Arginine-iron-hexametaphosphate complex as a novel nitrogen plant nutrition reducing nitrate leaching in Scots pine (Pinus sylvestris) seedling production.

SUMMARYLong-term fertilization experiment has been conducted since 1981 to study the effect of soil management practices on soil fertility, soil carbon and nitrogen sequestration, soil culturable microbe counts and crop yields at the Nanhu Experimental Station in the Hubei Academy of Agricultural Sciences (situated in the middle reach of the Yangtze River and the rice–wheat cropping system). The experiment was designed with the following eight treatments: (1) unfertilized treatment: Control; (2) inorganic nitrogen fertilizer treatment: N; (3) inorganic nitrogen plus inorganic phosphorus fertilizer treatment: NP; (4) inorganic nitrogen, inorganic phosphorus plus inorganic potassium fertilizer treatment: NPK; (5) pig dung compost (manure) treatment: M; (6) inorganic nitrogen fertilizer plus manure: NM; (7) inorganic nitrogen, inorganic phosphorus fertilizer plus manure treatment: NPM and (8) inorganic nitrogen, inorganic phosphorus, inorganic potassium fertilizer plus manure treatment: NPKM. The results showed that long-term application of organic manure in combination with inorganic fertilizer significantly (p< 0.05) increased soil organic C concentrations compared with the corresponding inorganic fertilizers alone. Soil organic C contents were significantly (p< 0.05) increased in balanced application of NPK fertilizers in comparison to unbalanced application of fertilizers. After 30 years of experiment, soil organic C and total N sequestration rate averagely were 0.48 t ha−1year−1and 28.3 kg ha−1year−1in the fertilized treatments respectively; nevertheless, it were 0.27 t ha−1year−1and 9.7 kg ha−1year−1in the unfertilized treatment. Application of organic fertilizer in combination with inorganic fertilizer significantly (p< 0.05) increased culturable microbial counts compared with the corresponding inorganic fertilizers alone. The balanced application of NPK fertilizers significantly (p< 0.05) increased culturable microbial counts compared with unbalanced application of fertilizers. The average grain yield of wheat and rice was significantly (p< 0.05) higher in organic manure combined with inorganic fertilizer treatment than in inorganic fertilizer alone and unfertilized control. Therefore, long-term application of organic manure combined with inorganic fertilizer and balanced application of NPK fertilizers could increase soil organic C and total N sequestration, culturable microbial counts and crop grain yields.

When applying municipal sludge according to crop N requirements, the primary aim should be optimizing sludge application rates in order to maximize crop yield and minimize environmental impacts through nitrate leaching. Nitrate leaching and subsequent groundwater contamination is potentially one of the most important factors limiting the long-term viability of sludge application to agricultural soils. This study assessed maize grain yield and potential nitrate leaching from sludge-amended soils, using the SWB-Sci model, based on crop nitrogen requirements and inorganic fertilizer. The following hypotheses were tested using the SWB­-Sci model and 20 years of measured weather data for 4 of the 6 South African agro-ecological zones. Under dryland maize cropping, grain yield and nitrate leaching from sludge-amended soils compared to inorganic fertilizer: (1) will remain the same across agro-ecological zones and sites, (2) will not vary across seasons at a specific site, and (3) will not vary across soil textures. Model simulations showed that annual maize grain yield and nitrate leaching varied significantly (P > 0.05) across the four agro-ecological zones, both for sludge-amended and inorganic fertilizer amended soils. The annual maize grain yield and nitrate leaching from sludge-amended soils were 12.6 t∙ha-1 and 32.7 kgNO3-N∙ha−1 compared to 10.2 t∙ha-1 and 43.2 kgNO3-N∙ha−1 for inorganic fertilizer in the super-humid zone. Similarly, maize grain yield and nitrate leaching varied significantly across seasons and soil textures for both sludge and inorganic fertilizer amended soils. However, nitrate losses were lower from sludge-amended soils (2.3–8.2%) compared to inorganic fertilizer (11.1–26.7%) across all zones in South Africa. Therefore, sludge applied according to crop N requirements has a lower environmental impact from nitrate leaching than commercial inorganic fertilizer. Further validation of these findings is recommended, using field studies, and monitoring potential P accumulation for soils that received sludge according to crop N requirements.

