Bacterial Coated Fertilizer Induced Resistance Against Wheat Stripe Rust

Wheat is the second largest consumed cereal by humans after Rice and its high yield and production is very critical for ever increasing global population. The wheat crop is grown all over Pakistan and threatened by several limiting factors. Stripe rust, caused by Puccinia striiformis, is the most destructive wheat pathogen and can reduce yield up to 70% in Pakistan. The present study aimed at exploring the role of Zabardast urea, a bacterial coated urea with zinc, in inducing resistance against wheat stripe rust. The study involved the collection and maintenance of stripe rust inoculum on Morroco cultivar which later used to inoculate seedlings of Akbar-2019 and Galaxy-2019 resistant and susceptible varieties with three different fertilizer levels viz. specialty fertilizer zabardast urea, plain urea with zinc and plain urea. The results demonstrated the positive role of bacterial coated urea with zinc and reduced the disease severity by 10% and 5% in susceptible and resistant cultivars, respectively, leaving resistant variety asymptomatic. The plain urea with zinc also decreased disease severity in susceptible variety Galaxy-2013 by 6% in comparison with plain urea treatment underlying the role of zinc in combating stripe rust. The study underlines the importance of specialty fertilizers in inducing resistance against stripe rust in wheat and needs further experimentation exploring the mechanisms involved in disease resistance under field conditions.

Effects of Rice Husk Biochar Coated Urea and Anaerobically Digested Rice Straw Compost on the Soil Fertility, and Cyclic Effect of Phosphorus

Fertilizer application in rice farming is an essential requirement. Most of the high-yielding varieties which are extensively grown throughout the country require recommended levels of fertilizers to obtain their potential yields. However, effective, and efficient ways of fertilizer application are of utmost importance. Coated fertilizers are used to reduce leaching nutrients and improve the efficiency of fertilizer. However, conventional coated fertilizers such as Sulphur coated urea and urea super granules are not popular among rice farmers in Sri Lanka owing to the high cost. Mixing urea-coated rice husk biochar causes a slow release of nitrogen fertilizer. This coated fertilizer and rice straw compost reduction the cost of importations of nitrogen-based fertilizers per unit area of cultivation. The study aimed to evaluate the effects of rice husk biochar coated urea and anaerobically digested rice straw compost on the soil fertility, and the cyclic effect of phosphorus. Concerning the pot experiment, rice grain yield was significantly higher in Rice husk biochar coated urea, triple super phosphate (TSP), and muriate of potash (MOP) with anaerobically digested rice straw compost. The lowest yield was observed in the control. The release of phosphate shows a cycle effect which is an important finding. Rice husk biochar coated urea can potentially be used as a slow-releasing nitrogen fertilizer. In addition, the urea coated with biochar is less costly and contributes to mitigating pollution of water bodies by inorganic fertilizers (NPK).

Zinc-Coated Urea for Enhanced Zinc Biofortification, Nitrogen Use Efficiency and Yield of Basmati Rice under Typic Fluvents

Deficiency of Zn in human diet is an emerging health issue in many developing countries across the globe. Agronomic Zn biofortification using diverse Zn fertilization options is being advised for enhancing Zn concentration in the edible portion of rice.A field study was carried out to find out the Zn fertilization effects on biofortification of basmati rice and nutrient use efficiencies in the Himalayan foothills region. Amongst the Zn nutrition treatments, 4.0% Zn-coated urea (ZnCU) + 0.2% Zn foliar spray (FS) using ZnSO4·7H2O recorded the highest grain (3.46 t/ha) and straw (7.93 t/ha) yield of basmati rice. On average, the rice productivity increase due to ZnCU application was ~25.4% over Commercial Urea. Likewise, the same Zn fertilization treatment also resulted in the maximum Zn (35.93 and 81.64 mg/kg) and N (1.19 and 0.45%) concentration in grain and straw of rice, respectively. Moreover, N use efficiency (NUE) was also highest when ZnCU was applied at 4.0% (ZnSO4·7H2O) in comparison to soil application. From the grain quality viewpoint, Zn ferti-fortification had significant effect on elongation ratio and protein concentration of grain only and respective Zn fertilization treatment recorded highest quality parameters 1.90 and 7.44%, respectively. Therefore, ZnCU would be an important low-cost and useful strategy for enhancing yield, NUE and biofortification, and also in minimizing the Zn malnutrition related challenges in human diet in many developing economies.

