EFFECT OF SEEDING RATE ON PRODUCTIVITY AND ...

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Mar 31, 2014 - 2320 – 8694. Production and Hosting by Horizon Publisher .... Partial budgeting (CIMMYT, 1988) and crop enterprise budget technique ...
Journal of Experimental Biology and Agricultural Sciences, March - 2014; Volume – 2(1S)

Journal of Experimental Biology and Agricultural Sciences http://www.jebas.org

ISSN No. 2320 – 8694

EFFECT OF SEEDING RATE ON PRODUCTIVITY AND PROFITABILITY OF GROUNDNUT (Arachis hypogaea L.) Konlan S1*, Sarkodie-Addo J2, Asare E2, Kombiok M J3 and Adu-Dapaah H4 1

Cocoa Research Institute of Ghana (CRIG), New Tafo-Akim, Ghana. Kwame Nkrumah University of Science and Technology, Kumasi, Ghana. Savanna Agricultural Research Institute (SARI), Nyankpala, Ghana. 4 Crop Research Institute (CRI), Fumesua, Kumasi, Ghana. 2 3

Received – December 18, 2013; Revision – January 06, 2014, Accepted – March 10, 2014 Available Online - March 31, 2014

KEYWORDS Agro-ecologies Rain-fed Seeding rate Marginal lands Net benefits

ABSTRACT A multi-location experiment was conducted at Anwomaso in the humid forest and Nyankpala in the Guinea savanna agro-ecologies to study the effect of seedling rate on the yield and profit response of groundnut. The study was conducted for a period of two years (2006 and 2007) in both locations in randomized complete block design with 3 replicates. Tested seeding rates were SP1 [30 cm x 15 cm (222,222 plants per hectare)], SP2 [40 cm x 10 cm (250,000 plants per hectare)] and SP3 [50 cm x 10 cm (200,000 plants per hectare)]. The results revealed that dry pod production was highest under the SP1 seeding rate in both years and locations. Consequently, the same seeding rate recorded the highest net benefits and benefits-costs ratio, making it the optimum seeding rate for groundnut production in both humid forest and Guinea savanna agro-ecologies in Ghana.

* Corresponding author E-mail: [email protected] (Konlan Sampson) Peer review under responsibility of Journal of Experimental Biology and Agricultural Sciences.

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1 Introduction In Ghana, groundnut (Arachis hypogaea L.) is typically grown by smallholder farmers as subsistence and cash crop (Tsigbey et al., 2003; Naab et al., 2005). Yields obtained from the crops are traditionally low and are affected by a combination of several factors including unreliable rains, pest and disease occurrences, poor seed technology and agronomic practices as well as increased cultivation on marginal lands (Konlan, 2010). In Ghana Groundnut is usually cultivated in mixtures with other food crops (Kafiriti, 1994; Tsigbey et al., 2003) or in pure stands from home compounds to large fields (AtuaheneAmankwa et al., 1990). The establishments of sole groundnut in wide rows result in sub-optimum plant population densities and often lead to lower yields ha-1 due to inefficient utilization of crop growth resources (Konlan, 2010). This practice which happens elsewhere (Schilling & Masari, 1992; Kafiriti, 1994) has continued in Ghana over the years in the face of competing uses for scarce land and pressing need for cash income by the farm family. Seeding rates which determine the population density and consequently the area available to individual plant has been shown to affect crop growth and yield performance (Ntare, 1990). High density cropping in groundnut is known to reduce weed competition for space and growth resources (Lee et al., 1994). It was reported by Dalley et al. (2004) and Yelverton & Coble (1991) to exhibit greater light interception compared to low density cropping. The adoption of high density cropping has primarily been driven by the potential for higher yields obtained from such systems compared to low density production systems. Reports of studies confirming high yields in high density corn and soybean (Mickelson et al., 1997) attributed such performance to decreased weed competition, disease and pest occurrence, and increased light interception (Board et al., 1992; Wells et al., 1993; Dalley et al., 2004). A decade of groundnut research in Senegal revealed a continuous increase in pod yield with increasing plant population density, which became multiples with the addition of chemical fertilizers (Schilling, 2002). Buchanan & Hauser (1980) had earlier reported higher yields (42 to 52 %) as density increased. In another study, Norden & Lipscomb (1974) reported that pod yield in high density cropping system was 16 % higher when compared to conventional low density system. Similarly, Duke & Alexander (1964) had reported that yields from large seeded Virginia bunch types were 14 % higher in high density compared to the conventional low density crop. A study by Jaaffar & Gardner (1988) showed that higher seeding rates gave greater ground cover, leaf area indices, canopy light interception, crop growth rates and ultimately higher pod yields when compared to conventional low density groundnut crop. These findings were later confirmed by Stewart et al. (1997) and recently by Ahmad et al. (2007). The advantages associated with high density groundnut systems are however not exploited by the current research and production systems in Sub-Saharan Africa. Most groundnut _________________________________________________________

