Enhance Nutrient Use Research Articles

Opinion: Smart nanofertilizers for growth enhancement and stress resilience in agriculture

Smart nanofertilizers (NFs) represent a promising frontier in agricultural technology, offering precise nutrient delivery and stress resilience to enhance crop growth and productivity while minimizing the environmental impact. This opinion article explores the potential of smart NFs in revolutionizing traditional fertilization practices and addressing the challenges facing modern agriculture. By harnessing the unique properties of nanomaterials, smart NFs including noble metal nanoparticles, green NFs, and novel NFs from industrial waste enable targeted nutrient delivery, enhanced nutrient use efficiency, and stress tolerance in plants. However, their widespread adoption faces regulatory, safety, and scalability challenges that require interdisciplinary collaboration and concerted efforts from stakeholders. Despite these hurdles, smart NFs hold immense promise for promoting sustainable agriculture and ensuring food security in frequently changing global climatic conditions.

Integrated deep banding and fertigation of phosphorus improves cotton yield by regulating root spatial distribution and growth

Context or problemTraditionally, 100 % phosphorus (P) fertilizer application as a band at various depths before sowing significantly influenced crop root growth and yield by reducing P fixation and optimizing its spatial distribution. However, with the advent of drip fertigation in Xinjiang, China, P fertilization practices have shifted from 100 % basal to a combination of basal and fertigation for enhanced P nutrition in cotton. Despite this, the impact of pre-sowing P band application on cotton growth under drip fertigation remains unclear. Objective or research questionThis study aimed to determine the optimal P fertilizer banding depth for cotton under a drip fertigation system. MethodsField trials were conducted comparing different basal P fertilizer application depths (5 cm, 15 cm, and 25 cm, denoted as D5, D15, and D25, respectively) with 50 % of the P rate and the remaining 50 % applied as topdressing via drip fertilization. A control (CK) involving 50 % broadcasted P fertilizer and 50 % topdressed P was included. The study focused on the effects of P application depth on soil P availability, root growth patterns, P utilization, and cotton yield. ResultsAt the boll opening stage, the D15 treatment exhibited a significant 18.69 %-49.76 % increase in available phosphorus in the 10–40 cm soil layer compared to the CK. During the peak boll to boll opening stage, the D15 treatment significantly outperformed the CK in terms of total root biomass density (11.62 %-17.54 %), total root length (16.75 %-24.81 %), total root surface area (23.07 %-37.59 %), and total root volume (20.69 %-26.23 %). Moreover, root activity and growth parameters were notably higher in the D15 treatment within the 10–40 cm soil layer. ConclusionsApplying 50 % of the P fertilizer as a band at a 15 cm depth before planting drip-irrigated cotton is optimal. This practice enhances soil P availability, stimulates root growth and distribution, and ultimately improves P utilization and cotton yield. Implications or significanceBanding P fertilizer at a 15 cm depth in combination with drip fertigation demonstrates superior yield benefits. This technology offers a novel approach to fertilizer application, enhancing nutrient use efficiency and crop productivity in drip-irrigated systems.

Phytobiomes: Harnessing the Power of Microbial Communities for Plant Health

Phytobiomes encompass the dynamic ecosystems surrounding plants, which include a diverse range of microbial communities such as fungi, bacteria, algae, viruses, and nematodes. These microorganisms interact intricately with plants, influencing their health, growth, and resilience. Beneficial fungi form symbiotic relationships with plant roots, enhancing nutrient absorption, while bacteria play a role in nitrogen fixation and disease suppression. Algae contribute to soil health and organic matter decomposition, and viruses, though often seen as harmful, can provide resistance to certain pathogens. Nematodes, both beneficial and parasitic, regulate soil nutrient cycles and influence plant growth. Harnessing the potential of these microbial communities offers promising solutions for sustainable agriculture. By promoting beneficial interactions within the phytobiome, it is possible to improve plant productivity, enhance nutrient use efficiency, and increase tolerance to environmental stresses such as drought, salinity, and pathogens. Phytobiome research aims to uncover the complex relationships within these microbial networks to develop novel agricultural practices that reduce reliance on chemical inputs. This holistic approach not only promotes plant health but also ensures ecological balance, contributing to the long-term sustainability of agroecosystems in the face of environmental challenges. Understanding the power of microbial communities within phytobiomes is key to advancing future agricultural innovations.

