Diammonium Phosphate Fertilizer Research Articles

Humic Acid-Functionalized Lignin-Based Coatings Regulate Nutrient Release and Promote Wheat Productivity and Grain Quality.

The rational application of fertilizers is crucial for achieving high crop yields and ensuring global food security. The use of biopolymers for slow-release fertilizers (SRFs) development has emerged as a game-changer and environmentally sustainable pathway to enhance crop yields by optimizing plant growth phases. Herein, with a renewed focus on circular bioeconomy, a novel functionalized lignin-based coating material (FLGe) was developed for the sustained release of nutrients. This innovative approach involved the extraction and sustainable functionalization of lignin through a solvent-free esterification reaction with humic acid─an organic compound widely recognized for its biostimulant properties in agriculture. The primary objective was to fortify the hydration barrier of lignin by reducing the number of its free hydroxyl groups, thereby enhancing release control, while simultaneously harnessing the agronomic benefits offered by humic acid. After confirming the synthesis of functionalized lignin (FLGe) through 13C NMR analysis, it was integrated at varying proportions into either a cellulosic or starch matrix. This resulted in the creation of five distinct formulations, which were then utilized as coatings for diammonium phosphate (DAP) fertilizer. Experimental findings revealed an improved morphology and hardness (almost 3-fold) of DAP fertilizer granules after coating along with a positive impact on the soil's water retention capacity (7%). Nutrient leaching in soil was monitored for 100 days and a substantial reduction of nutrients leaching up to 80% was successfully achieved using coated DAP fertilizer. Furthermore, to get a fuller picture of their efficiency, a pot trial was performed using two different soil textures and demonstrated that the application of FLGe-based SRFs significantly enhanced the physiological and agronomic parameters of wheat, including leaf evolution and root architecture, resulting in an almost 50% increase in grain yield and improved quality. The results proved the potential of lignin functionalization to advance agricultural sustainability and foster a robust bioeconomy aligning with the premise "from the soil to the soil".

Biodegradable maleic–itaconic polymer‐coated phosphatic fertilizer improved phosphorous recovery in calcareous soil

AbstractBackgroundThe poor nutrient recovery of phosphatic (P) fertilizers in calcareous soils is a serious worldwide problem resulting in sub‐optimal P use efficiency. This is mainly attributed to P fixation with calcium (Ca) and magnesium (Mg) ions in the soil solution. As a result, most of the applied P (in the form of fertilizer) becomes insoluble or immobilized in soil due to complex edaphic processes, making it unavailable to plants. Polymer‐coated fertilizers are relatively new approaches to minimizing P‐fixation. However, concerns have been recently raised on the environmental effects of synthetic polymers and microplastic loads in agroecosystems.AimHere we developed and investigated the effectiveness of biodegradable polymer‐coating on commercial diammonium phosphate (DAP) fertilizer to improve P availability in the soil, hence making P more accessible for plant uptake.MethodsThe polymers were coated on DAP fertilizer granules, and two products based on increasing polymer concentration (namely, C‐1 and C‐2, respectively) were achieved. The coated and uncoated DAP granules were characterized for surface properties to confirm the appropriate coating of polymers using scanning electron microscopy (SEM) and crushing strength by a universal telson machine. The biodegradable polymer‐coated C‐1 and C‐2 fertilizers were tested for P availability compared to commercial DAP using spinach as a test plant.ResultsThe SEM micrographs indicated a uniform coating of biodegradable polymers on DAP granules. Application of C‐1 increased the plant's fresh and dry biomass (+10.71% and +18.09%) over commercial DAP, respectively. The C‐1 application increased the N, P, and K uptake by +24.9%, +66.7%, and +11% over commercial DAP. In contrast, C‐2 produced less biomass than C‐1 due to relatively less nutrient uptake and different concentrations of ingredients in C‐2.ConclusionTogether, our results showed that the novel biodegradable polymer approach has demonstrated the potential to improve P recovery and agronomic yield in alkaline soils.

