Amount Of Nitrogen Fertilizer Research Articles

Impact of fertilization modes on the quality of japonica rice during storage under a rice–crab co-culture system

This study investigated the impact of three different fertilization modes (traditional [FP1], one-time application of organic and inorganic fertilizer [FP2], and one-time application of inorganic fertilizer [OPT]) on the quality of japonica rice (O. sativassp.japonica) during storage under a rice–crab co-culture system. A field study was conducted, with rice samples collected every two months over a one-year storage period for quality analysis. The results showed that protein accumulated with increasing the amount of nitrogen fertilization, whereas amylose content and eating quality showed the opposite trend, further causing changes in rice quality during storage. After 12 months of storage, the FP2 group had the highest breakdown value (1972.50); its chalkiness degree (6.15), setback value (−788.5), and malondialdehyde content (2.03 μmol/g) were the lowest. These results indicated that FP2 treatment improved the appearance quality and starch pasting properties of rice. Additionally, the head milled rice rate improved in all fertilization treatment groups, while the eating quality scores in the FP1 and OPT groups, as well as the pH of rice soup in all fertilization treatment groups, decreased. Overall, the initial harvest of rice treated with FP2 boasted high quality and maintained superior appearance, eating, and nutritional qualities throughout storage. These findings show that FP2 may be an ideal fertilization mode under an ecological rice–crab co-culture system.

Optimization of Crop Yield Prediction Through Linear Modelling and Deep Learning Techniques Used in Precision Agriculture

The substantial advancements in computer science and engineering have sparked interest in precision agriculture and led to the development of more advanced instruments and methods for enhancing farming practices. This study focuses on the use of machine learning and mathematical models for fertilisation optimisation and yield prediction as part of a Precision Agriculture strategy. In particular, provides the outcomes of forecasting winter wheat production and protein content across four farms using the amounts of nitrogen fertiliser sprayed on the fields. To maximise net yields on the next crop, fertiliser treatments have to be prescribed based on these projections. In particular, contrast approaches based on neural networks (deep and shallow) and multiple regression (linear and non-linear). The greatest results are obtained by a deep neural network that incorporates spatial sampling and is based on the stacked autoencoder, according to the findings.

Optimizing fertilizer use by providing soil quality information: experimental evidence from Madagascar

BackgroundImproving food security in sub-Saharan Africa (SSA) requires increasing agricultural productivity. The increased and effective use of chemical fertilizers is widely recognized as one of the key strategies for achieving this goal. However, many smallholder farmers in SSA still grow crops without using fertilizer, and even when they do use fertilizer, the amount applied is often less than the recommended level. In addition to various constraints related to input markets and farmers’ socioeconomic characteristics, uncertainty about crop yield response is known to discourage fertilizer use. The purpose of this study was to investigate how site-specific information on soil characteristics can help farmers optimize their fertilizer application decisions by reducing uncertainty in yield response. Our unique approach uses simple binary information about the expected effectiveness of nitrogen fertilizer based on a single soil parameter.MethodologyThe simple binary information was generated for a focal rice plot of each 70 household. Based on the evaluation of oxalate-extractable phosphorus content in the soil composites collected from each of these plots, each plot was categorized into either high or low in terms of the expected effectiveness of nitrogen application. A randomized controlled trial was conducted to estimate the impact of providing this simple binary information primarily on nitrogen application rate and, consequently, on rice yield and income at plot-level and household-level.ResultsThe results showed that first, compared to those in the target plots of the control households, the nitrogen application rate was greater in the target plots of the treatment households who were informed of the high expected effectiveness. Second, information that the expected effectiveness was high increased the amount of nitrogen fertilizer in the target plot compared to that in other plots with no information about expected effectiveness within a household. Third, this change in fertilizer allocation led to higher rice yields and higher rice incomes at the household level.ConclusionsThese results highlight how the binary information about the expected effectiveness with a single soil parameter can improve fertilizer allocation among rice plots and its use efficiency to increase rice productivity and income.

