INTERCROPPING OF POTATO WITH BRINJAL

A field experiment was conducted to find out the spacing of potato brinjal intercropping system and land utilization and economic return at the Regional Agricultural Research Station, Jamalpur during rabi 2017-2018. The experiment was laid out in randomized complete block design (RCBD) with three (3) replications and six treatments. Cultivation of potato with brinjal at potato (60 cm × 25 cm) + brinjal (120 cm × 75 cm), Potato (50 cm × 20 cm) + Brinjal (100 cm × 70 cm), Potato (50 cm × 20 cm) + Brinjal (100 cm × 75 cm) might be agronomically feasible and economically profitable for potato and brinjal intercropping system as compared to sole treatment. Potato (50 cm × 20 cm) + Brinjal (100 cm × 70 cm) best performed in gross return, gross margin and potato equivalent yield (PEY 49.14 tha-1) compared with the other treatments. The total yield of intercropped crops was greater than sole cropping, shown by LER>1. The overall advantage of intercropping ranged from 73 to 92%. The highest land equivalent value of 92% was recorded for Potato (50 cm × 20 cm) + Brinjal (100 cm × 70 cm) arrangements indicated a yield advantage of 92% over sole crop. Viable agronomic option in increasing land use efficiency and increased food security. It is, therefore, imperative to demonstrate the best treatment under farmer’s condition.


INTRODUCTION
Bangladesh is one of the major horticultural countries in South Asia.Brinjal (Solanummelongena L.) is an important vegetable for its commercial and nutritional value in the world as well as in Bangladesh."Begoon" (Brinjal or Eggplant) is a very common and favorite vegetable in Bangladesh which has a link with the social, cultural and economic lives of rural people.Brinjal is the most important vegetable of the country.Brinjal (Solatium melongena), Linnaeus belongs of the family Solanaceae is also known as eggplant or aubergine is a popular nutritious and grown vegetable in Bangladesh as well as in the world and has got multifarious use as a dish item It is thought to be originated in Indian subcontinent because of maximum of genetic diversity and closely related species of solanuin are grown in this reason.Potato is the number one vegetable crop of Bangladesh both in terms of area and production [1].It alone constitutes more than 50% of the total annual vegetable production in the country [2].In northern part of Bangladesh Potato-Maize-Transplant aman rice turning into a major cropping pattern nowadays [3].Also, Jamalpur region Potato is the most important crop in area and production in Bangladesh especially in char.Jamalpur district which most potato growing area of Bangladesh 1643 acres area produced 6238 MT [4].The use of an intercropping system is one method of increasing crop productivity and intensity of crops [5].Intercropping has several advantages such as additional income from companion crops, insurance against crop failure, increase productivity, stability of production, and maximization of products, soil fertility and pest control [6][7][8].The inventory of main river char lands estimated their total area at 8,444 km2 or almost 6% of Bangladesh [9].Due to decreasing cultivable land, some farmers of char areas (river flood plain) under greater Mymensingh district (together five district) in Bangladesh have been practicing garden pea with onion, coriander with onion and vegetables, pulse and oilseed crops with wheat are common practice to the farmers of char areas [10][11][12].Brinjal and potato are the most important crop in area and production in Bangladesh especially in char.Jamalpur district which most brinjal production area of Bangladesh 6987 acres area produced 25449 MT [13].Farmers of this area practiced intercropped potato with brinjal and after harvest.But they do not know suitable combination of intercropped system.This suggests that the system can help to raise productivity to achieve food security, but the system has never been researched and no studies have been made to improve the productivity of the system.To this effect, an experiment was conducted at Jamalpur to assess the compatibility of the companion crops and identify best cropping ratio that maximize land use efficiency.