374 Efficacy of phytase and/or chromium tripicolinate supplementation on nutrient digestibility and blood metabolites in grower pigs

Abstract Phytase supplementation is widely used in diet formulations to enhance nutrient use efficiency in pigs, while supplemental chromium tripicolinate has been shown to help optimize glucose metabolism by enhancing insulin sensitivity. Therefore, the objectives of this metabolism study were to examine potential synergies of these additives to evaluate if nutrient digestibility and/or blood metabolites could be improved in grower pigs. Grower pigs [n = 6; body weight (BW) = 21.8 ± 0.19 kg; Genesus genetics] were randomly allotted by initial BW to four treatments in a 2 x 2 factorial arrangement of treatments. Treatment (Trt) 1 consisted of a control diet without phytase while Trt 2 had decreased levels of calcium and phosphorus with added phytase (1,500 FYT/kg; HiPhorius; dsm-firmenich, Plainsboro, NJ). Treatment 3 was the control diet without phytase with added chromium from chromium tripicolinate (200 ppb; Chromax, Kent Nutrition Group, Inc., Muscatine, IA) while Trt 4 consisted of the diets with decreased levels of calcium and phosphorus with added HiPhorius (1,500 FYT/kg) and chromium tripicolinate (200 ppb). With six metabolism crates available and four treatment groups, it took a 4-wk duration to allow for each pig to be evaluated on each of the four treatments. The pigs were allowed a 4-d acclimation period followed by a 3-d collection period with the experimental diets fed at 4% BW divided into two meals each day. Water was added at 2.5 times the amount of feed fed each day. A second group of grower pigs (n = 6; BW = 19.6 ± 0.12 kg; Genesus) were utilized following the same procedures as above and pooled with the first group for data analysis. On the last day of the collection period, blood samples were collected before the meal (fasting) and then 2 h after the meal (post-meal). Added phytase resulted in a reduction (P < 0.05) in fasting blood urea nitrogen. Nitrogen digestibility and nitrogen retention were both improved (P < 0.01) with pigs fed supplemental phytase. Furthermore, dry matter digestibility was also improved (P < 0.001) in pigs fed added phytase. Supplemental chromium was without effect on any of the nitrogen and/or dry matter digestibility measurements. These data suggest that supplemental phytase has positive effects by significantly improving nitrogen and dry matter digestibility with no further improvements observed from supplemental chromium.

In-depth exploration of nanoparticles for enhanced nutrient use efficiency and abiotic stresses management: Present insights and future horizons

Nanotechnology is an innovative method of elevating agricultural output without sacrificing quality due to nanoparticles (NPs) unique characteristics and numerous potential uses. It is also nature-friendly, advantageous to living organisms, and cost-effective. Sustainable agricultural practices are gaining attention on NPs and nanofertilizers (NFs) as practical substitutes for traditional fertilizers and pesticides that nanotechnology could surpass some of the issues with traditional farming methods. There should be an emphasis on cutting-edge studies of NPs applications in agriculture. This article presents a positive perspective on the mechanisms leading to the formation of NPs and their application as NFs for managing nutrients in agriculture. We also share up-to-date findings on NPs interactions with plants, the fate of NPs and potential risks associated with them in plants. The as well as on the role of NPs nanomaterials in decreasing abiotic and heavy metal toxicity stress. NFs help reduce the environmental damage caused by traditional, inorganic fertilizers. Due to their enhanced responsiveness and ability to pierce the epidermis, NFs can decrease nutrient surplus while increasing nutrient usage efficiency. It was also established that NPs are essential for protecting against abiotic stress. However, some studies have shown that NPs are harmful to higher plants because the NPs they are deposited upon the surface of cells or in the cell organelles, leading to oxidative stress symptoms. In this review article, we explore the utilization of NPs for nutrient and abiotic stress management for crop production and protection during the climate change era.

