NPK Treatment Research Articles

Effects of Organic Matter Addition on Soil Carbon Contents, CO2 Emissions, and Bacterial Compositions in a Paddy Field in South China

Increasing soil organic carbon (SOC) contents and reducing carbon dioxide (CO2) emissions in paddy soil fields can result in positive impacts on climate change mitigation and soil quality. However, SOC accumulation and its microbial driving factors under enhanced fertilization strategies (e.g., organic matter application) are still unclear. Therefore, we investigated the effects of organic matter addition on SOC variations, CO2 fluxes, and their relationships with soil bacterial compositions and functions through a 6-year fertilizer experiment in rice fields involving two fertilization types, namely chemical fertilizer (NPK) and chemical fertilizer combined with organic matter (NPK+OM). The results showed significantly higher and lower SOC contents (p < 0.05) in the 10–20 cm soil layer under the NPK+OM treatment before rice transplanting and after rice harvest, respectively, than those under the NPK treatment. The lower SOC contents after rice harvest might be due to the great nutrient consumption, resulting in higher rice yields in the NPK+OM than those in the NPK treatment by 6.68 to 32.35%. Compared with NPK, NPK+OM reduced the in-situ CO2 fluxes by 38.70–118.59%. However, the ex-situ SOC mineralization rates were not affected by NPK+OM in the 0–10 and 10–20 cm soil layers. The 16S rRNA sequence indicated a significant increase in the abundance of non-singleton amplicon sequence variants (ASVs) in the NPK+OM treatment scenario compared to those in the NPK treatment scenario. The top three most important soil bacterial phylum influenced by NPK+OM were LCP-89, BRC1, and Rokubacteria in April, as well as Firmicutes, Nitrospinae, and BRC1 in July. Soil Actinobacteria was negatively correlated with the SOC contents in April and July. The results of the present study demonstrate the economic and ecological benefits of the organic matter addition in rice production, as well as the contribution of soil bacteria to SOC accumulation and CO2 emission reduction.

Differences in Fine Root Foraging Traits of Two Dominant Tree Species (Cunninghamia lanceolata and Quercus acutissima) in Subtropical Forests

Root biomass and length growth, functional traits, and their responses to soil nutrient availability are crucial for resource acquisition under environmental change. Previous studies have focused on the response of root morphological, architectural, and chemical traits to fertilization, while less attention has been given to root biomass and length growth, as well as mycorrhizal symbiosis, impeding a full understanding of root resource acquisition strategies. Here, using a nutrient addition experiment (control, inorganic, and organic nutrients), we explored the responses of function-based root (absorptive fine roots [AFRs] versus transport fine roots [TFRs]) growth, functional traits (morphological, architectural, and chemical traits), and mycorrhizal colonization of C. lanceolat and Q. acutissim, which are the dominant tree species in subtropical China. The results showed that the fine root biomass and total root length of AFRs for both tree species basically decreased significantly after nutrient addition, but TFRs responded less sensitively than AFRs. Nutrient addition significantly increased the mycorrhizal colonization rate in C. lanceolata but decreased it in Q. acutissima. The diameter of AFRs for C. lanceolata increased significantly, while the branch ratio and branch intensity decreased significantly in both inorganic nutrients (NPK) and organic nutrients (F); however, the opposite response pattern occurred for Q. acutissima. Fine root biomass, total root length, and root nutrient concentration exhibited the most plastic responses to changes in nutrient availability. The magnitude of the plastic response of fine root traits was slightly higher in the NPK treatment than in the F treatment. Our findings suggest that the responses of fine root traits and mycorrhizal fungi to nutrient addition were species-specific: C. lanceolata depended on mycorrhizal fungi for resource acquisition, while Q. acutissima could acquire soil nutrient resources by increasing root branching. The contrasting nutrient acquisition strategies between tree species may facilitate plant species coexistence and distribution under soil nutrient change. Fine root biomass and total root length emerged as more pivotal indicators for nutrient acquisition strategies compared to morphological traits.

Community assembly of organisms regulates soil microbial functional potential through dual mechanisms.