METHODS AND MATERIALS
The district lies between 24°34´ and 25°26´ north latitudes and between 89°40´ and 90°12´ east longitudes and it is situated at elevation 23  ecological zone Old Brahmaputra Floodplain under Agro-Ecological Zone 9 [14].The experiment was conducted at the Regional Agricultural Research Station, Jamalpur during rabi 2017-2018 to find out the spacing of potato -brinjal intercropping system and land utilization and economic return.Design of the experiment was RCB with 03 (three) replications having the unit of plot 3m × 3.75m.BARI Alu -25 (Asterix) and BARI Begun-8 were used as a variety in the experiment.Treatments included in the experiment were: T1 = Sole potato (50 cm × 20 cm), T2 = Sole brinjal (100 cm × 75 cm), T3 = potato (50 cm × 20 cm) + Brinjal (100 cm × 60 cm), T4 = potato (50 cm × 20 cm) + Brinjal (100 cm × 70 cm), T5 = potato (50 cm × 20 cm) + Brinjal (100 cm × 75 cm), T6 = potato (60 cm × 25 cm) + Brinjal (120 cm × 75 cm).Fertilizers were applied for sole potato: N:P2O5:K2O:S @ 160:100:160:20 kg /ha and sole brinjal 80-24-60-10-1.0-0.3 kg/ha N-P-K-S-Zn-B fertilizers were applied in the form of Urea, triple super phosphate, Muriate of potash, Zypsum, Zinc Sulphate and Boric acid respectively [15].For sole potato at the time of final land preparation cow dung @ 10 t/ha was applied and other fertilizers were applied as following doses.For sole brinjal: Half cow dung should be applied during the final land preparation.Remaining cowdung and full phosphorus, sulphur, zinc and boron should be applied in three equal splits 21, 35 and 50 days after transplanting.Potato sown on November 23, 2017 and Brinjal: November 30, 2017.Intercultural operations like watering, weeding and spraying insecticides were followed as and when necessary.One pheromone trap was used for everyone decimal land to control of brinjal fruit and shoot borer.Irrigation was applied two times during the potato growing period and brinjal was grown when necessary.Yield of potato and yield of brinjal was calculated in t ha -1 considering the whole plot harvest area.Five plants of brinjal in each plot were selected randomly to collect data on yield components.Collected data were analyzed statistically with the help of STAR software and mean separation was done as per LSD test at 5% level of significance.
Economic analysis was performed considering the price of potato and brinjal prevailed at the harvesting period in the local market.Potato equivalent yield (PEY) was also calculated considering the local market price at the harvesting time following the formula as stated by a researcher [16].LER indicates the efficiency of intercropping for using the resources of the environment compared with mono-cropping [17].The LER was calculated as follows: Land equivalent ratio (LER) = (YAB/YAA) + (YBA/YBB) [18].
Where: YAB=yield of crop A (potato) when intercropped with crop B (brinjal) YBA=Yield of crop B (brinjal) when intercropped with crop A (potato) YAA=Yield from sole planted crop A (potato) YBB=Yield from sole planted crop B (brinjal)

Effect of brinjal
Yield and yield components like plant height, single fruit weight, fruit length, fruit breadth, no. of fruit/plant, weight of fruit/plant and yield differed significantly influenced by different intercropping system (Table 2).The highest plant height was found in Potato (50 cm × 20 cm) + Brinjal (100 cm × 75 cm) due to closer spcing of brinjal population and the lowest from potato (50 cm × 20 cm) + brinjal (100 cm × 70 cm).Single fruit weight was obtained from sole brinjal (100 cm × 75 cm) might be due to over space to increased side branching.Fruit length, fruit breadth, no. of fruit/plant, weight of fruit/plant was highest from sole brinjal (100 cm × 75 cm).The highest yield was observed in sole brinjal (100 cm × 75 cm) which was statistically similar to potato (50 cm × 20 cm) + brinjal (100 cm × 70 cm).

Combined yield
The highest combined yield of the crops (42.89 t ha -1 ) was obtained from potato (50 cm × 20 cm) + brinjal (100 cm × 70 cm) (Table 3).The highest yield in the intercropping treatment could be attributed to growing spaces being varied; temporal growth variance between two varying crops; a combined increase in making better use of light, soil moisture content and nutrients as discussed by a researcher.The highest yield in intercropping as opposed to sole cropping was supported by several studies.Partial LERs for potato and brinjal grown in the intercropping systems are less than unity (Table 3) indicating that both potato and brinjal are compatible for intercropping under different cropping intensities.The highest PLER for potato (0.94) and brinjal (0.98) was recorded for potato (50 cm × 20 cm) + brinjal (100 cm × 70 cm) compared with Potato (50 cm × 20 cm) + Brinjal (100 cm × 75 cm) treatment combination.The highest TLER for potato (0.94) and brinjal (0.98) was recorded from (50 cm × 20 cm) + brinjal (100 cm × 70 cm) Total LER was significantly different from 1.00 in all intercropping treatments, which shows an advantage over pure stands in terms of the use of environmental resources for Plant growth as reported by previous researcher [21][22][23][24][25][26][27][28][29][30].In this study, TLER ranged from 1.73 to 1.92.The intercropped yield advantage in terms of total LER indices was greatest in the cases of Potato (50 cm × 20 cm) + Brinjal (100 cm × 70 cm) intercropping arrangement (1.92) which might be attributed to more efficient total resource exploitation and greater overall production as opposed to the other intercropping treatments [31][32][33][34][35][36][37][38].This indicated that additional 0.92 ha (92%) more area would have been needed to get equal yield to planting potato and brinjal in pure stands.This result is in agreement with the findings of several other intercropping studies, a researcher demonstrated the advantages of intercropping systems where, LER of greater than 1 was recorded [39][40][41].This might indicate that in a suitable combination plants can complement each other in a more efficient use of environmental resources, mainly light, water and nutrients.The current intercropping systems demonstrate that farmers could benefit by growing the Potato (50 cm × 20 cm) + Brinjal (100 cm × 70 cm) in Jamalpur region.

Table 3 :
Effect of arrangement of potato-brinjal intercropping on combined yield and land equivalent ratios of the component crops