Enhancing Bok Choy growth through synergistic effects of hydrogel and different nitrogen fertilizer forms

The application of hydrogel to sandy soil has shown promise in enhancing crop production, offering alternative solutions to address the growing food demand. Here, we investigated the impact of hydrogel and different nitrogen (N) fertilizer forms (NH4+, NO3− and Urea) on Bok Choy (Brassica rapa var. chinensis) production through the evaluation of the plant growth parameters, photosynthesis, nutrient uptake, and soil physicochemical properties. Our findings reveal that the application of hydrogel significantly increased plant height (16.27 %), fresh weight (FW) (61.14 %), dry weight (DW) (65.69 %) weight, plant nutrient concentration, and uptake. Additionally, it improved photosynthetic parameters and induced alterations in soil physicochemical properties. The synergistic effects of hydrogel varied with different nitrogen forms, with NH4+–N fertilizer demonstrating the most efficiency in enhancing Bok Choy production (119.65 % FW) compared to control. Pearson correlation analysis established close associations between Bok Choy growth parameters, photosynthesis, nutrient accumulation, and soil physicochemical properties. Principal component analysis (PCA) underscored the significant influence of hydrogel and NH4+–N on various growth parameters in Bok Choy. The stimulated growth observed can be attributed to increased nutrient uptake, improved photosynthesis, and the maintenance of soil physicochemical properties. These findings carry significant implications for the practical application of hydrogel in the field, providing a valuable strategy to enhance nutrient use efficiency and crop production in sandy soil.

Nano Fertilizers: New Vistas towards Sustainable Agriculture and Climate Change Mitigation: A Review

To ensure the food and nutritional security of the burgeoning global population, food production needs to be doubled in developing countries by 2050. Currently, 30-40% of agriculture production predominantly relies on chemical fertilizers. Precise crop nutrition, low nutrient efficiency, maintaining soil fertility, less damage to soil flora and minimal environmental footprint are the major challenges in modern agriculture. Recent developments in the application of nanotechnology to produce agriculture inputs emerged as a sustainable solution for addressing the challenges in modern intensive agriculture by replacing synthetic bulk fertilizers with their nanoparticle size ( less than 100 nm), superior properties and smart delivery system. Nano fertilizers had the potential to fulfill the requirements of plant nutrition along with imparting sustainability in crop production without compromising the yield of the crops. Some of the current research studies have been reviewed in this paper with citation and these results showed that nano fertilizers have a substantial effect on plant growth, development and physiological parameters including chlorophyll content and photosynthetic activity, it depends on their composition, method and time of application. Their enhanced nutrient use efficiency, correlated with mitigating greenhouse gas emissions. Hence evolving as a cutting-edge approach for sustainable agriculture in climate change is enlightened in this review.

Enhancing Productivity and Nutrient use Efficiency in Winter Maize (Zea mays L.) by Pant Fertilizer Band Placement cum Earthing Machine

Enhancing Productivity and Nutrient use Efficiency in Winter Maize (Zea mays L.) by Pant Fertilizer Band Placement cum Earthing Machine

Impact of Nano-fertilizers on Productivity and Profitability of Wheat (Triticum aestivum L.)

Yield stagnation, multi-nutrient deficiencies coupled with reduced fertilizer-use efficiency have emerged as major challenges to the food-systems of South Asia. Modern scientific tools to enhance nutrient use efficiencies along with augmented crop yields became utmost necessity to sustain food security of developing world. In this context, a field study was undertaken to understand the influence of numerous nano-fertilizers on wheat productivity, profitability and nutrient-use efficiency. Results revealed that application of 100% NPK coupled with foliar-spray of Nano- N + P + K + Zn increased grain and straw yield by 29.8 % and 13.7 %, respectively over 100% NPK. The crop fetched a net return of ₹ 72141.50 with B:C ratio of 5.51 with 75% NPK + nano-N. As a result, the wheat crop produced when Nano-N + 75% NPK was applied produced a greater yield (grain, straw, and biological), as well as financial gains.

Enhancing nutrient use efficiencies for rainfed rice through fertilizer splitting

Enhancing nutrient use efficiencies for rainfed rice through fertilizer splitting

Bacterial indole-3-acetic acid: A key regulator for plant growth, plant-microbe interactions, and agricultural adaptive resilience

