Maize and Potato Intercropping

Open Agriculture. 2017; 2: 411–416

Research Article

Beyenesh Z. Kidane*, Mereseit H.Hailu, Haile T. Haile Maize and Potato Intercropping: A Technology to Increase Productivity and Profitability in Tigray https://doi.org/10.1515/opag-2017-0044 received November 21, 2016; accepted May 22, 2017 1 Introduction

Abstract: Smallholders have limited landholding in Agriculture is the leading sector in the national economy the highlands of Tigray and therefore there is a critical and is the core driver for Ethiopia’s growth and long-term need to improve land use efficiency (LUE). One way to food security accounting for nearly 46% of GDP, 73% of improve the LUE is through intercropping of companion employment, and nearly 80% of foreign export earnings crops including maize and potato. An experiment was (ATA 2014). Furthermore, more than 95% of the country’s conducted to evaluate the intercropping ratio as a means agricultural output is generated by subsistence farmers to improve land use efficiency during the 2012 cropping who, on average, own less than one hectare of cultivated season. The treatments tested were three intercropping land (USDA 2010). Agricultural productivity is therefore, ratios of maize: potato in 1:1, 1:2, 2:1 row arrangement constrained by limited cultivation areas and high compared against the maize and potato only cropping. population growth. The objective of the study was to identify the best Tigray is the most food insecure region of the country. intercropping ratio that maximizes land use efficiency. Increasing food production to feed the fast growing Land equivalent ratio (LER) was used to compare the population living worldwide in drought-prone areas like land use efficiency of the intercrops with each sole crop. Tigray, Ethiopia, relies on two options, either increase the The total yield of intercropped crops were greater than arable land to be cultivated or improve land productivity. sole cropping, shown by LER>1. The overall advantage of The first option is less realistic and may not address the intercropping ranged from 35 to 58%. The highest land problem of water scarcity in view of land scarcity and equivalent value of 58% was recorded for one maize and limited land reserve (Tsegay et al. 2015). The use of an two potato rows arrangements indicated a yield advantage intercropping system is one method of increasing crop of 58% over sole crop. The partial land equivalent value of productivity and intensity of crops (Sullivan 2000). both crops in intercropping was less than one indicating Intercropping has several advantages such as the cohesiveness of both crops in intercropping. Thus, it additional income from companion crops (Samsuzzaman can be concluded that 1maize: 2 potato intercropping is a et al. 1999), insurance against crop failure (Beyenesh viable agronomic option in increasing land use efficiency 2008), increase productivity (Sharaiha et al. 2004), stability and increased food security. It is, therefore, imperative to of production, and maximization of products, soil fertility demonstrate the best treatment under farmer’s condition. and pest control. This functional diversity contributes to ecological processes to promote the sustainability of the Keywords: Hawzen, Intercropping arrangement, Land whole farm system (Vandermeer 1989; Altieri 1999). Equivalent Ratio (LER), sole cropping, grain yield, tuber The agricultural system in Tigray has been mainly yield cereal based. Maize (Zea mays L.) is the principal cereal crop which is grown both under rainfed and irrigation usually, for human food, but sometimes, as a cash crop. Maize is a cereal crop that is grown widely throughout the world in a range of agro-ecological environments. More maize is produced annually than any other grain. The grains are rich in vitamins A, C and E, carbohydrates, *Corresponding author: Beyenesh Z. Kidane, Mekelle Agricultural essential minerals, and contain 9% protein. They are also Research Center Mekelle, Ethiopia, E-mail: [email protected] Mereseit H. Hailu, Haile T. Haile, International Potato Center, Meklle rich in dietary fiber and calories which are a good source Ethiopia of energy.