Effect of BioNiK-Phos and Phosphorus-based fertilizers on yield of hybrid sunflower in Northern Uganda

The sunflower oil seed industry is one of the promising business sectors in Uganda for both domestic and export markets. Both open-pollinated varieties and hybrids are grown in Uganda. Average yields of open-pollinated varieties in farmers’ fields range from about 750-900 kg ha-1 and hybrids about 2,000 kg/ha. For high production and productivity, sunflower requires fertilizers. The objective of this study was to establish the effects of BioNik-Phos and di-ammonium phosphate (DAP) fertilizers micro-dosing on yield of sunflower hybrid (PAN 5057) in Northern Uganda in 2021b and 2022a seasons. Field experiments were laid using a randomized complete block design (RCBD) with 4 replications per location in 3 locations in Alebtong District (Abako, Aloi and Angeta). There were significant (P < 0.05) differences in sunflower yields across treatments in all the three locations (Abako: 1,250-3,524 kg ha-1, Aloi: 1,274-3,488 kg ha-1 and Angeta: 1,238-3,369 kg ha-1) in 2021 with or without micro-dosing with BioNiK-Phos and DAP fertilizer. A similar trend was recorded for 2022a season (Abako: 1,268-3,500 kg ha-1, Aloi: 1,357-3,607 kg ha-1 and Angeta: 1,286-3,417 kg ha-1). The effect of DAP fertilizer micro-dosing on sunflower hybrid productivity was three folds in both years. BioNiK-Phos effect was, however, not significantly different (P < 0.05) from the control. This is the first report of the effect of BioNiK-Phos and DAP fertilizers micro-dosing of sunflower in Northern Uganda.

Poly(ε-caprolactone)-grafted-chitosan copolymers: Synthesis and use as tunable and biodegradable coating for water soluble fertilizers

The urgent need for efficient agriculture to increase crop and food has fueled the development of coated fertilizers with a slow-release kinetics, water economy and full degradability to avoid negative environmental impact. In this context, we herein report the synthesis of poly(ε-caprolactone) (PCL) grafted from chitosan (CS) as a new class of biodegradable coating materials. The CS-g-PCL were prepared following a one-pot, two-step strategy, in which the primary amines of CS first react with ε-caprolactone (CL) to form CL-oligomers linked to CS via amide bonds terminated with hydroxyls, which together with the native hydroxyls of CS initiate the ring-opening polymerization of CL after addition of Sn(C ≡ CPh)4 as catalyst. Owing to the great stability of the used catalyst, the high molar mass of PCL grafted onto CS was successfully obtained under trivial open-air conditions. Different copolymers (CS-g-PCL) were prepared by varying the CS content. The structural characterization of CS-g-PCL was carried out using FTIR, 1H NMR, X-ray diffraction, contact angle and size exclusion chromatography (SEC) while the thermal and mechanical characterization of the prepared CS-g-PCL were compared to the neat PCL. Next, using a laboratory rotary drum, CS-g-PCL was implemented to uniformly coat granular diammonium phosphate fertilizer (DAP). Consequently, the kinetic releases of nitrogen and phosphorus were significantly delayed compared to that observed from uncoated DAP (conventional fertilizers). Finally, the degradation of CS-g-PCL was examined under aerobic conditions and showed a significant increase in their biodegradability with respect to neat PCL.

Effect on biomass production and phosphorus use efficiency of maize by using citric acid amended di-ammonium phosphate fertilizer

Phosphorus (P) is a critical factor influencing maize (Zea mays L.) development and yield. To explore the influence of P on maize growth, a pot experiment was conducted during the summer of 2021. There were five treatments T1 = No DAP/CA, T2 = 5 ml (80 mg kg−1 soil) DAP, T3 = 5 ml (120 mg kg−1 soil) DAP, T4 = 5 ml (80 mg kg−1 soil) DAP and 2 mM citric acid, T5 = 5 ml (120 mg kg−1 soil) DAP and 2 mM citric acid. Citric acid-amended P fertilizers (i.e., CA and DAP) exhibited significant effects (p < 0.05) on all the parameters studied in comparison to the sole application of DAP. Among phosphorus fertilized treatments, the DAP 120 + CA produced significantly higher biomass yield (16.37 g pot−1), while sole DAP 80 produced lower biomass (10.61 g pot−1); the DAP 120 + CA produced significantly higher plant length (34.273 cm), while sole DAP 80 produced lower plant length (30.467 cm); DAP 80 + CA produced significantly higher phosphorus recovery (25.583%), while sole DAP 120 produced lower phosphorus recovery (19.863%); DAP 120 + CA showed significantly higher phosphorus use (69.565 mg plant-1), while sole DAP 80 showed lower phosphorus use (39.154 mg plant-1); the highest total PUE (40.503%) was recorded in DAP 120 + CA treatment, while sole DAP 80 treatments showed lower PUE (22.743%); and the highest PCN (4.25 mg g-1) was recorded in DAP 120 + CA treatment while sole DAP 80 treatments showed lower PCN (3.69 mg g-1). In conclusion, the use of citric acid-amended P fertilizers (CA and DAP) significantly improved all parameters studied, compared to the sole application of DAP. The DAP 120 + CA treatment showed the highest values for biomass yield, plant length, phosphorus recovery, phosphorus use, total PUE, and PCN, while the sole DAP 80 treatment showed lower values for these parameters. The findings suggest that growing maize using citric acid-amended DAP could be more beneficial to get a higher crop yield of maize. Thus, fertilizer application in maize agriculture can be a technique for boosting both economic and environmental profitability.

