Observations on Cassava (Manihot esculenta Crantz) Root Yield and Soil Fertility under Different K - Sources

The lingering problem of scarcity and high cost of synthetic fertilizers in Nigeria, following changes in Government policies on subsidy, procurement and distribution of inorganic fertilizers, has made inorganic fertilizers unaffordable by the resource – poor farmers, who, incidentally, are the chief food producers in Nigeria. Therefore, the need arises to critically evaluate the potential of certain organic wastes in maintaining and improving soil fertility and crop productivity. To partly meet this need, hence, this paper reports the results of a two – year trial, aimed at evaluating efficacy of different K sources in improving fertility of an Alfisol and performance of cassava (Manihot esculenta Crantz).The experiment was laid out in a randomized complete block design with three replicates. The different K sources included: Muriate of potash (MOP); cocoa pod ash (CPA); NPK (15 – 15 – 15); bone ash (BA) and control or check (C). The results obtained indicated existence of significant (P = 0.05) differences among the K sources with respect to their effects on nutrient status of an Alfisol and cassava root yield. At the end of 2012 cropping season, K sources resulted in significant increases in soil organic carbon (SOC) from 0.40 g kg-1 for C to 0.47, 0.64, 0.51 and 0.59 g kg-1 for MOP, CPA, NPK, and BA, respectively. Similarly, at the end of 2013 cropping season, K sources significantly increased SOC from 0.22 g kg-1 for C to 0.40, 0.69, 0.45 and 0.63 g kg-1 for the respective MOP, CPA, NPK, and BA. At the end of 2012 cropping season, K sources significantly increased total N from 0.20 g kg-1 for C to 0.23, 0.46, 0.41 and 0.35 g kg-1 for MOP, CPA, NPK, and BA, respectively.  At the end of 2013 cropping season, K sources significantly increased total N from 0.07 g kg-1 for C to 0.10, 0.52, 0.37 and 0.43 g kg-1 for MOP, CPA, NPK, and BA, respectively. Mean values of cassava root yield data across the two years of experimentation indicated that, K sources significantly increased cassava root yield from 4.52 t ha-1 for C to 6.70, 8.69, 5.97 and 6.28 t ha-1 for MOP, CPA, NPK, and BA, respectively. Keywords. Cassava, fertility, observations, yield, sources

Evaluating Changes in Fertility Status of an Alfisol and Cassava (Manihot esculenta Crantz) Performance under Different Weed Species in a Cassava Field in Southwestern Nigeria

Although, empirical evidence from many parts of the world indicates that, vegetation (plants) can ameliorate soil conditions on lands, once badly degraded, and hence, improving productive potential of such lands. However, in Southwestern Nigeria, there is hitherto, dearth of published scientific data and information on the relative effectiveness of weed species in ameliorating poor soil conditions, with resultant improved agricultural productivity of such soils. To this end, this study was designed to assess ameliorating effects of certain weed species on a severely degraded Alfisol and yield performance of cassava (Manihot esculenta Crantz). The study was carried out at the Teaching and Research Farm of the Ekiti State University, Ado ­­- Ekiti, Ekiti State, Nigeria, during 2011 and 2012 cropping seasons. The experiment was laid out in a randomized complete block design with three replicates. The different weed species included: Tithonia diversifolia (TD); Pueraria phaseoloides (PP); Chromolaena odorata (CO); Panicum maximum (PM); Aspilia Africana (AA); and weed – free (WF), which served as the control treatment. The results obtained indicated existence of significant (P = 0.05) differences among the weed species as regards their ameliorating effects on nutrient status of a degraded Alfisol, cassava root yield and yield components. At the end of 2011 cropping season, weed species significantly increased soil organic carbon (SOC) from 0.33 g kg-1 for WF to 0.70, 0.62, 0.77, 0.40 and 0.55 g kg-1 for TD, PP, CO, PM and AA, respectively. Similarly, at the end of 2012 cropping season, weed species significantly increased SOC from 0.22 g kg-1 for WF to 0.74, 0.67, 0.83, 0.45 and 0.60 g kg-1 for the respective TD, PP, CO, PM, and AA. At the end of 2011 cropping season, weed species significantly increased total N from 0.18 g kg-1 for WF to 0.36, 0.49, 0.42, 0.25 and 0.31 g kg-1 for TD, PP, CO, PM and AA, respectively. At the end of 2012 cropping season, weed species significantly increased total N from 0.13 g kg-1 for WF to  0.40, 0.56, 0.48, 0.30 and 0.35 g kg-1 for the respective TD, PP, CO, PM, and AA. Means of cassava root yield data across the two years of experimentation indicated that, weed species significantly reduced cassava root yield from 9.23 t ha-1 for WF to 4.27, 7.31, 5.61, 4.57 and 5.37 t ha-1 for  TD, PP, CO, PM and AA, respectively. Keywords: Cassava, field, fertility, status, species, weed