Unraveling the influence of community assembly processes on soil ecosystem functioning presents a major challenge in the field of theoretical ecology, as it has received limited attention. Here, we used a series of long-term experiments spanning over 25 years to explore the assembly processes of bacterial, fungal, protist, and nematode communities using high-throughput sequencing. We characterized the soil microbial functional potential by the abundance of microbial genes associated with carbon, nitrogen, phosphorus, and sulfur cycling using GeoChip-based functional gene profiling, and determined how the assembly processes of organism groups regulate soil microbial functional potential through community diversity and network stability. Our results indicated that balanced fertilization (NPK) treatment improved the stochastic assembly of bacterial, fungal, and protist communities compared to phosphorus-deficient fertilization (NK) treatment. However, there was a nonsignificant increase in the normalized stochasticity ratio of the nematode community in response to fertilization across sites. Our findings emphasized that soil environmental factors influenced the assembly processes of the biotic community, which regulated soil microbial functional potential through dual mechanisms. One mechanism indicated that the high phosphorus levels and low soil nutrient stoichiometry may increase the stochasticity of bacterial, fungal, and protist communities and the determinism of the nematode community under NPK treatment, ultimately enhancing soil microbial functional potential by reinforcing the network stability of the biotic community. The other mechanism indicated that the low phosphorus levels and high soil nutrient stoichiometry may increase the stochastic process of the bacterial community and the determinism of the fungal, protist, and nematode communities under NK treatment, thereby enhancing soil microbial functional potential by improving the β-diversity of the biotic community. Taken together, these results provide valuable insights into the mechanisms underlying the assembly processes of the biotic community that regulate ecosystem functioning.

Effect of Balance and Imbalanced Fertilization on Soil Physical Properties, Growth and Yield of Rice in Chhattisgarh, India

Effect of balance and imbalanced fertilization on soil physical Properties, nutrient uptake, growth and yield of rice in Chhattisgarh was studied under long-term fertilizer experiment during kharif 2019-20 at research farm of Indira Gandhi Krishi Vishwavidyalaya, Raipur (C.G.). The experiment comprised of different levels or doses of NPK fertilizers alone and in combination with zinc sulphate, farmyard manure (FYM), blue green algae (BGA) and green manuring (GM) was laid out in randomized block design with four replications and ten treatments viz. Control, 50% NPK, 100% NPK, 150% NPK, 100% NPK+ZnSO4@ 10kgha-1,100% NP, 100% N, 100% NPK + FYM @5t ha-1, 50% NPK+BGA@ 10kg ha-1 and 50% NPK + GM @40kg ha-1. The results showed that the physical properties like total porosity, gravimetric and volumetric moisture content, hydraulic conductivity, infiltration rate, water stable aggregates and mean weight diameter of the soil were increased, while the bulk density was reduced significantly with the 100% NPK FYM treatment over all other treatments. However, the use of imbalanced (100% N and 100% NP) fertilizer, super optimal (150% NPK) and sub optimal (50% NPK) rate of inorganic fertilizer as compared to the unfertilized control showed significant effect on the physical properties of soil. Integrated nutrient management practice including FYM and recommended dose of NPK showed as best treatment with respect to growth and yield parameters like plant height, no. of tillers and no. of grains as compare to other treatments. The grain (5065 kg ha-1) and straw (7075 kg ha-1) yield of rice was registered higher in 150% NPK treatment followed by 100% NPK FYM treatment (4855 kg ha-1 and 6565 kg ha-1) and lowest in control treatment (2350 kg ha-1 and 2680 kg ha-1).

Potential of Integrated Nutrient Managements (INM) on Nutrient Uptake (N, P and K) by Chickpea

This work estimated the potential uses of NPK by chickpea under using of different combination of bio-fertilizer. The field experiment was conducted at Research Field, Department of Soil Science, JNKVV, Jabalpur (M.P.). The field is located in the south-eastern part of Madhya Pradesh at 23013’ North latitude, 790 57’ East longitudes at an altitude of 393 meter above the mean sea level. The experimental field was well-drained with levelled topography. The experiment was carried out on chickpea (JG-14). The experiment was consists of three main-plot treatments of NPK and six sub-plot treatments of vermicompost and biofetilizers which were replicated three times in a split plot design (SPD) with treatments error was P>0.05 value during analysis. The results revealed that the INM influence directly on NPK (nitrogen, phosphorus and potassium) uptake. The treatment 100% NPK (65.08 and 26.39 kgha-1) with combination vermicompost and Rhizobium+ PSB+KSB+ Trichoderma (biofetilizers) (61.77 and 27.45 kgha-1) highest nitrogen uptake. Phosphorus uptake estimated maximum in treatment of 50% NPK (7.24 and 4.03 kgha-1) with combination vermicompost and biofetilizers (10.03 and 4.92 kgha-1) moreover potassium uptake found highest in 100% NPK (5.10 and 27.11 kgha-1) with vermicompost and biofetilizers (4.92 and 27.80 kgha-1) in grain and stover respectively.

Influence of Organic and Inorganic Fertilizers on Tea Growth and Quality and Soil Properties of Tea Orchards' Top Rhizosphere Soil.