Response of the growth and survival of tree species planted in a degraded land with a supplement of diammonium phosphate (DAP) fertilizer

AbstractDegraded lands pose significant challenges for tree establishment and growth due to poor soil quality and limited nutrient availability. This research aims to explore the potential of using DAP (diammonium phosphate) fertilizer as a supplement for enhancing the survival and growth of tree species in degraded lands; Casuarina equisetifolia L., Grevillea robusta var. robusta R.Br., and Olea europaea subsp. cuspidata (Wall. &amp; G. Don). To achieve the objectives, seedlings of the species were planted in degraded land using a randomized complete block design (RCBD), with a supplement of DAP fertilizer. Six replications, each consisting of 20 seedlings, were used for each of the species with the DAP treatment. The survival and growth data were collected from January 2015 to May 2022. One‐way ANOVA, t‐test, and mean survival percentage were used for data analysis. The results revealed that the mean final survival percentage of C. equisetifolia that received DAP fertilizer (73.6%) was higher than that of C. equisetifolia without fertilizer (44.4%). The statistical t‐test also showed significant differences between the mean survival percentages of C. equisetifolia planted with a supplement of DAP and without fertilizer (p = 0.033). The mean survival percentage of O. europaea and G. robusta, whether fertilized or not, was poor (0%–7%). The one‐way ANOVA result showed significant differences in both fertilized and unfertilized seedlings among the C. equisetifolia, G. robusta, and O. europaea species (p &lt; 0.001). The dry biomass of C. equisetifolia grown with a supplement of DAP fertilizer and the unfertilized was 15.4 kg/tree and 11.2 kg/tree. The t‐test result revealed no significant differences in the dry biomass of the C. equisetifolia grown with a supplement of DAP fertilizer and without fertilizer. Finally, it is concluded that the effect of DAP fertilizer on the growth and survival of the species is species‐specific.

Optimizing Phosphorus Fertilizer Use on the Loess Plateau: Impact on Soil Properties and Crop Production Efficiency

Various phosphorus (P) fertilizers are commonly utilized in agricultural production on the Loess Plateau. However, there exists a widespread issue of improper matching between P fertilizers, crop types, and soil types. This study proposes a scientifically based approach to managing phosphate fertilizer through a matching experiment. A field experiment was conducted to investigate the effects of different P fertilizers on soil P profiles in a wheat–corn rotation between October 2017 and September 2021. The experiment adopted a randomized block design. P fertilizer was applied as a basal fertilizer at rates of 115 kg P2O5 ha−1 during the wheat season and 90 kg P2O5 ha−1 during the maize season. Nitrogen (N) fertilizer application rates were 120 kg N ha−1 for wheat and 180 kg N ha−1 for maize. N fertilizer was divided into two applications, with 60% applied at pre-planting and 40% at the jointing stage of wheat or the V12 stage of maize. P fertilizer variants utilized in the study included ammonium dihydrogen, ammonium phosphate, calcium-magnesia phosphate fertilizer, calcium superphosphate, and ammonium polyphosphate. The transformation process of phosphate was examined, revealing that the commonly considered dominant diammonium phosphate fertilizer was not the optimal choice in this production system. Ammonium polyphosphate, calcium superphosphate, and ammonium dihydrogen were deemed more suitable for application in Loess soil. Furthermore, an analysis was conducted on the relationship between P fractions, soil properties, and soil Olsen-P. This research emphasizes the significance of strategic phosphate fertilizer use in agriculture to ensure efficient production and to help address the global P scarcity.