Improving fertility of an acid Alfisol and maize (Zea mays L.) yield performance with integrated application of organic and inorganic soil amendments

In view of the limitations or inadequacies of sole use of organic or inorganic fertilizers to improve soil fertility, as well as high cost and scarcity in Nigeria, of inorganic limes, commonly used for reducing soil acidity. There is a dire need to critically assess the potential of combined application of readily available and cheap organic and inorganic fertilizers, as nutrient sources to improve soil fertility, and the use of organic limes to reduce soil acidity, and thus, ensure balanced crop nutrition with attendant high crop yield. To this effect, a two – year study was designed to evaluate the influence of wood ash – based soil amendments on chemical properties of an acid Alfisol and grain yield of maize (Zea mays L.). The experiment was carried out at the Teaching and Research Farm of the Ekiti State University, Ado – Ekiti, Ekiti State, Nigeria, during 2011 and 2012 cropping seasons. The experiment was laid out in a randomized complete block design with three replications. The wood ash – based soil amendments included: sole wood ash (SWA); wood ash + NPK (15 – 15- 15) fertilizer (WA+ NPK); wood ash + ammonium sulphate fertilizer (WA+AS); and no fertilizer (NF) (check), which served as the control treatment. The results obtained indicated existence of significant (P = 0.05) differences among the wood ash – based soil amendments as regards their effects on chemical properties of the Alfisol and maize grain yield. At the end of 2011 cropping season, application of the wood ash – based soil amendments resulted in significant (P = 0.05) increases in soil organic carbon (SOC) from 0.61 g kg-1 for NF to 1.47, 1.32 and 1.09 g kg-1 for SWA, WA+ NPK, and WA+AS, respectively. Similarly, at the end of 2012 cropping season, application of the wood ash – based soil amendments resulted in significant increases in SOC from 0.43 g kg-1 for NF to 1.65, 1.51 and 1.17 g kg-1 for SWA, WA+ NPK, and WA+AS, respectively. At the end of 2011 cropping season, application of the wood ash – based soil amendments significantly increased total nitrogen from 0.26 g kg-1 for NF to 0.40, 0.57 and 0.51 g kg-1 for SWA, WA+ NPK, and WA+AS, respectively. At the end of 2012 cropping season, the wood ash – based soil amendments significantly increased total nitrogen from 0.14 g kg-1 for NF to 0.51, 0.66 and 0.60 g kg-1 for the respective SWA, WA+ NPK, and WA+AS.  Means of maize grain yield data across the two years of experimentation indicated that, the wood ash – based soil amendments significantly increased maize grain yield from 0.86 t ha-1 for NF to 2.26, 2.57 and 2.47 t ha-1 for the respective SWA, WA + NPK and WA + AS. Of all the fertilizer combination treatments, wood ash + NPK fertilizer gave the highest maize grain yield and yield components in both years, and therefore, a judicious and balanced combination of wood ash and NPK fertilizer is recommended for maize cultivation. Key words: Acid, alfisol, fertility, inorganic, maize, organic, soi

EFFECTS OF DIFFERENT NITROGEN SOURCES AND VARYING ORGANIC FERTILIZER RATES ON THE PERFORMANCE OF MAIZE (Zea mays l.) IN EKITI STATE, SOUTHWESTERN NIGERIA