Research Progress Related to Sorghum Biological Nitrification Inhibitors

To meet the growing population’s demand for food, humans have introduced large amounts of nitrogen fertilizers into agricultural systems, resulting in highly nitrified environments in most farmland soils. In highly nitrified environments, the application of nitrogen fertilizer easily leads to the formation of nitrate (NO3−) and subsequent leaching, resulting in very low utilization rates. Moreover, nitrogen loss can cause harm to both the environment and human health, making it necessary to inhibit the nitrification process. Nitrification inhibitors can suppress nitrification, and inhibitors derived biologically from plant roots are gaining attention due to their low cost and environmental friendliness. Sorghum, as a crop capable of growing in arid environments, holds economic value and also possesses the ability to secrete biological nitrification inhibitors. This article utilizes sorghum as a case study to review different types of BNIs (MHPP, sorgoleone, and sakuranetin), their mechanisms of inhibition, and influencing factors. This article summarizes the contributions of these inhibitors in reducing N2O emissions and increasing food production, while also providing insight into future research directions for sorghum’s biological nitrification inhibitors in terms of agricultural production efficiency. BNIs are expected to play an important role in improving agricultural production and reducing environmental pollution.

The impact of bacillus sp. NTLG2-20 and reduced nitrogen fertilization on soil properties and peanut yield

The excessive use of nitrogen (N) fertilizers has led to farmland degradation and reduced crop yields. To address this drawback, reducing the amount of nitrogen fertilizer and Bacillus sp. NTLG2-20 inoculant are the optimal cultivation method. The impact of different N rates (0, 20, and 40 kg ha-1) combined with the Bacillus sp. NTLG2-20 inoculant on soil chemical properties, growth, development, and peanut yield was designed in the field in Phuoc Hung commune, An Phu district from May to August 2023. The field experiment was designed with 6 treatments and 4 replications. The research results showed that different N rates adequately augmented soil chemical traits such as pH, cation exchange capacity (CEC), soil organic matter (SOM), total N, available phosphorous (AP), and exchangeable potassium (EK). Furthermore, different N fertilizers rates combined with Bacillus sp. NTLG2-20 inoculant adequately augmented plant height, number of leaves, total chlorophyll, nodulous number and weight per groundnut plant. Reducing N fertilizer application by 50% (20 kg N ha-1) was the optimal N reduction rate when combined with the Bacillus sp. NTLG2-20, which resulted in 17.6% higher peanut yield compared to no N application and no difference compared to 100% of recommended N application (P<0.01)). Bacillus sp. NTLG2-20 inoculant increased peanut yield by 19.6% when compared to no Bacillus sp. NTLG2-20 inoculant (P<0.01). Nitrogen – fixing ability of Bacillus sp. NTLG2-20 promoted peanut yield and reduced fifty percentage of the N fertilizer application. Bacillus sp. NTLG2-20 is the promising species for the production of biological fertilizer in the future.

Insights into the Early Steps of the Symbiotic Interaction between Soybean (Glycine max) and Sinorhizobium fredii Symbiosis Using Transcriptome, Small RNA, and Degradome Sequencing.

Symbiotic nitrogen fixation carried out by the soybean-rhizobia symbiosis increases soybean yield and reduces the amount of nitrogen fertilizer that has been applied. MicroRNAs (miRNAs) are crucial in plant growth and development, prompting an investigation into their role in the symbiotic interaction of soybean with partner rhizobia. Through integrated small RNA, transcriptome, and degradome sequencing analysis, 1215 known miRNAs, 314 of them conserved, and 187 novel miRNAs were identified, with 44 differentially expressed miRNAs in soybean roots inoculated with Sinorhizobium fredii HH103 and a ttsI mutant. The study unveiled that the known miRNA gma-MIR398a-p5 was downregulated in the presence of the ttsI mutation, while the target gene of gma-MIR398a-p5, Glyma.06G007500, associated with nitrogen metabolism, was upregulated. The results of this study offer insights for breeding high-efficiency nitrogen-fixing soybean varieties, enhancing crop yield and quality.

Mitigation of ammonia volatilization from organic and inorganic nitrogen sources applied to soil using water hyacinth biochars

The recent global population explosion has increased people’s food demand. To meet this demand, huge amounts of nitrogen (N) fertilizer have been applied in the worldwide. However, ammonia (NH3) volatilization is one of the primary factors of N loss from soil after N application causing decrease crop N utilization efficiency and productivity. Incubation experiments were conducted on an acidic clayey soil with two different N sources (urea and anaerobic digestion effluent; ADE), two differently-produced biochars, and three biochar application rates (0%, 0.25%, and 1.0% w/w). Ammonia volatilization was lower from urea (14.0–23.5 mg N kg−1) and ADE (11.3–21.0 mg N kg−1) with biochar application than those without biochar (40.1 and 26.2 mg N kg−1 from urea and ADE alone, respectively). Biochar application significantly mitigated volatilization and reduction percentages for urea and ADE were 40%–64% and 18%–55%, respectively. 1.0% biochar application mitigated volatilization significantly compared to 0.25% application regardless of N source and biochar types. Possible mechanism for volatilization mitigation for urea and ADE were increased N immobilization by soil microorganisms and accelerated net nitrification rate due to increased soil nitrifying bacteria, respectively. Overall, our results clarified different mechanisms for N volatilization mitigation from different (inorganic vs. organic) N sources with biochar application.