Organic-based fertilizers have been ratified to be effective in ameliorating tea growth and the fertility of soil. However, the effect of integrated fertilization on tea growth and quality and the chemical properties of the soil in tea gardens are unclear. To address this, from 2020 to 2021, five different treatments were carried out in the greenhouse of the Tea Research Institute, Hangzhou, CAAS, including CK (control), NPK (chemical fertilizers), RC (rapeseed cake), NPK+B (chemical fertilizer + biochar), and NPK+RC, to investigate the effects of different fertilizations on soil chemistry and tea growth and quality. The results indicated that NPK+B and NPK+RC significantly improved the different amino acid and catechin concentrations in the young shoots, stems, and roots of the tea compared to the CK. The plant growth parameters, e.g., the plant height, no. of leaves, mid-stem girth, and fresh weights of stems and leaves, were significantly increased with integrated fertilization (NPK+B and NPK+RC) compared to the CK and solo organic and inorganic fertilizers. The chlorophyll contents (Chl a, Chl b, and Chl a+b) were generally higher with NPK+RC than with the CK (37%, 35%, and 36%), RC (14%, 26%, and 18%), and NPK (9%, 13%, and 11%) treatments. Integrated fertilization buffered the acidic soil of the tea garden and decreased the soil C:N ratio. NPK+RC also significantly increased the soil's total C (31% and 16%), N (43% and 31%), P (65% and 40%), available P (31% and 58%), K (70% and 25%), nitrate (504% and 188%), and ammonium (267% and 146%) concentrations compared to the CK and RC. The soil macro- (Mg and Ca) and micronutrients (Mn, Fe, Zn, and Cu) were significantly improved by the RC (100% and 72%) (49%, 161%, 112%, and 40%) and NPK+RC (88% and 48%) (47%, 75%, 45%, and 14%) compared to the CK. The chlorophyll contents and soil macro- and micronutrients were all significantly positively correlated with tea quality (amino acids and catechin contents) and growth. These results indicated that integrated fertilization improved the soil nutrient status, which is associated with the improvement of tea growth and quality. Thus, integrated nutrient management is a feasible tool for improving tea growth, quality, and low nutrient levels in the soil.

The interaction between selenium and other elements in soil and rice roots shaped by straw and straw biochar regulated the enrichment of selenium in rice grain.

The absorption and transport of selenium (Se) in rice depend on the shared transport proteins and channels with other elements. However, the interactions between Se and other elements within the soil-rice system and their relationship with Se-enriched rice are still not well understood. Hence, we conducted pot experiments to investigate the transformation of Se forms in soil and the absorption and enrichment of Se in rice, which varied with other elements influenced by straw and straw biochar returning in Se-rich red paddy soil. Partial least squares path modeling (PLS-PM) analysis was carried out to reveal the interaction between Se and other elements and the crucial processes in Se enrichment in rice grains. The results showed that the incorporation of straw and straw biochar into the fields increased the content of soil-soluble Se (SOL-Se) but significantly decreased the content of iron-manganese oxide-bound Se (FMO-Se) and organic matter-bound Se (OM-Se). Moreover, the rise in the soil-bioavailable Se was mainly attributed to the activation of FMO-Se and OM-Se. Compared with the NPK treatment, the contents of Se in rice grain were increased by 69.22% and 38.09%, under straw and biochar returning, respectively. However, the contents of Se in the leaves decreased. Variation partitioning analysis (VPA) indicated that the migration of Se in rice plants was significantly influenced by differences in rice tissues and their interactions with other nutrients [nitrogen (N), phosphorus (P), potassium (K), and Se], explaining 51.5% and 35.3% of the variations in Se content in different rice parts, respectively. The PLS-PM analysis demonstrated that the absorption of Se by rice roots and its transportation from the leaves to grains were crucial processes affecting Se enrichment in rice. However, these processes were modulated by the interaction between soil properties and root nutrients (N, P, and Se) induced by straw and straw biochar incorporation. The present study provides further understanding of the main factors and key processes in regulating Se absorption and transformation in the soil-rice system to more efficiently utilize Se-rich paddy fields through agricultural management measures.

