Effect of intercropping sunflower with soybean at different interrow and intra-row spacing on land use efficiency

Abstract

Sunflower (Helianthus annuus L.) and soybean (Glycine max) were relatively new crops of economic
significance in Uganda before 1990s compared to traditional cash crops such as cotton, tea and
coffee. By 2000 many smallholder farmers in the Mid-Northern Agro-ecological Zone of Uganda
started planting sunflower and soybean as sources of household income. However, sunflower and
soybean are planted in same piece of land using different planting patterns that may lead to
differences in yields. This study evaluated the effect of inter-row and intra-row spacing on yields
of sunflower and soybean intercrop. A 4 x 4 factorial experiment in a randomized complete block
design was used to determine performance of sunflower and soybean under four inter-row spacings
(75, 90, 105 and 120 cm) and four intra-row spacings (30, 40, 50 and 60 cm) and sole sunflower and
sole soybean. Under intercrop, a ratio of 1:1 sunflower/soybean was used. Sole sunflower was
planted at 90 cm x 30 cm; while sole soybean was planted at 50 cm x 25 cm. Mean yields of
sunflower from intercrop were 2517 and 1219 kg ha-1, compared to 3241 and 1655 kg ha-1 from sole
sunflower at Acwec Omio and Ngetta Zonal Agricultural Research and Development Institute
(NgeZARDI), respectively. Yield of soybean was 1100 and 2978 kg ha-1 (p<0.01), compared to 3364
and 2590 kgha-1 from sole soybean at Acwec Omio and NgeZARDI, respectively. The highest Land
Equivalent Ratios (LER) were 1.29 at inter-row spacing of 90 cm between rows and 1.25 at intrarow spacing of 30 cm within rows. The lowest LER of 0.8 was from 120 cm x 60 cm spacing. An
intercrop between sunflower and soybean at a spacing of 90 cm between rows and 30 cm within
rows, was the most appropriate, since LER were above 1.2, an indication that land was efficiently
utilized. Sunflower can be intercropped with soybean, enabling farmers to raise income by
cultivating two crops in same piece of land, above all conserve the fertility of land.