A two – year field experiment was conducted at the Teaching and Research Farm of the University of Ado - Ekiti, Nigeria, during the 2006 and 2007 cropping seasons to appraise the influence of different N – sources, organic fertilizer rates, and the interactions between these two factors on growth and yield indices of maize (Zea mays L.). The design was a split – plot, laid out in a randomized complete block, with three replicates. N sources constituted the main – plot treatment, namely: control, urea, calcium ammonium nitrate (CAN), and NPK 15-15-15. Organic fertilizer rates constituted the sub – plot treatment, which were: 0 (control), 2, 4, 6, and 8 t ha-1.  The results indicated that there were significant differences (p≤ 0.05) between the treatments in growth and yield parameters of maize. The two – year average values indicated that N - sources significantly increased maize leaf area from 0.52 m2/plant for control to 0.74, 0.91 and 1.04 m2/plant for urea, CAN, and NPK, respectively. Similarly, organic fertilizer rates significantly increased maize leaf area from 0.48 m2/plant for 0 (control) to 0.66, 0.79, 0.93 and 1.09 m2/plant for 2, 4, 6, and 8t ha-1, respectively. N – sources significantly increased maize grain yield from 1.94 t ha-1 for control to 3.78, 5.27, and 6.47 t ha-1 for urea, CAN and NPK, respectively. Similarly, increase in organic fertilizer rates resulted in a significant increase in maize grain yield from 1.67t ha-1 for 0 (control) to 2.03, 2.50, 3.06 and 3.72t ha-1 for 2, 4, 6, and 8t ha-1, respectively. The interactions between N sources and organic fertilizer rates significantly increased growth and yield components of maize. The treatment combination of NPK fertilizer and 8 t ha-1 organic fertilizer resulted in the highest values of growth and yield components of maize in both years. &nbsp

EFFECTS OF FERTILIZER TYPES ON MAJOR SOIL NUTRIENTS AND PERFORMANCE OF MAIZE (ZEA MAYS L.) IN ADO – EKITI, SOUTHWESTERN NIGERIA

A two – year field experiment was conducted at the Teaching and Research Farm of the University of Ado - Ekiti, Nigeria, during early 2006 and 2007 cropping seasons to appraise the influence of fertilizer types on major soil nutrients and performance of maize (Zea mays L.). The experiment was laid out in a randomized complete block, with three replications. Treatments included: no fertilizer (NF) (control), inorganic fertilizer (IF), organic fertilizer (OF), and inorganic + organic fertilizer (IF + OF). The results obtained indicated that there were significant differences (P ≤ 0.05) among the fertilizer types in growth and yield indices of maize. NF and IF decreased soil organic carbon (SOC) by 74 and 57%, respectively, contrasting increases of 31 and 18% for OF, and IF + OF, respectively. Similarly, NF and IF decreased total nitrogen (N) by 71 and 52%, respectively, compared to increases of 28 and 43% for OF, and IF + OF, respectively. The percentage decreases in available phosphorus (P) were 74 and 66% for NF and IF, respectively, as against increases of 33 and 54% for OF, and IF + OF, respectively. The two – year average values indicated that fertilizer types significantly increased maize leaf area from 0.52 m2/plant for NF to 0.77, 0.67 and 0.92 m2/plant for IF, OF, and IF + OF, respectively. Similarly, fertilizer types significantly increased maize grain yield from 1.93 t ha-1 for NF to 5.89, 5.21 and 6.32 t ha-1 for IF, OF, and IF + OF, respectively.Â

Responses of an Acid Alfisol and Maize (Zea mays L.) to Liming in Ado – Ekiti, Southwestern Nigeria

