Response of maize growth and development to mineral fertilizer and soil characteristics in Northern Ghana

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1 IJAAR 2 (2014) ISSN Response of maize growth and development to mineral fertilizer and soil characteristics in Northern Ghana Atakora, W. K. 1 *, Fosu, M. 1, Safo, E. Y. 2, Tuffour H. O. 2 and Tetteh, F. M. 3 1 Savanna Agricultural Research Institute, P. O. Box TL 52, Tamale, Ghana. 2 Department of Crop and Soil Sciences, Faculty of Agriculture, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana. 3 Soil Research Institute, Kumasi, Ghana. Article History Received 29 April, 2014 Received in revised form 14 May, 2014 Accepted 22 May, 2014 Key words: Stover yield, Mineral nutrient, Maize, Soil. Article Type: Full Length Research Article ABSTRACT Soil nutrient depletion- as a result of continuous cultivation of soils without adequate addition of external inputs- is a major challenge in the Northern region of Ghana. This has led to the adoption of integrated soil fertility management techniques which combines the use of mineral fertilizers as well as maintains soil quality and health. Field experiments were conducted in 2010 to compare the response of maize growth and development to mineral fertilizer and soil characteristics in Northern Ghana. Mineral fertilizers (N-P 2 O 5 -K 2 O) at the rate of 0-0-0, , , , , , , , , and kg ha -1 were applied to the experimental field located at Kpalesawgu in Tolon-Kunbungu district of Northern Ghana. The treatments were laid out in randomized complete block design with four replications. Soil sampled at 15 cm depth analysis using Genstat statistical package showed less coefficient of variation in percent nitrogen, organic carbon, available phosphorus and ph. Minimum and maximum recorded were and 0.081, and 0.940, and 0.038; and and for percentage nitrogen, organic carbon, available phosphorus and ph, respectively. On the contrary, soil physical characteristics showed quite remarkable variation in percentage silt, clay and stones. Minimum and maximum values recorded were and 14.45, 17.0 and 21.3; and 4 and for silt, clay and stones, respectively. Statistical analyses showed that mineral fertilizer significantly affected maize grain yield (P<0.05) as well as stover weight (P<0.001). Similarly mineral fertilizer affected harvest index significantly (P<0.05). Regression analysis showed positive correlation between number of days for 50% tasseling and number of days to physiological maturity (P<0.001). However there is an inverse relationship between the numbers of days to physiological maturity BluePen Journals Ltd. All rights reserved INTRODUCTION Maize is one of the staple food crops being competed for by both livestock and man. Maize seems to be useful to livestock than man as all parts of maize including the stover are consumed by animals. The significant Corresponding author. williatnet@yahoo.com. importance of maize for both animal and man call for its improvement both in quality and quantity. Poor soil quality and poor soil health have led to reduced yield. In Ghana, maize is produced predominantly by small holder resource poor farmers under rain-fed conditions (SARI, 1996). Low soil fertility and low application of external inputs are the two major reasons that account for low productivity in maize (Adu, 1995; Benneh et al., 1990).