Cultivation of Norway spruce and Scots pine on organic nitrogen improves seedling morphology and field performance

The present study aimed to determine the effect of different container volumes and doses of controlled release fertilizer (CRF) on the morphophysiological aspects of Balfourodendron riedelianum seedlings in the nursery and verify if these responses were replicated in the field. For the production of seedlings in nursery, three container volumes (180 and 280 cm³ polypropylene tubes and 500 cm³ plastic bags) and four doses of CRF (0, 4, 8, and 12 g L-1 of substrate) were tested, and the seedlings were grown for 240 days. At the end of the nursery period, the following parameters were measured: height (H); stem diameter (SD); dry mass of shoot, root, and total; root length; leaf area; and chlorophyll fluorescence. The H/SD ratio and the Dickson Quality Index were calculated. The same treatments were evaluated in the field at 540 days after planting. Survival, height, and diameter increase, aerial dry mass, leaf area, chlorophyll a fluorescence and chlorophyll index (a, b and total) were measured. Basic fertilization using CRF had a positive influence on the production of B. riedelianum seedlings. It is recommended to use a 180 cm³ tube and a dose of 12 g L-1 CRF for the production of seedlings. The results obtained in the nursery for the production of seedlings were confirmed to occur in the field.

This paper uses a translog stochastic frontier model to estimate the relationship between maize yield and an interplay of soil carbon, soil nitrogen and inorganic nitrogen fertilizer using plot-level data collected from smallholder farmers in Dedza and Ntcheu Districts of Malawi in 2013/2014 growing season. One of the covariates in the model is nitrogen applied to a plot from inorganic fertilizers. Farmer use of nitrogen is influenced through participation in a non-random targeted Farm Inputs Subsidy Program (FISP) of the Malawi Government. A control function approach is therefore applied to correct for possible endogeneity of participation in the FISP.Results show that inorganic nitrogen fertilizer has significant positive effect on maize output whereas an increase in soil carbon is associated with low maize output but interaction between soil carbon and soil nitrogen as well as with inorganic nitrogen significantly increases maize output. These results seem to be linked to Carbon to Nitrogen (C:N) ratio in the soil. The accumulation of C beyond the optimal C:N ratio is known to reduce rate of decomposition, nutrient cycling, shoot: root ratio and biomass in grasses including maize. Under such circumstances, increasing nitrogen brings the C:N ratio to beneficial levels. The results further show that inorganic nitrogen is a substitute to labour, seed and land. The substitution relationship suggests that improvements in inorganic nitrogen require reduction in labour, seed use and land. It has further been shown that only 45.03% of the plots have marginal value cost ratios of greater than one which shows that considerable number of plots are not profitable. For 66.20% of the plots, applied inorganic nitrogen fertilizer exceeds optimal levels signifying suboptimal use of the input. The results suggest that inorganic nitrogen is profitable at low levels of application which is largely due to prevailing high nitrogen-maize price ratio. The prominent issue for policy consideration from these results is that soils in Malawi are depleted of nitrogen leading to unfavorably high C:N ratios which negatively impact maize production. Given that nitrogen-maize price ratio is already high in Malawi, farmers will need programs that enhance their access to nitrogen fertilizers at low prices for nitrogen fertilizer application to be profitable. Such programs need to be implemented simultaneously with a package of intensification practices that fix and retain nitrogen in the soil. Keywords: Inorganic nitrogen, Soil carbon, Soil nitrogen, Translog stochastic frontier model, Control function approach DOI : 10.7176/JESD/11-2-04 Publication date: January 31 st 2020

Maize yield response to nitrate leaching at early growth stage under crop and site-specific biosolid application