Influence of Biodegradable Polymer Coated Urea on Nitrogen Uptake and Utilization of Maize (Zea mays L)

Controlled release nitrogen fertilizers could be an excellent management approach for improving nitrogen fertilizer efficiency. The present study aimed to investigate the effect of coated urea fertilizers to increase nitrogen uptake and utilization of maize. The nitrogen use efficiency of maize from various biodegradable polymer-coated urea fertilizers, such as palm stearin coated urea (PSCU), pine oleoresin coated urea (POCU), and humic acid coated urea (HACU), was determined in a pot culture experiment conducted at the Department of Soil Science and Agricultural Chemistry, Tamil Nadu Agricultural University, Coimbatore, during 2021. The coating materials have been coated on urea with different coating thicknesses, viz., PSCU - 5, 10, 15%, POCU – 2, 4, 6%, and HACU - 5, 10, 15%. Among all the treatments, T11: HACU 15% produced highest grain yield (72.0g plant-1) followed by T7: POCU 4% (69.7 g plant-1) and T4: PSCU 10% (69.0g plant-1). In terms of dry matter production, T10: PSCU 10% produced maximum dry matter (186.5g plant-1), followed by T11: HACU 15% (186.2 g plant-1), and T7: POCU 4% (185.3g plant-1). The nitrogen uptake by the maize plant was higher in T7: POCU 4 % (1.62g plant-1), followed by T11: HACU 15% (1.59 g plant-1) and T4: PSCU 10% (1.59g plant-1). Irrespective of treatments, the highest nitrogen utilization by the maize crop was found in T7: POCU 4% (73.9%) followed by T4: PSCU 10% (71.1%) and T11: HACU 15% (70.9%) treatments. When compared to uncoated urea fertilizer, all coated urea fertilizers outperformed uncoated urea fertilizer in terms of grain yield, dry matter accumulation, and nitrogen uptake. To improve the nitrogen use efficiency, coated urea fertilizers prove to be a promising alternative to uncoated urea fertilizers.

A Degradable Inverse Vulcanized Copolymer as a Coating Material for Urea Produced under Optimized Conditions

Global enhancement of crop yield is achieved using chemical fertilizers; however, agro-economy is affected due to poor nutrient uptake efficacy (NUE), which also causes environmental pollution. Encapsulating urea granules with hydrophobic material can be one solution. Additionally, the inverse vulcanized copolymer obtained from vegetable oils are a new class of green sulfur-enriched polymer with good biodegradation and better sulfur oxidation potential, but they possess unreacted sulfur, which leads to void generations. In this study, inverse vulcanization reaction conditions to minimize the amount of unreacted sulfur through response surface methodology (RSM) is optimized. The copolymer obtained was then characterized using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). FTIR confirmed the formation of the copolymer, TGA demonstrated that copolymer is thermally stable up to 200 °C temperature, and DSC revealed the sulfur conversion of 82.2% (predicted conversion of 82.37%), which shows the goodness of the model developed to predict the sulfur conversion. To further maximize the sulfur conversion, 5 wt% diisopropenyl benzene (DIB) as a crosslinker is added during synthesis to produce terpolymer. The urea granule is then coated using terpolymer, and the nutrient release longevity of the coated urea is tested in distilled water, which revealed that only 65% of its total nutrient is released after 40 days of incubation. The soil burial of the terpolymer demonstrated its biodegradability, as 26% weight loss happens in 52 days of incubation. Thus, inverse vulcanized terpolymer as a coating material for urea demonstrated far better nutrient release longevity compared with other biopolymers with improved biodegradation; moreover, these copolymers also have potential to improve sulfur oxidation.

