Impact of combined organic and inorganic nutrient management on soil fertility status and productivity of wheat crop (Triticum aestivum L.)

Introduction

Wheat (Triticum aestivum L.) is one of the world's most important staple crops, widely grown across diverse agro-climatic regions. India ranks as the second-largest wheat producer globally, after China, accounting for roughly 14% of total world production. In India, it serves as the second most important food grain after rice and is prized for its nutritional qualities, including a good protein content (typically 10-14% in whole wheat flour), carbohydrates, dietary fiber, B vitamins (such as thiamine and niacin), and minerals. The presence of gluten makes it particularly suitable for baked products. Major global wheat producers include China, the European Union, India, Russia, the United States, Canada, Australia, and Pakistan. India's wheat output reached a record level of approximately 117.9 million tonnes in 2025 (harvested around June), cultivated over a substantial area, reflecting improvements in high-yielding varieties, irrigation, and management practices. Earlier estimates for the 20225-26 crop year placed production around 115-118 million tonnes. In South Asian wheat-based rotations (often rice-wheat or maize-wheat), farmyard manure remains a widely accessible organic source. It is frequently applied to the preceding kharif crop, with residual benefits to rabi wheat. Long-term studies show that partial substitution of nitrogen through FYM can sustain or even enhance yields while improving soil organic carbon and microbial activity. For instance, integrating FYM at appropriate rates with reduced inorganic fertilizers has demonstrated comparable productivity to full chemical fertilization in various cropping systems. Poultry manure, with its higher nutrient concentration and faster mineralization rate (e.g., quicker nitrogen release compared to FYM), serves as an effective alternative or supplement. It supplies readily available nitrogen along with phosphorus and other micronutrients. Studies indicate that combining poultry manure (e.g., 5-10 t/ha) with 75% of the recommended fertilizer dose often matches or exceeds yields from 100% inorganic fertilizers, while enhancing soil biological health. Green manuring with legumes (e.g., Sesbania, cowpea, green gram, or Leucaena leaves) or incorporating summer legume residues adds substantial nitrogen (often 20-60 kg N/ha) and organic matter to the soil, benefiting following wheat crops. Preceding wheat with green manure crops or mulching with nitrogen-rich leaves (e.g., Leucaena) can reduce synthetic nitrogen requirements while maintaining productivity. These practices improve soil organic carbon, suppress weeds, and enhance microbial diversity. For timely or late-sown wheat, basal application of fertilizers at sowing is recommended, with adjustments based on soil testing especially for potassium and micronutrients. While higher fertilizer doses have driven past yield gains, future strategies must emphasize site-specific nutrient management (SSNM), split applications, and integration of organics to minimize environmental footprints (e.g., reduced leaching and greenhouse gas emissions) and sustain soil productivity. On degraded or oxide-rich soils, banded or lower-dose applications help maintain balance.

Materials and methods

Initial Plant Populationm: At 30 days after sowing (DAS), the number of plants per meter row length was counted from three locations (designated with sticks) in each plot.

Plant height

In order to record height in centimeters (cm) at 30, 60, and 90 DAS as well as at harvest, five plants were randomly tagged in each plot. Before the ear emergence, the height was measured from the ground to the base of a fully opened leaf, and after heading, it was measured up to the base of the ear head.

Dry weight

At 30, 60, 90 DAS, and harvest, plants were taken from two locations in each plot's second row on either side, each measuring 25 cm in length. After being sun-dried separately, the plant components were oven-dried at 70ºC ± 2ºC until they reached a consistent weight. The dry matter accumulation of plants per meter row length was calculated by summing the dry weight values of the plant sections.

Straw yield (kgha -1 )

By deducting the grain yield from the total amount of food gathered and converting it to kilograms per hectare, the straw yield from the net-plot area was calculated.

Harvest index (HI)

The harvest index, which is determined using Donald's (1962) formula, is economic yield expressed as a percentage of biological yield.