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Konlan et al

research activities ignore the evaluation of new varieties under high intensity cropping before their release to farmers in spite of the fact that high density cropping offers the best sustainability options for subsistence agriculture since these technologies would greatly improve the incomes of these farmers engaged in low external input small scale production systems. As a response, this experiment was set up to evaluate productivity and economic feasibility of high density cropping in the Guinea savanna and humid forest agro-ecological zones of Ghana. The main objective being to increase pod production per unit area and hence profitability of groundnut cultivation without significant increases in production cost or land area under the crop. 2 Materials and Methods 2.1 Experimental Site The study was conducted in 2006 and 2007 major seasons at Anwomaso and Nyankpala, respectively representing the humid forest and Guinea savanna agro-ecological zones of Ghana. Nyankpala (9o 25’N, 1o 00’S) is located 16 km west of Tamale and is 183 metres above sea level. The land, climate and vegetation of Nyankpala is as described by Konlan et al. (2013a). Anwomaso (6° 41.850' N, 1° 31.545' W) is located near KNUST in the humid forest at 292 m above sea level. The land, climate and vegetation of Anwomaso are also as described by Konlan et al. (2013b). 2.2 Experimental design and treatments The experiment was laid out in randomized complete block design with 3 replicates. Gross plots measured 6 m2 with a net plot of 4 m2. Treatments evaluated were three spacing arrangements comprising SP1 (30 cm x 15 cm) giving a population of 222,222 plants ha-1, SP2 (40 cm x 10 cm) giving a population of 250,000 plants ha-1 and SP3 (50 cm x 10 cm) giving a population of 200,000 plants ha-1. 2.3 Management practices Land preparation at both sites involved manual clearing with a cutlass, followed by a single tractor ploughing and harrowing operations before sowing on flats. Two manual weeding operations were carried out at each site using the hand-hoe and hand puling respectively, at 3 and 6 weeks after planting (WAP). Time of planting differed with regard to the locations due to the differences in the start of cropping seasons between Anwomaso and Nyankpala. Seeds were sown on May 18 and harvested on September 24 at Anwomaso in 2006. The Nyankpala crop was sown on June 7 and harvested on October 15. In 2007, the Anwomaso trial was planted on May 17 and harvested on the September 28, while the Nyankpala crop was planted on June 4 and harvested on October 15. Harvesting in both years and locations was done by hand-pulling and plucking.

Effect of seeding rate on productivity and profitability of groundnut (Arachis hypogaea L.).

2.4 Data collected

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mean monthly rainfall in 2007 during the period of the experiment was 161 % higher than in 2006 (Figure 1). The reverse was observed at Nyankpala with the average monthly rainfall in 2006 being 18 % higher than in 2007 (Figure 2). There were no wide variations in minimum, mean and maximum monthly temperatures, as well as the monthly average during the period of the experiment in both years and locations (Table 1). The relatively higher annual rainfall at Anwomaso (Figure 1) and Nyankpala (Figure 2) in 2007 and 2006 respectively, did not lower temperatures significantly (Table 1) in those years.

2.4.1 Initial soil status determination Six representative soil samples were taken from each block up to the depth of 0-15 cm using soil auger. The samples were taken in a Zigzag (W-pattern) across each replicate. The samples were then prepared and analyzed in laboratory by the method describe by Walkley & Black (1934) and Thomas (1982) to obtain the baseline soil information for each location. 2.4.2 Plant stand, number of pods per plant and dry pod yield Data on plant stand (m2) was taken two weeks after planting (WAP) using the net plots. Estimate of number of pods per plant and pod yield per hectare was achieved following the procedure described by Konlan et al. (2013b).

3.2 Initial soil analysis Analysis of soil samples from Anwomaso and Nyankpala sites revealed that the Anwomaso sample contained higher percentage silt and clay, and lower percentage sand compared to the Nyankpala sample (Table 2). Also, percent Ca2+, Mg2+, organic carbon, available P, effective cation exchange capacity, pH, organic carbon and total N were higher at Anwomaso. The Nyankpala samples recorded higher Calcium, base saturation and bulk density (Table 2).

2.4.3 Economic analysis Partial budgeting (CIMMYT, 1988) and crop enterprise budget technique (Wesley et al., 1993) were used to organize experimental information relating to costs and benefits of the seeding rates as described by Konlan (2010). The benefits cost ratio (BCR) which is the net benefit divided by the operational cost (CIMMYT, 1988; Wesley et al., 1993) was used to compare profitability of seeding rates as:

3.3 Growth and yield There was no significant (α=0.05) influence of the tested seeding rates on plant stand at both locations and years although higher seeding rates resulted in relatively more plants per square meter (Table 3). The seeding rates were not also found to significantly (α=0.05) influence the number of pods per plant in both years at Anwomaso and Nyankpala (Table 3). Dry pod yield was also not significantly (α=0.05) influenced by the seeding rates in both locations and years although higher seeding rates resulted in relatively higher pod yields in 2006 (Table 3). In 2007, pod yield increased at Anwomaso with increasing seeding rate. The differences in pod yield observed at Anwomaso in 2007 were significant (α=0.05). At Nyankpala, both lower (SP3) and higher (SP2) seeding rates significantly (α=0.05) reduced pod yield in 2007 compared to the medium (SP1) rate (Table 3).