Enhancing crop production and carbon sequestration of wheat in arid areas by green manure with reduced nitrogen fertilizer

Green manure with appropriate amount of chemical nitrogen fertilizer can increase crop yield, but also aggravate soil carbon emissions. However, it is unclear whether incorporation of green manure into the cropping pattern with reduced nitrogen amount can alleviate this situation and enhance carbon sequestration potential. So, a field experiment with split-plot design was set up in 2018 of northwest China, and studied the effects of nitrogen reduction on crop productivity, carbon emissions, and carbon sequestration potential in 2021–2023. The main plots were two cropping patterns, including multiple cropped green manure after wheat harvest (W-G) and fallow after wheat harvest (W). Three nitrogen application levels formed the split-plots, including local conventional nitrogen amount (N3, 180 kg ha−1), nitrogen amount reduced by 15% (N2, 153 kg ha−1) and 30% (N3, 126 kg ha−1). The results showed that W-G increased grain yield of wheat and energy yield of wheat multiple cropped green manure pattern. The multiple cropped green manure after wheat harvest with local conventional nitrogen amount reduced by 15% (W-GN2) had the significant increasing-effect, and increased grain yield of wheat by 9.6% and increased total energy yields by 39.3% compared to fallow after wheat harvest with local conventional nitrogen amount (W–N3). Relative to W–N3, W-GN2 did not significantly increase carbon emissions of wheat season, and increased total carbon emissions of cropping pattern by 11.1%. Compared to multiple cropped green manure after wheat harvest with local conventional nitrogen amount (W-GN3), W-GN2 decreased carbon emissions by 5.8% in wheat season and decreased by 3.9% in the whole cropping pattern. Therefore, W-GN2 gained high carbon emission efficiency based on grain yield, and were 9.9% and 11.2% higher than W–N3 and W-GN3, respectively. In addition, W-GN2 enhanced soil total nitrogen, carbon, and organic carbon contents, compared with W–N3, thus increasing soil carbon sequestration potential index (net primary productivity/carbon emissions). We conclude that multiple cropped leguminous green manure after wheat harvest with local conventional nitrogen amount reduced by 15% can enhance crop productivity and carbon sequestration potential of farmland in arid areas.

Key factors affecting NH3-N in the Huaihe River Basin due to human activities.

Human activity factors have a significant impact on changes in ammonia nitrogen (NH3-N) content in rivers. Existing research mainly focuses on human activity factors as type factors, and lacks research on the key factors affecting river NH3-N among human activity factors. Therefore, this paper aims to study the key factors affecting human activities on NH3-N in the Huaihe River through various statistical analysis methods. The study found that changes in NH3-N content in the Huaihe River are mainly affected by land use patterns in the basin. There are two different ways in which land use affects NH3-N in rivers: direct effects and indirect effects. We also studied the main pathways through which changes in key factors in human activities affect NH3-N in the Huaihe River by constructing a structural equation model. The results showed that crop sowing area and afforestation area have a significant direct effect on NH3-N in the Huaihe River. In addition, crop sowing area and afforestation area can also affect river NH3-N by regulating the amount of nitrogen fertilizer and human excrement. This study is of great significance for understanding how human activities regulate NH3-N content in rivers.

Does the Amount of Pre-Sowing Nitrogen Fertilization Affect Sugar Beet Root Yield and Quality of Different Genotypes?