On the other hand, Potato (Solanum tuberosum L.) is precipitation was 536 mm while the total rainfall of the the world’s leading vegetable crop by virtue of its inherent growing season was 469 mm. The average minimum potential for tonnage production, remunerative income temperature was 10oC and maximum temperature was and good nutritional values. It is a starchy, tuberous crop. 27oC. The study has a one season rainfall pattern with Potato is a promising tuber crop gradually becoming an extended rainy season from March to November with important in the highlands of Tigray and plays both as the peak season in August. The area has a mixed farming dietary and income generating. The eastern and southern system with crop dominance. The dominant crops growing zones are particularly the highest potato production in the area are wheat, maize barley, teff and vegetables which accounts for more than 83% of total area and more mainly potato and tomato. The soil of the experimental than 74% of total production of the region with an average site was sandy loam in texture (Rowell 1994). According to yield of 10 t ha-1 (CSA 2003). Both crops are grown mainly rating of Tekalign (1991), the soil was almost neutral (6.3) independently though some farmers often undertake and low in total nitrogen (0.05%), low available Olsen P maize and potato intercropping due to diminishing (5.45ppm) and medium in CEC (20 mq/100g soil) suitable land for food production. However, the procedure is not optimized and there is a great variation on yield productivity (BOARD 2010). In the region, both crops are 3.2 Experimental design and treatments considered as food security crop and there is a great need to improve their productivity through intercropping. The field experiment was laid out in a randomized Most studies in Ethiopia have focused on cereal and complete block design with three repeats. The treatments legume intercropping and identified suitable genotype consisted three intercropping combinations viz: two combinations, plantings dates, and population densities rows of maize + one row of potato, one row of maize + of various species while, little attention was given to one row of potato, one row of maize + two rows potato , other intercropping systems (Bantie et al. 2014). Several maize only and potato only. The maize variety used was authors have reported the superiority of maize/potato Melekasa II and Gera for potato. Both potato and maize intercropping to sole (Amin et al. 1996; Sharaiha Battikhi were sown at the same time in rows 75 cm apart with 25 cm 2002; Tesfay et al. 2006; Yayeh 2015). This suggests that intra-row spacing based on the required treatment. Maize the system can help to raise productivity to achieve food seeds were sown at the rate of two seeds per hill and the security but the system has never been researched and seedlings thinned to one plant per hill after three weeks. no studies have been made to improve the productivity of Recommended hand weeding and harvesting practices the system. To this effect, an experiment was conducted were followed, and fertilizers were applied at rates of 50 at Hawzen to assess the compatibility of the companion kg urea and 100 kg Dap ha-1 for maize and 195 kg Dap ha-1 crops and identify best cropping ratio that maximize land and 165 kg urea for potato. use efficiency.

2 Objectives 3.2.1 Treatments tested 1. Two rows of maize planted with one rows of potato –– To assess the compatibility of companion crops. (maize was planted in 75 cm × 25 cm and distance –– To identify the best cropping ratio that gave land use between potato and maize is 37.5 cm) (2 maize: 1 advantages of the component crops in intercropping potato). system. 2. Potato was planted between rows of maize (maize planted in 75 cm × 25 cm) (1 maize: 1 potato). 3 Materials and Methods 3. One row of maize planted with two rows of potato (potato was planted in 75 cm × 25 cm and distance between potato and maize is 37.5 cm) (1 maize: 2 3.1 Site description potatoes). 4. Maize only. The experiment was conducted during the 2012 cropping 5. Potato only. at Hawzen district. Geographically, the site is located at 39° 27’ 2’’ E and 13° 15’ 16’’ N, altitude of 2120 meters above sea level. The long term average (1971-2000) annual Maize and Potato Intercropping: A Technology to Increase Productivity and Profitability in Tigray 413

3.3 Data collection and measurements would imply that there was no advantage of intercropping over pure crops. An LER greater than 1.0 would show Data on plant height, cobs per plant, cob length, and a yield advantage of intercropping over pure crops, In tubers per plant were determined from 10 randomly contrast, when LER is lower than one the intercropping sampled plants per plot during physiological maturity. negatively affects the growth and yield of the plants grown The grain and tuber yield of each crop of the component in mixtures (Ofori and Stern 1987). crop in the intercrop was determined from the harvestable -1 plot and converted to tones ha . 4 Results and discussion

3.4 Data analysis 4.1 Maize component

Data was subjected to analysis of variance (ANOVA) The plant height, number of cobs plant-1, cob length following statistical procedures of SAS version 9.2. The and grain yield under the different treatments are level of significance was set at (p ≤ 0.05). Whenever shown in Table 1. Both cob plant-1 and cob length were treatment effects were significant, the means were not significantly influenced by the different treatments separated using Duncan’s multiple range tests. while plant height and grain yield were significantly The land use efficiency was calculated. The land (P<0.01) influenced by the treatments. Plant height was equivalent ratio is considered a measure of the efficiency the highest in sole cropping, 28% taller compared to the of grain or economic yield of the crop in mixture, compared intercropping treatments that consist of one row of maize with sole crops, and based on land use. LER indicates the and two rows of potato intercropping ratio (Table 1). The efficiency of intercropping for using the resources of the increase in plant height under sole cropping might be environment compared with mono-cropping (Mead and attributed to the absence of other species competition for Willey 1980). The LER was calculated as follows: (Willy growth resources. and Osiru 1972) Likewise, the grain yield of maize was significantly (P<0.01) influenced by the effect of treatments as such it Land equivalent ratio (LER) = (YAB/YAA) + (YBA/YBB) was the highest under sole cropping (4.7 t ha-1) followed by two rows of maize intercropped with one row of Where: potato (4.4 t ha-1) which resulted in an increase of 28% YAB=yield of crop A (maize) when intercropped with crop and 20% as compared to intercropping treatment that B (potato), consists of one maize and one potato row arrangement YBA=Yield of crop B (potato) when intercropped with crop (3.6 t ha-1). The yield increase under sole cropping as A (maize), opposed to intercropping treatments might be attributed YAA=Yield from sole planted crop A (maize), to the highest plant population and decrease in inter YBB=Yield from sole planted crop B (potato). competition among plants. A LER of 1.0 would indicate that the amount of land The combined mean data presented in Table 1 showed required for both crops in the different pattern was the significant yield advantage for 2 maize:1 potato planting same as that for each crop grown individually. It is also an arrangement compared to the other intercropping indicator of complementary of the component crops. This treatments according to the productivity of maize plants,