2 Int. J. Adv. Agric. Res. 68 The soils of the major maize growing areas in Ghana are low in organic carbon (<1.5%), total nitrogen (<0.2%), exchangeable potassium (<100 mg/kg) and available phosphorus (<10 mg/kg) (Adu, 1995, Benneh et al., 1990). Soil fertility depletion in the smallholder farms is the fundamental biophysical root cause for declining per capita food production in sub-saharan Africa. The soils in the Tolon-Kunbungu district of Ghana are plainthisols with less inherent fertility. However, the area has suffered gross soil nutrient mining due to continuous cropping coupled with low levels of nutrient inputs and poor nutrient conservation practices. The situation is further accentuated by mounting population growth and land scarcity. The results of this loss in soil productivity has been a continuous decline of maize yields in farmers fields (to less than 2.0 t ha 1 ) whilst the maize cultivars grown have a potential of greater than 6.0 t ha 1. The use of mineral fertilizers on staple food crops of maize (Zea mays L.) has generally been restricted to only a few farmers endowed with resources. Mineral fertilizers are important and quickest way of nutrient supply to soil and play an important role in activating various enzymes (Tisdale et al., 1990). However, in addition to other constraints, their high cost and short supply at the time of need deter the farmers from using recommended doses (FAO, 1978). This necessitates the need to explore alternative potential sources of plant nutrients and means of retaining the limited nutrient sources in the soil. Crop growth depends on, among other things, nutrients. Both macro- and micronutrients are essential for plant growth and if a plant does not get enough of a particular nutrient it needs, the deficiency symptoms show in the general appearance of the plant. Plant nutrients are normally abundant in the soil. In addition to decreasing natural reserves in soil and inadequate fertilizer use, nutrient deficiencies are compounded by the prevailing soil environment. For example, if a soil is too acidic (ph<4.0) or too alkaline (ph 7.0), some nutrients in the soil solution become unavailable for uptake by the maize crop. The objective of the experiment is therefore to determine the response of maize growth and development to mineral fertilizer and soil characteristics in Northern Ghana. MATERIALS AND METHODS Study area The study was carried out at Kpalesawgu in the Northern region of Ghana. The site is located about 16 km west of Tamale and lies on latitudes N and longitude W of the interior Guinea Savanna agro-ecological zone of Ghana, which has a mean daily temperature of 26 C (SARI, 1996). The area has a uni-modal rainfall pattern averaging about 1100 mm annually (Dankyi et al., 2005). The experimental field lies within the Guinea Savanna zone and this was strategically selected for a number of reasons: (i) it is an important breadbasket area (ii) it is an important growing area for maize, (iii) the highest concentration of past soil fertility management research is located within this area, (iv) the nearness to large local and regional markets for inputs and outputs. The study covered a period of six months (June to December 2010). Experimental design A randomized complete block design with four replications was used. The plot size was 10 m 5 m with plant spacing of 80 cm 40 cm. Treatments applied were 0-0-0, , , , , , , , , and N-P 2 O 5 -K 2 O kg ha -1. The blocks were arranged from east to west with eleven plots each and a surface area of 75 m 2 (15 m long and 5 m wide) separated by 1 m alley and has eight rows per plot. The plants were monitored and phenological data as well as management information were collected. These include sowing date, date of fertilizer application, date of flag leaf stage, date of flowering, date for grain filling and date of maturity. The phonological stages were noted when 50% of plant population attained that stage. Final total biomass and grain yield were also measured from a plot size of 9 m 2 by harvesting above-ground biomass and separating them into the various components according to the procedure described in Hoogenboom et al. (1999). Grain yield and total biomass were expressed in kg ha 1. Soil samples were taken from each experimental plot and also at different horizons (0 10, 10 20, 20 30, 30 40, 40 50, 50-60, 60-70, 70-80, 80-90, , , , , , and cm). Soil organic carbon, ph, soil particle distribution, bulk density and saturation were all determined as described in Hoogenboom et al. (1999). The experimental field had been under fallow since Before then, the field was used to farm sorghum. The land was ploughed, harrowed and ridged. Maize variety Obaatanpa was planted on 18th June, 2010 with a spacing of 80 cm x 40 cm. Three seeds were planted and later thinned to two plants/hill. Thinning was done before fertilizer was applied. 50% of nitrogen, phosphorus and potassium were applied two weeks after planting. The remaining nitrogen was applied five weeks after planting. The fertilizer was banded on both sides of the plant and buried. Data were analyzed using Genstat statistical package. Means were separated using least significance difference at 5%.

3 Temperature (Degree celcius) Atakora et al Tmax Tmin Day of the year Figure 1. Daily minimum and maximum temperature at Kpalesawgu in Northern Ghana during Table 1. Mean monthly weather of Kpalesawgu, Northern Ghana for Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Temp. max ( C) Temp. min ( C) Rainfall (mm) RESULTS AND DISCUSSION Weather Mean monthly maximum and minimum temperature recorded during the growing season (June to November) was 30.8 and 22.5 C respectively (Table 1). Maximum rainfall occurred September with a total monthly rainfall of mm. However lower minimum and maximum temperatures were recorded within the first and last fifty days of the year with intermittent low temperatures occurring between June and October as a result of increased rainfall (Figure 1). Rainfall distribution is quite poor with most of the rain concentrating between May and October with intermediate dry spells (Figure 2). Crop yields are sometimes affected in the intermittent dry periods during the growing season which occurs in the 5th-7th week of the crop growth. Timely planting therefore ensures that the crop water requirements are met to increase productivity. Soil characteristics Chemical analysis of soil samples from the experimental field showed significantly low mineral content. Minimum and maximum cation exchange capacity recorded was 7.2 and 3.7 Cmol.kg -1 soil with mean and standard

