On- farm precision nutrient prescription under pre- dominant cereal- cereal systems using Nutrient Expert®

The project was aimed at optimizing nutrient use and maximizing the productivity of cereal–cereal systems through on-farm precision nutrient prescriptions using Nutrient Expert® (NE), in various cereal-growing areas of India. The study was initiated by the All India Coordinated Research Project on Integrated Farming System (AICRP-IFS) in 11 states of India. NE was used as a tool for providing better fertilizer recommendations in rice, maize, and wheat, which was evaluated in the predominant rice-rice (RRS), rice-wheat (RWS), rice-maize (RMS), maize-wheat (MWS), and other rice-based cropping systems (ORBS) in comparison with the official state fertilizer recommendation (SR) and farmers' fertilizer practice (FFP).

The nutrient use in FFP highlighted the generally unbalanced nutrient management practices adopted by farmers. Farmers applied higher doses of nitrogen (N), sub-optimal doses of phosphorus (P) and almost negligible amounts of potassium (K) fertilizer, as compared to the recommended rates for different crops at various locations. NE recommended relatively lower N use (20-154 kg/ha in RWS, 53-131 kg/ha in RRS), optimal P use (21-55 kg/ha in RWS, 12-31 kg/ha in RRS) and adequate rates of K use (44-174 kg/ha in both RWS and RRS) as compared to the other practices. As a result of nutrient optimization, annual saving of fertilizer cost in the NE recommendation over FFP was Rs. 2,334 per ha in RWS, Rs. 3,790 in RRS, and Rs. 1,320 per ha in RMS.

The results also revealed that NE-based fertilizer recommendations at the on-farm sites improved productivity and profitability of cereal systems over the existing practices. The system productivity, compared in terms of rice equivalent yield, was maximized under NE and was 2 to 14% higher in RWS, 1 to 15% higher in RRS, 3 to 17% higher in MWS, and 5 to 13% higher in ORBS over SR. The corresponding yield increase due to NE over FFP was 16 to 29% in RWS, 6 to 28% in RRS, 30 to 118% in MWS, and 14 to 28% in ORBS. The yield increase in NE over SR and FFP was mainly due to balanced application of fertilizers during the critical crop growth stages. The average net benefit in NE-based fertilizer recommendation over the FFP was Rs. 26,206 in RWS, Rs. 25,550 in RRS, Rs. 42,800 in MWS, and Rs. 23,580 in ORBS. The study highlighted the significance of balanced nutrient prescriptions by NE as a viable option for sustaining higher productivity and profitability of cereal based systems in India.