Integration of Brassica amendments and summer irrigation for weed suppression in clusterbean (Cyamopsis tetragonoloba) in hot arid regions

A field experiment was conducted during 1998-99 to ascertain the efficacy of Brassica amendments (mustard oil-cake and pod straw @ 2.5 tonnes/ha) during summer months in suppression of weeds and on seed yield of subsequent clusterbean [Cyamopsis tetragonoloba (L.) Taubert] crop. Incorporation of Brassica amendments with I summer irrigation at high soil temperature (39-44°C) resulted in significant reduction by 43% and 11% in the population of summer and rainy-season weeds, respectively, in all the amended plots compared to their application at the time of normal sowing in July at moderate soil temperature (23-35°C). The significant reduction in summer weeds was equal with the amendment of mustard oil-cake and mustard pod straw. Of the common summer weed species, kag nasha (Corchorus tridens L.), balu ka sag (Gisekia pharnacioides L.), heliotrope (Heliotropium subulatum Hochst.), stink grass [Eragrostis ciliaris (L.) R.Br.], and carpet weed [Mollugo cerviana (L.) Ser.] were suppressed completely in amended plots. These combinations also significantly reduced the weed population by 44% during succeeding rainy season in clusterbean crop. Mustard oil-cake with I irrigation increased the seed yield by 3 and 61% over its incorporation in rainy season and non-amended control. The corresponding values for mustard pod straw were 7 and 32% respectively.