4 Total rainfall (mm) Int. J. Adv. Agric. Res Day of the year Figure 2. Daily rainfall at Kpalesawgu in Northern Ghana during Table 2. Chemical characteristics of the experimental field. Parameter Mean Min. Max. Std. deviation Std. Error of Mean Variance CEC (Cmol.kg -1 soil) Ca (Cmol.kg -1 soil) K (Cmol.kg -1 soil) Na (Cmol.kg -1 soil) Organic carbon (%) Mg (Cmol.kg -1 soil) ph (1:2.1 Water) N (%) Avail. P (mg kg -1 soil) CV deviation of 5.8 and 0.866, respectively (Table 2). This is however similar to what was found by Adu (1995) and Benneh et al. (1990). Similarly, available phosphorus and total nitrogen recorded were found to be low. Mean values recorded were mg kg -1 soil and 0.048% respectively, with standard deviations of and Very low organic matter was found and this however reduced the effect of the mineral fertilizer on crop yield. Increased run off and erosion are characterized by such soils of which the experimental field was not an exception. Mean organic carbon recorded was 0.56% and a standard deviation of The effects of mineral fertilizer were suppressed when organic matter was low. Soils with low organic matter are characterized by increased run-off, leaching and excessive erosion due to poor soil structure. Soil aggregates are loose and are susceptible to nutrient loss. Soils from the experimental fields had low wetness, low volumetric water content and poor porosity due to higher bulk density. Mean value recorded was 1.6 g cm -3 (Table 3). This was compounded by low organic matter content of the soil (Table 2), low soil porosity and poor soil structure. Soil hydraulic conductivity is also affected as a result of high soil bulk density recorded. This however affected plant root penetration in search of scarce mineral resources need for plant growth. This however means that not all the mineral fertilizer that was applied was used up by the plant. It is therefore necessary to consider not only the application of mineral fertilizers as the panacea to increased maize yield but also other practices

5 Atakora et al. 71 Table 3. Physical characteristics of the experimental field. Physical characteristics Mean Min. Max. Std. deviation Std. error of Mean Variance Bulk density (g/cm 3 ) Clay (%) Drained upper limit (mm/mm 3 ) Silt (%) Saturated lower limit (mm/mm 3 ) Stones (%) CV Table 4. Observed yield parameters of Obaatanpa maize grown at Kpalesawgu in Northern Ghana. Treatment (kg/ha N-P 2O 5-K 2O) Unit grain wt. (g) Harvest index Stover (kg/ha) Yield (kg/ha) Probability function <0.001 <.001 <0.001 <0.001 Least significant difference Coefficient of variation that will improve soil structure, bulk density and porosity of the soil. Higher bulk densities hinder oxygen and water movement in the soil. It is also a measurement of the degree of compaction of the soil. One of the most important factors agriculturally in terms of bulk density is plant growth. If the soil has a high bulk density (compaction), the seed will be restricted in emergence and root growth will be affected. This will affect total plant growth and yield. The use of tractors will directly affect the soils bulk density causing extreme compaction especially if the soil is wet. Careful management on the land is required to create an ideal bulk density for optimum plant growth and healthy soil. Yield Result of maize grain and stover yield is presented in Table 4. The highest grain yield was recorded when kg ha -1 N-P 2 O5-K 2 O was applied. This is in contrast with FAO recommendation of kg ha -1 N, P and K, respectively (MoFA, 2003). This however was not site specific and comprise pooled means from highly fertile maize growing areas in the forest regions of Ghana. Grain and stover weight recorded was 3831 and 7562 kg ha -1. Grain yield recorded when no mineral fertilizer was applied was 231 kg ha -1. However stover weight recorded was 533 kg ha -1. This is mostly the case in Northern Ghana when no mineral fertilizers are applied and this has led to increased use of inorganic fertilizer to increase maize yield. Moreover, grain yield obtained for N-P 2 O 5 -K 2 O kg ha -1 was significantly different (P<0.05) from all the other treatment except for and N-P 2 O 5 -K 2 O kg ha -1. Similarly, there was no significant difference (P>0.05) between grain yield when and ; and ; and ; and N-P 2 O 5 - K 2 O kg ha -1 were applied. The degree of insignificance difference between and N-P 2 O 5 -K 2 O kg ha -1 showed that phosphorus is a limiting nutrient precisely in the experimental field (Table 2). This however affected maize root growth, shoot development, stover and grain yield. Low ph values recorded affect phosphorus availability as it increased phosphorus

