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The Response of Sweet Potato (Ipomoea batatas Lam.) to Inter‐ and Relay‐cropping with Maize (Zea mays L.)
Author(s) -
Oswald A.,
Alkämper J.,
Midmore D. J.
Publication year - 1996
Publication title -
journal of agronomy and crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.095
H-Index - 74
eISSN - 1439-037X
pISSN - 0931-2250
DOI - 10.1111/j.1439-037x.1996.tb00472.x
Subject(s) - intercropping , agronomy , ipomoea , cultivar , biology , competition (biology) , crop , interspecific competition , shoot , cropping , cropping system , productivity , horticulture , agriculture , botany , macroeconomics , economics , ecology
Four sweet potato cultivars were inter‐ and relay‐cropped with maize at two locations in Peru. Increasing interspecific competition drastically reduced tuber yields of all cultivars; fewer tubers m −2 were produced and no tolerant genotype was identified. Likewise the mean tuber weight declined linearly for two cultivars when competition became severe. Shoot development was less affected. Under intense competition the plant top was favoured in assimilate partitioning to the detriment of tuber formation. Overall reduction in assimilate production due to mixed cropping was the major cause of yield loss. Various intercropping combinations were found with the same productivity but distinct proportions of the component crops (sweet potato + maize). Land equivalent ratio (LER) exceeded sole crop productivity only for the combinations with the highest maize yields. Biomass production was clearly increased by intercropping but there was no increment in marketable yields. Relay‐cropping reduced tuber and maize yields and had the lowest productivity of all combinations tested.