Impact of integrated use of soil amendments and nano fertilizers on soil properties under temperate conditions of Kashmir

Introduction

Conventional agriculture has exerted considerable pressure on soil quality and its capacity to function sustainably. The post-Green Revolution challenges confronting Indian agriculture have raised serious concerns regarding long-term agricultural sustainability and national food security. The widespread and indiscriminate use of high-analysis chemical fertilizers has contributed to the depletion of soil organic matter, increased salinity and sodicity, soil contamination, and an overall decline in soil health (Shambhavi et al., 2017) [26] . Over the past three decades, the consumption of inorganic fertilizers has increased substantially to meet the growing demand for food. However, excessive and imbalanced fertilizer application can adversely affect soil, water and atmospheric environments. Continuous overuse of chemical fertilizers may alter soil organic matter, microbial populations and soil reaction, thereby negatively influencing overall soil health (Erisman et al., 2008) [9] . Moreover, excessive fertilizer application can contaminate surface and groundwater resources through leaching and surface runoff. The integrated use of organic and inorganic nutrient sources has emerged as an effective approach for improving crop productivity while maintaining soil fertility and sustainability. Unlike the sole application of either chemical fertilizers or organic manures, integrated nutrient management can provide a more balanced supply of essential nutrients and improve soil physical, chemical and biological properties. Such an approach not only enhances crop productivity but can also sustain soil productivity and provide a cost-effective nutrient management strategy, particularly for developing countries. Organic amendments contribute to the improvement of soil structure, organic carbon content and microbial activity, while mineral fertilizers provide nutrients in readily available forms, including nitrate, phosphate, exchangeable calcium and soluble potassium. Therefore, the combined application of organic and inorganic nutrient sources can exert a more beneficial influence on plant growth, yield and soil physicochemical properties than the sole application of inorganic fertilizers. Furthermore, decomposition of organic amendments and the subsequent release of nutrients are influenced by temperature, moisture regimes, season and management practices. The incorporation of organic materials can also contribute to climate-change mitigation by enhancing soil carbon sequestration (Ryals and Silver, 2013) [25] .In recent years, advances in nanotechnology have introduced nano-fertilizers as an innovative approach to improving nutrient-use efficiency and sustainable crop production. Nano-fertilizers can be applied directly to the soil, through irrigation water, or as foliar sprays to improve nutrient availability and plant growth. Their nanoscale properties may facilitate more efficient nutrient delivery and uptake, potentially reducing nutrient losses and improving fertilizer-use efficiency. Nanofertilization has also been associated with enhanced physiological and biochemical processes in plants, including carbon metabolism and antioxidant enzyme activity, which can positively influence crop productivity and quality (Gerdini, 2016) [10] . Thus, nanotechnology offers considerable potential for addressing some of the limitations associated with conventional fertilizer practices and promoting sustainable soil health and crop production (Lal, 2008) [14] . In strawberry, the application of nano-fertilizers has been reported to improve fruit quality attributes, including phenolic content and aroma (Cvelbar et al., 2021) [8] , while nano-based approaches have also demonstrated potential in enhancing tolerance to environmental stresses such as fluoride toxicity (Mozafari et al., 2018) [21] . Nanofertilizers are designed to supply essential nutrients in a controlled and efficient manner, with nutrients and, in some formulations, growth-promoting substances delivered through nanoscale carriers or formulations. Consequently, their integration with organic amendments and conventional fertilizers may provide a promising strategy for improving nutrient availability, soil health, crop productivity and produce quality in sustainable horticultural production systems.

Materials and Methods

Experimental location

The study was conducted at Faculty of Horticulture, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir, Shalimar, Srinagar (J&K) India

Pot Experiment 2.2.1 Soil Collection for pots

Bulk soil collected from the research field of Soil Science, Faculty of Horticulture, SKUAST-Kashmir Shalimar was crushed and passed through a 5.0 mm sieve, which reduce the particle size even further. Soil was loaded into each pot and then total volume of the soil in pot was calculated.