Indole-3-acetic acid (IAA), a fundamental phytohormone categorized under auxins, not only influences plant growth and development but also plays a critical role in plant-microbe interactions. This study reviews the role of IAA in bacteria-plant communication, with a focus on its biosynthesis, regulation, and the subsequent effects on host plants. Bacteria synthesize IAA through multiple pathways, which include the indole-3-acetamide (IAM), indole-3-pyruvic acid (IPyA), and several other routes, whose full mechanisms remain to be fully elucidated. The production of bacterial IAA affects root architecture, nutrient uptake, and resistance to various abiotic stresses such as drought, salinity, and heavy metal toxicity, enhancing plant resilience and thus offering promising routes to sustainable agriculture. Bacterial IAA synthesis is regulated through complex gene networks responsive to environmental cues, impacting plant hormonal balances and symbiotic relationships. Pathogenic bacteria have adapted mechanisms to manipulate the host’s IAA dynamics, influencing disease outcomes. On the other hand, beneficial bacteria utilize IAA to promote plant growth and mitigate abiotic stresses, thereby enhancing nutrient use efficiency and reducing dependency on chemical fertilizers. Advancements in analytical methods, such as liquid chromatography–tandem mass spectrometry, have improved the quantification of bacterial IAA, enabling accurate measurement and analysis. Future research focusing on molecular interactions between IAA-producing bacteria and host plants could facilitate the development of biotechnological applications that integrate beneficial bacteria to improve crop performance, which is essential for addressing the challenges posed by climate change and ensuring global food security. This integration of bacterial IAA producers into agricultural practice promises to revolutionize crop management strategies by enhancing growth, fostering resilience, and reducing environmental impact.

Improving productivity, nutrient efficiency and economics of chamomile (Matricaria chamomilla L.) using phosphate and potassium solubilizing bacteria

Chamomile (Matricaria chamomilla L.) is a vital medicinal and aromatic plant, widely recognized for its industrial applications. However, sustainable cultivation of chamomile faces challenges due to the excessive use of chemical fertilizers, which can negatively impact soil health and the environment. There is a growing need to explore alternative agricultural practices that enhance nutrient use efficiency while minimizing environmental harm. Field experiments were conducted from 2022 to 2024 at the CSIR-CIMAP Research Centre in Bengaluru to evaluate the effects of phosphate solubilizing bacteria (PSB) and potassium solubilizing bacteria (KSB) on the performance and nutrient use efficiency of chamomile. Various treatment combinations of Recommended Dose of Fertilizers (RDF: 100 kg N, 60 kg P2O5, and 40 kg K2O ha-1) with PSB and KSB were tested, including co-inoculation and sole applications, to determine their impact on plant growth, yield and economic returns. Co-inoculating PSB and KSB with 100% RDF significantly increased plant height (48.09 cm) and branch count (15.43), outperforming RDF alone and other treatments. Sole applications of PSB or KSB with 100% RDF were comparable to 75% RDF combinations. The highest agronomic use efficiency (27.28%) and microbial response (37.49%) were achieved with 100% RDF+PSB+KSB, leading to a 137.49% yield increase. The highest concentrations of key compounds, α-bisabolol oxide B and α-bisabolol, were observed with 75% RDF+PSB+KSB. α-bisabolol peaked in the RDF-alone treatment. The 100% RDF+PSB+KSB treatment achieved the highest net monetary returns (US$ 5110 ha-1) and a benefit-to-cost ratio of 2.41, similar to 75% RDF+PSB+KSB. Overall, 75% RDF with PSB and KSB significantly enhances chamomile performance, increases soil bacterial populations, boosts nutrient mineralization, reduces chemical fertilizer use, and minimizes environmental impact. This approach offers a promising pathway for sustainable chamomile cultivation, leading to higher yields, improved economic returns, and reduced environmental impact.

Enhancing Nutrient Use Efficiency through Nano Urea in Pigeon Pea Based Intercropping System

A field experiment was conducted at Birsa Agricultural University Ranchi during the kharif seasons of 2021 and 2022 to evaluate N uptake and Nutrient Use Efficiency (NUE) for nitrogen as influenced by pigeon pea-based intercropping systems and nitrogen management. Pigeon pea + sweet corn intercropping systems with 100% recommended nitrogen (N1), recorded significantly higher total nitrogen uptake (196.6 kg/ha) which was at par with 50% RDN + 2 spray of nano urea (189.1 kg/ha). Whereas partial factor productivity (PFP), agronomic efficiency (AE), apparent recovery use efficiency (ARUE), economic nutrient use efficiency (ENUE), partial nutrient balance (PNB) of pigeon pea + sweet corn intercropping was recorded maximum (27.4 kg/kg, 13.4 kg/kg, 64.8 %, 1.66 kg yield/ ₹ invested in nitrogen & 0.88 kg/kg) respectively, while in nitrogen management, 50% RDN + 2 sprays of Nano urea performed better in terms of PFP, AE, ARUE, ENUE & PNB (52.5 kg/kg, 24.1 kg/kg, 115.4 %, 3.20 kg yield/ ₹ invested in nitrogen & 1.43 kg/kg respectively) when compared to the other nitrogen management.