The low productivity of most Nigerian soils has been ascribed to the problem of acidity of the soils. Therefore, there is a dire need to address this problem of soil acidity, with a view to increasing the productivity of the soils, and hence, achieving sufficiency of food production. To this end, a two – year experiment was carried out in 2010 and 2011 cropping seasons at the Teaching and Research Farm of the Ekiti State University, Ado – Ekiti, Ekiti State, Nigeria, to determine the effects of different liming materials on the fertility status of an acid Alfisol and grain yield of maize (Zea mays L.). The experiment was laid out in a randomized complete block design with three replicates. The different liming materials included: Calcium ammonium nitrate (CAN); Calcium carbonate (CC); Wood ash (WA) and unlimed treatment, which served as the control (C). The results obtained indicated existence of significant (P = 0.05) differences among the different liming materials as regards their effects on chemical properties of  acid Alfisol and grain yield of maize. At the end of 2010 cropping, liming significantly (P = 0.05) increased soil organic carbon (SOC) from 0.40 g kg-1 for C to 0.52, 0.60 and 0.68 g kg-1 for CAN, CC and WA, respectively. Similarly, at the end of 2011 cropping, liming significantly increased SOC from 0.33 g kg-1 for C to 0.48, 0.55, and 0.74 g kg-1 for the respective CAN, CC and WA. At the end of 2010 cropping, liming significantly increased total N from 0.07 g kg-1 for C to 0.21, 0.14 and 0.29 g kg-1 for CAN, CC and WA, respectively. Similarly, at the end of 2011 cropping, liming significantly increased total N from 0.04 g kg-1 for C to 0.17, 0.10 and 0.34 g kg-1 for the respective CAN, CC and WA. Combining means of maize grain yield data across the two years of experimentation, liming resulted in significant increases in maize grain yield from 0.70 t ha-1 for C to 1.88, 1.67 and 2.67 t ha-1 for CAN, CC and WA, respectively. Of all the liming materials, wood ash gave the highest maize grain yield and yield components in both years, and therefore, wood ash is recommended for maize cultivation. Keywords: Acid, alfisol, liming, maize, southwestern Nigeria

EFFECTS OF INCREASING MAIZE PLANTING DENSITY IN A CASSAVA/MAIZE MIXTURE AND WEEDING FREQUENCY ON THE PERFORMANCE OF CASSAVA (Manihot esculenta Crantz) IN ADO – EKITI, SOUTHWESTERN NIGERIA

A two – year field experiment was conducted at the Teaching and Research Farm of the University ofAdo-Ekiti, Nigeria, during 2005 and 2006 cropping seasons to determine the effects of increasingmaize planting density in a cassava/maize mixture and weeding frequency on the performance of cassava(Manihot esculenta Crantz). The design was a split–plot, laid out in a randomized completeblock, with three replications. Varying maize planting densities constituted the main – plot treatment,namely: sole cropped cassava (10,000 plants ha-1) as the control, and cassava + maize mixture at fourmaize planting densities of 20,000, 40,000, 60,000, and 80,000 plants ha-1. Weeding frequency wasthe sub – plot factor, which included: the control (i.e. no weeding, W0), weeding once (W1), at fourweeks after planting (WAP), weeding twice (W2) at 4 and 8 WAP, and weeding thrice (W3) at 8, 12 and16 WAP. The results obtained indicated that there were significant differences (p≤ 0.05) between thetreatments in respect of growth and yield parameters of cassava. The two-year average values indicatedthat increase in maize planting density resulted in a significant decrease in cassava leaf areafrom 2.74 m2/plant for sole cropped cassava (control) to 2.43, 2.20, 2.02 and 1.74 m2/plant for cassava+ maize mixture at 20,000 maize plants ha-1 , 40,000 maize plants ha-1, 60,000 maize plants ha-1 and80,000 maize plants ha-1, respectively. Similarly, increase in maize planting density resulted in a significantdecrease in cassava tuber weight from 9.71 t ha-1 for sole cropped cassava (control) to 9.24,8.78, 8.27 and 7.80 t ha-1 for cassava + maize mixture at 20,000 maize plants ha-1, 40,000 maizeplants ha-1, 60,000 maize plants ha-1 and 80,000 maize plants ha-1, respectively. Weeding significantlyincreased cassava leaf area from 1.68 m2/plant for W0 to 1.95, 2.01, and 1.80 m2/plant for W1 (4WAP), W2 (4 and 8 WAP) and W3 (8, 12 and 16 WAP), respectively. Similarly, weeding significantlyincreased cassava tuber yield from 4.96 t ha-1 for W0 to 6.35, 8.75 and 5.90 t ha-1 for W1 (4 WAP), W2(4 and 8 WAP) and W3 (8, 12 and 16 WAP), respectively. The interactions between maize plantingdensity and weeding had significant effects on growth and yield of cassava. The treatment combinationof sole cropped cassava (10,000 plants ha-1) and W2 (4 and 8 WAP) resulted in the highest valuesof growth and yield indices of cassava in both years

Effects of different companion crops and increasing NPK fertilizer levels on the performance of maize (zea mays l.) in southwestern Nigeria