The excessive use of inorganic nitrogen fertilizers poses significant environmental threats, including nitrate leaching and greenhouse gas emissions. Conversely, organic fertilizers enhance soil microbial activity and long-term fertility. This study investigates the integrated application of organic and inorganic nitrogen fertilizers to optimize soil health and crop productivity while mitigating environmental impacts. A field experiment was conducted over a single maize growing season using a randomized block design. Six treatments were applied: no fertilizer (T1), chemical fertilizer only (T2), 15% (T3), 30% (T4), or 45% (T5) sheep manure combined with chemical fertilizer, and sheep manure only (T6). Soil samples were analyzed for pH, dissolved organic carbon (DOC), nitrate (NO₃⁻), ammonium (NH₄⁺), and the microbial gene abundance of key nitrifiers (AOA, AOB) and denitrifiers (nirK, nirS). The 100% sheep manure treatment (T6) resulted in significantly higher soil DOC (34 ± 4.58 mg/kg) and NO₃⁻ (3.31 ± 0.51 mg/kg) concentrations, promoting enhanced microbial diversity and activity. In contrast, the inorganic-only treatment (T2) yielded the highest grain nitrogen content (9.43 ± 2.24 mg/kg), indicating immediate nutrient availability. Heat map and Principal Component Analysis (PCA) revealed distinct clustering of microbial gene expressions (AOA, AOB, nirK, nirS) in response to fertilization, with high organic inputs fostering a more diverse and active microbial community. Redundancy Analysis (RDA) showed strong correlations between these environmental factors and gene expression. The results demonstrate that integrating organic and inorganic fertilizers creates a synergistic effect. This approach optimizes nutrient cycling by balancing immediate crop availability with long-term soil building. It enhances microbial functional capacity for nitrification and denitrification, thereby improving soil health and reducing potential environmental impacts like nitrate leaching and greenhouse gas emissions. We conclude that the integration of organic and inorganic fertilization is a key strategy for supporting sustainable agricultural productivity.

A field experiment was conducted during 2014 at Universiti Putra Malaysia, Serdang, Malaysia, to evaluate the effect of incorporation of crop residues with supplemental inorganic fertilizers on yield and quality of maize crop. Treatments included an unfertilized control, incorporation of maize residue, soybean residue and a mixture of maize and soybean residue with and without phosphorus and potassium fertilizer and the use of a complete inorganic nitrogen, phosphorus and potassium fertilizer. Results showed that soybean and maize + soybean residue applied without inorganic fertilizers or with inorganic fertilizer (phosphorus and potassium) increased maize yield and enhanced grain quality of maize. However, incorporation of maize residue without supplemental inorganic fertilizer was ineffective in increasing grain cob yield (11,237 kg/ha) and grain quality ( 11.1% protein content, 10.9 o brix sugar content and 4.77% oil content) of the maize crop above that of control (10,323 kg/ha green cob yield, 8.30 % protein content, 9.00 o brix sugar content and 4.77% oil content). The application of soybean residue with supplemental phosphorus and potassium fertilizer gave maize yield (37,290 kg/ha) similar to that of the complete inorganic fertilizer treatment (36,500 kg/ha). Therefore, inorganic nitrogen fertilizer can be replaced with soybean residues without any reduction in maize yield and grain quality.