Soil Characteristics 2.3.1 Mechanical and chemical properties

Mechanical and chemical analyses were performed on the samples under investigation. According to the results mentioned in Table 1 the soil analyzed was a sandy clay loam, slightly alkaline reaction, electrical conductivity within safe limits, low organic carbon, nitrogen and medium phosphorus and potassium. Parihar and Sandhu, 1968) [30] .

4 Porosity (%) 48. 23 Majumdar and Singh, 2005) [31] . [13] 3

Organic Carbon (%) 0.25 Walkley and Black's rapid titration method (Jackson, 1973) [13] 4

Available N (kg ha -1 ) 235.76 Modified alkaline potassium permanganate method (Subbiah and Asija, 1956) [27] 5

Available P (kg ha -1 ) 11.98 0.5 M Sodium bicarbonate extractable P method (Olsen et al., 1954) [22] 6

Available K (kg ha -1 ) 184.72 Ammonium acetate extractable K method (Jackson, 1973) [13] 7

Zinc (mg kg -1 ) 0.45 Lindsay and Norvell. 1978. [16] 8

Copper (mg kg -1 ) 0. 19 10 Manganese (mg kg -1 ) 1.96

Experimental Details

There were a total of ten treatment combinations with 3 replications taking the number of pots to thirty (30). Statistical design was Completely Randomized Design (CRD).

Soil Chemical Parameters 2.5.1 Soil pH

The pH of the soil was tested by mixing soil and water (1:2) in a glass-calomel electrode (Jackson, 1973) [13] .

The EC was calculated by measuring the salt bridge in the suspension used to evaluate the EC. (Jackson, 1973) [13] .

Walkley and Black's rapid titration test was used to estimate organic carbon (Jackson, 1973) [13] .

The available nitrogen concentration was determined using a modified alkaline potassium permanganate method (Subbiah and Asija, 1956) [27] , and the results were expressed in kilograms per hectare.

The extractable P method with 0.5M sodium bicarbonate was used to determine the available phosphorus. (Olsen et al., 1954) [22] . The colour intensity created by stannous chloride was determined using a spectrophotometer at 660 nm and quantified as phosphorus kilograms per hectare.

The ammonium acetate extractable K technique was used to extract the available potassium (Jackson, 1973) [13] , and the potassium concentration was determined using a flame photometer and quantified as kilograms per hectare.

DTPA-extractable micronutrient cations

Availability of DTPA-extractable micronutrient cations (Zn, Fe, Cu and Mn) was assessed by extracting 10g of soil sample with 20 mL of diethylene triamine penta acetic acid (DTPA) extractant as described by Lindsay and Norvell (1978) [16] .

The extract was fed to Atomic Absorption Spectrophotometer (Thermo).

Results and Discussion

Effect of nano fertilizers and soil amendments on physical properties of soil 3.1.1 Bulk Density

The data presented in Table 2 revealed that the application of nano fertilizers and soil amendments significantly influenced the bulk density of soil. The lowest bulk density (1.24 g cm⁻³) was recorded in T 8 (Neem cake @ 50% + nano zeolite @ 5 g kg⁻¹ soil + RDF @ 50%), followed by T 7 (1.26 g cm⁻³), T 5 (1.27 g cm⁻³), T 4 (1.28 g cm⁻³), T 3 (1.29 g cm⁻³), T 2 (1.30 g cm⁻³), T 1 (1.31 g cm⁻³) and T 9 (1.33 g cm⁻³). The highest bulk density (1.35 g cm⁻³) was recorded in T 10 (control).

Overall, the combined application of neem cake, nano zeolite and RDF resulted in a greater reduction in soil bulk density compared with the control. Among the treatments, T 8 exhibited the most favourable effect, indicating improved soil structural condition and greater pore space.

Particle Density

The results presented in The results suggest that the incorporation of organic amendments, particularly neem cake, in combination with nano zeolite and reduced levels of RDF, favourably modified soil physical characteristics. T 8 recorded the lowest particle density, whereas the control exhibited the highest value.

