Abstract
An experiment was conducted by introducing potato and vegetable pea as intercrops in winter maize to evaluate production potentiality of the intercropping in relation to nutrient expense and solar radiation interception during three consecutive Rabi seasons in 2000-01, 2001-02 and 2002-03 on a silty-loam to silty-clay-loam soil at the Regional Agricultural Research Station, Jamalpur, Bangladesh. The treatments comprised combination of two intercropping viz. maize + potato and maize + pea; two row arrangements viz. single-row and paired-row maize planting and five levels of NPK viz. 0, 25, 50, 75 and 100% recommended dose @ 115 kg N, 30 kg P and 125 kg K ha1 for potato and 27 kg N, 30 kg P and 60 kg K ha1 for pea along with 254 kg N, 52 kg P, 110 kg K, 45 kg S, 2.9 kg Zn and 1.7 kg B ha1 for maize as full recommended doses. Three sole crops of maize, potato and pea were also tested. Thus, the experiment consisted of 23 treatments and these were investigated in randomized complete block design with three replications. The results revealed that number of grains cob1, 1000- grain weight, grain yield plant1, grain and dry matter yield ha1 of maize as well as EIOR were higher under sole maize by 15.89, 10.18, 19.98, 21.47, 19.63 and 26.7%, respectively than intercropped maize + potato, while these were higher by 3.99, 2.0, 2.8, 5.8, 5.08 and 7.45%, respectively over maize + pea intercropping. Yield and growth attributes of both potato and pea were better in sole crops than their intercropping. Intercropping maize with single-row potato was the most compatible row arrangement and the combination gave the highest TDM (23.45 t ha1), MEY (25.40 t ha ̈1), LER (1.77), ATER (1.45), TCPR (1.84 and 1.95 on the basis of economic yield and dry matter yield, respectively), NER (1.14), PER (1.22), KER (1.04), RIER (0.96), total NEE, PEE, KEE and REE (259.0, 1243.1, 216.7 and 74.81 based on economic yield and 75.99, 354.7, 71.79 and 17.17 based on TDM, respectively), LER in terms of nitrogen, phosphorus, potassium and radiation expense efficiency (1.61, 1.62, 1.49 and 1.68, respectively), labour use efficiency (157.9 kg DM man-day1), total protein yield (1730.6 kg ha1) and BCR (3.43). The maize equivalent yield, yield advantage and gross margin of maize intercropping with single-row potato planting were greater by 127.2%, 77% and Tk. 84803.4 ha1, respectively, than sole maize. Single-row maize alternate with single-row potato row arrangement with 100% level of NPK gave the highest gross margin (Tk. 147705.0 ha1), while the highest BCR (3.43) was found in 75% level of NPK in the same row arrangement. Among the NPK levels, 75% level in single-row maize + single-row potato row arrangement was the most agro-economic level of NPK than rest of the NPK levels as evidenced by the benefit-cost ratio. The findings also revealed that maize + pea intercropping performed better in respect of dry matter accumulation plant1, CGR, number of grains cob1, 1000-grain weight, grain and dry matter yield of maize and EIOR in most of NPK levels compared to corresponding potato involving intercropping. The higher number of grains cob1 (487.2), 1000- grain weight (336.8 g) and grain yield of maize (10.53 t ha1) were obtained from single-row maize with 2-row pea planting with 100% level of NPK for pea but application of additional NPK at different levels the pod yield did not differ significantly indicating that no additional supplementation of NPK was necessary for pea.