Table 1: Yield and yield components of maize with different planting patterns (Hawzen 2012) Planting patterns Pl.ht (cm) Cob (plant) Cob length (cm) Yield PLER (t ha-1)

Two rows of maize/one row potato 2.15a 1.60a 25.27a 4.41b 0.94a One row of maize/one row potato 2.01a 1.70a 25.43a 3.99c 0.85b One row of maize/two rows potato 1.98b 1.70a 25.53a 3.66d 0.78c Maize only 2.38a 1.30a 26.07a 4.69a 1d CV (%) 6.40 17.20 6.20 7.60 7.40

Values followed by the same letter in a column are statistically similar at 0.05% level according to Duncan’s multiple range tests, pl.ht= plant height, PLER= partial land equivalent ratio 414 B.Z. Kidane, et al. which reached 4.41 ton/ha, compared to 3.66 ton/ha in 1 59% compared to the sole cropped potato arrangement maize:2 potato planting pattern which might be attributed due to low plant population per unit area. to the decreased inter and intra competition between The combined mean data presented in Table 2 shows potato and maize. The increased yield for this treatment that there is an advantage to 1 maize:2 potato over other resulted in the low density of potato plants per unit area intercropping treatments according to the productivity which allowed maize plants to get a greater domain, for of potato plants, which reached 27.82 ton/ha, compared large biological activity compared with maize in the two with 14.09 ton/ha in 2 maize:1 potato. This significant potato and one maize arrangement, where there was a increase in potato yield was attributed to the decreased high density of potato plants. inter and intra competition between potato and maize; The partial land equivalent ratio of maize in and potato plants, which resulted from low density of the intercropping system were significantly (P<0.01) maize plants per unit area that allowed potato plants to influenced by maize /potato intercropping arrangements get a greater domain, which is needed for large biological (Table 3). The highest PLER of 0.94 was recorded for activity compared with potato under 2 maize: 1 potato two rows of maize / one row of potato compared to the intercropping arrangements, were there was a high plant 1 maize: 2 potato planting pattern (PLER = 0.78). The density of maize plant. The results are in agreement with results revealed that an increase in maize planting ratio Ebwongu et al. (2001) who reported that productivity increased partial land use efficiency of maize in either of of the potato crop decreased when intercropped with the intercropping patterns. The results of this study are in maize compared to the plantation of potato only, while it agreement with Yilmaz et al. (2001) and Yayeh (2015). increased by increasing plant density during intercropping treatments. The partial land equivalent ratio of potato in 4.2 Potato component intercropping systems were significantly (P<0.01) influenced by maize / potato intercropping arrangements Plant height, tuber per plant and tuber yield under the (Table 3). The highest PLER (0.80) was resulted from one different treatments is shown in Table 2. Plant height was row of maize / two rows of potato compared with 0.41 for significantly (P<0.01) influenced by the planting ratio. the 2 maize: 1 potato planting pattern. The results revealed The greatest plant height was potato only which resulted that increase in potato planting ratio increased partial in an increase of 28% over one maize/one potato row land use efficiency of potato in either of the intercropping arrangement which resulted in the shortest plant height patterns. The results are in agreement with Ebwongu et al. (91.7 cm). (2001) who reported that productivity of the potato crop Intercropping maize-potato in different spatial decreased when intercropped with maize compared to arrangement significantly affect potato tuber yield the planting potato only while it increased by increasing (P<0.01). There was a significant increase in productivity plant density during intercropping treatments. The trend of sole cropped potato (34.3 t ha-1) compared with the implies that an increase in the number of rows of potato intercropped treatments which ranged from 14 to 27 tons increased tuber yield showing flexibility for variation ha-1. The lowest potato mean tuber yield was obtained at in potentiality for intensification of cropping. Similar 2 maize: 1potato (14.09 tons ha-1). The reduction ratio of findings were reported by Yilmaz et al. (2001), Sharaiha potato productivity in 2 maize: 1 potato arrangement was et.al. (2004), Tesfay et al. 2006 and Yayeh (2015).