Pertumbuhan Tanaman Tomat (Solanum lycopersicum) dengan Media Abu Terbang (Fly Ash) dan Abu Dasar (Bottom Ash)

The use of fly ash and bottom ash as a plant medium can reduce waste from burning coal. The ash waste contains micro and macro nutrients that plants can use for growth. The ash contains the elements Na, K, Ca, Mg, Cu, Zn, and MN. This research aims to determine the effect of fly ash, bottom ash, and their combination on the growth of tomato plants (Solanum lycopersicum). This research used RAL (Completely Randomized Design) with 12 factors and 3 replications, namely k0 (negative control, not given anything), k1 (positive control, given urea fertilizer), a1 (400 g/polybag fly ash), a2 (800 g/polybag fly ash), a3 (1200 g/polybag fly ash), b1 (400 g/polybag base ash), b2 (800 g/polybag base ash), b3 (1200 g/polybag base ash), ab1 (200 g/polybag fly ash + 400 g/polybag fly ash), ab2 (400 g/polybag fly ash + 200 g/polybag fly ash), ab3 (600 g/polybag fly ash + 400 g/polybag fly ash), and ab4 (400 g/polybag fly ash + 600 g/polybag fly ash). The observation variable is the growth of tomato plants, including plant height, number of leaves, number of branches, stem diameter and wet weight. The results showed that there was an effect of using fly ash and bottom ash as a planting medium on the growth of tomato plants for 90 DAP in the AB4 treatment. The combination of 400 g/polybag fly ash + 600 g/polybag fly ash gave good results in plant height, number of leaves, number of branches, and fresh weight of tomato plants, but in terms of branch diameter, NPK treatment gave good results.

Variations in crop yield caused by different ratios of organic substitution are closely related to microbial ecological clusters in a fluvo-aquic soil

ContextPartial substitution of chemical fertilizer with organic fertilizer (PSCFOF) can improve soil quality and reduce the overreliance of crop yield on chemical fertilizers. However, the relationship between alterations in crop yield and soil microbial community in response to various substitution ratios is not comprehensively understood. ObjectivesThis study aimed to investigate the impact of PSCFOF on soil nutrient supply, enzyme activity, bacterial and fungal community, and crop yield. MethodsAn 11-year (2009 – 2021) field experiment was carried out in a winter wheat–summer maize double-cropping system with four fertilization regimes (no fertilizer, NF; pure chemical fertilizer, NPK; 30% organic substitution, NPKLM; and 50% organic substitution, NPKHM). Co-occurrence network analysis was applied to examine the importance of ecological clusters and keystone species in controlling microbial activities and crop yields. ResultsThere were no significant differences in soil nutrient contents and annual crop yield between the NPK and NPKLM treatments. However, the NPKHM treatment resulted in significant reductions in crop yield by 9.49%− 16.78%, despite increasing soil organic matter (SOM), total nitrogen (TN), available nitrogen (AN), and available phosphorus (AP) by 9.05%, 7.26%, 11.67%, and 26.62%, respectively. This contrasting effect was primarily attributed to the influence of a specific ecological cluster (module 2), rather than the entire microbial community. Long-term 50% organic substitution would suppress keystone species within module 2, such as Aggregatilinea, Luteimonas, Usitatibacter and Microvirga. These species were specifically correlated with soil carbon enzyme activities, including β-glucosidase, invertase, and dehydrogenase, and contributed significantly and positively to crop yield. ConclusionsOrganic substitution at different ratios altered soil nutrient content, enzyme activities and microbial community in different intensities and directions. Long-term 30% organic substitution could preserve soil fertility and microbial community, leading to stable crop yield; whereas 50% organic substitution could inhibit keystone species, reduce extracellular enzyme activity and ultimately lead to a decrease in crop yield. ImplicationsOur results highlight the importance of ecological clusters within soil microbial co-occurrence network in regulating crop yield, presenting a new perspective on the variations in crop yield resulting from varying ratios of organic substitution.

Impacts of Long-term Application of Fertilizer and Manures on Physico-chemical Properties, Phosphorus Uptake and Crop Yield at Different Growth Stages of Wheat

A field experiment was conducted on wheat in a sandy loam soil (Typic Haplustept) at IARI farm, New Delhi during 2018-19 in a long-term fertilizer experiment to study the physico-chemical properties of soil, crop yield, phosphorus uptake and phosphorus availability. The experiment was designed with seven different treatments, replicated thrice in a randomized complete block design. The treatments details were T1: Control, T2: 100%N, T3: 100%NP, T4: 100%NPK, T5: 150% NPK, T6: 100%NPK+5t FYM and T7: 100% NPK+ Zn-5 kgha-1. The results revealed that pH and electrical conductivity were highest under control and lowest recorded under 100% NPK+FYM. Available phosphorus content at all four stages was wheat significantly greater under NPK+FYM followed by 150% NPK treatment and lowest under nitrogen alone (100% N) and unfertilized treatment (control). Initially available phosphorus in soil ranged from 13.5 to 39.8 and 15.4 to 37.9 kg ha-1 at 0-15 cm and 15-30 cm depth, respectively. At the tillering stage, available P was 20.7 to 43.7 and 16.5 to 38.1 kg ha-1 at 0-15 cm and 15-30 cm depth, respectively. At panicle emergence, it was 24.1 to 48.4 kg ha-1 and 18.6 to 42.3 at 0-15 cm and 15-30 cm depth. At harvest of wheat crop, available P ranged from 20.5 to 41.8 and 16.5 to 39.1 kg ha-1 at 0-15 cm and 15-30 cm depth, respectively. Total phosphorus uptake and crop yield significantly increased under 150% NPK treatment followed by 100% NPK+FYM.