Alternative Starter Fertilization Strategies in Maize (Zea mays L.) Cultivation: Agronomic Potential of Microgranular Fertilizer and Plant Growth-Promoting Microorganisms and Their Impact on the Soil Native Microbial Community

Phosphorous (P) starter fertilization can increase maize (Zea mays L.) yield. Widespread application in soils with sufficient P availability leads to environmental risks. Subsequently, alternative strategies to support the maize plant’s early development are needed to lower P surpluses. Here, we conducted field experiments comparing standard starter fertilizer diammonium phosphate (DAP) (20.1 kg P ha−1) to microgranular fertilizer (MG) (2.4 kg P ha−1) and combined in-furrow inoculation with Bacillus atrophaeus and mycorrhizal fungi (Rhizoglomus irregulare, Funneliformis mosseae, and Funneliformis caledonium), alone and in combination. The soil microbial community inside and between the maize rows was monitored by quantitative PCR (qPCR)-based quantification of eight fungal and bacterial groups. The yield did not vary between fertilization with DAP or MG and no fertilizer control. The combined microorganism inoculum (MO), however, enhanced the yield by 4.2%. The soil microbial community composition was not affected by the MO application. However, on one field site and inside the rows, it leads to a significant increase in overall microbial gene copy numbers by 9.3% and a significant decrease in the relative abundance of the bacterial phylum of Bacillota (Firmicutes) by 18%. The in-furrow MO application is thus a promising option for starter fertilizer replacement.

Bio-Organically Acidified Product-Mediated Improvements in Phosphorus Fertilizer Utilization, Uptake and Yielding of Zea mays in Calcareous Soil.

The demand for a better agricultural productivity and the available phosphorus (P) limitation in plants are prevailing worldwide. Poor P availability due to the high pH and calcareous nature of soils leads to a lower P fertilizer use efficiency of 10-25% in Pakistan. Among different technologies, the use of biologically acidified amendments could be a potential strategy to promote soil P availability and fertilizer use efficiency (FUE) in alkaline calcareous soils. However, this study hypothesized that an acidified amendment could lower soil pH and solubilize the insoluble soil P that plants can potentially uptake and use to improve their growth and development. For this purpose, the test plant Zea mays was planted in greenhouse pots with a recommended dose rate of 168 kg ha-1 of P for selected phosphatic fertilizers, viz., DAP (diammonium phosphate), SSP (single superphosphate), and RP (rock phosphate) with or without 2% of the acidified product and a phosphorus solubilizing Bacillus sp. MN54. The results showed that the integration of acidified amendments and PSB strain MN54 with P fertilizers improved P fertilizer use efficiency (FUE), growth, yield, and P uptake of Zea mays as compared to sole application of P fertilizers. Overall, organic material along with DAP significantly improved plant physiological-, biochemical-, and nutrition-related attributes over the sole application of DAP. Interestingly, the co-application of RP with the acidified product and MN54 showed a higher response than the sole application of DAP and SSP. However, based on our study findings, we concluded that using RP with organic amendments was a more economically and environmentally friendly approach compared to the most expensive DAP fertilizer. Taken together, the current study suggests that the use of this innovative new strategy could have the potential to improve FUE and soil P availability via pH manipulation, resulting in an improved crop productivity and quality/food security.

Herbage Yield Evaluation of Pennisetum purpureum Grass Genotypes

This trial was conducted to assess the agronomic traits and forage dry matter yield of six Pennisetum purpureum grass genotypes in the great rift valley of Ethiopia. The experiment was carried out for four consecutive years in a randomized complete block design with three replications. Diammonium phosphate (DAP) fertilizer at the rate of 100 kg/ha was uniformly applied at planting and additionally, urea at the rate of 50 kg/ha was top dressed after each forage harvesting. Data on plant height, tiller number, dry leaf stem ratio, and forage dry matter yield were analyzed using the general linear model procedures of SAS, and the least significant difference was used for mean comparisons. Combined analysis indicated that the tested genotypes varied significantly (P&lt;0.05) for plant height at harvest, number of tillers per plant, dry leaf stem ratio, and forage dry matter yield. Genotype 16788 gave the longest mean plant height while the standard check (Zehone-03) gave the shortest value. The highest mean number of tillers per plant was recorded for genotype 14983 followed by 16788, Zehone-03, 16808, and 14984 genotypes, respectively while the lowest was recorded for genotype 15743. The highest dry leaf stem ratio was measured from genotype 14983 and Zehone-03 followed by 14984, 15743, and 16808 genotypes, respectively while genotype 16788 gave the lowest value. Genotypes 14983 and 15743 gave the highest herbage yield while the lowest was from genotype 16808 and standard check (Zehone-03). In general, P. purpureum grass genotypes showed variations in terms of agronomic performance and herbage yield in the study area.