A field experiment was conducted to assess the effect of farmyard (cattle) manure (FYM) and inorganic nitrogen (N) phosphorus (P) fertilizers on growth and tuber yield of potato (Solanum tuberosum L.). The treatments consisted of factorial com- bination of 4 levels of FYM (0. 10, 20 and 30 t h -1 ) and three levels of inorganic NP fertilizers (0, 33.3%, 66.6% recommended rates) laid out in a Randomized Complete Block Design (RCBD) replicated three times. Results demonstrated that the applica- tion of 20 or 30 t ha -1 FYM + 66.6% of the recommended inorganic NP fertilizers significantly increased total tuber yield over the application of full dose of inor - ganic NP fertilizers without FYM in vertisol whereas in nitosol, the highest level of FYM (30 t ha -1 ) + 66.6% of the recommended inorganic NP fertilizers significantly improved total tuber yield over the application of full dose of inorganic NP fertil- izers without FYM. The application of 10 t ha -1 FYM + 66.6% of the recommended inorganic NP fertilizers and 20 or 30 t ha -1 FYM + 33.3% of the recommended inor- ganic NP fertilizers gave a total tuber yield, which was on par with the tuber yield obtained due to the application of full dose of inorganic NP fertilizer alone, in both soils. Thus, the application of 10 t ha -1 and 20 or 30 t ha -1 FYM resulted in a saving of 33.3% and 66.6% of the recommended NP fertilizers, respectively without sig- nificantly reducing the total tuber.

Organic amendment has long been recognized as an effective approach to improve soil fertility and plant nutrition. Most studies on long-term organic amendment in fields have focused on cereals. The effects of long-term organic amendment on legumes remain largely unknown. Here we studied the impact of organic amendments, including straw and manure on the soil fertility, nodulation, seed yield, and seed quality in a 27-year experiment. The long-term fertilizer treatments were laid out using a randomized complete block design designed with three replications in the first year of experimentation (1990). Fertilization treatments were CK (no fertilization), NPK (inorganic nitrogen, phosphorus and potassium fertilizers), NPKS (Straw together with inorganic N, P, and K fertilizers), and NPKM (manure together with inorganic N, P, and K fertilizers). The layout was subsequently maintained in the following years to clearly understand the effect of long-term application of each treatment. Maize (Zea mays L.)-wheat (Triticum aestivum L.) rotation was the main long-term experiment cropping system from 1990 to 2011; from 2012 it becomes wheat-soybean (Glycine max L.) rotation. We found that NPKS, NPKM, and NPK increased organic matter by 34.7%, 36.24%, and 17.17%, respectively, and total nitrogen by 28.9%, 29.7%, and 25.2%, respectively, in comparison with CK. Organic amendment also increased enzymatic activity of phenol oxidases and β-1,4-glucosidases. The NPKS and NPKM increased soybean yields by 30.8% and 29.6%, respectively, in comparison with NPK alone and CK. The soybean yields significantly correlated with NO3-N, available phosphorus, available potassium and soil organic matter. Both the inorganic fertilizers and organic amendments did not significantly alter soybean nodule number and size. NPKS and NPKM applications significantly reduced fat content by 1.17% and 1.26%, respectively, as opposed to NPK fertilized treatments alone (0.34%), compared with those under CK, but did not affect soybean protein. Overall, the combination of straw returning with inorganic fertilizers and manure with inorganic fertilizers improves soil fertility and increases soybean productivity. However, organic amendments together with inorganic fertilizers might have an undesirable effect on soybean fat content. Organic amendments combined with NPK application have the highest value of protein content and increased nitrogen to the soil. High nitrogen reduced fat and increased protein content. Therefore, rate of N inputs should be adjusted under the application of organic amendments together with inorganic fertilizers in fluvo-aquic soil.

Producers in semi-arid and highland regions have difficulty in increasing diversity in crop rotations due to unfavorable conditions imposed by cool temperatures, inadequate rainfall, and shorter growing periods. In such conditions, some cultural practices that increase productivity such as fertilization appear as a promising alternative. Fertilization and the form of fertilizer have a substantial influence on sunflower (Helianthus annuus L.) seed yield and quality. The objective of this study was to determine the responses of the oilseed sunflower to organic (vermicompost and leonardite) and inorganic (nitrogen and phosphorus) fertilizers, or their combinations in a highland environment. To this end, the field research was carried out in 2017 and 2018 in Erzurum, Eastern Anatolia, Turkey. In this study, it was found that the organic and inorganic fertilizers alone and their combinations significantly affected all the plant parameters. The highest seed yield (4854 kg ha-1) and oil yield (2114 kg ha-1) were obtained from the combined use of nitrogen and vermicompost. Moreover, the use of vermicompost alone yielded the highest oil content (46.8%). According to the results of this study, combined applications of organic (vermicompost) and inorganic (nitrogen) fertilizers had the highest yield and agronomic characteristics in oilseed sunflower production; so, these applications can be recommended for the similar ecological conditions, that is, short growing season and high altitude.

