Abstract

Media summary

Key words

Africa, melon, Nigeria, Oxic PaleUstalf, plantain, potassium

Introduction

Plantain (Musa AAB) often plays a dominant role in farming systems of the forest zone of West Africa as well as in many other African nations. Production remains largely in the hands of small-scale farmers who over the years have ingeniously integrated it into various cropping systems like bush fallow, homestead farms and taungya systems (Wilson 1987). In bush fallow rotations, plantain can either be the first or last crop in the sequence. Farmers often intercropped on these soils without adequate knowledge of the right quantity of fertilizers to be applied. There is sparse literature on the effect of various rates of potassium fertilizer on plantain-melon intercrop on Oxic PaleUstalfs in the southern western part of Nigeria. Therefore, an experiment was conducted in 1993 and 1995 cropping seasons to evaluate the effect of four different levels of K fertilizer on the yield and yield components of these crops in intercrop.

Methods

The trial was conducted at the on-farm research site at Ayepe located at 7⁰15^l N latitude for both the 1993 and 1995 cropping seasons. Soils at the site were collected and analysed as outlined in Akinyemi et al. (2003). Suckers of plantain (Musa AAB) cv Agbagba were planted at a spacing of 3 x 2m and were intercropped with melon (Clocynthis citrullus). These crops were established in the alleys of plantain at populations of 20,000, 53,000 and 5,000 plants/ha. Seeds of melon were planted at the rate of three seeds/hole and later thinned to two. The suckers of plantain were treated with furadan 3 G to control incidence of plantain weevil (Cosmopolites sordidus). The experimental treatments consisted of four levels of potassium (120, 240, 360 and 480 kg K/ha) and a control. The experimental design was a randomised complete block with four replications, which were farmers’ fields. A plot size of 13 x 10m was adopted al all locations. Nitrogen and phosphorus were applied at the rate of 100 kgN/ha and 60 kg P/ha, respectively. Potassium fertilizer was applied in two equal amounts 2 and 4 months after planting (MAP). Plots were hand weeded regularly throughout the trial. The following data were collected: plant height, stem girth, number of functional leaves/plant, number of days to shooting, number of suckers/stools at harvest, height of oldest sucker at harvest, number of hands/bunch; number of fingers/bunch and bunch weight for plantain. Plantain was harvested as they matured. Melon fruits were collected at maturity, weighed and softened by beating with a piece of wood and allow to rot to facilitate seed removal. Seeds were washed and air-dried for 3d. The following data were collected: fruit weight, seed weight of fruit, seed number/frit and total seed yield. Data were subjected to analysis of variance using the general linear model procedure of the statistical analysis systems (SAS Inst., 1999) and means were separated using the Duncan multiple range test at 5%. Partial budgeting analysis was performed after CIMMYT (1988).

Results

This soil was deficient in K and plantain-melon intercropped responded to the application of the fertilizer (Table 1). The morphological attributes of plantain increased significantly (p<0.05) with increasing K fertilizer (Table 2). Results of yield and yield components of plantain intercropped with melon showed that number of hands and fingers bunch^-1, mean length of plantain bunch as well as mean bunch and total bunch weight responded significantly (p<0.05) to K fertilizer applied and maximum yield was obtained at 360 kg K ha^-1 in both cropping seasons (Table 3). In Table 4, results of yield attributes of melon intercropped with plantain are presented and it shows that these attributes were not significantly different at all the levels of K fertilizer applied but all these were significantly different from the control. Similarly, the following attributes of melon intercropped with plantain increased as the K fertilizer applied increased but not significantly in both years. Optimum K fertilizer for melon was 240 kg K ha^-1.

Table 1: Physical and chemical properties of the soil at the experimental site.

Discussion

Application of potassium decreased plantain days to shooting while at a dosage of 480 kg ha^-1, it reduced the bunch yield of plantain. This response might be explained by the fact that K is needed in the process of photosynthesis and in the formation of carbohydrate (Obiefuna, 1984, Bhargara et. al. 1992; Shailendra et. a.l.; 1999; Espinosa and Belalcazar, 2000). In plantain and banana the bunch was the organ mostly affected by lack of K, according to Lahav and Turner (1983) .

Turner and Barkus (1980) reported that while low K supply reduced the total plantain dry matter by half, the bunch was reduced by 80% but the roots were unaffected. In this study, potassium significantly increased plantain bunch yield up to 360 kg K/ha. Higher plantain bunch yield was obtained in non-intercropped fields (results not presented) compared with that intercropped with melon. This showed that K requirement of plantain in this study was affected by the companion crop in the intercropping system. In a mixture like this, the ability of mixture components in competing for nutrient has been found to depend on lateral root spread, root density as well as duration of the crop on the field (Wilson and Allison, 1978; Akinyemi and Tijani –Eniola, 2000). Akinyemi et al. (2003) reported that the critical soil exchangeable K in plantain intercropped with arable crops such as cassava, maize and melon on an Alfisol ranged between 0.20 and 0.21 cmol/kg. Results of the partial budgeting method for the intercrop at different K fertilizerrates were N10, 000.00 (or $384.60) in 1993 and N 6, 700.00 ($ 257.69) in 1995 cropping seasons.

Table 2. Effect of K fertilizer on morphological parameters when intercropped with melon

† Means followed by same letter in same year and column are not significantly different at 5% (DMRT).

Table 3. Effect of K on yield and yield components of melon intercropped with plantain

Table 4. Effect of K fertiliser on the yield and yield components of melon intercropped with plantain

† Means followed by same letter in same year and column are not significantly different at 5% (DMRT).

Conclusion

In conclusion, the optimum K fertilizer that will give the best marginal rate of return was estimated to be 360 kg K ha^-1.

References

Akinyemi, S.O.S. and Tijani-Eniola, H. Effect of Cassava density on Productivity of plantain and cassava intercropping system. Fruits, 2000, 55: 17 – 23.

Akinyemi, S.O.S., Tijani-Eniola, H., and Olaleye, A.O. (2003). Response of plantain intercropped with arable crops to varying levels of potassium fertilizer on an Alfisol. Journal of Plant Nutrition (USA). 26 (8): 1235-1246.

Bhargaara, B. S; Raghupathi, H. B and Reddy, M. M. C (1992) Dynamics of added potassium in a red soil under Bananas and Plantains. Journal of the India Society of Soil Science, 40 (3) 439 – 442.

CIMMYT (1988). From Agronomic data to farmer recommendation: An Economic Traning Manual. Completely Revised edition. 30p.

Espinosa, J. and Belalcazar, S (2000). Fertilization of plantain in high densities. Better Crops International 14 (1): 16 – 19.

Lahav, E. And Turner D. W. (1983) Bananas Nutrition; IPI Bulletin No 7. PP 61.

Obiefuna, J. C. Effect of Potassium Application During the Floral Initiation Stage of Plantain (Musa A A B). Fertilizer Research, 1984, 5: 315 – 319

SAS Institute Inc. Statistical Analyses Systems User’s Guide: Statistics. Version 8 edition. Cary, North Carolina, 1999.

Shailendra Agrawal, Patel R. K; Pandey S. D. Influence of higher level of nitrogen and potassium on growth and yield potential of in-vitro banana. Mysore. Journal of Agricultural Sciences, 1999, 32 (4) 275 – 280.

Turner, D. W. and Barkus, B. An Empirical Relationship Between Climate, and Nutrition and Nutrient Concentrations in Banana Leaves. Fruits, 1980, 35: 151 – 158.