Cassava growth and yield on ultisol of different soil organic carbon content and NPK fertilizer levels

The demand for cassava tuber in Indonesia is high, however, domestic production is still limited therefore increasing production is important. Ultisol soils have the potential for cassava production, but low soil fertility in such soils needs to be improved. The research aimed to evaluate the effect of soil organic carbon (SOC) and NPK fertilizer on the growth and yield of cassava tuber in an ultisol. The experiment was conducted at the Jonggol Experimental Farm, IPB Bogor, West Java from September 2022 to January 2023. The experiment used a split-plot design with three replications. The main plot was SOC level of 1.93 (control), 2, 3, and 4%, and the subplot was NPK 15-15-15 level of 150, 300, 450, and 600 kg ha-1. SOC level was increased through the application of cow manure 0, 3.59, 54.93, and 106.27 tons ha-1 corresponding to SOC levels of 1.93 (control), 2, 3, and 4%, respectively. Results showed that enhancing SOC up to 3% and NPK 300 kg ha-1 were enough to support cassava growth as shown by plant height, stem diameter, and leaf number. The leaf number was the highest in the 3% SOC+150 kg NPK, 2% SOC+300 kg NPK or+450 kg NPK, and control+600 kg ha-1 NPK treatment. Leaf greenness was only affected by adding NPK fertilizer; a high greenness value was obtained at NPK level of > 150 kg ha-1 and 300 to 600 kg ha-1 resulting in non-significantly leaf greenness. The status of N and K in the leaves increased by SOC and NPK treatments, while the P status was unaffected. SOC at a level of 3% and NPK at a level of 150 kg ha-1 stimulated cassava to produce the highest fresh tuber weight (1.85 kg per plant) at 4 months after planting. Cassava productivity in ultisol soil can be increased by applying cow manure of 54.93 tons ha-1 to enhance SOC up to 3% combined with NPK of 150 kg ha-1.
 Keywords: Extensification; food security; intensification; tuber production; nutrient uptake

Enhancing photosynthesis and root development for better fruit quality, aroma, and lessening of radioactive materials in key lime (Citrus aurantifolia) using Trichoderma harzianum and Bacillus thuringiensis

The present study was conducted to investigate the effects of Trichoderma harzianum and Bacillus thuringiensis alone or with gradual levels of NPK on photosynthesis, growth, fruit quality, aroma improvement and reduced radionuclides of key lime fruits. The lemon seedlings were treated with (T0) without fertilizers as control, (T1) 100g of NPK at 100%, (T2) 5 g of Trichoderma. harzianum at 50% + 50 g of NPK at 50%, (T3) 5 g of Bacillus thuringiensis at 50% + 50 g of NPK at 50 %, (T4) 7.5 g of Trichoderma harzianum at 75% + 25 g of NPK at 25 %, (T5) 7.5 g of Bacillus thuringiensis at 75% + 25 g of NPK at 25 %, (T6) 10 g of Trichoderma harzianum at 100 % and (T7)10 g of Bacillus thuringiensis at 100 %. The results showed that T2 increased net photosynthetic rate, stomatal conductance, transpiration rate, internal CO2 concentration, fresh and dry root biomass by 209%, 74%, 56%, 376%, 69.4% and 71.6%, while, T5 increased root volume, root length, and root tip number by 27.1%, 167%, and 67%, respectively over the control trees. The microbial treatments developed cortex, vascular cylinder and tracheal elements of the root. Fruit number, length, diameter, weight, pulp thickness, pulp/peel ratio, juice, total soluble solids (TSS), pigment contents and antioxidant activity increased significantly in the T2 treatment. Vitamin C, total phenols, total flavonoids, and total sugar content increased by 1.59-, 1.66-, 1.44- and 2.07- fold in T5 treated fruits compared to the control. The two microbes increased volatile compounds and decreased radionucleotides in the fruit, moreover, 27 identified and 2 (two) unmatched volatile compounds were identified by GCMS analysis. It is concluded that T. harzianum and B. thuringiensis with 25–50 g NPK treatments improved photosynthesis, root structure, fruit growth, fruit quality, aroma and lessened radionuclides in key lime fruits.