Coupling of reduced inorganic fertilizer with plant-based organic fertilizer as a promising fertilizer management strategy for colored rice in tropical regions

Effects of rice straw and nitrogen fertilization on greenhouse gas emissions and carbon storage in tropical flooded soil planted with rice

The determination for properly combined application rate of organic and inorganic fertilizers is the key to coordinating soil nutrient supplies and rice growth demands, thereby obtaining improved economic and ecological returns in rice ratooning. A complete randomized block design (RCBD) trial with different configurations of organic and inorganic nitrogen fertilizers was conducted to determine the optimal substitution rate of organic nitrogen for inorganic nitrogen and its effect on the related physiological attributes and yield performance of the main and ratoon rice crops in 2018−2019. The results showed that 30% organic and 70% inorganic nitrogen in the mixture fertilizer (GM2) could produce the best effect on root activity, nitrogen nutrient uptake and its utilization, as well as the dry matter accumulation and its partitioning. This in turn resulted in improved productive panicles and harvest index, and hence increased grain yield by 10.36% and 15.48% in GM2 regime relative to that in CF treatment. Moreover, the uptake and utilization efficiency, agronomic utilization efficiency and partial productivity of nitrogen fertilizer were 44.37%, 23.82 kg/kg and 48.97 kg/kg, respectively under the optimal GM2 treatment, which were much higher than those in CF treatment by 12.66%, 5.05% and 13.4%, respectively. The results suggested that properly combined application of organic and chemical nitrogen fertilizer could improve soil nutrient supply to guarantee an efficient plant growth and rational dry matter allocation, thereby increasing the harvest index and grain yield in rice ratooning.

Improved efficiency in dairy systems is a significant challenge for the future, to meet increased food demand while competing for inputs, adapting to climate change, and delivering ecosystem services. Future grazing systems can play a major role to supply healthier foods within systems with a reduced reliance on fossil fuels and chemical inputs, while also delivering environmental, biodiversity, and animal welfare benefits. Can we design lower-input systems that deliver efficient levels of output in a positive environmental context? Lower-input systems will have a lower reliance on concentrates and inorganic fertilizers, and an increased reliance on extended grazing seasons and high quality forage. Multiple strategies will be needed to maximize nitrogen use efficiency, including a strong reliance on legume-based swards that displace inorganic nitrogen fertilizer. Expected environmental benefits include a reduction in GHG emissions and nitrate leaching, an increase in C sequestration and a reduced reliance on the use of herbicides and pesticides. In comparison with confinement feeding systems, the relatively low energy density and high climate sensitivity of grazing diets requires both effective pasture management and robust and adaptive animals. The appropriate cow for grazing systems must be able to harvest pasture efficiently by re-calving every 365 days to efficiently utilize peak pasture supply, achieve large intakes of forage relative to their genetic potential for milk production (i.e., aggressive grazers) and be adaptable to fluctuations in feed supply. Legume-based multi-species grassland mixtures can maximize the use of symbiotically-fixed nitrogen, and displace the use of inorganic N fertilizer. There is a need for system-scale experiments that use legume-based mixtures within paddocks, and in grassland leys within crop rotations. Moreover, lower-input systems will need a combined focus on research and knowledge transfer for rapid testing and implementation. New opportunities and requirements will arise as policy, society, and the markets demand a higher level of environmental sustainability from food systems and products. This raises the possibility of public-private partnerships for the demand and reward of provision of environmental benefits. To deliver these benefits, future food systems will need to be redesigned to incorporate the enhanced supply of a range of ecosystem goods and services, which should be better incentivized through the market price returned to producers.