Assessment of Post-Harvest Soil Macro and Micronutrient Content Under Nutrient Omission Conditions

A field experiment was carried out at the Main Maize Research Station, Anand Agricultural University, Godhra, Gujarat during two successive kharif seasons in 2022 and 2023 to evaluate the impact of nutrient omission on the nutrient status of soil after harvest of maize. Evaluating soil fertility is essential for ensuring adequate and balanced fertilization for high crop productivity. A nutrient omission trial helps identify the most limiting nutrients for crop growth. If a particular nutrient is excluded while all others are supplied at appropriate levels and the plants exhibit poor growth, the omitted nutrient is considered a limiting factor. On the other hand, if a nutrient is omitted but plant growth remains healthy, then that nutrient is not a limiting factor for crop production. The study was designed using a Randomized Block Design (RBD) with three replications and included fourteen different nutrient omission treatments: control (T1), 160 kg N ha-1 (T2), 20 kg P2O5 kg ha-1 (T3), N160P20 kg ha-1 (RDF) (T4), N160P20K60kg ha-1 (T5), N160P20S20 kg ha-1 (T6), N160P20Zn5 kg ha-1 (T7), N160P20Fe10kg ha-1(T8), N160P20K60S20 kg ha-1(T9), N160P20K60Zn5kg ha-1(T10), N160P20K60Fe10 kg ha-1 (T11), N160P20K60S20Zn5kg ha-1 (T12), N160P20K60S20Fe10kg ha-1 (T13) and N160P20K60S20Zn5Fe10 kg ha-1 (T14). The maize hybrid GAWMH 2 was cultivated for both kharif seasons to assess treatment effects. The organic carbon, soil EC, pH, DTPA-Mn and Cu did not exhibit significant influence by different nutrient omission treatments during both years 2022 and 2023. Among the different treatments studied, significantly higher available nitrogen (239 and 245 kg ha-1), phosphorus (51.84 and 53.50 kg ha-1), potassium (252 and 254 kg ha-1) and sulphur (10.59 and 10.70 mg kg-1) in soil after harvesting of maize was observed under the application of T14 (N160P20K60S20Zn5Fe10 kg ha-1) treatment during both the year. While, lower content (195, 193, 42.41, 41.16, 217, 213 kg ha-1, 8.55 and 8.30 mg kg-1) was observed with control treatment (T1) during 2022 and 2023. Throughout both years of the study, there was a noticeable improvement in the soil’s available nitrogen, phosphorus, and potassium compared to the initial levels. In 2022, nitrogen levels increased by 14.90%, followed by a 17.78% rise in 2023. Phosphorus availability also improved, showing a 12.69% increase in 2022 and 16.30% in 2023. Likewise, available potassium rose by 7.23% in 2022 and 8.06% in 2023 relative to the initial soil nutrient content. Nutrient omission treatments did not significantly affect the available zinc and iron contents in the soil after maize harvest in 2022. However, in 2023, available zinc and iron were significantly higher in treatment T14 while the lowest zinc and iron content observed in the control treatment (T1).