Porosity

The data pertaining to the effect of nano fertilizers and soil amendments on soil porosity are presented in Table 2. The highest soil porosity was recorded in T 6 (49.36%), closely followed by T 8 (49.35%), T 4 (49.17%), T 3 (49.18%), T 7 (48.75%), T 5 (48.76%), T 9 (48.22%), T 2 (47.76%) and T 1 (47.56%). The lowest porosity (48.24%) was recorded in T 10 (control). The higher porosity observed under the amended treatments may be attributed to the incorporation of organic matter and the improvement in soil aggregation and pore-space distribution. The combined application of neem cake and nano zeolite, particularly when integrated with RDF, resulted in comparatively higher porosity than the control.

Infiltration Rate

The data presented in Table 2 revealed a significant improvement in soil infiltration rate following the application of nano fertilizers and soil amendments. The highest infiltration rate (0.48 cm s⁻¹) was recorded in T 8 (Neem cake @ 50% + nano zeolite @ 5 g kg⁻¹ soil + RDF @ 50%), followed by T 7 (0.46 cm s⁻¹), T 6 (0.44 cm s⁻¹), T 5 (0.42 cm s⁻¹), T 4 (0.40 cm s⁻¹), T 3 (0.37 cm s⁻¹), T 2 (0.35 cm s⁻¹), T 1 (0.33 cm s⁻¹) and T 9 (0.30 cm s⁻¹). The lowest infiltration rate (0.24 cm s⁻¹) was recorded in T 10 (control). The higher infiltration rate under the amended treatments indicates improved soil structure, aggregation and pore continuity. T 8 showed the most pronounced improvement, suggesting that the combined application of neem cake, nano zeolite and RDF at the specified rates was effective in improving soil water movement.

Effect of Nano Fertilizers and Soil Amendments on Chemical Properties of Soil 3.2.1 pH

The results presented in Table 3 revealed that the application of nano fertilizers and soil amendments improved soil pH compared with the control. The highest soil pH (6.97) was recorded in T 8 (Neem cake @ 50% + nano zeolite @ 5 g kg⁻¹ soil + RDF @ 50%), followed by T 7 (6.86), T 6 (6.81), T 5 (6.78), T 2 (6.71), T 1 (6.69), T 4 (6.67), T 3 (6.65) and T 9 (6.47). The lowest soil pH (6.43) was recorded in T 10 (control).

The results indicate that the combined application of neem cake and nano zeolite along with RDF was more effective in maintaining a favourable soil pH than the control. T 8 recorded the highest pH value, indicating a positive influence of the integrated nutrient and soil amendment treatment on soil chemical conditions.

Electrical Conductivity

The data pertaining to the effect of nano fertilizers and soil amendments on soil electrical conductivity are presented in Table 3. The highest electrical conductivity (0.69 dS m⁻¹) was recorded in T 8 (Neem cake @ 50% + nano zeolite @ 5 g kg⁻¹ soil + RDF @ 50%), followed by T 7 (0.61 dS m⁻¹), T 6 (0.56 dS m⁻¹), T 5 (0.53 dS m⁻¹), T 2 (0.50 dS m⁻¹), T 1 (0.48 dS m⁻¹), T 4 (0.44 dS m⁻¹), T 3 (0.40 dS m⁻¹) and T 9 (0.36 dS m⁻¹). The lowest electrical conductivity (0.25 dS m⁻¹) was recorded in T 10 (control). The comparatively higher electrical conductivity under the amended treatments may be associated with greater availability of soluble nutrients and other ionic constituents released through the decomposition of organic amendments and application of fertilizers. Nevertheless, the recorded EC values remained within a relatively low range, indicating that the treatments did not result in excessive salt accumulation.

Organic Carbon

The data presented in Table 3 revealed that the application of nano fertilizers and soil amendments significantly enhanced soil organic carbon content compared with the control. The highest organic carbon content (0.51%) was recorded in T 8 (Neem cake @ 50% + nano zeolite @ 5 g kg⁻¹ soil + RDF @ 50%), followed by T 7 (0.49%), T 6 (0.46%), T 5 (0.44%), T 2 (0.41%), T 1 (0.39%), T 4 (0.34%), T 3 (0.35%) and T 9 (0.34%).