Selection of best compound fertilizer amended potting mixture for successful growth of black pepper (&lt;em&gt;Piper nigrum l.&lt;/em&gt;) hybrid (“Dingirala”) nursery plants

Black Pepper, Piper nigrum L.) is a perennial, evergreen, climbing vine and it is widely used as a spice and flavoring agent in the food industry and ayurvada medicine throughout the world. Therefore, continuous supply of pepper is important for the sustainability of these sectors. Pepper is usually propagated vegetatively using stem cuttings. Cuttings are planted in polythene bags filled with a mixture of equal parts of topsoil, cow dung, sand, and coir dust. Scarcity of cow dung and expensiveness resulted with huge demand are the limiting factors in commercial production of pepper. Incorporation of nitrogen and phosphorus containing fertilizers to potting mixture in the absence of cow dung may at least supply plant nutrients which highly essential for early growth of plants. Therefore, this study was carried out to investigate the effect of different compound fertilizer for nursery plants of P. nigrum L, hybrid “Dingirala” in the absence of cow dung in the potting mixture. Four different levels (1, 2, 3, 4 g per pot) of four different compound fertilizers were taken as treatments such as T1- Yara Complex (N:P:K 12:11:18), T2- Yara Grower ( N:P:K 21:7:14), T3- NPK Balance (N:P:K 15:15:15) K as SOP, T4- NPK Balance (N:P:K 15:15:15) K as MOP and T5 a phosphate fertilizer Di-ammonium phosphate (DAP) (N:P:K 18:46 :0). All were mixed into a modified potting mixture of topsoil: sand: coir dust 2:1:1 without cow dung. Control was the potting mixture already recommended by Department of Export Agriculture (top soil: sand: coir dust: cow dung, 2:1:1:1) without inorganic fertilizer. Each treatment contained three replicates per treatment. Complete Randomized Block Design (RCBD) was the experimental design and each block consisted with 50 plants. Two nodal cuttings of Black pepper hybrid Dingirala were planted and maintained in a propagator under a net house at central research station Matale (IM3a). After 105 days from establishment, survival percentage, growth parameters such as shoot length (cm), number of leaves and shoot dry weight (g) were measured. Soil parameters such as soil pH and EC and total N%, P% and K% of tissues were analyzed. Significantly highest (P&lt;0.05) survival rate (91%) was recorded from recommended potting mixture used as control in this experiment and cuttings treated with 1g of Di-ammonium phosphate. Significantly highest (P&lt;0.05) shoot length (39.1cm) was recorded from cuttings treated with 1g of Yara complex fertilizer (N:P:K 12:11:18) and Significantly highest (P&lt;0.05) number of leaves (9.0) was recorded from cuttings treated with 1g of DAP fertilizer.Therefore, cuttings planted with top soil: sand: coir dust: cow dung, 2:1:1:1 is the best potting mixture and in absence of cow dung with normal potting mixture with 1g of Di-ammonium phosphate excelled all compound fertilizers in terms of overall growth, soil and leaf nutrient parameters of Hybrid "Dingirala" pepper nursery plants over the first 105 days after establishment.

Effects of Variety and Seeding Rate on Performance of Sweet Lupin (Lupinus angustifolius) at Holetta, in the Central Highlands of Ethiopia

The study was executed to evaluate the agro-morphological and nutritional performance of four narrow-leafed blue sweet lupin varieties (Australian lupin, Probor, Sanabor, and Vitabor) sown with five seeding rates (60, 70, 80, 90, and 100 kg/ha) during the main cropping seasons of 2014 and 2015 at Holetta in the central highlands of Ethiopia. Randomized complete block design replicated three times in factorial arrangements was used for experimenting. The lupin varieties were sown in rows with an inter-row spacing of 30 cm. At sowing, diammonium phosphate fertilizer at the rate of 100 kg/ha was uniformly applied for all treatments in both years. Data were collected on plant height, dry matter yield, number of pods per plant, number of seeds per pod, seed yield, and nutritive value. All measured data were subjected to analysis of variance using procedures of SAS general linear model. The result revealed that plant height, number of pods per plant, and number of seeds per pod of lupin varieties were significantly (P&lt;0.001) affected by experimental years. The varietal difference was the major cause of variation (P&lt;0.05) for dry matter yield, the number of pods per plant, and seed yield. The Sanabor, Probor and Vitabor varieties had 38, 23, and 20% dry matter yield advantage over the introduced Australian lupin variety, respectively. The Sanabor variety which produced the highest seed yield had 25, 17, and 14% seed yield advantages over Vitabor, Australian lupin, and Probor variety, respectively. The seed yield performance of lupin varieties was positively correlated with the number of pods per plant while it was negatively correlated with the number of seeds per pod. The dry matter yield and number of seeds per pod were also significantly (P&lt;0.05) affected by seeding rates of lupin varieties. The dry matter yield of lupin varieties increased with increasing seeding rates indicating the tested lupin varieties had a low tillering performance. The number of seeds per pod of lupin varieties decreased with increasing seeding rates. On the other hand, the nutritive values did not differ significantly (P&gt;0.05) among the tested lupin varieties. However, Vitabor variety gave better CP and IVDMD followed by Australian lupin while Probor variety gave the lowest CP and IVDMD. Vitabor variety which exhibited better ash, CP, and IVDMD contents produced the lowest NDF, ADF, and ADL contents when compared with other varieties. Generally, Sanabor and Probor varieties had better forage dry matter yield and seed yield but Vitabor and Australian lupin had relatively better nutritive values. For forage production, lupin varieties should be sown with the highest seeding rate (100 kg/ha) while the lowest seeding rate (60 kg/ha) is recommended for seed production. However, this research should be done across locations and over years to prove the above-recommended seeding rates for forage and seed productions in the study area and similar agro-ecologies. Keywords: dry matter yield, herbage quality, plant height, pod number, seed yield, seeding rate.

