|dc.description.abstract||Tomato (Lycopersicon lycopersicum L) production among the subsistance farmers in Zambia virtually stops during the rainy season and in low during the dry season. Field trials were carried out during the rainy and dry seasons at Zamseed farm, Lusaka, Zambia to detrmine the effects
of different tillage systems on growth and yield of tomato. The rainy season trial was conducted from January to May, 1999 while the irrigated trial was done from June to October, 1999. The tillage systems used were: furrow, ridge planted on the side, ridge planted on top, raised bed and flat seedbed (control). For each season treatments were arranged in a randomized complete block design with four replications. Parameters measured were seedling mortality, plant height, lateral branches, days to 50 % flowering and fruiting , fruit size (mm), diseased fruits, soil moisture content and yield of tomato.Plant height at 14 weeks after transplanting was significantly ( P<0.01) higher in raised bed and ridge planted on top treatments i.e., 81.4 cm and 73.8 cm, respectively across seasons. The shortest plants were in the flat seedbed, ridge planted on side and the furrow tillage systems.The raised bed and the ridge planted on top treatments delayed maturity at 50 days and 49 days, respectively, compared to the furrow, ridge on side and flat seedbed at 42 days, 45 and 38 days respectively. The raised bed and the ridge planted on top also increased lateral branches to 17 and 15, respectively, compared to the furrow, ridge planted on side and flat seedbed which averaged 13.The largest fruit size (60mm) was obtained from the ridge plated on side while the smallest sizes (28mm) were obtained from the furrow and the flat seedbed. Seedling mortality was reduced from 13 388 in furrow to 6250, 1388 and 4 166 on flat seedbed, raised bed and ridge planted on side, respectively. Similar/, diseased fruits per ha reduced from 65 972 in furrow to 55 902, 24 305 and 17 361 on the flat seedbed, raised bed and ridge planted on top,respectively.
Tomato yield was significantly (P<0.01) higher in raised bed (50.6 t/ha), followed by the ridge planted on top (41 t/ha), furrow (37.6 t/ha), ridge planted on the side (36.9 t/ha) and flat seedbed (control) (35.8 t/ha). In addition, the rainy season recorded lower average yield (14.3
t/ha) compared to (66.6 t/ha) under irrigation.Total yield for combined analysis was positively and significantly correlated (r=0.74*) with plant height and also between total yiel and number of lateral branches (r=0.8*). The study showed that different tillage systems have profound effects on the tomato plant
performance, with the ridge planted on top and raised bed giving the highest yields; while the largest tomato fruits were obtained in all treatments except the furrow. Differential responses observed for some of the measured characteristics between rainy and irrigated season did not
have significant effect on final yield. The best yields were during the irrigated season regardless of the tillage system used.
Economic returns were highest during the rainy season as supply decreased and prices increased.During the same season,-gross margins were highest on raised bed and ridge planted on top tillage systems, with Kl 1 498 796 and K7 693 187 returns respectively; however, the raised bed tillage system used the highest labour cost. In addition, the ridge planted on the side obtained (K2 085 078). Lower gross margins (K-292 486 and K922 952) were observed on the flat and the furrow treatments, respectively. On the other hand, the furrow and the flat seedbed tillage VI systems recorded the highest gross margins (K2 625 849 and K2 405 639), respectively, under irrigated conditions. There was no significant difference in gross margins (Kl 732 431 and Kl 723 891) for the ridge planted on side and the ridge planted on top, respectively. The raised bed tillage system had the lowest gross margin (Kl 223 681) and highest variable costs (K7 790 681). The conclusion is that the tillage systems with highest and lowest yields during the rainy season
were the raised bed and the flat seedbed, respectively while the raised bed and the ridge planted on top obtained the highest and lowest yields under the irrigated season, respectively.||en_US