scholarly journals Effect of nitrogen application rate on soil fungi community structure in a rice-fish mutualistic system

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Shumei Cai ◽  
Weiguang Lv ◽  
Haitao Zhu ◽  
Deshan Zhang ◽  
Zishi Fu ◽  
...  
Keyword(s):  
Community Structure ◽  
Paddy Soil ◽  
Soil Fungi ◽  
Application Rate ◽  
N Application ◽  
Total N ◽  
Available N ◽  
N Application Rate ◽  
Rice Fish ◽  
Rice Monoculture

Abstract Rice-fish mutualistic production systems rationalise the use of water and soil resources in an improved approach to sustainable food production. However, drivers of fungi community structure in paddy soil, including effects of nitrogen (N) application rate, are unclear in these systems. Here, we assessed soil fungi community and soil physicochemical responses in paddy soil to contrasting rates of N application in a rice-fish system. To clarify the mutualistic effects, the rice-fish system was compared with a standard rice monoculture under a 325.5 kg ha−1 N application rate. The results showed that N application rate affected abundance of paddy soil fungi (P < 0.05). Alpha diversity and richness of fungi were lower in the rice-fish system, but evenness increased with a decrease in N application rate, while the rate of N determined diversity of soil fungi in the rice-fish system. Dominant genera in the two systems differed, and soil physicochemical properties were more important drivers of soil fungi community structure in the rice-fish mutualistic system than in rice monoculture. Total N, available N and P regulated the abundance of dominant fungi. Our results indicate that management of soil fungi may contribute to sustainable agricultural production.

Effect of Fertilizer Nitrogen on Weed Emergence and Growth

Weed Science ◽  
2008 ◽  
Vol 56 (5) ◽  
pp. 714-721 ◽  
Author(s):  
Amy E. Sweeney ◽  
Karen A. Renner ◽  
Carrie Laboski ◽  
Adam Davis
Keyword(s):  
Untreated Control ◽  
Soil Depth ◽  
Application Rate ◽  
N Fertilizer ◽  
Grass Species ◽  
Weed Species ◽  
N Application ◽  
Available N ◽  
N Application Rate ◽  
Weed Emergence

The timing of nitrogen (N) fertilizer application may influence germination, emergence, and competitiveness of weeds. Research was conducted to determine the influence of total inorganic soil N (Nit) on the germination, emergence, and growth of five weed species. In a greenhouse experiment, seed of five weed species were exposed to four levels of N, and seed germination was measured. In the field, urea ammonium nitrate (UAN 28%) was applied at multiple rates at three spring timings, and Nit, weed emergence, and growth were measured for 21 to 35 d after application (DAA). Germination of the four dicotyledonous and single grass species was not stimulated by 450 ppmw of N compared with the untreated control. In the field, Nitof 112 or 168 kg N ha−1, measured at 7 and 21 DAA, was always greater than Nitin the untreated control. The duration of the available N pulse in the upper 8 cm of soil was dependent on N application rate and timing. At 8 to 16 cm of soil depth, Nitwas greater when 168 kg N ha−1was applied compared with no N at 21 and 35 DAA in 2004. Emergence of common lambsquarters increased as N application rate increased for each application date in 2003, but not in 2004. Emergence of ladysthumb increased with N application rate for the April 15, 2003, date; emergence of giant foxtail increased with N application rate for the April 6, 2004, date. Weed biomass was always greater when 168 kg N ha−1was applied compared with no N, and at four of six N application dates, when 112 kg N ha−1was applied. This research shows that spring N fertilizer applications increase Nitand weed growth, but the influence of N on weed emergence is dependent on the weed species, seed source, and environmental conditions.

scholarly journals Nitrogen Fertilizer Rates can be Lowered without Compromising Cotton Yield under Drip Irrigation System

2021 ◽  
Vol 25 (03) ◽  
pp. 709-714
Author(s):  
Tao Yang
Keyword(s):  
Irrigation System ◽  
Application Rate ◽  
N Fertilizer ◽  
Drip Irrigation System ◽  
Cotton Yield ◽  
N Application ◽  
N Content ◽  
Total N ◽  
N Application Rate ◽  
Xinjiang Of China