The lowest organic carbon content (0.26%) was recorded in T 10 (control). The increase in organic carbon under the amended treatments may be attributed primarily to the addition and decomposition of neem cake, which contributed organic residues to the soil. The combined application of neem cake and nano zeolite with RDF, particularly in T 8 , resulted in the highest accumulation of organic carbon, indicating improved soil organic matter status and overall soil quality.

Effect of nano fertilizers and soil amendments on organic carbon 3.3.1 Available Nitrogen

The results from Table 3 confirmed that the application of nano fertilizers and soil amendments boosted available nitrogen as compared to control. T 8 (Neem Cake @ 50% + Nano Zeolite @ 5 g kg (Neem Cake @ 50% + Nano Zeolite @ 5 g kg -1 soil + RDF 50%) > T 7 (Neem Cake @ 50% + Nano Zeolite @ 2 g kg -1 soil + RDF 50%) > T 6 (Neem Cake @ 25% + Nano Zeolite @ 5g kg -1 soil + RDF 75%) >T 5 (Neem Cake @ 25% + Nano Zeolite @ 2g kg -1 soil + RDF 75%) >T 2 (Neem Cake @ 50% + RDF @ 50%) >T 1 (Neem Cake @ 25% + RDF @ 75%) >T 4 (Nano Zeolite @ 5 g kg -1 soil + RDF @ 100%)>T 3 (Nano Zeolite @ 2 g kg -1 soil + RDF @ 100%)>T 9 (100% RDF through Nano fertilizer).

Available Phosphorus

Data pertaining to the effect of nano fertilizers and soil amendments on available phosphorus content is presented in Table 3. Among all treatments, the significantly highest available phosphorus (20.45 kg/ha,) was observed in T 8 (Neem Cake @ 50% + Nano Zeolite @ 5 g kg -1 soil + RDF 50%) followed by 19.87 kg/ha, in T 7 (Neem Cake @ 50% + Nano Zeolite @ 2 g kg -1 soil + RDF 50%) > 18.84 kg/ha, in T 6 (Neem Cake @ 25% + Nano Zeolite @ 5g kg -1 soil + RDF 75%) > 18.01 kg/ha, in T 5 (Neem Cake @ 25% + Nano Zeolite @ 2g kg -1 soil + RDF 75%) > 17.70 kg/ha, in T 2 (Neem Cake @ 50% + RDF @ 50%) > 17.07 kg/ha, in T 1 (Neem Cake @ 25% + RDF @ 75%) > 16.09 kg/ha, in T 4 (Nano Zeolite @ 5 g kg -1 soil + RDF @ 100%) > 15.94 kg/ha, in T 3 (Nano Zeolite @ 2 g kg -1 soil + RDF @ 100%) > 15.00 kg/ha, in T 9 (100% RDF through Nano fertilizer).The lowest values for available phosphorus (11.96 kg/ha) were recorded in T 10 (control).

Available Potassium

The perusal of data in Table 3 revealed that treatment T 8 (Neem Cake @ 50% + Nano Zeolite @ 5 g kg -1 soil + RDF 50%) recorded significantly highest available potassium (292.46 kg/ha) followed by 281.40 kg/ha in T 7 (Neem Cake @ 50% + Nano Zeolite @ 2 g kg -1 soil + RDF 50%) > 267.21 kg/ha in T 6 (Neem Cake @ 25% + Nano Zeolite @ 5g kg -1 soil + RDF 75%) > 258.92 kg/ha in T 5 (Neem Cake @ 25% + Nano Zeolite @ 2g kg -1 soil + RDF 75%) > 237.78 kg/ha in T 2 (Neem Cake @ 50% + RDF @ 50%) > 232.51 kg/ha in T 1 (Neem Cake @ 25% + RDF @ 75%) > 249.77 kg/ha in T 4 (Nano Zeolite @ 5 g kg-1soil + RDF @ 100%) > 241.66 kg/ha in T 3 (Nano Zeolite @ 2 g kg-1 soil + RDF @ 100%) > 222.01 kg/ha in T 9 (100% RDF through Nano fertilizer).The lowest values for available potassium (183.45 kg/ha) was recorded in T 10 (control).

