*2.6. Calculation of Grain Yield, Protein Yield and Micronutrient Uptake*

Both rice and wheat were harvested at harvest maturity and threshed produce obtained from net plot areas were cleaned, dried and weighed at 14% moisture content and expressed as Mg ha−1. The protein yield was calculated based on the nitrogen concentration in grain. For determining the nitrogen content, the plant sample (0.5 g each) was digested by using 10 mL of analytical grade concentrated sulphuric acid along with a pinch of digestion mixture (CuSO4 + K2SO4) to determine total nitrogen content. The samples were analyzed by using Kjeldahl's apparatus [39] and were expressed as percentage. The zinc (Zn), iron (Fe), manganese (Mn) and copper (Cu) concentrations in rice and wheat plant samples were determined as per the procedure described by [40] using Atomic Absorption Spectrophotometer (AAS) and expressed as mg kg−1. For calculating the uptake in grain, grain yield was measured at 12% moisture content. For rice, white rice kernel was used instead of rough rice.

*Sustainability* **2022**, *14*, 5986




**Table 3.** Energy equivalents used for calculation of energy input and output in production system [16–18].