Phosphorus Uptake of Oil Palm Leaves on the Axillary Application of Diammonium Phosphate Fertilizer

Fertilization costs for almost all oil palm plantation companies range from 40-60% of the total plant maintenance costs. Farm fertilizer consumption and world fertilizer prices for the three main macronutrients increase yearly, but the use efficiency is low. Meanwhile, pressure came from environmentalists regarding the effects of pollution by excessive use of fertilizers. Application of fertilization through axillary oil palm midrib is expected to overcome inefficiency. This study examined the phosphorus uptake of three-year-old oil palm leaves on the application of diammonium phosphate fertilizer through two positions of the axil, the top and bottom, with four dosage levels, namely 200. 250. 300 and 350 grams per tree. The split-plot design method was used in the research conducted at PT Bumitama Gunajaya Agro oil palm plantation, West Kalimantan. The results showed that Phosphorus uptake was relatively the same in all leaf axil positions and doses and control with the highest dose of 350g/tree through the soil. The results indicate that fertilization of oil palm is possible to do through any axils with a lower amount than it through the soil.

Impacts of U.S. countervailing duties on phosphate fertilizers

AbstractCountervailing duties are a trade policy instrument by which importing governments tax imports that are found to benefit from foreign subsidies. Thus, in effect, these duties attempt to remedy market distortions generated by foreign subsidies by further distorting market mechanisms. On March 11, 2021, the U.S. International Trade Commission issued duties ranging between 19.97% and 47.05% on Moroccan phosphate imports upon finding that Moroccan exports had been receiving unfair government subsidies. In this research, we estimate the impacts of these duties on U.S. diammonium phosphate and triple superphosphate fertilizers, as well as long‐run downstream prices of five U.S. row crops with the largest phosphate usage. Using these results, we assess the implications for gross receipts in the U.S. fertilizer industry and gross margins for American farmers. We also calculate the implied change in expenditure for agricultural end users. We find that the countervailing duties have increased U.S. phosphate fertilizer prices by approximately 34% over counterfactual levels. This corresponds to an expected downstream price response ranging from around 10% for corn, cotton, and sorghum to between 1% and 4% for soybeans and wheat. This market distortion generates a $23 billion increase in gross receipts for a concentrated domestic fertilizer industry while shrinking gross margins for American farmers by 2% and 8% and increasing agricultural user expenditures by approximately $10.84 billion.

Exploiting poly(ε-caprolactone) grafted from hydrohydroxymethylated sunflower oil as biodegradable coating material of water-soluble fertilizers

In the present study, hyperbranched poly(ε-caprolactones) were prepared and used as coating materials to prepare slow release diammonium phosphate (DAP) fertilizer. Firstly, the sunflower oil was hydrohydroxymethylated by one-pot two-step process using Rh(acac)(CO)2 as catalyst, and triethylamine as ligand. Next, the bio-based hyperbranched poly(ɛ-caprolactone) (PCL) were prepared in open air by in-situ ring-opening polymerization of ε-caprolactone using hydrohydroxymethylated sunflower oil as macro-initiator and tetra(phenylethynyl)tin (Sn(C ≡ CPh)4) as catalyst. The structures of the prepared polymers (SFO-O-g-PCL) were confirmed by nuclear magnetic resonance (1H NMR) and the infrared spectroscopy (FTIR). Furthermore, molecular weight values around 20.000 g.mol−1 of PCL grafted in SFO-O-g-PCL were obtained, the thermal stability and morphology of the coated film were also evaluated using thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) respectively. The hydrophobic character of the films prepared from SFO-O-g-PCL was confirmed by measuring the contact angle of water droplets. In the second part, the DAP granular fertilizers were uniformly coated by the prepared material (SFO-O-g-PCL) using a laboratory rotary drum. Then the slow release performance in water of the coated and uncoated DAP fertilizer granules was evaluated by tracking the cumulative concentration of P2O5 released. Thus, it was found that only 10 % of P2O5 was released after 2 h of essay from the coated DAP compared to a total release of P2O5 from uncoated DAP (conventional fertilizer) during the same period. This finding opens a wide perspective to combine the advantages of hydrophobic polyesters and bio-based oils to produce biodegradable coating agents.