6 Int. J. Adv. Agric. Res. 72 Table 5. Observed growth parameters of Obaatanpa maize grown at Kpalesawgu in Northern Ghana. Treatment N-P 2O 5- K 2O (kg ha -1 ) No. of days 50% Silking No. of days 50% tasseling No. of days maturity Probability function < <.001 Least significant difference Coefficient of variation mobilization. Grain and stover weight recorded when N-P 2 O 5 -K 2 O kg ha -1 was 1055 kg ha -1. Correspondingly, there was no significant difference (P>0.05) in harvest index for and N- P 2 O 5 -K 2 O kg ha -1. Meanwhile, application N above 80 kg ha -1 did not significantly affect harvest index. Growth parameters The results of maize growth parameters that is number of days to 50% silking, number of days to 50% tasseling and number of days to physiological maturity is presented in Table 5. Application of nitrogen and potassium at 120 and 150 kg ha -1 and 45 and 60 kg ha -1 respectively did not affect number of days to 50% silking. However number of days to 50% tasseling was affected when 90 kg ha -1 potassium was applied with 120 and 150 kg ha -1 nitrogen. The result further indicated no significant difference (P>0.05) between means of number of days to 50% silking when and ; and ; and ; ; ; and N-P 2 O 5 -K 2 O kg ha -1 was applied. On the contrary, application of and ; and ; and ; and ; and N-P 2 O 5 -K 2 O kg ha -1 affected significantly (P<0.05) the number of days to 50% silking. Similar to number of days to 50% silking, application of and ; and ; and ; and N- P 2 O 5 -K 2 O kg ha -1 did not significantly (P>0.05) affect number of days to 50% tasseling. However, there was significant difference (P<0.05) between means of number of days to 50% tasseling when and ; and ; and ; and ; and ; and and N-P 2 O 5 -K 2 O kg ha -1 was applied. Also, application of 120 and 150 kg ha -1 nitrogen did not affect number of days to physiological maturity when phosphorus and potassium were 60 and 90 kg ha -1. However in contrast, number of days to physiological maturity was affected when 0, 40 and 80 kg ha -1 nitogen were applied. There was no significant difference (P>0.05) between means of number of days to physiological maturity when and ; and ; and ; and ; and and kg ha -1 (Table 5). Correlation Correlation results showed positive relation between number of days to 50% silking and number of days to physiological maturity (P<0.05) (Table 6). There is therefore a linear correlation between number of days to 50% silking and number of days to physiological maturity. The results further indicated increasing number of days to 50% silking which resulted to increasing number of days to physiological maturity (Figure 3). Reducing number of days to silking and physiological maturity could be apanacea to reduced maize yields in areas of uncertain length of growing periods. Application of and N-P 2 O 5 -K 2 O kg ha -1 resulted in lower number of days to 50% silking and physiological maturity. The values obtained were and ; and and respectively (Table 5). Also, there is a positive correlation between number of days to 50% tasseling and number of days to

7 Days to 50% silking Atakora et al Number of days to maturity No_Dmaturity Figure 3. Correlation between number of days to 50% silking and number of days to physiological maturity of Obaatanpa maize grown at Kpalesawgu in Northern Ghana. Table 6. Linear regression analysis of number of days to 50% silking and number of days to physiological maturity. Source Degree of freedom Sum of squares Mean square Variance Probability function Regression <0.001 Residual Total

8 D50%_Tasseling Days to 50% tasseling Int. J. Adv. Agric. Res Number of days to maturity No_Dmaturity Figure 4. Correlation between number of days to 50% tasseling and number of days to physiological maturity of obaatanpa maize grown at Kpalesawgu in Northern Ghana Table 7. Linear regression analysis of number of days to 50% tasseling and number of days to physiological maturity. Source Degree of freedom Sum of squares Mean square Variance Probability function Regression <.001 Residual Total physiological maturity (P<0.05) (Table 7). Increasing number of days to 50% tasseling also resulted to increasing number of day to physiological maturity (Figure 4). On the contrary, grain yield increases with increasing number of days to physiological maturity but decreases with prolong increases in number of days to maturity (Figure 5). Conclusion The relevance of mineral fertilizer cannot be underestimated if maize yield is to be increased when soil fertility is low. The results of this study showed higher grain yield when mineral fertilizer was applied and minimal grain yield when no mineral fertilizer was applied.

9 Grain_Yield_kg_ha Grain yield (kg ha -1 ) Atakora et al Number of days to maturity No_Dmaturity Figure 5. Correlation between number of days to 50% tasseling and number of days to physiological maturity of obaatanpa maize grown at Kpalesawgu in Northern Ghana. The results further indicate the effect of soil bulk density on root penetration and growth. Low organic matter content affected efficiency of mineral fertilizer use. Increased application of mineral nitrogen higher than 80 kg ha -1 did not significantly affect grain yield. However, the highest grain yield was obtained when kg ha -1 N-P 2 O 5 -K 2 O was applied; this was not significantly different from when and kg ha -1 N- P 2 O 5 -K 2 O was applied. In the same way maize, stover weight increased significantly with the application of mineral fertilizer. Furthermore, correlation analysis showed linear relationship between number of days to 50% silking, tasseling and physiological maturity. In conclusion, number of days to physiological maturity increases with increases number of days to 50% silking and tasseling. ACKNOWLEDGEMENTS This work forms part of Master of Science research project of the first author at Kwame Nkrumah University of Science and Technology, Kumasi-Ghana and was funded by the Alliance for a Green Revolution in Ghana and CSIR-Savanna Agricultural Research Institute. The authors greatly acknowledged their support. REFERENCES Adu S. V. (1995). Soils of the Nasia basin. Memoir No. 6. Soil Research Institute. Kumasi. Benneh G., Agyepong G. T. & Allotey J. A. (1990). Land degradation in Ghana. Commonwealth Secretariat, London and University of Ghana. Legon. Dankyi A. A., Sallah P. Y. K., Adu-Appiah A. & Gyamera A. (2005).

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