Enhancing Yield, Uptake and Nutrient Use Efficiency of Brinjal Through Soil Test Crop Response Approach

ABSTRACT Fertilizer requirement for the crop should be based on yield response to the added fertilizer nutrient, nutrient requirements of a crop, nutrient supply from indigenous sources and the fate of added fertilizers to the soil in the short and long term. Thus, the soil test crop response (STCR) approach can be adopted for calculating fertilizer requirements by crops. The field experiments were conducted at the Eastern Dry Zone of Karnataka, University of Agricultural Sciences, Bangalore, in three phases. Soil test data, yield and NPK uptake by brinjal crop were used for achieving four important basic parameters, viz. nutrient requirement, contribution of nutrients from fertilizers, soil and organic manure, to develop the targeted yield equation and these equations were validated in comparison with Low-Medium-High (LMH) approach and generally recommended dose (GRD). It was found that 1.11, 0.46, and 0.30 kg of N, P2O5, and K2O respectively were required for producing one quintal of brinjal fruit under integrated approach. The contribution of NPK from soil toward crop uptake was 26.07%, 5.94% and 36.89% respectively; from organic manure was 16.15%, 8.66% and 31.55% respectively and from fertilizers was 42.27, 11.73 and 170.84% respectively. The STCR integrated approach with FYM, at the target yields 35 and 30 t ha−1, enhanced the fruit yield to an extent of 12.90% and 9.94%, respectively, over GRD. It also exhibited higher NPK uptake and use efficiency and better profitability. Hence integrated STCR targeted yield approach could be sustainable nutrient management option(s) for improving the productivity of brinjal.

Barley Growth and Phosphorus Uptake in Response to Inoculation with Arbuscular Mycorrhizal Fungi and Phosphorus Solubilizing Bacteria

ABSTRACT Biostimulants and bioinoculants offer the potential to enhance nutrient use efficiency within agricultural cropping systems and thus reduce the amount of mineral fertilizers needed to support crop growth. Considerable uncertainty, however, exists about their efficacy under different management regimes. The present field-based study investigated the effects of phosphorus (P) solubilizing bacteria (PSB) and mycorrhizal (AMF) inoculants in the presence of a range of mineral-based P fertilizers, including triple superphosphate (TSP), struvite and rock phosphate (RP), on the growth, yield, and P uptake of barley (Hordeum vulgare L.). Two consecutive field experiments performed in a low P soil (Eutric Cambisol) revealed that the bioinoculants (PSB and AMF) promoted plant P uptake and grain yield. Moreover, in comparison to P fertilizers lacking bio-inoculants, the application of external P sources combined with bio-inoculants led to significant increases in leaf P concentration, total P uptake, plant dry matter, grain P concentration, and crop yield. Grain yield significantly correlated with P uptake by roots and above-ground parts (i.e. stems, leaves, and spikes) as well as grain P concentration in both seasons. It is concluded that bioinoculants can help improve sustainable P use ultimately leading to greater sustainability of cropping systems and resilience in soil P cycling.

Landscape-based nutrient application in wheat and teff mixed farming systems of Ethiopia: farmer and extension agent demand driven approach

IntroductionAdapting fertilizer use is crucial if smallholder agroecosystems are to attain the sustainable development goals of zero hunger and agroecosystem resilience. Poor soil health and nutrient variability characterize the smallholder farming systems. However, the current research at the field scale does not account for nutrient variability across landscape positions, posing significant challenges for targeted nutrient management interventions. The purpose of this research was to create a demand-driven and co-development approach for diagnosing farmer nutrient management practices and determining landscape-specific (hillslope, mid-slope, and foot slope) fertilizer applications for teff and wheat.MethodA landscape segmentation approach was aimed to address gaps in farm-scale nutrient management research as well as the limitations of blanket recommendations to meet local nutrient requirements. This approach incorporates the concept of interconnected socio-technical systems as well as the concepts and procedures of co-development. A smart mobile app was used by extension agents to generate crop-specific decision rules at the landscape scale and forward the specific fertilizer applications to target farmers through SMS messages or print formats.Results and discussionThe findings reveal that farmers apply more fertilizer to hillslopes and less to mid- and foot slopes. However, landscape-specific fertilizer application guided by crop-specific decision rules via mobile applications resulted in much higher yield improvements, 23% and 56% at foot slopes and 21% and 6.5% at mid slopes for wheat and teff, respectively. The optimized net benefit per hectare increase over the current extension recommendation was $176 and $333 at foot slopes and $159 and $64 at mid slopes for wheat and teff (average of $90 and $107 for wheat and teff), respectively. The results of the net benefit-to-cost ratio (BCR) demonstrated that applying landscape-targeted fertilizer resulted in an optimum return on investment ($10.0 net profit per $1.0 investment) while also enhancing nutrient use efficiency across the three landscape positions. Farmers are now cognizant of the need to reduce fertilizer rates on hillslopes while increasing them on parcels at mid- and foot-slope landscapes, which have higher responses and profits. As a result, applying digital advisory to optimize landscape-targeted fertilizer management gives agronomic, economic, and environmental benefits. The outcomes results of the innovation also contribute to overcoming site-specific yield gaps and low nutrient use efficiency, they have the potential to be scaled if complementing innovations and scaling factors are integrated.