Di-ammonium phosphate (DAP) and plant density improve grain yield, nodulation capacity, and profitability of peas (Pisum sativum L.) on ferralsols in eastern D.R. Congo

Sustaining high crop yield and profitability on marginal soils, such as degraded ferralsols, calls for the use of adequate farming practices. In this study, we assessed for four cropping seasons the effect of di-ammonium phosphate (DAP) fertilizer application doses (100, 150, and 200 kg ha−1) and plant densities (100,000, 166,666, and 250,000 plants ha−1) on growth, yield, nodulation capacity, and profitability of two pea varieties (Adei and Rwanda) under degraded ferralsols in eastern Democratic Republic of Congo (DRC). Results showed that pea growth, yield, nodulation, and profitability were significantly affected by the DAP dose and the plant density. Application of 150 kg ha−1 of DAP improved pea yields from 730 to 1720 kg ha−1 and nodulation from 17 to 22 nodules per plant. The number of active nodules was positively correlated with total number of nodules, DAP doses, yield parameters, and plant height. High grain yield was recorded during the long rainy season (1400 kg ha−1) compared to the short one (930 kg ha−1). All DAP doses were profitable according to the agronomic efficiency (AE) and value–cost ratio (VCR) analyses. For improved and profitable pea production on degraded South-Kivu ferralsols, applying 150 kg ha−1 of DAP combined with low plant density are to be recommended and preferably in the long rainy season.

Uptake of heavy metal in wheat from application of different phosphorus fertilizers

IntroductionExcessive use of phosphorus-based fertilizers may lead to environmental damage and accumulation of heavy metals (HMs) in soil and crops. Materials and methodsThis study was carried out to investigate the uptake of heavy metals in wheat grains grown using different phosphates fertilizers using Flame Atomic absorption spectrometer. The experiment comprised of four treatments viz., control and recommended doses of phosphorous using Single Super Phosphate (SSP), Nitro Phosphate (NP) and Di-ammonium Phosphate (DAP) fertilizers. ResultsResults revealed that SSP and DAP application increases concentration of Cr and Pb and Cu respectively in soil samples. All elements except Cd were detected in wheat grains. Cu and Cr concentrations measured in wheat grains grown using fertilized soil were within recommended limits but Pb, Ni and Zn were higher. The trend for the translocation factor of heavy metals was found to be: Cd < Cr < Cu < Ni < Pb < Zn while the daily intake of metals followed the opposite trend i.e Zn > Pb > Ni > Cu > Cr > Cd. The Health Risk Index (HRI) for lead was > 1 for adults and children. ConclusionApplication of phosphatic fertilizer results in the accumulation of HMs in the order; SSP > DAP > NP in soil.

Methylcellulose/lignin biocomposite as an eco-friendly and multifunctional coating material for slow-release fertilizers: Effect on nutrients management and wheat growth

To obviate adverse effects from the non-biodegradability of certain polymer-based slow-release fertilizers (SRFs) and to offset higher operational costs, the use of biopolymers as coating material has recently caught interest in the research circles. The present work aims to design a sustainable coating material based on biodegradable polymers. To this end, Alfa plant was initially exploited as a viable sustainable source for the extraction of lignin (LGe), which was in turn integrated into the development of a three-dimensional cross-linked network, including methylcellulose (MC) as a matrix and citric acid (CA) as a cross-linking agent. Then, the designed coating material was applied onto Di-ammonium Phosphate (DAP) and Triple Superphosphate (TSP) water-soluble fertilizers in a rotating pan machine. Chemical, physical, and biodegradation studies have confirmed that the coating material is environmentally-friendly. Nutrients release experiments in water as well as in soil environments have proved the effectiveness of the MC and MC/LGe coating layers in delaying the nutrients discharge. Besides, the nutrients release from coated DAP and TSP lasted longer than 30 days. Furthermore, the coating film enhanced the fertilizers mechanical resistance and boosted the soil water retention capacity. The agronomic evaluation has also confirmed their remarkable potential in enhancing wheat leaf area, chlorophyll content and biomass, in addition to the roots architecture and the final fruiting efficiency. These results showed that this hybrid composite could be used as an efficient coating material to produce slow-release fertilizers with multifunctional performances.