Effect of nano fertilizers and soil amendments on micro nutrient status of soil 3.4.1 Zinc

The perusal of data in Table 4 revealed that treatment T 8 (Neem Cake @ 50% + Nano Zeolite @ 5 g kg-1 soil + RDF 50%) recorded significantly highest zinc (0.77 ppm), followed by 0.75 ppm in T 7 (Neem Cake @ 50% + Nano Zeolite @ 2 g kg -1 soil + RDF 50%) > 0.72 ppm in T 6 (Neem Cake @ 25% + Nano Zeolite @ 5g kg -1 soil + RDF 75%) > 0.71 ppm in T 5 (Neem Cake @ 25% + Nano Zeolite @ 2g kg - 1 soil + RDF 75%) > 0.69 ppm in T 2 (Neem Cake @ 50% + RDF @ 50%) > 0.67 ppm in T 1 (Neem Cake @ 25% + RDF @ 75%) 0.65 ppm in T 4 (Nano Zeolite @ 5 g kg -1 soil + RDF @ 100%) > 0.63 ppm in T 3 (Nano Zeolite @ 2 g kg -1 soil + RDF @ 100%) > 0.60 ppm in T 9 (100% RDF through Nano fertilizer).The lowest values for zinc (0.46 ppm) was recorded in T 10 (control).

Iron

The results from Table 4 confirmed that the application of nano fertilizers and soil amendments boosted the iron of Strawberry compared to control. T 8 (Neem Cake @ 50% + Nano Zeolite @ 5 g kg -1 soil + RDF 50%) recorded significantly highest value for iron i.e. 2.63 ppm, 2.61 ppm, 2.57 ppm, 2.55 ppm, 2.53 ppm, 2.51 ppm 2.47 ppm, 2.45 ppm, 2.41 ppm and T 10 (control) recorded lowest values for iron of 2.02 ppm. The highest to lowest order of treatments are as T 8 (Neem Cake @ 50% + Nano Zeolite @ 5 g kg -1 soil + RDF 50%) > T 7 (Neem Cake @ 50% + Nano Zeolite @ 2 g kg -1 soil + RDF 50%) > T 6 (Neem Cake @ 25% + Nano Zeolite @ 5 g kg -1 soil + RDF 75%) >T 5 (Neem Cake @ 25% + Nano Zeolite @ 2 g kg -1 soil + RDF 75%) >T 2 (Neem Cake @ 50% + RDF @ 50%) >T 1 (Neem Cake @ 25% + RDF @ 75%) >T 4 (Nano Zeolite @ 5 g kg -1 soil + RDF @ 100%) >T 3 (Nano Zeolite @ 2 g kg -1 soil + RDF @ 100%) >T 9 (100% RDF through Nano fertilizer).

Copper

Data pertaining to the effect of nano fertilizers and soil amendments on copper is presented in Table 4. Among all treatments, the significantly copper (0.32 ppm) was observed in T 8 (Neem Cake @ 50% + Nano Zeolite @ 5 g kg-1 soil + RDF 50%) followed by 0.31 ppm in T 7 (Neem Cake @ 50% + Nano Zeolite @ 2 g kg -1 soil + RDF 50%) > 0.30 ppm in T 6 (Neem Cake @ 25% + Nano Zeolite @ 5g kg -1 soil + RDF 75%) > 0.29 ppm in T 5 (Neem Cake @ 25% + Nano Zeolite @ 2g kg -1 soil + RDF 75%) > 0.28 ppm in T 2 (Neem Cake @ 50% + RDF @ 50%) > 0.26 ppm in T 1 (Neem Cake @ 25% + RDF @ 75%) > 0.25 ppm in T 4 (Nano Zeolite @ 5 g kg -1 soil + RDF @ 100%) > 0.24 ppm in T 3 (Nano Zeolite @ 2 g kg -1 soil + RDF @ 100%) > 0.22 ppm in T 9 (100% RDF through Nano fertilizer).The lowest values for copper (0.18 ppm) were recorded in T 10 (control).

