Nano-NPK foliar sprays boost soil nitrogen and wheat nitrogen uptake in two-year field trial

Combining conventional fertilizer with foliar sprays of a commercial nano-NPK formulation increased soil nitrogen availability and plant nitrogen uptake in wheat, according to a two-year field experiment conducted at SKUAST-Jammu, Chatha, in the sub-tropical plains of Jammu, India. The study, published open access in Discover Applied Sciences on 28 October 2026, measured post-harvest soil nitrogen fractions and nitrogen uptake in grain, straw and roots across twelve fertilizer treatments.

The researchers ran the experiment over two rabi seasons, 2021–22 and 2022–23, using a randomized block design with three replications. Treatments combined three levels of the recommended dose of nutrients (RDN) — 100%, 75% and 50% — with two or three foliar sprays of a nano-NPK product guaranteed at 8% nitrogen, applied at 4 mL per litre at the tillering, jointing and booting stages. The wheat variety used was RSP-561. Treatment means were separated with Fisher’s protected LSD at p = 0.05 and reported with grouping letters and standard error.

Post-harvest soil from the top 15 centimetres was analysed for available nitrogen, ammoniacal-N, nitrate-N, total N and organic N. The treatment receiving 100% RDN plus three nano-NPK sprays (T8) recorded the highest available nitrogen, 274 kg per hectare in 2022–23, a 46% increase over the unfertilized control. The same treatment also showed the highest ammoniacal-N at 115 kg per hectare, the highest nitrate-N at 93 kg per hectare and the highest grain nitrogen uptake at 64.05 kg per hectare, 59% above the control.

Nitrogen use efficiency, expressed as apparent nitrogen recovery efficiency calculated from total plant N uptake, also improved. It rose from 37% under 100% RDN alone (T2) to 54% under the full dose plus three sprays (T8), and reached its maximum of 59% under 75% RDN with three sprays (T9). These figures quantify how integrating nano-fertilizers with the recommended dose changed the proportion of applied nitrogen recovered by the crop.

Correlation analysis linked the soil nitrogen fractions to crop uptake. Available N, nitrate-N and ammoniacal-N were strongly correlated with grain nitrogen uptake (r = 0.84, 0.89 and 0.84, respectively) and with straw nitrogen uptake (r = 0.82, 0.89 and 0.85). Organic and total nitrogen showed weaker associations with uptake, suggesting the available and mineral fractions tracked crop nitrogen capture more closely in this system.

A notable result concerned fertilizer savings. In the second season, the treatment with 75% RDN plus three nano-NPK sprays (T9) was statistically at par with the full recommended dose, sharing the same LSD grouping for nitrogen uptake. The authors note this indicates scope for a 25% reduction in conventional fertilizer without a penalty in nitrogen uptake, but they explicitly condition this on yield and economic validation, which the reported nitrogen measurements alone do not provide.

The study addresses a practical problem: wheat is central to global food security, yet productivity in the sub-tropical plains of Jammu remains below the national average, which the authors attribute largely to inefficient nitrogen management. Nitrogen use efficiency is described as a key economic and ecological consideration in wheat production, and nano-fertilizers are proposed as one innovative approach to improving it.

The findings are specific to this two-year trial with variety RSP-561 at a single location, and the reported article is an early-access version subject to further edits before the final Version of Record. Within those limits, the authors conclude that integrating nano-fertilizers with the recommended nutrient dose enhances soil nitrogen availability and uptake and improves apparent nitrogen recovery, supporting more efficient nutrient management in wheat-based systems.

Subject of Research: Effects of nano-NPK foliar fertilization integrated with recommended nutrient doses on soil nitrogen fractions and nitrogen uptake in wheat

Article Title: Nano-fertilizer integration enhances soil nitrogen fractions and nitrogen uptake in wheat (Triticum aestivum L.)

Article References: Reddy, B. J., Kour, S., Khan, Z., Ali, A., & Jaafar, A. A. K. (2026). Nano-fertilizer integration enhances soil nitrogen fractions and nitrogen uptake in wheat (Triticum aestivum L.). Discover Applied Sciences. https://doi.org/10.1007/s42452-026-09704-9

Image Credits: AI Generated

DOI: 10.1007/s42452-026-09704-9

Keywords: nano-fertilizer, wheat, nitrogen use efficiency, soil nitrogen fractions, foliar spray, field experiment, nitrogen uptake, Jammu, RSP-561, apparent nitrogen recovery, integration, enhances