Assessing the Effects of Whey Hydrogel on Nutrient Stability in Soil and Yield of Leucosinapis alba and Hordeum vulgare

Agriculture and related crop production are highly dependent on climate and economic factors, and agricultural intensification is associated with a dramatic increase in the consumption of fertilizers. A significant amount of the elements from the most commonly used fertilizers is degraded and lost due to climatic and environmental factors. The soil application of novel whey-based hydrogel represents an innovative approach toward efficient fertilizing and soil water balance that resonates with the concepts of sustainable agriculture and circular economy of waste products. Results of previous research show the positive effect of whey-based hydrogel on water retention after the various levels of hydrogel have been applied into artificial soil. With a view to verifying the effect of the whey hydrogel on soil quality and related crop cultivation in real conditions, the pot experiment compared two different doses of whey hydrogel with control soil, with the conventional NPK treatment of soil and with a mixing strategy combining the conventional NPK treatment with hydrogel application. The controlled pot experiment was conducted with haplic Cambisol, with white mustard (Leucosinapis alba) and spring barley (Hordeum vulgare) as the testing crops. Soil pH, organic carbon (C), total nitrogen (N), available forms of the essential macronutrients (P, K, Ca, and Mg), and the cation exchange capacity (CEC) were determined in Cambisol samples before and after the experiment. The crop yields of barley and mustard were compared among the various treatments of experimental soils. Results demonstrated that the amendment of whey-based hydrogel increased the bioavailable nutrients’ concentrations, which persisted even after the harvest. The nutritional quick boost after the whey-based (co)-application significantly increased the experimental crop yield.

Responses of Crop and Soil Phosphorus Fractions to Long-Term Fertilization Regimes in a Loess Soil in Northwest China

Contrasting fertilization modifies soil phosphorus (P) transformation and bioavailability, which impact crop P uptake and P migration in the soil profile. A long-term (25-year) fertilizer experiment was employed to investigate crop yield, P uptake and changes in sequentially extracted P fractions in the soil profile, and their relationships on a calcareous soil derived from loess material under a winter wheat and summer maize double-cropping system. The experiment involved seven nutrient management treatments: control (CK, no nutrient input), N, NK, NP, and NPK, representing various combinations of synthetic nitrogen (N), phosphate (P), and potassium (K) applications, as well as combinations of NPK fertilizers with either crop residues (SNPK, where S refers to maize stalk or wheat straw) or manure (MNPK, where M refers to dairy manure). Wheat and maize yields were significantly higher with P input fertilizer relative to the P-omitted treatments. Long-term application of P-containing fertilizers markedly raised the contents of inorganic (Pi) and organic (Po) P fractions at 0–20 cm depth compared with the P-omitted treatments. Moreover, both Pi and Po fractions were markedly higher under MNPK than under NPK and SNPK treatments. For achieving high yield for wheat and maize, the critical contents of labile P were 54 and 63 mg kg−1, and those of moderately labile P were 48 and 49 mg kg−1, respectively, defined by the linear plateau model. In addition, the change points of labile P and moderately labile P were 99 and 70 mg kg−1, above which CaCl2-P content significantly increased. Moreover, long-term P input significantly accumulated different P fractions in the deeper soil layers up to 100 cm, with large portions of organic P being a composite of labile and moderately labile P, especially in MNPK treatment. Our results suggest that excessive P supply with organic manure resulted in massive P accumulation in the topsoil and promoted soil P fraction transformation and availability in the deep soil layers, especially in an organic P form that has often been neglected.

Investigation of nitrogen fixation activity soybeans plants by mineral fertilizers foliar treatment