There has always been a specific focus on nitrogen fertilization in sugar beet production due to its important effect on sugar beet root yield and quality. For stable sugar beet growth and satisfactory root yield and quality, balanced N fertilization is crucial. Thus, this study aimed to investigate spring N fertilization in two seasons as the following treatments: N0—control, N1—only pre-sowing fertilization, and N2—pre-sowing with topdressing. Four different genotypes were included in the study (Serenada, Colonia, Fred, and Danton). The experiment was set up in a plain area, belonging to the temperate climate zone in Eastern Croatia (Županja and Vrbanja), with the long-term mean (LTM) (March–October) air temperature around 16 °C and the total precipitation of 515 mm. Pre-sowing N fertilization had a smaller impact on root yield in the year with higher precipitation (31% higher than LTM). Therefore, the average yields with pre-sowing fertilization (N1) and pre-sowing fertilization with top dressing (N2) were very similar and were only 7% higher than those of the control. In a season with less rainfall (29% less than LTM), pre-sowing fertilization with top dressing (N2) had a more pronounced effect on the increase in sugar beet root yield, which was 17% higher compared to that of the control treatment. The sugar beet sucrose content and quality parameters (brei impurities, loss of sugar in molasses, extractable sugar) differed when N fertilization was applied among locations in both seasons. The white sugar yield was the highest at N2 treatment with pre-sowing and topdressing N fertilization. In general, according to the average of all locations and years of research, the Serenada hybrid achieved the highest average root yield (81.1 t ha−1), while Colonia exhibited the highest root sugar content (14.5%) and white sugar yield (9.7 t ha−1).

Environmental transport of excess nitrogen fertilizer in peach orchard: Evidence arising from 15N tracing trial

In pursuit of high fruit yield, overwhelming amount of nitrogen (N) fertilizer was unreasonably applied in orchard, resulting in lower fertilizer N uptake and higher environmental loss. It is crucial to propose appropriate fertilization timing and optimal N management by clarifying fruit tree N uptake pattern in orchard systems. Here, a 15N isotope enrichment trial was conducted in peach orchard to assess the transport of applied synthesized fertilizer-N to the plant and environment in the Taihu Lake region. Ammonium sulfate ((NH4)2SO4, 10.12 atom % 15N), as the N source, was applied with four split applications at 382.5 kg N ha−1 during one plant growth cycle. Results showed N deriving from fertilizer (NDFF) accounted for 24.5% in leaves and 38.4% in fruits, respectively. During the annual growth cycle, the applied fertilizer-N uptake and utilization was higher in reproductive growth stage than vegetative growth stage. After harvest, 28.8% of applied fertilizer-N was absorbed by peach tree, 9.5% was lost to the environment through surface runoff, ammonia (NH3) volatilization and nitrous oxide (N2O) emission, 29.6% was retained in the 0–160 cm soil profile, the remaining 32.1% was unaccounted N including N leaching and N loss from the N removal progress. Generally, more applied fertilizer-N moved to the environment in high N input peach orchard. In order to promote optimal N management, the applied fertilizer-N rate should be reduced by 30% and emphasized on fertilization at the reproductive growth period according to tree N uptake pattern.

Low nitrogen priming improves nitrogen uptake and assimilation adaptation to nitrogen deficit stress in wheat seedling.

Early-stage low nitrogen priming promotes root growth and delays leaf senescence through gene expression, enhancing nitrogen absorption and assimilation in wheat seedlings, thereby alleviating growth inhibition under nitrogen deficit stress and supporting normal seedling development. Verifying the strategies to reduce the amount of nitrogen (N) fertilizer while maintaining high crop yields is important for improving crop N use efficiency (NUE) and protecting the environment. To determine whether low N (LN) priming (LNP) can alleviate the impact of N-deficit stress on the growth of wheat seedlings and improve their tolerance to N-deficit stress, we conducted hydroponic experiments using two wheat cultivars, Yangmai 158 (YM158, LN tolerant) and Zaoyangmai (ZYM, LN sensitive) to study the effects of LNP on wheat seedlings under N-deficit stress. N-deficit stress decreased the plant dry weight, leaf area, and leaf N content (LNC), while LNP could significantly reduce this reduction. Distinct sensitivities to N-deficit stress were observed between the wheat cultivars, with ZYM showing an early decrease in leaf N content compared to YM158, which exhibited a late-stage reduction. LNP promoted root growth, expanded N uptake area, and upregulated the expression of TaNRT1.1, TaNRT2.1, and TaNRT2.2 in wheat seedlings, suggesting that LNP can enhance root N uptake capacity to increase N accumulation in plants. In addition, LNP improved the activity of glutamine synthase (GS) to enhance the capacity of N assimilation of plants. The relative expression of TaGS1 in the lower leaves of priming and stress (PS) was lower than that of no priming and stress (NS) after LNP, indicating that the rate of N transfer from the lower leaves to the upper leaves became slower after LNP, which alleviated the senescence of the lower leaves. The relative expression of TaGS2 was significantly increased, which might be related to the enhanced photorespiratory ammonia assimilation capacity after LNP, which reduced the N loss and maintained higher LNC. Therefore, LNP in the early stage can improve the N absorption and assimilation ability and maintain the normal N supply to alleviate the inhibition of N-deficit stress in wheat seedlings.