Table 2: Yield and yield components of potato with different planting patterns (Hawzen 2012) Treatment combination Pl.ht (cm) Tuber /plant) Yield t ha-1 PLER

Two rows maize/one row potato 91.70b 11.33a 14.09d 0.41c One row maize/one row potato 97.33ab 10.20a 18.22c 0.53b One row maize/two rows of potato 109.37ab 11.17a 27.82b 0.80a Potato only 117.23a 12.03a 34.36a 1d Cv% 10.4% 16.2% 6.78% 6.4% Values followed by the same letter in a column are statistically similar at 0.05% level according to Duncan’s multiple range tests, pl.ht= plant height, PLER= partial land equivalent ratio Maize and Potato Intercropping: A Technology to Increase Productivity and Profitability in Tigray 415

4.3 Combined yield growth as reported by Mead and Willey (1980). In this study, TLER ranged from 1.35 to 1.58. The The combined yield of maize and potato in intercropping combined yield advantage in terms of total LER indices systems were significantly (P<0.01) influenced by the was greatest in the cases of 1 maize: 2 potato intercropping intercropping arrangements (Table 3). The highest arrangement (1.58) which might be attributed to more combined mean yield of the component crops (31.11 t ha-1) efficient total resource exploitation and greater overall was obtained from one maize: two potato rows followed production as opposed to the other intercropping by one maize: one potato row planting pattern with a yield treatments. This indicated that additional 0.58 ha of 22.20 t ha-1 (Table 3). The highest yield in the former (58%) more area would have been needed to get equal intercropping treatment could be attributed to growing yield to planting maize and potato in pure stands. This spaces being varied; temporal growth variance between two result is in agreement with the findings of several other varying crops; a combined increase in making better use of intercropping studies (Minale et al. 2001; Javanmard et al. light, soil moisture content and nutrients as discussed by 2009, Temesgen and Wondimu 2012) who demonstrated Jamshidi et al. (2007). The highest yield in intercropping as the advantages of intercropping systems where, LER of opposed to sole cropping was supported by several studies greater than 1 was recorded. This might indicate that in a (Amin et.al (1997), Sharaiha et.al. (2004), Tesfay et al. suitable combination plants can complement each other (2006), Temesgen and Wondimu (2012) and Yayeh (2015). in a more efficient use of environmental resources, mainly Partial LERs for potato and maize grown in the light, water and nutrients (Willey, 1979). The current intercropping systems are less than unity (Table 3) intercropping systems demonstrate that farmers could indicating that both maize and potato are compatible benefit by growing the companion crops with different for intercropping under different cropping intensities. cropping intensity in the dry lands of Tigray. The highest PLER for potato (0.80) was recorded for one row of maize / two rows of potato compared with (0.41) in the 2 maize:1 potato planting pattern. Likewise, the 5 Conclusion and Recommendation highest PLER for maize (0.94) was recorded from two rows of maize / one row of potato compared with (0.78) The experimental results have demonstrated that the sole in 1 maize:2 potato planting pattern. Partial equivalence planting of either maize or potato results in maximum of either crop increased as equivalence of the other crop yield. The results imply that yield increased with component decreased. increased population density of the component crops, the corresponding reduction in plant density for intercropping therefore leads to a reduction in yield. 4.4 Land Equivalent Ratio (LER) Though the reduction in plant density of each component crops led to a reduction in yield of both crops Total LER were significantly (P<0.01) influenced by as evidenced by the partial LER (<1), the total yield of intercropping arrangements (Table 3). Total LER was intercropped crops were greater than sole cropping as significantly different from 1.00 in all intercropping shown by TLER which were more than unity (TLER>1). treatments, which shows an advantage over pure stands This indicates the cohesiveness of the component crops in terms of the use of environmental resources for Plant under intercropping.

Table 3: Effect of spatial arrangement of maize/potato intercropping on combined yield and land equivalent ratios of the component crops (Hawzen 2012) Planting pattern Combined yield PLER M PLERP TLER t ha-1

Two rows maize/one row potato 18.50 0.94c 0.41a 1.35b One row maize/one row potato 22.20 0.85b 0.53b 1.38b One row maize/two rows of potato 31.11 0.78a 0.80c 1.58c Maize only - 1d --- 1a Potato only - ---- 1d 1a CV% 7.4 6.4% 3.9%

Values followed by the same letter in a column are statistically similar at 0.05% level according to Duncan’s multiple range tests, PLERM= partial land equivalent ratio maize, PLERP= partial land equivalent ratio potato .TLER= total land equivalent ratio 416 B.Z. Kidane, et al.

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