Effects of fresh leaf materials of Sesbania sesban (L.) Merrill on the growth and photosynthetic pigments of nightshade (Solanum nigrum L. var. popolo)

Abstract Solanum nigrum L. is one of the African leafy vegetable consumed in Kenya. High cost of inorganic fertilizers has made it inaccessible by smallholder farmers leading to low yields. A study was conducted at Maseno University, Kenya to investigate the effects of Sesbania sesban fresh leaf materials on the growth of Solanum nigrum L. The study was conducted under greenhouse conditions using 3litre pots. Each pot was filled with 2kg of top soil and five treatments of fresh leaf materials of S. sesban incorporated at the rates of 0g (control), 15g, 30g, 45g and 60g. Ten seeds of S. nigrum L were planted in each pot and were watered daily until they germinated after which they were thinned to five seedlings per pot. The experiment was laid out in a completely randomized design (CRD) with 5 replications. Data on stem length, number of leaves per plant, leaf length, leaf breath were collected each week from the fifteen day after germination. Fresh and dry weights of the stems and roots, Leaf chlorophyll and carotenoids contents were determined at the end of the experiment. The data collected was subjected to ANOVA and means separated and compared using the least significant difference (LSD) at P = 0.05, using SAS statistical package. The study showed that there was a significant effect of application of fresh leaf material of S. sesban on the growth of S. nigrum plants, variety: popolo. Treatment consisting of 45g of fresh leaf material of S. sesban had the highest number of leaves, leaf area, plant height, fresh weight of the shoots and roots, and dry weights of shoots and roots. Chlorophyll a (chl a) and chlorophyll b (chl b) contents increased in all the treatments receiving fresh leaf materials of S. sesban. There were no significant differences in Chl a and chl b contents among the treatments receiving fresh leaf materials. Carotenoids contents of S. nigrum increased with increasing amounts of fresh leaf material of S. sesban. However, there was no significant difference in carotenoids contents between treatments. In conclusion fresh leaf material of sesbania promoted growth and increased photosynthetic pigments of S. nigrum, probably this was due to high amounts of nutrients supplied by S. sesban. The under exploited potential of S.sesban green manure can be harnessed in growing S. nigrum plants.