**3.2 Effect of integrating FYM with mineral fertilizer on crop production and soil fertility**

#### *3.2.1 Average agronomic and economic yields*

Application of FYM plus mineral fertilizer increased yield and income. The highest yield was measured at 6 tha−1 in the treatment of FYM plus NP fertilizer. FYM application without mineral fertilizer as organic nutrition only, decreased yield by 44% (**Figure 10**). Application of FYM + N, FYM + NP, FYM + NK, FYM + NPK, and FYM + NPKMg achieved similar yield levels, but FYM + PK fertilizer significantly decreased yield and income due to inadequate availability of N applied as FYM in the treatment. Integrating FYM with NK fertilizer resulted in the highest income measured at 1433 \$ha−1 (**Figure 10**). The economic yield at FYM + NP treatment was

#### **Figure 8.**

*Effect of balanced nutrition, omitting nutrient, and FYM on soil carbon content in 0–30 cm depth.*

#### **Figure 9.**

*Effect of balanced nutrition, omitting nutrient, and FYM on soil pH in 0–30 cm depth.*

#### **Figure 10.**

*Effect of integrated nutrition and FYM on average crop yields (n = 62 years); Grain yield with the same letters showed the insignificant difference.*

14 \$ lower than the economic yield at FYM + NK, because the historical P fertilizer price was higher than K fertilizer price (data not shown). Application of only FYM significantly decreased yield and income, because of the insufficient availability of nutrients in the FYM for the crops.

#### *3.2.2 Trend of average agronomic and economic yields*

Improvement of crop varieties during the 62 years of the trial resulted in increasing yield and income trends in all the treatments. The integrated nutrition supported the highest yield and income compared to FYM application only (**Figures 11** and **12**). The decline in yield during 1968–1980 was caused by the low N fertilizer rate in1958–1980 and the reduction of potato growth by nematodes infection in 1973–1982. Increased N fertilizer rate after 1980 and cultivating nematode resistance variety after 1982 reversed decreasing yield levels. The yield was high at integrated nutrition treatment because nutrients were balanced and adequately available compared to only FYM

*Effect of Balanced and Integrated Crop Nutrition on Sustainable Crop Production in a Classical… DOI: http://dx.doi.org/10.5772/intechopen.102682*

#### **Figure 12.**

*Effect of integrated nutrition and FYM on the trend of average economic yield.*

application. Crop yield and income at integrated nutrition was even higher than at the balanced nutrition (NPKMg) because until 2008, the treatments with FYM received the nutrients from the FYM in addition to nutrients from the mineral fertilizer.