The results of the study of nitrogen-fixing activity during foliar treatment of vegetative soybean plants with liquid mineral fertilizers containing macro-microelements in various forms in the foothill zone of Kabardino-Balkaria are presented. The object of research is the early ripe soybean variety SK Veda. The soil of the experimental plot is a leached, medium-thick, low-humus, heavy loamy chernozem on carbonate clays, with a humus content in the arable layer of 3.1 %, pHkcl 5.0, mobile phosphorus 7.5 and exchangeable potassium 8.0 mg/100 g of soil. Encrustation of soybean seeds was carried out using a specific film-forming agent based on soybean phosphatides with the inoculant Nitrofix. The results of studies for 2020-2022 are given. with an assessment of the dynamics of the formation of the symbiotic apparatus by the number of nodules (pcs/m2) and by the mass of nodules (g/m2) in ontogeny of the macrosymbiont. The peak of nodule formation in soybean plants of the SK Veda variety fell on the flowering phase. The highest nodulation rates were noted in the control variant: in 2020 - 306 pcs/m2; in 2021 - 408 pcs/m2; in 2022 - 96 pcs/m2. It has been shown that foliar treatment of soybean plants with nutrient deficiency correctors has an impact on nodulation rates, with differences being noted depending on the treatment time. In the variant of Polydon NPK treatment in the primordial leaf phase, the nodulation parameters were minimal in the experiment over the years of the study (86; 216; 56 pcs/m2). Treatment of SK Veda soybean plants in the primordial leaf phase with molybdenum-containing fertilizers ensures the formation of larger nodules. The values of the nodule weight in the flowering phase in the variant of the treatment of Polydon plants with molybdenum in the primordial leaf phase increased by 1.56; 2.09; 1.11 times, respectively, for 2020, 2021, 2022. Nitrogenase activity averaged 26.4-281.6 µg N2/plant.h over the years of the study hour. In the control (inoculation with nitrogen-fixing microorganisms), the activity of nitrogenase was 208.3 µg N2/plant.h. Inoculation of soybean seeds with nitrogen-fixing microorganisms and foliar treatment of plants with Polydon molybdenum increased nitrogenase activity by 35.2-19.1 % and increased protein content by 5.0-3.9 % relative to control, depending on the treatment phase.

PENGARUH PUPUK NPK TERHADAP PERTUMBUHAN DAN HASIL PRODUKSI JAGUNG MANIS (Zea mays saccharata Sturt.) DI LAMPUNG UTARA

Sweet corn (Zea mays saccsharata Sturt.) is one of the plants that is widely produced and a source of food staples in Indonesia, such as processed food, drinks, and so on. The low productivity of sweet corn in North Lampung is caused by the use of excessive doses and the wrong fertilization method. This problem can be overcome by implementing a good cultivation system, including applying fertilization with the right dosage so that plants can produce according to their potential results.The purpose of this study was to determine the effect of NPK fertilizer treatment on the growth and yield of sweet corn at the best dose of NPK fertilizer on the growth and yield of sweet corn. This research was conducted experimentally using RAL (Completely Randomized Design). It consists of one factor with 3 levels, namely K0: Control, K1: Giving NPK 150 kg/ha (1.8 kg/plant plot) K2: Giving NPK 300 kg/ha (3.6 kg/plant plot).The results showed that the NPK treatment had a significant effect on plant height at 30 HST. The stem diameter showed a significant effect when the sweet corn was 30 and 45 HST. The number of leaves shows that NPK fertilizer has no real effect. The length of the cobs with husks, the length of the cobs without husks, the weight of the husked cobs, the weight of the cobs without husks and the weight of the stover showed real results. 

Management of Macro-Nutrients for Sesame (Sesamum Indicum) under Changing Climate Scenarios of Thai Region

Sesame (Sesamum indicum) is an important oil seed crop containing more than 50% quality oil and a good source of protein in the world. Its economic production is governed by its management practices. To find the optimum dose of NPK fertilizer in the sandy loam soils under arid conditions, two-year field experiment was carried out during Kharif season 2021 and 2022 at Adaptive Research Farm (ARF), Karor Zone, Layyah Punjab Pakistan. Five treatments of NPK were used to optimize the NPK for Sesame cultivar TH-6 with three replications. Results showed that the maximum grain yield 765.3 kg ha-1 was recorded in 2021 as compared to 738.6 kg ha-1 in 2022 at ARF, where N113P113K60 (113 kg Urea ,113 kg P2 O5 ,60 kg ha-1 K2 O) was applied. Minimum yield and yield components were produced where NPK were not applied. It was concluded that the application of NPK at the rate of could improve yield and yield components of sesame in the agro-climatic conditions of Karor, Layyah.

Phytoremediation efficacy of Nerium oleander L. for removal of Cd, Ni, and Pb- contaminated soil