Occupational safety assessment of biogenic urea nanofertilisers using in vitro pulmonary, and in vivo ocular models

Nanomaterials (NMs) are now gaining popularity to be used in agriculture as fertilisers to reduce the dose of conventional fertilisers and enhance nutrient use efficiency. Urea has found its application as a conventional nitrogenous fertiliser since long, however, the nutrient use efficiency of the bulk form of urea is low due to issues related to ammonia volatilisation. This study proposes a biogenic synthesis route to develop urea nanoparticles that can be used as nano-fertiliser for better uptake and hence improved nutrient efficiency. Large scale production and widespread application of these nano-fertilisers to the agricultural fields will enhance the direct exposure to workers and farmers. Therefore, the occupational safety evaluation becomes critical. In this study, we report a new method for synthesis of urea nanoparticles (TNU, absolute size: 12.14 ± 7.79 nm) followed by nano-safety evaluation. Herein, the pulmonary and ocular compatibilities of TNU were investigated in vitro and in vivo respectively. The assay for cellular mitochondrial activity was carried out on human lung fibroblasts (WI-38) under varied TNU exposure concentrations up to 72 h. The acute biocompatibility effect, ocular irritation and sub-lethal effects were measured on New Zealand Rabbit. The results show that TNU do not exhibit any cytotoxicity and detrimental cell mitochondrial activity up to the highest tested concentration of 1000 μg/mL and 72 h of testing. The animal experiment results also show that neither acute nor sub-lethal toxic effects can be detected after TNU ocular instillation up to 21 days when tested up to environmentally relevant concentration of 15 μg/mL. These results suggest the occupational safety of biogenic urea nanoparticles and support its application as nanofertiliser.

Decomposition and nitrogen mineralization of <em>Gliricidia sepium</em> leaf green manure under diverse nutrient management strategies in irrigated lowland rice cropping systems in Sri Lanka

The utilization of green manure has become an essential strategy for enhancing soil fertility and substituting synthetic fertilizers. The decomposition and release of nutrients through mineralization processes are influenced by soil microbial activity, which in turn depends on the nutrient management practices employed. depending on nutrient management approaches. The study aimed to investigate the decomposition and N mineralization of Gliricidia sepium leaf green manure in an irrigated lowland rice ecosystem under different nutrient management systems (NMS), for a duration of eight weeks. Litterbags were placed at two soil depths, namely the topsoil, and subsoil, within three NMS; 100% Department of Agriculture (DOA) recommended inorganic fertilizer application (CNM), 50% of DOA recommended inorganic fertilizer combined with the organic fertilizer application (INM), and 100% organic fertilizer application (ONM). The treatments were arranged in a randomized complete block design and litterbags were retrieved weekly to determine dry mass, total N content, and total organic carbon content remaining in the leaves. The rate of decomposition and nutrient release was estimated using an exponential decay equation and analysis of variance was carried out using the repeated measures MIXED model. A consistent biphasic pattern of decomposition and mineralization was observed across all NMS treatments and soil depths, characterized by an initial rapid phase followed by a slower phase. However, significant differences (p<0.05) were observed among the treatments. The ONM treatment combined with topsoil placement exhibited a shorter time for 50% and 80% reduction in biomass and nitrogen content. Approximately 80% of the nitrogen content was released into the soil solution within 4-5 weeks of green manure incorporation, regardless of the nutrient management system employed. These findings suggest that with proper application rates and appropriate depth of placement, Gliricidia sepium green manure can effectively replace a significant portion of mineral nitrogen fertilizer, thereby enhancing nutrient use efficiency in lowland rice-based systems.