GENERATING NITROGEN RECOMMENDATIONS FOR MAIZE: ECONOMIC CONSIDERATIONS

The use of excessive amounts of nitrogen fertilizers in crops usually results in nitrogen (N) losses, increasing environmental pollution and contributing to climate change, while also elevating crop production costs. This study aimed to determine in maize (Zea mays L.): (1) the economic optimal nitrogen rate (EONR), economic optimal yield (EOY), and N use efficiency (NUE) utilizing the current N/maize (grain) price ratio (N/MPR) for attainable yield levels; and (2) the effect of an increase in the N/MPR on the EONR, EOY, net income (NI), NUE, and the loss of N. Data from 140 maize response experiments to increasing rates of N, conducted between 2010 and 2019 across 18 states in Mexico under rainfed and irrigated conditions, were analyzed. In these experiments, the average maximum yields were 4.971 ± 2.716 Mg ha-1 under rainfed conditions and 11.776 ± 2.366 Mg ha-1 under irrigated conditions. The EONR, EOY, and NUE were determined with the current N/MPR for attainable yield levels. At these levels, both the EONR and NUE increased with higher EOY and decreased with increased yield without N treatment. An increase in N/MPR reduced EONR and its associated costs without significantly affecting EOY and NI. The reduction in EONR resulted in higher NUE and, consequently, lower N losses. By utilizing N/MRP in economic optimization, recommended N rates for maize can be reduced, leading to decreased N losses and environmental pollution.

Effects of Different Proportions of Organic Fertilizer Replacing Chemical Fertilizer on Soil Nutrients and Fertilizer Utilization in Gray Desert Soil

Organic fertilizer can improve soil management and alleviate soil nutrient loss caused by excessive fertilization. This study determines a fertilization scheme that can achieve high and stable crop yield and effective soil fertilization by exploring the effects of different organic fertilizer proportions on soil nutrient content, fertilizer utilization rate, and wheat yield. The experiment was conducted from 2018 to 2020 using the Xinchun 38 wheat variety and gray desert soil. The experiment used six treatments: no fertilizer (CK), with normal nitrogen and phosphorus fertilizer (CF). The amount of conventional chemical nitrogen fertilizer was reduced by 6%, 12%, 18%, and 24%, respectively, and supplemented with organic nitrogen fertilizer of the same proportion. The experimental treatment codes were SF6, SF12, SF18, and SF24, respectively. Plant samples from six wheat growth stages and 0–20 cm soil samples were collected to analyze the nitrogen and phosphorus content and organic matter; dry matter accumulation, crop yield, and yield components were measured at the harvest stage. Soil available nitrogen, phosphorus, potassium, and soil organic matter contents increased with the replacement ratio of organic fertilizer after three consecutive years of application. The available nutrients and organic matter in soil treated with SF18 and SF24 were significantly higher than those in CK and CF. The dry matter accumulation and nutrient accumulation of wheat increased with increasing organic fertilizer replacement rates of SF18 and SF24, respectively. Nitrogen and phosphorus fertilizer utilization rates, partial productivity, and agricultural use efficiency also increased, with the SF18 and SF24 treatments having higher organic fertilizer replacement rates than those in the other treatments. The number of ears, 1000-grain weight, and yield of wheat treated with SF18 treatment produced the best results. Therefore, continuously using organic fertilizer as a partial replacement for conventional fertilizer can increase wheat growth and soil nutrient availability, which can improve the utilization rate of fertilizer, thereby achieving stability and even a significant increase in yield.