Manganese

The perusal of data in Table 4 revealed that treatment T 8 (Neem Cake @ 50% + Nano Zeolite @ 2 g kg-1 soil + RDF 50%) recorded significantly highest manganese (2.60 ppm) followed by 2.58 ppm in T 7 (Neem Cake @ 50% + Nano Zeolite @ 5 g kg-1 soil + RDF 50%) > 2.54 ppm in T 6 (Neem Cake @ 25% + Nano Zeolite @ 5g kg-1 soil + RDF 75%) > 2.52 ppm in T 5 (Neem Cake @ 25% + Nano Zeolite @ 2 g kg-1 soil + RDF 75%) > 2.50 ppm in T 2 (Neem Cake @ 50% + RDF @ 50%) > 2.48 ppm in T 1 (Neem Cake @ 25% + RDF @ 75%) > 2.44 ppm in T 4 (Nano Zeolite @ 5 g kg-1 soil + RDF @ 100%) > 2.42 ppm in T 3 (Nano Zeolite @ 2 g kg-1 soil + RDF @ 100%) > 2.38 ppm in T 9 (100% RDF through Nano fertilizer).The lowest values for manganese (1.94 ppm) was recorded in T 10 (control). T2: Neem Cake @ 50% + RDF @ 50% T3: Nano Zeolite @ 2 g kg -1 soil + RDF @ 100% T4: Nano Zeolite @ 5 g kg -1 soil + RDF @ 100% T5: Neem Cake @ 25% + Nano Zeolite @ 2g kg -1 soil + RDF 75% T6: Neem Cake @ 25% + Nano Zeolite @ 5g kg -1 soil + RDF 75% T7: Neem Cake @ 50% + Nano Zeolite @ 2g kg -1 soil + RDF 50% T8: Neem Cake @ 25% + Nano Zeolite @ 5g kg -1 soil + RDF 75% T9: 100% RDF (through Nano fertilizer) T10: Control (Untreated) T 1: Neem Cake @ 25% + RDF @ 75% T 2: Neem Cake @ 50% + RDF @ 50% T 3: Nano Zeolite @ 2 g kg -1 soil + RDF @ 100% T 4: Nano Zeolite @ 5 g kg -1 soil + RDF @ 100% T 5: Neem Cake @ 25% + Nano Zeolite @ 2g kg -1 soil + RDF 75% T 6: Neem Cake @ 25% + Nano Zeolite @ 5g kg -1 soil + RDF 75% T 7: Neem Cake @ 50% + Nano Zeolite @ 2g kg -1 soil + RDF 50% T 8: Neem Cake @ 25% + Nano Zeolite @ 5g kg -1 soil + RDF 75% T 9: 100% RDF (through Nano fertilizer) T 10: Control (Untreated) T2: Neem Cake @ 50% + RDF @ 50% T3: Nano Zeolite @ 2 g kg -1 soil + RDF @ 100% T4: Nano Zeolite @ 5 g kg -1 soil + RDF @ 100% T5: Neem Cake @ 25% + Nano Zeolite @ 2g kg -1 soil + RDF 75% T6: Neem Cake @ 25% + Nano Zeolite @ 5g kg -1 soil + RDF 75% T7: Neem Cake @ 50% + Nano Zeolite @ 2g kg -1 soil + RDF 50% T8: Neem Cake @ 25% + Nano Zeolite @ 5g kg -1 soil + RDF 75% T9: 100% RDF (through Nano fertilizer) T10: Control (Untreated) slow-release K formulations. Zhou and Huang (2007) [29] attributed the gradual release of K from nano-zeolite to the ion-exchange properties of zeolite, highlighting its potential as a nutrient reservoir. Guo et al. (2008) [11] further suggested that zeolite can be recharged by the addition of dissolved nutrients, thereby extending its nutrient-retention function. The increased availability of micronutrients, including Zn, Fe, Cu and Mn, under T 8 may also be associated with improved nutrient retention, enhanced organic matter decomposition and favourable changes in the soil chemical environment. Zinc is involved in numerous enzymatic reactions and plays an important role in growth-regulating processes. Iron is essential for chlorophyll synthesis and photosynthetic activity, while copper functions as a cofactor for several enzymes and is involved in electron transport. Manganese is required for enzyme activation and contributes to photosynthesis, respiration and nitrogen metabolism. Therefore, improved availability of these micronutrients under the integrated treatment could contribute to better plant nutritional status and physiological performance. The present findings are consistent with Ahmed et al. (2010) [2] , who reported that the combined application of inorganic fertilizers and zeolite improved N, P and K uptake and nutrient-use efficiency in different plant parts. The authors attributed these effects to the capacity of zeolite to retain nutrients in the soil and subsequently release them for plant uptake. Overall, the results indicate that the combined application of neem cake, nano-zeolite and nano-fertilizers produced complementary effects on soil physical and chemical properties. The improvement in bulk density, porosity and infiltration rate indicates better soil structural conditions, whereas the changes in pH, EC and organic carbon reflect improved soil chemical status. The enhanced availability of macro-and micronutrients further demonstrates the potential of the integrated nutrient-management approach to improve nutrient retention and supply. Thus, the application of neem cake in combination with nano-zeolite and nano-fertilizers may provide a promising strategy for improving soil quality, nutrient-use efficiency and the overall soil environment for sustainable crop production.

