2024, Vol. 7, Special Issue 7

author(s)
BS Bishoyi, B Duary, SS Nanda, UK Behera, C Patra, I Das and D Sahoo

abstract
A field experiment was conducted at the Instructional Farm of the College of Agriculture, Chiplima, Sambalpur, Odisha for two consecutive years (2019 and 2020) in kharif seasons where submergence tolerant rice (Cultivar ‘Swarna sub 1’) was taken as test crop to investigate the effect of nursery management on seedling vigour and post flood survival of rice (Oryza sativa L.) as well as to study its subsequent effect on growth and yield under submergence. Application of fertilizers and sowing of the pre germinated seeds were done as per the treatments. The Main field lay out was done as per the nursery lay out. A common Fertilizer dose of N:P₂O₅:K₂O at 80:40:40kg ha^-1 was applied in the main field. Plants were completely submerged at 10 DAT with a water depth of 1.1 meter for a period of 15 days. From the experimental findings it revealed that application of N:P₂O₅:K₂O at 100:40:40 kg ha^-1 in the rice nursery produced the highest dry matter production plant^-1, seedling length and leaf area seedling^-1 at transplanting in nursery and was comparable with application of N:P₂O₅:K₂O at 80:40:40 kg ha^-1 (25 kg N ha^-1 from FYM at 5 t ha^-1). The lower seeding density of 40 g m^-2 and seedlings of 40 days old registered significantly higher dry matter production, seedling length and leaf area seedling^-1 in nursery than the higher seeding density of 60 g m^-2 and seedlings of 30 days old respectively. The highest survival of plants after de submergence in the main field was recorded with application of N:P₂O₅:K₂O at 80:40:40 kg ha^-1 (25 kg N ha^-1 from FYM at 5 t ha^-1) which was significantly higher than all other nutrient treatments. The lower seeding density of 40 g m^-2 and seedlings of 40 days registered significantly higher post flood survival % than the higher seeding density of 60 g m^-2 and seedlings of 30 days old, respectively. The chlorophyll content of rice leaves before submergence was significantly higher in the treatment receiving N:P₂O₅:K₂O at 100:40:40 kg ha^-1 (N₄) than all other nutrient management practices. The lower seeding density of 40 g m^-2 (D₁) and the seedlings of 30 days (T₁) recorded significantly higher chlorophyll content in rice leaves before submergence as compared to higher seeding density of 60 g m^-2 (D_­­2) and older seedlings of 40 days (T₂). Application of N:P₂O₅:K₂O at 80:40:40 kg ha^-1 (N₂) in the main plot treatment of rice nursery recorded the highest value of chlorophyll after de-submergence which was statistically at par with application of N:P₂O₅:K₂O at 100:40:40 kg ha^-1 (N₄) and was significantly higher than that of other nutrient management treatments. The lower seeding density of 40 g m^-2 (D₁) in the nursery resulted significantly higher chlorophyll content in rice leaves just after de-submergence than higher seeding density of 60 g m^-2 (D₂). The older seedlings of 40 days (T₂) produced significantly higher chlorophyll content of leaves after de-submergence than that of younger seedlings of 30 day (T₁). Application of N:P₂O₅:K₂O at 80:40:40 kg ha^-1 (N₂) in the main plot treatment of rice nursery recorded significantly higher value of dry matter production m^-2 than all other nutrient treatments in the main field at 45 DAT, 105 DAT and at harvest. This treatment also recorded significantly higher grain yield, straw yield and return rupees^-1 invested than all other nutrient treatments. The lower seeding density of 40 g m^-2 (D₁) in the nursery and older seedlings of 40 days recorded significantly higher dry matter production at 45 DAT, 75 DAT and at harvest as well as significantly higher grain yield, straw yield and return rupees^-1 invested than higher seeding density of 60 g m^-2 (D₂) in the nursery and younger seedlings of 30 days, respectively.