NB= GR - TVC BCR = NB / TVC Where; NB = Net Benefit GR = Gross Returns TVC = Total Variable Cost of Production BCR = Benefit-Cost Ratio 3 Results 3.1 Rainfall and temperature The total amount of rainfall at Anwomaso was higher in 2007 than in 2006 during the period of the experiment. As a result,

Table 1 Change in temperatures at Anwomaso and Nyankpala during study period. Anwomaso (o C) Month May June July Aug Sept Oct Mean

Tmin 22.0 20.6 20.8 20.5 21.1 21.7 21.1

2006 Tmean 27.1 26.0 25.6 24.9 25.6 26.6 26.0

Tmax 32.2 31.4 30.3 29.2 30.1 31.5 30.8

Tmin 22.2 22.6 22.9 22.1 22.0 21.9 22.3

Nyankpala (o C) 2007 Tmean 27.6 27.1 26.3 26.0 26.1 26.4 26.6

Tmax 32.9 31.6 29.6 29.9 30.2 30.9 30.9

Tmin 23.7 23.4 23.5 22.0 22.5 23.0 23.0

2006 Tmean 28.3 27.6 27.2 26.0 26.3 27.3 27.1

Tmin (minimum temperature), Tmax (maximum temperature), Tmean (mean temperature), Amean (annual mean).

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Tmax 32.9 31.7 30.9 29.9 30.0 31.5 31.2

Tmin 24.4 24.1 23.7 23.1 22.7 23.1 23.5

2007 Tmean 28.8 28.1 27.4 26.0 26.5 28.2 27.5

Tmax 33.1 32.0 31.0 28.9 30.3 33.3 31.4

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Figure 1 Total monthly rainfall during the period of the experiment at Anwomaso in 2006 and 2007.

Figure 2 Total monthly rainfall during the period of the experiment at Nyankpala in 2006 and 2007.

Table 2 Physico-chemical properties of soil of the Anwomaso and Nyankpala sites. Description (0-15 cm depth) Parameter

Anwomaso

Nyankpala

68.5 15.9 15.6 33.7 13.2 72.3 1.43

73.3 14.3 12.4 35.2 10.5 74.1 1.46

0.31 2.10 0.72 0.23 1.31 5.34 1.32 7.80 0.073

0.21 2.33 0.48 0.18 1.12 4.33 0.37 6.50 0.044

Mineralogical Sand (%) Silt (%) Clay (%) Ca + Mg Carbonate (%) Available P (mg/kg) Base saturation (%) Bulk density (g/cm3) Exchangeable Cations K Ca Mg Na (Al+H) ECEC (c mol/kg) Organic Carbon pH 1:2 (CaCl2) Total N (%) 3.4 Net benefits and benefits-costs ratio. The net benefits (NB) or returns to treatments and benefitscosts ratio (BCR) were generally higher in 2007 than in 2006 at Anwomaso and vice versa at Nyankpala (Table 4). This was because of higher dry pod yield obtained in 2007 at Anwomaso and in 2006 at Nyankpala. Seeding rates also impacted positively on both NB and BCR with the rate giving medium plant population density (SP1) also giving higher NB and BCR in both years at Anwomaso and Nyankpala. The two

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year average NB and BCR of the SP1 seeding rate were therefore higher for both locations (Table 4). 4 Discussions The higher rainfall in 2007 at Anwomaso did not lead to lower temperatures in that year compared to 2006. Despite the differences in average rainfall and temperature during the period of the experiment in 2006 and 2007, plant population density did not show wide variations within locations with regard to seeding rates.

Effect of seeding rate on productivity and profitability of groundnut (Arachis hypogaea L.).

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Table 3 Plant population density, number of pods per plant and dry pod yield as affected by seeding rates at Anwomaso and Nyankpala.

Seeding rate SP1 SP2 SP3 Lsd 0.05 CV (%)

Plant density (m-2)

Number of pods per plant

Dry pod yield (t ha-1)

Anwomaso 2006 2007 4.1 4.2 4.3 4.2 4.2 4.1 ns ns 9.0 3.8

Anwomaso 2006 2007 3.9 4.1 3.4 4.1 3.9 4.2 ns ns 13.4 13.1

Anwomaso 2006 2007 1.38 3.40 0.90 3.71 0.74 3.29 ns 0.4 4.1 13.5

Nyankpala 2006 2007 4.2 4.3 4.1 4.5 3.8 4.3 ns ns 18.6 15.7

Nyankpala 2006 2007 3.6 4.1 3.8 4.0 4.0 3.8 ns ns 14.6 11.3

Nyankpala 2006 2007 1.72 1.01 1.62 0.89 1.51 0.72 ns 0.2 2.0 14.1

SP1 (30 cm x 15 cm), SP2 (40 cm x 10 cm), SP3 (50 cm x 10 cm), t ha -1 (tons per hectare), ns (no significant differences; P