Effect of the Cultivation Systems and Split Fertilizer Applications on the Growth and Yields of Tatsoi (Brassica rapa subsp. narinosa)

Tatsoi [Brassica rapa subsp. narinosa (L.H.Bailey) Hanelt] is a leafy vegetable with potential for cultivation in a riparian wetland ecosystem. The floating culture system has the advantage of ensuring a sufficient water supply in the growing substrate due to the continuous upward water movement caused by capillarity force. This study evaluated the responses of the tatsoi plant to split fertilizer applications under conventional cultivation and floating culture systems. The fertilizer treatments consisted of control (F0), single (F1), split into 2 (F2), split into 3 (F3) or split into 4 applications (F4). The results showed that early growth of tatsoi was better using floating culture than the conventional system. However, tatsoi adapted well to conventional and floating culture systems as long as sufficient nutrients were available. A single application of 6 g NPK fertilizer (16:16:16 v/v/v) at transplanting provided sufficient nutrients, as indicated by the number of leaves, total leaf area, canopy area, stem dry weight, and leaf dry weight at harvest. The leaf SPAD values in the tatsoi plants were higher in the floating culture system than in the conventional system at 14 and 20 DAT fertilized with a 4-split application. Transplanting occurred 14 days after seed planting (DAP), and harvest occurred 49 days later. A quadratic regression model using leaf length (L), leaf width (W), or L×W as predictors was reliable for non-destructive leaf area estimation in the tatsoi plant. It is recommended for farmers to apply a single NPK fertilizer at the rate of 6 g/plant to achieve an optimum yield in tatsoi cultivated using a conventional or floating culture system. HIGHLIGHTS Tatsoi plant grew well under conventional and floating culture systems as long as sufficient nutrients were available Splitting fertilizer into several times of application did not significantly better than single application of NPK fertilizer at time of transplanting SPAD values in the tatsoi leaves were higher in the floating culture than in the conventional system Length and width of leaves were reliable predictors for non-destructive accurate leaf area estimation in the tatsoi plant GRAPHICAL ABSTRACT

Responses of Leaf Celery to Floating Culture System with Different Depths of Water-substrate Interface and NPK-fertilizer Application

Wetland areas in Indonesia cover more than 33,3 million hectares, and slightly less than 40 % is inland swamp. During the rainy season, for up to 9 months annually, the wetlands are flooded, and no conventional agricultural activities can be done by local farmers. However, this condition can be seen as an opportunity to employ floating culture system. The objective of this research was to evaluate responses of leaf celery to floating culture system with different depths of water-substrate interface and NPK-fertilizer application. The results of this study indicated that the depth of water-substrate interface (WSI) should be maintained between 1 to 3 cm. At less than 1 cm, continuous contact between the water surface and the bottom part of the substrate cannot be ensured; meanwhile, aerobic substrate volume was reduced and caused significant effects on growth and yield in celery plants if WSI was deeper than 3 cm. Moreover, the effectiveness of NPK-fertilizer application was weakened if the depth of WSI was at 6 cm. Fresh leaf yield in celery plants harvested at 45 days after transplanting (DAT) can be predicted as early as 3 weeks earlier using the midrib length of the largest leaf or plant height as a predictor measured at 26 DAT. HIGHLIGHTS Depth of water-substrate interface (WSI) should be maintained between 1 to 3 cm for better growth and higher yield in floating culture system Effects of NPK fertilizer application diminished if WSI deeper than 3 cm Yield of celery harvested at 45 days after transplanting can be predicted as earlier as 3 weeks using midrib length of the largest leaf or plant height as predictor GRAPHICAL ABSTRACT

Tiller Size and Water Table Effects in Celery Growth on Floating Cultivation System

Jaya KK, Lakitan B, Bernas SM. 2020. Tiller size and water table effects in celery growth on floating cultivation system. Jurnal Lahan Suboptimal : Journal of Suboptimal Lands 9(2): 184-191.Riparian wetland is highly available and potential suboptimal lands for an alternative solution in extending agricultural activity, but several constrains need to be resolved. The objective of this study was to improve the diversification of vegetables for increasing riparian wetland with utilizing floating cultivation system. This study was conducted From November until December 2019 in Jakabaring (104°46’4” E; 3°01’35” S) Palembang. The design of experiments used in this study was arranged in split plot-completely randomized design with 2 factors (main plot and sub-plot). Main plot was the height of water table, namely: R1 (1 cm upper raft surface), R5 (5 cm upper raft surface), and R10 (10 cm upper raft surface). Sub-plot was the size of celery tiller, i.e., B1 (big size) and B2 (small size). Each combination treatment consisted of five replication. Results showed that there was no any significant effect on water table and tiller size combination treatments in all observed variables, such as: plant height, leaf area, number of petioles, root length, fresh weight, and dry weight of shoot and roots. But, root length was significant different in water table treatment. Therefore, cultivated celery using floating culture system from tiller of parent plants can be an alternative to increase agriculture activity by shortening the planting period to increase vegetable diversification in riparian wetland.