Effects of Environmental Stresses (Heat, Salt, Waterlogging) on Grain Yield and Associated Traits of Wheat under Application of Sulfur-Coated Urea

Abiotic stresses, such as heat, salt, waterlogging, and multiple-stress environments have significantly reduced wheat production in recent decades. There is a need to use effective strategies for overcoming crop losses due to these abiotic stresses. Fertilizer-based approaches are readily available and can be managed in all farming communities. This research revealed the effects of sulfur-coated urea (SCU, 130 kg ha−1, release time of 120 days) on wheat crops under heat, salt, waterlogging, and combined-stress climatic conditions. The research was done using a completely randomized design with three replicates. The results revealed that SCU at a rate of 130 kg of N ha−1 showed a significantly (p ≤ 0.05) high SPAD value (55) in the case of waterlogging stress, while it was the lowest (31) in the case of heat stress; the control had a SPAD value of 58. Stress application significantly (p ≤ 0.05) reduced the leaf area and was the highest in control (1898 cm2), followed by salt stress (1509 cm2), waterlogging (1478 cm2), and heat stress (1298 cm2). A significantly (p ≤ 0.05) lowest crop yield was observed in the case of heat stress (3623.47 kg ha−1) among all stresses, while it was 10,270 kg ha−1 in control and was reduced up to 35% after the application of heat stress. Among all stresses, the salt stress showed the highest crop yield of 5473.16 kg ha−1. A significant correlation was observed among growth rate, spike length, yield, and physiological constraints with N content in the soil. The SCU fertilizer was the least effective against heat stress but could tolerate salt stress in wheat plants. The findings suggested the feasibility of adding SCU as an alternative to normal urea to alleviate salt stresses and improve wheat crop growth and yield traits. For heat stress tolerance, the applicability of SCU with a longer release period of ~180 days is recommended as a future prospect for study.

IMPACT OF INORGANIC AND ORGANIC SOURCES OF NUTRIENTS ON NPK UPTAKE BY AMBRETTE AND ITS POST-HARVEST SOIL NPK STATUS

The roots, leaves and seeds of ambrette are considered as valuable traditional medicines. The bitter, sweet, acrid, aromatic seeds are used as tonic and are considered to possess cooling, aphrodisiac, ophthalmic, cardiotonic, digestive, stomachiecm carminative, pectoral diuretic, stimulant, antispasmodic and deodorant properties. Crop removes nutrients continuously from soil and therefore, their replenishment though fertilizers and manures are essential. To find out the integrated effect of inorganic fertilizers, neem coated urea, enriched pressmud compost and sea weed extract on NPK uptake by ambrette and its post – harvest soil NPK status, a field investigation was carried out at Farmer’s Field Sivapuri Village, Chidambaram Taluk, Cuddalore District during Kharif, 2018. The experiment was laid out in Randomized Block Design (RBD) with eight treatments and three replications. The crop was grown to maturity with proper cultural practices. The results revealed that application of integrated application of inorganic fertilizers, neem coated urea, enriched pressmud compost and sea weed extract resulted in significantly highest NPK uptake by ambretee and influenced the post – harvest soil fertility status with respect to available NPK.

Efficiency of fertilization with coated urea in the cultivation of cactus pear under rainfed conditions in Brazilian savannah

Cactus pear is an important species for animal feeding in the regions of dry climate. There is no information on the fertilization with coated urea in the cultivation of cactus pear under rainfed conditions in the savannah region. The aim of the current study was to evaluate the forage potential of Nopalea cochenillifera variety Doce in yellow latosol under rainfed conditions in the Brazilian savannah, comparing the fertilization with urea and coated urea in different levels. A randomized block design was adopted, in a 2 × 4 × 2 factorial scheme, with the factors corresponding to two sources of nitrogen (urea and urea coated with polymers, N+), four levels of nitrogen (0, 60, 120 and 240 kg/ha/year) and two harvests (year I and year II). The plants were evaluated after 1 year of growth, in each year of evaluation, regarding the characteristics of growth, production, chemical and mineral composition and nutritional value. The level of 240 kg/ha provided higher emission of cladodes per plant (17.33 and 18.17), respectively, for N+ and urea. The highest nitrogen use efficiency was found in the level of 60 kg N/ha (142 kg/ha/year). NFC values were 3.5 g/kg dry matter (DM) higher when the cactus pear was fertilized with urea in year I and 5.4 g/kg DM in year II. The use of conventional urea promoted better results of agronomic and nutritional characteristics of the cactus pear, under rainfed regime, when compared to the use of urea coated with polymers.