Optimizing Levels of Fertilizers and Spacing on Sugarcane Genotypes and Soil Nitrogen Fractions under Calcareous Soil
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Date
2021
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DRPCAU, PUSA
Abstract
A field experiment was conducted to optimize the levels of fertilizer and spacing for better performance of sugarcane genotypes and soil nitrogen fractions under Calcareous Soil during 2019-20 at Dr Rajendra Prasad Central Agricultural University Bihar. The treatment combination comprised two spacings (row to row-90 cm and 120 cm), three levels of fertilizers (100 % NPK of RDF, 125 % of NPK of RDF and 150 % of NPK of RDF) and six different sugarcane genotypes (CoLk 15466, CoLk 15467, CoP 15436, CoSe 15452, CoSe 15455, CoLk 94184) with having a total of thirty-six treatment combinations and three replications. The recommended dose of fertilizer 150:85:60 kg N: P2O5: K2O ha-1 was applied through urea, SSP and MOP. The half dose of N was used through basal dose, and the remaining half was used in two equal split doses. The P and K were applied as basal doses. Sugarcane crop was planted during the spring (February 2020) season.
The effect of row spacing on germination at 30 DAP and 45 DAP was statistically non-significant and significant, respectively. Germination per cent was highest in treatment with 90 cm of row spacing compared to 120 cm of the row spacing at both the stages of plant growth, i.e., at 30 DAP (27.8%) and 45 DAP (31.6%). At 30 DAP, fertilizer levels didn’t significantly affect, whereas, at 45 DAP,
the effect was significant. The highest germination per cent at 30 DAP (27.8%) was recorded in treatment with 150 % NPK of RDF, whereas the highest germination per cent at 45 DAP (32.4%) was recorded with 100 % NPK of RDF. At last, coming to genotype, it was concluded that at both the stages of plant growth, i.e., at 30 DAP
(30.7%) and 45 DAP (34.2%), genotype CoP 15436 recorded the highest germination per cent (30.7%). Also, at both stages, the effect of genotype on germination per cent was found to be significant. The effect of row spacing on plant population at both the stages of crop growth, i.e., at 120 DAP and 150 DAP, was statistically significant. Fertilizer treatment with 150 % NPK of RDF showed significantly the highest effect on plant population at both stages of plant growth. Genotype CoP 15436 also showed significantly superior results over the rest of the genotypes concerning plant population at both stages of plant growth. Significantly higher cane yield (85.0 t ha-1) was recorded in treatment with a narrow spacing of 90 cm compared to cane yield (74.8 t ha-1) in treatment with wider row spacing of 120 cm. Significantly higher juice recovery was found in treatment with 90 cm spacing (64.88 %) than 120 cm spacing (63.16 %). The effect of spacing on available soil nitrogen was observed to be non-significant. Availability of nutrients in the soil is strongly affected by 120 cm row spacing, 150% NPK of RDF and genotype CoLk 15467 and hence proved beneficial for improving the fertility status of the soil. In the case of nutrient uptake by sugarcane plant, we concluded that 90 cm row spacing, 150% NPK of RDF and either of the three genotypes viz., CoLk 15466, CoP 15436, CoSe 15452 proved best which enabled the plant to utilize the nutrients from the soil efficiently.
The effect of spacing on nitrate-nitrogen was non-significant. However, levels of fertilizer were found to have a statistically significant impact on nitrate-nitrogen fraction. Significantly highest nitrate-nitrogen content was observed in treatment with 150% NPK of RDF (23.6 mg Kg-1). Genotype was also found to have a significant effect on nitrate-nitrogen fraction. Genotype CoLk 15467 received the significantly highest value (23.9 mg Kg-1) for nitrate-nitrogen. While looking over data obtained on soil nitrogen fractions, whether it be inorganic fractions (NO3-- N + Exchangeable NH4+-N) or organic fractions (Hydrolyzable ammonical-Nitrogen + Hexose amine-Nitrogen + Amino acid-N + Unidentified-N), we concluded that 120 cm row spacing, 150% NPK of RDF and genotype CoLk 94184 supposed to maintain the nitrogen dynamics in the soil.