Effect of Previous Crops and Fertilizers Management of Stem Amaranth in Vegetables – Vegetables - Rice Cropping System
Authors: Pramanik Shila , Zakaria Mohammad , Hossain Mohammad Mofazzal , Haque Mohammad Moynul , Saleque Mohammad Abu 
Published: April 2021

Aims: To determine the effect of previous crops and fertilizers management on yield and yield parameters of stem amaranth (Amaranthus tricolor L.) in vegetables-vegetables-rice cropping system.
Study Design: A randomized complete block design (RCBD) with six treatment combinations having four replications was used for the experiment.
Place and Duration of Study: The field experiment was conducted in kharif-1 seasons (April to June) 2018 and 2019 at the research field of Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh.
Methodology: The layout was kept undisturbed for the cropping sequence over two years. Factor-A had three previous crops under the cropping system as P1= Potato (Potato - Stem Amaranth - T. Aman rice), P2= Garlic (Garlic -Stem Amaranth -T. Aman rice), P3= Cauliflower (Cauliflower -Stem Amaranth - T. Aman rice) and Factor-B had two level of fertilizers management as F1= Organic fertilizer (N based organic compost), F2= Inorganic fertilizer (Estimated inorganic fertilizer dose based on the soil test value without cow dung). The data were recorded on plant height, leaves per plant, stem diameter, stem yield (t ha-1) and stem dry matter content (%) during harvesting time.
Results: Significantly maximum plant height was observed (93.5cm) in inorganic fertilizer treated plot under previous crop cauliflower which was followed by (93.0cm and 75.0cm) under garlic and potato, respectively. Whereas, minimum plant height (61.8cm) receiving organic source of fertilizers when the previous crop was potato in 2019. The interaction of previous crops and fertilizer application showed significant variation on leaves per plant of stem amaranth both in 2018 and 2019. Stem diameter showed the same trend as that of stem dry matter and resulted insignificant influence due to previous crops and fertilizers management over the two years. In 2018, significantly higher stem yield was observed (38 t ha-1) in inorganic fertilizer treated plot under previous crop cauliflower which was followed by (36.1 t ha-1and 35.5 t ha-1) under garlic and potato, respectively. Whereas, lower stem yield (20.0 t ha-1) receiving inorganic source of fertilizers when the previous crop was cauliflower. Higher stem yield was observed (51.4 t ha-1) in (F2P2) treated plot which was followed by (44 t ha-1) under F2P3 and F2P1, respectively. Whereas, lower stem yield (22.0 t ha-1) receiving F1 source of fertilizers when the previous crop was P3 in 2019.
Conclusion: The experimental results of this study have shown that previous crops had a positive impact on the yield parameters of stem amaranth like plant height in 2018 and leaf numbers of plant both in 2018 and 2019. Interaction effect of previous crops and fertilizers management exerted significant variations only on leaves per plant of amaranth both in 2018 and 2019. Moreover, fertilizers management showed significant variation for plant height in 2019 and for stem yield both in 2018 and 2019.Therefore, it was concluded that stem amaranth after previous crop garlic with soil test based inorganic fertilizer could be high yielding and N based organic compost could be moderate yielding under Garlic- Amaranth – T. Aman cropping system.