Polymethyl methacrylate-g-carboxy-methylcellulose as an amphiphilic coating material for slow-release fertilizer

In the perspective of preparing coating material of water-soluble fertilizer with controlled and slow-release property, polymethyl methacrylate (PMMA) was grafted from carboxymethyl cellulose (CMC) through in-situ polymerization using potassium persulfate (KPS) as initiator. The prepared copolymers (PMMA-g-CMC) were fully characterized using Transform Infrared Spectroscopy (FTIR), Thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC), Dynamic light scattering (DLS), X-Ray diffraction (XRD), Brunauer Emmett Teller (BET), Scanning electron microscopy (SEM) and mechanical tensile testing. The molecular weight (Mn) was also evaluated using the size exclusion chromatography (SEC). Next, conventional water-soluble diammonium phosphate (DAP) fertilizer was coated by the prepared copolymers using laboratory rotary drum. The coating effectiveness was evaluated in terms of its uniformity and thickness. The successfully coated nanomaterials significantly delay the release rate of nitrogen (N) and phosphorus (P) in water and soil, compared to their release using uncoated fertilizers. Finally, aerobic biodegradation of the coating agent was also demonstrated.

IN-SITU WATER HARVESTING TECHNOLOGIES AND FERTILIZER RATES INCREASE MAIZE AND BEAN YIELDS IN THE SEMI-ARID KATUMANI, KENYA

&lt;p&gt;&lt;strong&gt;Background: &lt;/strong&gt;Crop production in the arid and semi-arid lands (ASALs) is constrained by erratic rainfall and poor soil fertility. Therefore, climate smart agriculture mechanisms such as &lt;em&gt;in-situ&lt;/em&gt; rainwater harvesting technologies and recommended fertilizer rates would be vital for ensuring food security.&lt;strong&gt; Objective&lt;/strong&gt;: To evaluate selected &lt;em&gt;in-situ&lt;/em&gt; water harvesting technologies and fertilizer rates on soil water content and yield of maize and beans at KALRO Katumani Research Center in Machakos County, Kenya during the 2019 and 2020 short and long rain seasons, respectively. &lt;strong&gt;Methodology:&lt;/strong&gt; The experiment was established in a randomized complete block design with a split-split plot arrangement, replicated three times, with &lt;em&gt;in-situ&lt;/em&gt; water harvesting technologies comprising of zai pits, ngolo pits, contour furrows and conventional tillage, as the main plots, whereas the split plots were varying rates of fertilizer inputs: Di-ammonium phosphate (DAP), goat manure and control. The split-split plots comprised of maize and beans cropping systems. Soil moisture content was assessed at 4, 8, 12 and 16 weeks after emergence, whilst nutrient uptake, use efficiency and crop yields at physiological maturity. Data was subjected to analysis of variance. &lt;strong&gt;Results: &lt;/strong&gt;Soil moisture, maize and beans yields, nutrient uptake and use efficiency were significantly (p&lt;em&gt; &lt;/em&gt;≤ 0.05) increased by &lt;em&gt;in-situ&lt;/em&gt; water harvesting technologies and fertilizer inputs. Highest soil moisture content was recorded under zai and ngolo pits and lowest in conventional tillage treatments. Ngolo pits recorded higher maize and beans grain yield. Application of DAP fertilizer increased maize and beans grain yield compared to control. Intercropping maize and beans increased grain yield significantly (p&lt;em&gt; &lt;/em&gt;≤ 0.05) compared to sole maize and sole beans. &lt;strong&gt;Implications. &lt;/strong&gt;There is need for promoting a combination of &lt;em&gt;in-situ&lt;/em&gt; rainwater harvesting technologies especially ngolo and zai pits with application of DAP+ manure in semi-arid areas where water is scarce coupled with poor soil fertility. &lt;strong&gt;Conclusion:&lt;/strong&gt; Ngolo and zai pits increased soil water retention capacity while application of DAP fertilizer led to increased crop yield and the study therefore recommends their adoption within the study area and extrapolation to areas of similar conditions. &lt;/p&gt;