Conclusion

The present study demonstrated that the integrated application of soil amendments and nano fertilizers significantly improved the physical, chemical, and nutrient status of soil under temperate conditions of Kashmir. Among the treatments, T8, comprising neem cake, nano zeolite, and nano fertilizers, consistently performed superior to the recommended dose of fertilizers and untreated control. It improved soil porosity, infiltration rate, pH, electrical conductivity, organic carbon, and the availability of major nutrients and micronutrients, while reducing soil bulk density and particle density. The improvement in soil properties under T8 may be attributed to enhanced soil aggregation, greater pore space, improved nutrient retention, and efficient nutrient availability resulting from the combined use of organic and nano-based inputs. Therefore, the integrated application of neem cake, nano zeolite, and nano fertilizers appears to be a promising approach for improving soil quality and nutrient availability in temperate agroecosystems of Kashmir. However, further multi-season and field-scale studies are recommended to validate the long-term effects, optimum application rates, and economic feasibility of this integrated nutrient management strategy.

Conflict of Interest

Author has no conflict of interest at all.

References

1. Agger JR, Meza LI, Cundy CS, Plaisted RJ, Anderson MW. Control of zeolite surface nucleation. In: Studies in Surface Science and Catalysis. 2005;158:35-42.
2. Ahmed OH, Sumalatha G, Muhamad AN. Use of zeolite in maize (Zea mays) cultivation on nitrogen, potassium and phosphorus uptake and use efficiency. International Journal of the Physical Sciences. 2010;5(15):2393-2401.
3. Allen ER, Hossner LR, Ming DW, Henninger DL. Release rates of phosphorus, ammonium, and potassium in clinoptilolite-phosphate rock systems. Soil Science Society of America Journal. 1996;60(5):1467-1472.
4. Andronikashvili T, Urushadze T, Eprikashvili L, Gamisonia M. Towards the biological activity of the natural zeolite-clinoptilolite-containing tuff. Bulletin of the Georgian National Academy of Sciences. 2008;2(3):99-107.
5. Ayan S, Yahyaoglu Z, Gercek V, Şahin A. Utilization of zeolite as a substrate for containerized oriental spruce (Picea orientalis L. (Link.)) seedlings propagation. In: International Symposium on Growing Media. 2005;779:583-590.
6. Bhandari AL, Sharma KN, Kapur ML, Rana DS. Supplementation of N through green manuring for maize growing. Journal of the Indian Society of Soil Science. 1989;37:483-486.
7. Butorac A, Filipan T, Basic F, Butorac J, Mesic M, Kisic I. Crop response to the application of special natural amendments based on zeolite tuff. Plant, Soil and Environment. 2002;48(3):118-124.
8. Cvelbar Weber N, Koron D, Jakopic J, Veberic R, Hudina M, Baša Cesnik H. Influence of nitrogen, calcium and nano-fertilizer on strawberry (Fragaria × ananassa Duch.) fruit inner and outer quality. Agronomy. 2021;11(5):997.
9. Erisman JW, Bleeker A, Hensen A, Vermeulen A. Agricultural air quality in Europe and the future perspectives. Atmospheric Environment. 2008;42(14):3209-3217.
10. Gerdini FS. Effect of nano potassium fertilizer on some parchment pumpkin (Cucurbita pepo) morphological and physiological characteristics under drought conditions. International Journal of Farming and Allied Sciences. 2016;5(5):367-371.