Effect of Three Different Nitrogen Rates and Three Rhizosphere N2- Fixing Bacteria on Growth, Yield and Quality of Peanuts

Raising prices of organic fertilizers, environmental relation of their usage and need for global foodstuff, placed a topic of universal interest in cultivation of legume plants for human nutrients and soil fertility supplementation. Three rates of N fertilizer were studied in the field: 0, 20 and 40 kg N/ha. Three bacterial strains were identified and inoculated in the experiment: Enterobacter asburiae (E. asburiae), Klebsiella quasipneumoniae (K. quasipneumoniae) and Enterobacter cloacae (E. cloacae). The soil samples were taken before and after experiment for chemical attributes analysis. The effect of N2 fertilizer and 3 bacterial strains was on soil chemical properties, yield components and yield of peanut plant. The results of present study showed that application of different N2 fertilizer rates was a little influence on the N2-fixing ability of rhizosphere bacteria, but high effect was significant at the peanut nodule number. In the 3 N fertilizer rates and 3 bacteria, which only had N2 fertilizer rate of 40 kg N/ha and E. asburiae significantly raised the maximum yield component and yield of peanut, while there was the lowest yield component and yield of peanut was observed in N fertilizer rate application of 0 kg N/ha and E. cloacae inoculation. The differences in rhizosphere bacterium strains between different N fertilizer rates was better than that caused by the nitrogen fertilizer amount. This could be due to the substantial improvement in soil chemical attributes at different soils, especially in, pH, OM and total N, as these significantly impacted the soil structure. HIGHLIGHTS Increasing pH, organic matter and total nitrogen of soil were statistically significantly different by 3 N2 fertilizer rates. There is a positive interaction between nitrogen rates and RNFB increasing yield of peanut. Number and weight of peanut nodules obtained the maximum value without applying N2 application compare to other treatments. The maximum yield components of peanut were inoculated with asburiae to compare with K. quasipneumoniae and E. cloacae and applied weight of 40 kg N/ha. The maximum yield of peanut was inoculated with asburiae to compare with K. quasipneumoniae and E. cloacae. GRAPHICAL ABSTRACT

Water use and carbon assimilation respond differently to nitrogen supplementation in mid-rotation Eucalyptus nitens

ABSTRACT Large amounts of nitrogen (N) fertiliser are often applied to commercial plantations in southern Australia to obtain high growth rates. The growth response to fertiliser can be realised through increased foliar N and hence improved leaf-level photosynthetic capacity, or through increased leaf area production, which in turn increases light capture and hence canopy-level photosynthesis. While extra leaf area is beneficial to a tree in this regard, extra leaves may also incur costs in terms of both carbon (C) and water. Since canopy water use scales with total leaf area, greater leaf area could cause stomatal closure in times of water shortage, reducing the C assimilation rate. Here, we used three factorial N × phosphorus fertiliser experiments in Eucalyptus nitens plantations across Tasmania, Australia, to assess the effects of 12 fertiliser treatments on C- and water-related gas exchange, foliar N and trunk shrinkage. As prior research in this system has demonstrated an increase in leaf area in response to high N, we investigated the potential physiological costs and benefits of this extra leaf area. N application appeared to have consequences for plant water use, as evidenced by greater trunk shrinkage and lower stomatal conductance. However, this varied by site and year, indicating that the response is dependent on environmental conditions. These results highlight the importance of considering site conditions when prescribing fertiliser application regimes because adding large amounts of N could have unintended consequences for growth due to increased leaf area and hence potential water use, especially in dry conditions.

Dynamics and microbial characteristics of nitrogen and carbon in saline-alkali paddy soil under different fertilization

The expansion of saline-alkali paddy fields, coupled with the application of large amounts of nitrogen (N) fertilizers, has given rise to a host of environmental concerns. While N and carbon (C) are vital indicators for assessing soil fertility, their dynamic characteristics in saline-alkali paddy soil remain obscure. To address this knowledge gap, we established paddy mesocosms with five distinct N-fertilizer treatments: control without N-fertilizer (CK), urea (U), urea with inhibitors (UI), organic–inorganic compound fertilizer (OCF) and C-based slow-release fertilizer (CSF). The objective was to monitor the dynamic changes of various N and soil organic-C (SOC) during a 137-day rice growing season, and to clarify the microbiological characteristics. By the end of the rice growing season, soil ammonia-N (NH4+-N) concentrations were UI > OCF > CSF > U > CK, and UI had a significant difference (p < 0.05) with all the other four treatments. Soil nitrate-N (NO3−-N) concentrations in OCF and CSF treatments were 5.64 ± 1.25 mg kg−1 and 6.81 ± 0.29 mg kg−1, respectively, significantly (p < 0.05) higher than U and UI treatments. NH4+-N showed a negative correlation with NO3−-N regardless of the N-fertilizer types, and a significant (p < 0.01) positive relationship with alkali-hydrolyzable N (AHN). A significant (p < 0.01) positive relationship existed between total-N (TN) and Bacteria 16S rRNA gene. The SOC had a significant (p < 0.05) positive relationship with mcrA gene. During the entire rice growing season, CSF treatment had lower mean TN and SOC concentrations than all the other treatments, and exhibited the highest TN and total organic-C (TOC) content in rice. In summary, the UI can increase the residual NH4+-N in saline-alkali paddy fields, and the CSF is a better choice for growing rice.

