Vol. 12, Issue 2 (2023)

Author(s):
Jayanthi T, PK Basavaraja, Nagaraju, RC Gowda, BC Mallesh and NB Prakash

Abstract:
A field experiment was carried out at ZARS, UAS, GKVK, Bengaluru to study the “Nutrient use efficiency as influenced by fertigation of water soluble fertilizers in aerobic rice” during Kharif 2015 and 2016. The present investigation includes 16 different treatment combinations replicated thrice with RCBD design where hybrid rice (KRH-4) was a test crop grown. The results indicated that, significantly higher grain and straw yield of rice were recorded with T₁₄ treatment, which received the fertigation with 100% STCR dose through water soluble fertilizers (WSF) at 8 (8 times) days interval over soil application of 100% conventional fertilizers as per package of practice. Similarly, significantly higher NRn and NRp (3.50 and 0.86 mg kg^-1, respectively) were recorded in fertigation with 100% STCR dose through WSF at 8 days interval (T₁₄) and the treatment T₁₁ recorded significantly higher NRk (2.27 mg kg^-1) for grain production of aerobic rice than conventional fertilizers treatments. Significantly higher AUE-N (67.05%) and AUE-K (140.99%) were recorded with fertigation with 30% STCR with WSF at 8 DI (T₁₆) and fertigation with 30% RDF with WSF at 8 DI (T10) recorded significantly higher AUE-P of 131.73%. Significantly higher apparent crop recovery efficiency of N, P and K was recorded (78.60, 44.40 and 132.51 kg kg^-1) in fertigation with 100% RDF+WSF at 8 DI (T₈), 30% RDF with WSF at 8 DI through fertigation (T₁₀) and 30% STCR with WSF at 8 DI (T₁₆), respectively. Significantly higher internal utilization efficiencies of N (78.15%), P (352.11%) and K (129.43%) were noticed in T₁₃, T₂ and T₁, respectively. Fertigation with 30% RDF with WSF at 8 DI (T₁₀) recorded significantly higher partial factor productivity of N, P and K (261.23, 522.46 and 522.46, respectively) than other treatments. However, lower agronomic use efficiency-NPK (25.97%, 51.93% and 51.93%, respectively) was observed in soil application of 100% RDF with conventional fertilizer as per PoP (T₂) treatment. Similarly, lower apparent crop recovery efficiency of N and P (29.9 and 14.37 kg kg^-1, respectively) were observed with soil application of 100% RDF with conventional fertilizer (T₂). Similarly, lower ACRE-K (56.02 kg kg^-1) was observed in soil application of 100% RDF with conventional fertilizer at 8 DI (T₄).