Field experiments were conducted at the Teaching and Research Farm of the University of Ibadan, Nigeria, during 2002 – 2003 cropping seasons to appraise the effects of different companion crops, increasing NPK fertilizer levels, and the interaction between these two treatments on the growth and yield indices of maize. The design was a split-plot arrangement, laid out in a randomized complete block with three replications. Companion crops constituted the main-plot treatment, namely: sole cropped maize (control), maize/melon, maize / cassava and maize / cassava / cocoyam. NPK fertilizer was the sub-plot factor, applied at five levels, namely: no fertilizer (control), 100, 200, 300 and 400 kgNPK ha-1. The results obtained indicated that there were significant differences (

Effects of time of nitrogen application and frequency of weeding on the performance of okra (Abelmoschus esculentus) in southwestern Nigeria

A two – year field experiment was carried out at the Teaching and Research Farm of the University of Ado – Ekiti, Nigeria, during 2005 and 2006 cropping seasons to evaluate the effects of time of nitrogen application, frequency of weeding and the interactions between these two treatments on the growth and yield of okra. The design was a split - plot arrangement, laid out in a randomized complete block, with three replications. Nitrogen application constituted the main – plot treatment, which were: no nitrogen (control); single dose N application at four weeks after planting (WAP); split N application, with half applied at 4 WAP, and the rest at 6 WAP, and single dose N application at 8 WAP. Weeding frequency was the sub – plot factor, which comprised: no weeding (control), weeding once at 3 weeks after planting (WAP), and weeding twice at 6 and 9 WAP. The results obtained indicated that there were significant differences (P ≤0.05) between the treatments in growth and yield parameters of okra. The two – year average values indicated that time of nitrogen application significantly increased okra leaf area from 2.15m2/plant for no nitrogen (control) to 2.71, 2.49 and 2.15m2/plant for single dose N application at 4 WAP, split N application at 4 and 6 WAP, and single dose N application at 8 WAP, respectively. The main effects of weeding on okra leaf area were 2.12, 2.63 and 2.19 m2/plant for no weeding (control), weeding once (3 WAP), and weeding twice (6 and 9 WAP), respectively. Time of nitrogen application significantly increased okra fruit yield from 7.1 t ha-1 for no nitrogen (control) to 10.7, 9.1 and 7.9 t ha-1 for single dose N application at 4 WAP, split N application at 4 and 6 WAP and single dose N application at 8 WAP, respectively. Similarly, weeding significantly increased okra fruit yield from 5.9 t ha-1 for noweeding (control) to 10.5 and 7.7 t ha-1 for weeding once (3 WAP) and weeding twice (6 and 9 WAP), respectively. The interactions between time of N application and weeding frequency had significant effects on growth and yield components of okra. The treatment combination of single dose N application at 4 WAP and weeding once (3 WAP) resulted in the highest values of growth and yield parameters of okra in both years

Assessment of Soil Fertility and groundnut (Arachis hypogeae) Yield Performance under different Weeding Regimes

A two–year field experiment was conducted at the Teaching and Research Farm of the Ekiti State University, Ado – Ekiti, Nigeria, during 2008 and 2009 cropping seasons to determine the effects of different weeding regimes on soil chemical properties and yield of groundnut (Arachis hypogeae). The experiment was laid out in a randomized complete block design (RCBD) with three replications. The different weeding regimes included: weeding once (W1) at three weeks after planting (WAP); weeding twice (W2) at 6 and 9 WAP; weeding thrice (W3) at 3, 6 and 9 WAP and no weeding (W0), which served as the control. The results indicated that there were significant (P = 0.05) differences among the different weeding regimes with respect to their effects on yield of groundnut. Relative to the initial nutrient status of the soil before 2008 cropping season, the percentage decreases in soil organic carbon (SOC) after cropping, adduced to weeding regimes were 58, 39, 49 and 28 % for W0, W1, W2 and W3, respectively. W1 and W3 resulted in 7 and 14 % increases in total N, respectively, contrasting decreases of 48 and 40 % for the respective W0 and W2. The percentage decreases in available P after cropping were 37, 20, 27 and 8 % for the respective W0,W1,W2 and W3. Across the two years of experimentation, weeding significantly increased groundnut seed yield from 0.43 t ha-1 for W0 to 1.23, 0.96, 1.51 t ha-1 for W1, W2 and W3, respectively.KEY WORDS: Soil Fertility, Groundnut, Yield, Weeding