Influence of modified fertilizers on crop growth, productivity and soil biological values under rice (Oryza sativa) - wheat (Triticum aestivum) cropping system of Punjab, India

In the last 60 years, chemical fertilizer has played a significant role in world food production. It provides around half of the total amount of N that crops need. Nitrates (NO₃) leaching, ammonia (NH₃) volatilization and nitrous oxide (N₂O) emissions contribute to low crop production efficiency (10 to 50 percent) principally due to the loss of N through these processes. Furthermore, nitrogen fertilizer production costs are extremely high. Technology like nitrogen inhibitors and slow-releasing nitrogen fertilizers are used to boost nutrient uptake, fertilizer use efficiency, and crop yields as a result of these situations. Typical Haplustept soils were studied to see how changing fertilizers affected growth, yield, and soil genetic indicators. Fertilizer doses and sources affect soil biological characteristics, which in turn affects enzymatic activity. In the right circumstances, enzymes alter the nitrogen supply in the soil and the plant's expansion and limestone structure. The Lovely Professional University School of Agriculture, Phagwara, Punjab, conducted two years of fertilizer studies in a rice-wheat cropping system on typical Haplustept soils from 2018 to 2020. Neem coated urea + PK + S + Zn-EDTA performed significantly better than the other treatments for almost all crop growth and agronomic yield attributing characteristics (plant height, number of tillers, effective tillers, panicle/spikelet length and grain per spik, test weight, grain and straw yields). At various stages of rice-wheat growth, enzyme activity in the soil (dehydrogenase and aryl sulfatase) was also measured in the current study. Enzyme activity peaked at the heading stage in surface soil in all treatments, and then steadily declined thereafter. For both stages of crop growth in surface soil, the highest dehydrogenase and aryl sulfatase activity was found in urea + PK + S + Zn -EDTA covered with Neem. Anhydrous ammonia was shown to have the lowest enzymatic activity.