11. Guo X, Li X, Park HS. Ammonium and potassium removal for anaerobically digested wastewater using natural clinoptilolite followed by membrane pretreatment. Journal of Hazardous Materials. 2008;151(1):125-133.
12. He ZL, Calvert DV, Alva AK, Li YC, Banks DJ. Clinoptilolite zeolite and cellulose amendments to reduce ammonia volatilization in a calcareous sandy soil. Plant and Soil. 2002;247:253-260.
13. Jackson ML. Soil chemical analysis. New Delhi: Prentice Hall of India; 1973. p. 151-154.
14. Lal R. Promise and limitations of soils to minimize climate change. Journal of Soil and Water Conservation. 2008;63(4):113-118.
15. Li Z, Zhang Y. Use of surfactant-modified zeolite to carry and slowly release sulfate. Desalination and Water Treatment. 2010;21(1-3):73-78.
16. Lindsay WL, Norvell WA. Development of a DTPA soil test for zinc, iron, manganese and copper. Soil Science Society of America Journal. 1978;42(3):421-428.
17. Liu M, Liang R, Zhan F, Liu Z, Niu A. Synthesis of a slow-release and superabsorbent nitrogen fertilizer and its properties. Polymers for Advanced Technologies. 2006;17(6):430-438.
18. Malhi SS, Haderlin LK, Pauly DG, Johnson AM. Improving fertiliser use efficiency. Better Crops. 2002;86:22-25.
19. Markovich A, Takac A, Illin Z, Ito T, Tognoni F. Enriched zeolites as substrate component in the production of paper and tomato seedling. Acta Horticulturae. 1995;396:321-328.
20. More SP, Ghonsikar CP. Effect of some organic manures on the availability of phosphorus. Journal of Indian Society of Soil Science. 1988;36:372-374.
21. Mozafari AA, Havas F, Ghaderi N. Application of iron nanoparticles and salicylic acid in vitro culture of strawberries (Fragaria × ananassa Duch.) to cope with drought stress. Plant Cell, Tissue and Organ Culture. 2018;132:511-523.
22. Olsen SR, Cole CV, Watanabe FS, Dean L. Estimation of available phosphorus in soil by extraction with sodium carbonate. USDA Circular. 1954;939:1-19.
23. Rahale S. Nutrient release pattern of nano fertilizer formulation [PhD Agriculture thesis]. Coimbatore: Tamil Nadu Agricultural University; 2011.
24. Rezaei M, Naeini SM. Adsorption and desorption kinetics in the loess soil. International Journal of Soil Science. 2009;4(2):27-45.
25. Ryals R, Silver WL. Effects of organic matter amendments on net primary productivity and greenhouse gas emissions in annual grasslands. Ecological Applications. 2013;23:46-59.
26. Shambhavi S, Kumar R, Sharma SP, Verma G, Sharma RP, Sharma SK. Long-term effect of inorganic fertilizers and amendments on productivity and root dynamics under maize-wheat intensive cropping in an acid Alfisol. Journal of Applied and Natural Science. 2017;9(4):20042012.
27. Subbiah BV, Asija GL. A rapid procedure for estimation of available nitrogen in soils. Current Science. 1956;25:259-260.
28. Subramanian KS, Paulraj C, Natarajan S. Nanotechnological approaches in nutrient management. In: Nanotechnology Applications in Agriculture. 2008. p. 37-42.
29. Zhou JM, Huang PM. Kinetics of potassium release from illite as influenced by different phosphates. Geoderma. 2007;138(3-4):221-228.
30. Prihar SS, Sandhu BS. A rapid method for soil moisture determination. Soil Science. 1968;105:142-144
31. Majumdar SP, Singh RA. Analysis of Soil Physical Properties. Agrobios (Delhi). Jodhpur: 49-51, 2005.