Strategy of increasing protein production based on lupin and nano disintegrator technology

The article considers the problem of providing food to the population. To solve this problem, it is proposed to master the process of protein production from lupin. The cultivation of lupin will allow the development of the northern territories of the country and will make it possible to accelerate the development of the northern sea route. It has been established that of all leguminous crops, lupin has the most nitrogen-fixing ability, which will allow further use of arable land for sowing other crops and reduce the amount of nitrogen fertilizers used. It is noted that lupine feed is difficult to digest. To solve this problem, high-temperature grain processing has been developed. This technology improves the process of feeding poultry and animals, but has disadvantages such as: high-temperature processing of lupin grain contributes to the destruction of a number of amino acids and reduces the effect of the vitamin complex; significant additional costs are required for hydrothermal exposure. To eliminate these shortcomings, a new lupin processing process is proposed using a disentangulatory technology. To improve the disintegrator technology, a nanodesintegrator process is proposed by using microturbines instead of electric motors, which increases the effect of grinding the structure and activating biological systems by 19.2 times.

Biological soil conditioner with reduced rates of chemical fertilization improves soil functionality and enhances rice production in vegetable-rice rotation

Soil is an essential source of nutrients for crop growth, but excessive chemical fertilizer can lead to soil acidification and decreased sustainability. Organic fertilizer helps improve soil physicochemical properties and increase soil utilization efficiency. However, soil functionality and crop sustainability response to organic fertilizers need further research. In this study, multiple fertilizer practices (including different amounts of nitrogen fertilizer or soil conditioners, traditional organic fertilizer), various rice varieties, and other rotation systems were applied to test the effects of soil conditioners on crop yield and soil fertility. The results showed that crop yield sustainability and stability were significantly positively correlated with soil pH, EC value, and nitrogen (Pearson r > 0.5). In addition, improving soil quality was beneficial to increasing crop yield sustainability and stability (R2 > 0.5). Chemical fertilizers and soil conditioners can increase soil nutrient content and improve crop yield sustainability index (>0.8). Applying soil conditioners can enhance the activity of soil catalase and urease in paddy soil, especially in the 12 and 15 m3 ha−1 soil conditioner treatments due to soil microbial activity being affected by soil salinity and organic matter content. Soil conditioners increase the mass of Nitrospira species in soil, decompose nitrogen in the soil, and reduce soil nitrate and nitrite content, thereby improving soil pH and reducing the risk of soil acidification caused by excessive chemical fertilizer. Combining soil conditioners and chemical fertilizer (20 % less than traditional fertilization) can promote soil quality and fertility while improving crop yield sustainability and stability.

INTERACTION OF NITROGEN AND PLANT DENSITY ON GROWTH AND YIELD OF TWO QUINOAS (Chenopodium quinoa Willd.) CULTIVARS IN FARS PROVINCE, IRAN

As a field crop, quinoa (Chenopodium quinoa Willd.) has great potential in improving food for humans and animals even under marginal lands. Experiments were carried out at Marvdasht, Iran, in 2017 and 2018 main crop growing season to evaluate the effect of 4 levels of nitrogen (0, 75, 150, and 225 kg/ ha), three levels of density (20, 30, and 40 plants /m2), and two cultivars of quinoa (Titicaca and Sajema). The factorial experiment was performed based on a randomized complete block design with three replications. The results showed that nitrogen fertilizer significantly affected all measured traits. By increasing the nitrogen and plant density, the plant height, grain yield, and biological yield increased. The highest harvest index and nitrogen use efficiency was obtained from the highest density level. In all studied traits, Titicaca cultivar had greater than Sajema. Due to the superiority of 225 kg /ha-1 of nitrogen and the density of 40 plants/m2 in terms of grain yield, it seems that this amount of nitrogen fertilizer and planting density to achieve good yields in the test and similar areas is also recommended. Also, the higher seed yield in Titicaca cultivar than Sajema is recommended for planting in the studied areas.