. The experiment consisted of early maize maturing cultivar (TZE COMP. 5 W) and a late maize maturing cultivar (TZL COMP. 1 SYN). Cropping system (intercropping and sole cropping) was assigned to the main plot and crop cultivar (lablab: ILRI 4612, NAPRI 2 and cowpea: IT89KD- 288, IT99K-241-2) was assigned to subplots. Results showed that intercropping cowpea or lablab into early maturing maize cultivar was more productive than intercropping into late maturing maize cultivar for number of pods (74.4 vs. 63.9), harvest index (0.22 vs. 0.20), grain yield (575.7 vs. 441.0) and fodder yield (2075.4 vs. 1758.2) for the legumes. Lablab cultivars had superior performance than cowpea for number of pods (113.5-114.2 vs. 81.1-81.5) and fodder yield (2968.9-3042.3 vs. 1725.4-1795.9 kg ha-1) whereas cowpea cultivars had superior performance than lablab for harvest index (0.29 vs. 0.17) and grain yield (802.3-833.9 vs. 587.8-632.4 kg ha-1), meaning that both legumes have potential in providing food and feed with lablab producing more fodder and cowpea more grain. Land equivalent ratio showed that intercropping advantage was higher when lablab and cowpea were intercropped with early maturing maize cultivar (1.34, 1.24) than with late maturing maize cultivar (1.10, 1.15). It is recommended that for higher lablab or cowpea/maize productivity in an intercrop, farmers should intercrop dual-purpose cultivars of these crops with maize of earlier maturities.Keywords: maize, lablab, cowpea, grain yield, fodder yiel

Sweet potato (Ipomoea batatas) growth and tuber yield as influenced by plant spacing on sandy loam in humid tropical environment

The choice of appropriate plant spacing that gives optimum  density of sweet potato (Ipomoea batatas (L.) Lam) is crucial for its productivity, considering that plant density of cover crops affects above-ground access to sunlight, degree of soil surface cover, and below-ground tuberization. The influence of plant planting and the ensuing plant density on growth and tuber yield of sweet potato in a sandy-loam soil in southern Nigeria was assessed in the 2012 and 2013 growing seasons. The field trials involved five plant spacings namely 90 × 90, 60 × 90, 60 × 60, 30 × 90, and 30 cm × 60 cm; corresponding to plant densities of 1.23, 1.85, 2.78, 3.70 and 5.56 plants m–2, respectively. Data were collected on vine girth, number of leaves, leaf area, tuber weight plant–1 and tuber yield, as well as on weed dry matter. Closer plant spacings resulted in higher number of leaves m–2 and leaf area index (LAI). However, tuber weight plant–1 was highest with the second widest spacing (60 cm × 90 cm) and decreased with spacing. By contrast, tuber yield increased with spacing; the closest spacing (30 cm × 60 cm) gave the highest value (12.95 t ha–1) which, however, was similar to 10.55 t ha–1 due to the second closest spacing (30 cm × 90 cm) which, in turn, was similar to 60 cm × 60 cm (9.55 t ha–1) and 60 cm × 90 cm (8.89 t ha–1). Tuber yield correlated with number of leaves (r = 0.57*) and LAI (r = 0.54*), suggesting that the increases in these growth variables due to denser plant population translated into greater photosynthetic activity and translocation of assimilates to the tubers, which manifested as increased tuber yield. Spacing had no influence on weed dry matter. Sweet potato growers on well-drained sandy loam and similar soils in the humid tropics should consider adopting 60 cm × 90 cm with ‘intercropping’ to maximize space and resource use. Alternatively, they should space sweet potato 30 cm × 90 cm in sole production to achieve the desired density (3.70 plants m–2) for optimizing resource use and tuber yield.Key words: leaf area index, number of leaves, tuber weight per plant, optimum tuber yield, sweet potat

Soil nutrient status and okra pod yield as influenced by plant density and cattle dung manure application

A field was carried out on an ultisol in humid area of Edo State, Nigeria to evaluate the effects of plant density and cattle dung manure application on soil nutrient status and okra pod yield. Treatments consisted of three levels of cow dung (0, 300 and 450 kg N ha-1) and three plant densities (47,619, 66,666 and 83,333 plants per hectare (pph)). A 3 x 3 factorial arrangement fitted into randomized complete block design and replicated three times. Data were collected on soil chemical properties and pod yield of okra. Routine analysis of the soil indicated that the soil was low in nutrient content, thus addition of cattle dung to the soil at various levels influenced the soil nutrient status positively. After cropping with okra, cattle dung application had significant influenced on soil pH, total N, available P and exchangeable Na. Higher plant densities had no significant effect on soil chemical properties except available P which increase as it increased. The highest pod yield (7.39 t ha-1) and relative yield efficiency (RYE) (4.39) were obtained from treatment combination of 83,333 pph and 450 kg N ha-1. However, integration of 83,333 and 300 kg N ha-1 had the optimum pod yield (7.13 t ha-1) and RYE (4.22)

Characteristics, food, health and economic values of the Nigerian pawpaw (Carica papaya) fruits

Five varieties of papaya fruits (spherical shape variety (OSV), oval shape variety (OSV), ellipsoid shape variety (ESV), cylindrical shape variety (CSV) and bulb shaped variety (BSV)) were assessed for their characteristics. On the basis of size and shape attributes, the smallest OSV measured 16.0 - 15.38 cm in diameter (longitudinal and latitudinal), and 100.04 - 96.73cm in circumference while the shape was oval. The BSV measured the biggest size which was 34.98 - 21.59 cm in long and lat. and 220.15 - 135.80 cm in circumference. The weights of matured ripe fruits varied from 0.952kg for SSV to 2.636 kg for BSV; but the values were not perfectly correlated with the fruit sizes. All the varieties had high moisture contents (MC) which were not significantly (p>0.05) among the varieties. The concentrations of crude protein (1.04 – 1.13 %), crude fiber (1.56 – 2.49 %) and ether extracts (0.16 – 0.18 %) were low in the fruits. The soluble carbohydrates were high, varying from 23.04 % in ellipsoid shaped variety (ESV) to and 30.62 % in bulb shaped variety (BSV). Calcium contents of the fruits varied from 27.0 mg/100g (BSV) to 31.0 mg/100 g (CSV) of fresh fruit. The fruits also contained potassium, sodium, magnesium, iron and zinc in appreciable levels. Ascorbic acid contents of the fruits were high and significantly varied amongst the different varieties. With the nutritive contents of papaya fruits are considered useful for various food preparations hence, exploring the economic potentials of the Nigerian papaya is recommended