A pot experiment was conducted to assess the effectiveness of Nerium oleander L. in phytoremediation of cadmium (Cd), nickel (Ni), and lead (Pb)- contaminated soil. This evaluation included the application of ethylene diamine tetra-acetic acid (EDTA) and a nutrient solution containing NPK. The results revealed that the inclusion of EDTA and NPK, in combination with varying metal concentrations, significantly increased the dry weight of the plants. The results demonstrated that oleander, when aided by EDTA and NPK, exhibited a high capacity to efficiently absorb and accumulate Pb without any amendments. The addition of EDTA increased Pb concentrations in both aerial parts and roots (84.9 mg kg-1 and 80.2 mg kg-1, respectively). For Nickel, in the presence of NPK, the concentration in roots was 80,2 mg kg-1. Cd accumulation was highest in the treatment with 100 mg kg-1 EDTA, reaching 72.9 mg kg-1 in the aerial parts. Particularly, NPK reduced Ni levels in aerial parts, while EDTA enhanced root metal uptake. The Translocation Factor (TF) was greater than 1 for Cd and Ni treatments, indicating oleander's remarkable ability to absorb and accumulate these heavy elements. The treatment involving Pb50+EDTA displayed the highest Bioaccumulation Factor (BAF) value at 1.7. Furthermore, for Pb50, Ni50 and Cd50, the NPK treatment exhibited the highest Bioconcentration Factor (BCF) values, ranging from 0.3 to 1.69. Nerium oleander L. exhibits promise for both Ni phytoextraction and Cd and Pb phytostabilization, suggesting its potential as an effective phytoremediation agent. Future research should focus on optimizing metal uptake conditions and investigating long-term plant health and soil impacts to refine sustainable strategies for mitigating metal pollution in contaminated environments.

Long‐term fertilization regulates dissimilatory nitrate reduction processes by altering paddy soil organic carbon components

AbstractTo enhance rice yields, synthetic nitrogen (N) fertilizers are often applied in rice paddy fields. Under waterlogged conditions, denitrification, anaerobic ammonium oxidation (anammox) and dissimilatory nitrate reduction to ammonium (DNRA) are the main N transformation processes. However, the effects of long‐term fertilization on the dissimilatory nitrate reduction processes remain largely unclear. Here, we investigated rates of denitrification, anammox and DNRA and the abundance of bacterial and nitrate reduction‐related genes (16S rRNA, narG, nirK, nirS, nosZ and hzsB) in rice paddy fields under different fertilization regimes [i.e., non‐fertilization (CK), NPK fertilization (NPK) and NPK fertilization plus straw returning (NPKS)]. The rates of denitrification, anammox and DNRA in the CK treatment were 46.18, 0.35 and 1.29 nmoL N g−1 h−1, respectively, which were significantly (p < .05) increased by 7.32%–27.78%, 2.45–4.12 folds and 1.01–13.23 folds by NPK and NPKS treatments. This was largely consistent with the increased bacterial and nitrate reduction‐related gene abundances in the NPK and NPKS treatments. In addition, NPKS also significantly increased the relative contribution of DNRA to the total nitrate reduction relative to NPK and CK treatments, indicating that NPKS was more beneficial to N retention in the paddy field. Changes in rates of dissimilatory nitrate reduction processes in response to NPK and NPKS treatments were correlated to variations of soil total N, ammonium contents, pH, soil organic carbon (SOC) contents and nitrate reduction‐related genes, among which SOC contents had the highest explanation. Specifically, fulvic‐like compounds, alkyl C and methoxyl and nitrogen‐alkyl C were the key components determining denitrification, anammox and DNRA rates, respectively. Overall, our study suggests that long‐term NPK and NPKS fertilization stimulate rates of dissimilatory nitrate reduction processes mainly by altering soil C components and NPKS is more effective in maintaining soil fertility in the paddy field.

Fertilization Weakens the Ecological Succession of Dissolved Organic Matter in Paddy Rice Rhizosphere Soil at the Molecular Level.

Dissolved organic matter (DOM) is involved in numerous biogeochemical processes, and understanding the ecological succession of DOM is crucial for predicting its response to farming (e.g., fertilization) practices. Although plentiful studies have examined how fertilization practice affects the content of soil DOM, it remains unknown how long-term fertilization drives the succession of soil DOM over temporal scales. Here, we investigated the succession of DOM in paddy rice rhizosphere soils subjected to different long-term fertilization treatments (CK: no fertilization; NPK: inorganic fertilization; OM: organic fertilization) along with plant growth. Our results demonstrated that long-term fertilization significantly promoted the molecular chemodiversity of DOM, but it weakened the correlation between DOM composition and plant development. Time-decay analysis indicated that the DOM composition had a shorter halving time under CK treatment (94.7 days), compared to NPK (337.4 days) and OM (223.8 days) treatments, reflecting a lower molecular turnover rate of DOM under fertilization. Moreover, plant development significantly affected the assembly process of DOM only under CK, not under NPK and OM treatments. Taken together, our results demonstrated that long-term fertilization, especially inorganic fertilization, greatly weakens the ecological succession of DOM in the plant rhizosphere, which has a profound implication for understanding the complex plant-DOM interactions.