Experimental finding

Initial plant Population Table 4.1 and Figure 4.1 show the observations made on the initial plant population per m-2 over the experiment period. Both organic and inorganic fertilizers have a highly noticeable and reliable effect. Treatment T9 (50% RDF from Nitrogen +25% Recommended Nitrogen from farm Yard Manures +25% Recommended Nitrogen from vermicompost) followed by T6 (50% RDF from Nitrogen +25% Recommended Nitrogen from farm Yard Manures +25% Recommended Nitrogen from Poultry manure) with (58.01 plants m-2) were significantly better than T1 (Control) with (42.52 plants m-2). There was a significant difference between the application of the various treatments. Plant height Table 4.2 and Figure 4.2 show the plant height observations that were made during the experiment period. Both organic and inorganic fertilizers have a highly noticeable and reliable effect. T9 (50% RDF from Nitrogen +25% Recommended Nitrogen from farm Yard Manures +25% Recommended Nitrogen from vermicompost) had a plant height of 21.52, 53.58, 88.70, and 92.37 cm, followed by T6 (75% RDF from Nitrogen +25% Recommended Nitrogen from vermicompost) with 20.23, 51.87, 84.58, and 89.58) cm, which were significantly higher than T1 (Control) with 13.92, 42.52, 69.91, and 74.88 cm in plant height. There was no significant difference between the treatments at 30 DAS and 60, 90 DAS, and harvest. Treatment T9 (50% RDF from Nitrogen +25% Recommended Nitrogen from farm Yard Manures +25% Recommended Nitrogen from vermicompost) had the highest plant height, measuring 92.37 cm. Treatment T6 (75% RDF from Nitrogen +25% Recommended Nitrogen from vermicompost) came in second with 89.58 cm, and treatment T1 (Control) had the lowest height, measuring 74.88 cm. 4.3 show the observations made on the dry weight during the experiment period. Both organic and inorganic fertilizers have a highly noticeable and reliable effect. T9 (50% RDF from Nitrogen +25% Recommended Nitrogen from farm Yard Manures +25% Recommended Nitrogen from vermicompost) had 18.04, 58.35, 68.97, and 71.61 grams of dry weight, followed by T6 (75% RDF from Nitrogen + 25% Recommended Nitrogen from vermicompost) with 17.37, 57.38, 64.27, and 67.91 grams of dry weight, which were significantly superior to T1 (Control) with 13.07, 42.37, 51.29, and 55.65 grams of dry weight. At 30 DAS, there was no significant difference between the various treatments, but at 60, 90 DAS, and harvest. T9 (50% RDF from Nitrogen + 25% Recommended Nitrogen from farm Yard Manures + 25% Recommended Nitrogen from vermicompost) had the highest dry weight (71.61 g), followed by T6 (75% RDF from Nitrogen +25% Recommended Nitrogen from vermicompost) with 67.91 g, and T1 (Control) had the lowest dry weight (55.65 g). Grain Yield, Straw yield Table 4. 11 and Figure 4.11 show the observations on grain yield and straw yield that were made throughout the experiment period. The application of the various treatments had a significant impact on grain yield. T9 (50% RDF from nitrogen +25% Recommended Nitrogen from farm yard manures +25% Recommended Nitrogen from vermicompost) had the highest grain yield (4469 kg ha-1), followed by T6 (75% RDF from nitrogen +25% Recommended Nitrogen from vermicompost) with 4379 kg ha-1. These treatments were significantly better than T1 (Control) with 3874 kg ha-1.

best treatment for most parameters. The control treatment (T1) consistently recorded the lowest values for all observed characters. The study clearly demonstrated the beneficial effect of combined application of inorganic fertilizers with organic manures in enhancing crop productivity through improved nutrient availability, better soil physical and biological properties, and efficient assimilate partitioning.

Conclusion

On the basis of the results obtained, it can be concluded that integrated nutrient management (INM) practices are highly effective in improving initial plant population, plant growth, dry matter accumulation, grain yield, straw yield, and harvest index of the crop. Among all the treatments, T9 (50% RDF from Nitrogen + 25% Recommended Nitrogen from Farm Yard Manure + 25% Recommended Nitrogen from Vermicompost) proved to be the most superior treatment. It recorded the highest initial plant population (58.01 plants m⁻²), plant height (92.37 cm), dry weight (71.61 g), grain yield (4469 kg ha⁻¹), straw yield (6141 kg ha⁻¹), and harvest index (42.14). Treatment T6 also performed well and was statistically at par with T9 in several parameters. The combination of organic and inorganic nutrient sources exhibited a synergistic effect, resulting in better nutrient availability, improved soil health, enhanced root proliferation, and efficient translocation of photosynthates. This led to superior yield attributes and higher productivity compared to the control (T1), which recorded the lowest values for all characters. The study clearly demonstrates that the use of vermicompost and FYM along with a reduced dose of chemical fertilizers can effectively substitute a significant portion of inorganic nutrients without compromising yield while simultaneously promoting long-term soil fertility through increased organic carbon content and microbial activity. Overall, the findings highlight the superiority of integrated nutrient management, particularly treatment T9, over sole dependence on chemical fertilizers or no fertilization. Adoption of such INM strategies can play a vital role in achieving sustainable agricultural production, higher crop productivity, and improved soil health.

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