Development and characterization of rice bran-gum Arabic based encapsulated biofertilizer for enhanced shelf life and controlled bacterial release.

Currently, microbe-based approaches are being tested to address nutrient deficiencies and enhance nutrient use efficiency in crops. However, these bioinoculants have been unsuccessful at the commercial level due to differences in field and in-vivo conditions. Thus, to enhance bacterial stability, microbial formulations are considered, which will provide an appropriate microenvironment and protection to the bacteria ensuring better rhizospheric-colonization. The present study aimed to develop a phosphobacterium-based encapsulated biofertilizer using the ion-chelation method, wherein a bacterial strain, Myroid gitamensis was mixed with a composite solution containing rice bran (RB), gum Arabic (GA), tricalcium phosphate, and alginate to develop low-cost and slow-release microbeads. The developed microbead was studied for encapsulation efficiency, shape, size, external morphology, shelf-life, soil release behavior, and biodegradability and characterized using SEM, FTIR, and XRD. Further, the wheat growth-promoting potential of microbeads was studied. The developed microbeads showed an encapsulation efficiency of 94.11%. The air-dried beads stored at 4°C were favorable for bacterial survival for upto 6 months. Microbeads showed 99.75% degradation within 110 days of incubation showing the bio-sustainable nature of the beads. The application of dried formulations to the pot-grown wheat seedlings resulted in a higher germination rate, shoot length, root length, fresh weight, dry weight of the seedlings, and higher potassium and phosphorus uptake in wheat. This study, for the first time, provides evidence that compared to liquid biofertilizers, the RB-GA encapsulated bacteria have better potential of enhancing wheat growth and can be foreseen as a future fertilizer option for wheat.

Point of Zero Charge of Soils - It’s Dynamics under Fertilizer Management Practices and Nutrient Availability

Aims: To study the dynamics of point of zero charge of different soil types and determine the availability of nutrients under the influence of specific fertilizer management practices.
 Study Design: Completely Randomized Design.
 Place and Duration of Study: Department of Soil Science, Assam Agricultural University, Jorhat, Assam; between March 2020 and December 2021.
 Methodology: We estimated the point of zero charge (PZC) components, i.e., the point of zero salt effect (PZSE) and point of zero net charge (PZNC) in six surface soil samples [black soil (Vertisol), laterite soil (Alfisol), red soil (Alfisol) of Odisha, and alluvial soils belonging to Entisol, Inceptisol, and Alfisol of Assam, India] through potentiometric titration and ion retention methods respectively. The soils were subjected to four specific fertilizer management practices under laboratory incubation, viz., FYM @ 5 t ha-1 (T1), NPK @ 80:40:40 for Odisha soils and 60:20:40 for Assam soils (T2), T1 + T2 (T3) and T3 + Lime requirement/ Gypsum requirement (T4). The PZC components and availability of nutrients were determined at 15 and 30 days after incubation.
 Results: The PZSE values of the soils ranged from 2.18 to 4.70, while PZNC values were achieved at relatively lower pH ranging from 2.03 to 4.10. Highest values of PZSE and PZNC were recorded under treatment T2 followed by T3, T4 and T1 for all the incubated soil samples, however there was a decrease in the PZC values with increase in days of incubation. Comparatively, the treatment T4 resulted as the most ideal fertilizer management practice. Besides providing optimum amount of primary and maximum amount of secondary nutrients, T4 regulated the PZC values favouring minimal loss of nutrients and enhanced nutrient use efficiency. The availability of nutrient ions is influenced by the difference between soil solution pH and PZC values of the soil, which recorded to be highest for Vertisol (OS1), followed by Entisol (AS1), Inceptisol (AS2), and Alfisol (AS3, OS2, OS3) soil orders.
 Conclusion: The exchange and availability of cationic nutrients get enhanced due to higher CEC in soils with high clay and organic matter percentage. The pH of these soils must therefore be regulated for better availability of anionic nutrients. Highly weathered soil of Alfisol order exhibit optimal CEC over a narrow pH range, favouring better availability of anionic nutrients and hence simultaneously require frequent fertilizer application along with organic manures for the enhanced retention, mobility and availability of nutrients in soil.