The effects of reducing N fertilizer use on soil NO3--N content and cotton yield were studied through a three-year (2015 to 2017) field experiment in South Xinjiang of China. Cotton was sown under drip irrigation system using five N fertilizer reduction treatments as: conventional N application rate (N100), N application rate reduced by 16.67% (N-16.67), 33.33% (N-33.33), 50% (N-50), and 100% (N-100). The data were recorded for changes in soil NO3--N content, and the SPAD value of cotton leaves was recorded at the peak bolling stage. The total N content of the plant was recorded at the boll formation stage, while yield was recorded at maturity. The results revealed that the soil NO3--N content in N-16.67, N-33.33, N-50, and N-100 treatments decreased by 10.8, 45.5, 60.7 and 72.3% compared to N100 treatment, respectively. The SPAD values of N-16.67 and N-33.33 treatments were significantly higher than those of N100 treatment, while the SPAD values of N-50 and N-100 treatments were significantly decreased. The total N content of cotton was significantly decreased with the increase in the proportion of N fertilizer reduced. The seed cotton yield in N-16.67 and N-33.33 treatments increased by 9.2 and 7.9% compared to the N100 treatment, respectively. However, the cotton yield decreased significantly when the N application rate was reduced by 50 and 100%. The relationship between the N fertilizer reduction rate and cotton yield suggested that the N application rate can be reduced by 18.47–45.50% without compromising the cotton yield in South Xinjiang of China. © 2021 Friends Science Publishers

scholarly journals Nitrogen fertilizer reduction in combination with Azolla cover for reducing ammonia volatilization and improving nitrogen use efficiency of rice

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11077
Author(s):  
Guoying Yang ◽  
Hongting Ji ◽  
Hongjiang Liu ◽  
Yanfang Feng ◽  
Yuefang Zhang ◽  
...  
Keyword(s):  
Grain Yield ◽  
Ammonia Volatilization ◽  
Rice Yield ◽  
Application Rate ◽  
N Fertilizer ◽  
Rice Grain ◽  
N Application ◽  
Total N ◽  
N Application Rate ◽  
Use Efficiency

Background Excessive nitrogen (N) application rate with low N use efficiency (NUE) caused a considerable amount of N losses, especially ammonia volatilization (AV). Proper N fertilizer reduction (RN) could significantly reduce AV. However, continuous RN led to a nutrient deficiency in the soil and therefore negatively impacted the NUE and rice yield. Paddy Azolla, a good green manure, is considered as a promising measure to decrease AV and improve NUE and grain yield of rice. However, there is limited information on the integrated effects of RN and Azolla cover on the AV, NUE, and rice yield, especially in the highly fertilized rice-growing systems. Methods The experiment was conducted including eight treatments: the control (without N fertilizer and Azolla cover), Azolla cover without N fertilizer (A), farmer’s N application rate (FN), FN + Azolla cover (FNA), 15% RN from FN (RN15), RN15 + Azolla cover (RN15A). 30% RN from FN (RN30), RN30 + Azolla cover (RN30A). The integrated effects of N fertilizer reduction and Azolla cover on AV, NUE, and rice grain was evaluated. Results RN15A and RN30A substantially reduced total AV by 50.3 and 66.9% compared with FN, respectively, primarily due to the lower surface water ammonia concentrations and pH. RN improved the efficiency of Azolla cover on reducing AV, with 4.1–9.9% higher than for FN. Compared with the FN, RN15A and RN30A enhanced apparent N recovery efficiency (ANRE) by 46.5 and 39.1%, which might be responsible for the lower NH3 emission and the increased total N uptake / total chemical N applied. Furthermore, RN15A and RN30A reduced yield-scaled volatilization by 52.3 and 64.3% than for FN, respectively. Thus, combining 15–30% RN with Azolla cover may be a way to reduce AV and improve ANRE without decreasing rice grain yield.

Effects of sediment nutrients and depth on small-scale spatial heterogeneity of submersed macrophyte communities in Lake Pleasant, Pennsylvania

2004 ◽  
Vol 61 (8) ◽  
pp. 1493-1502 ◽  
Author(s):  
R K Johnson ◽  
M L Ostrofsky
Keyword(s):  
Organic Matter ◽  
Community Structure ◽  
Spatial Heterogeneity ◽  
Environmental Gradients ◽  
Small Scale ◽  
Sediment Characteristics ◽  
Available Nitrogen ◽  
Total N ◽  
Available N ◽  
Prevailing Paradigm

Sediment concentrations of total and available nitrogen (N), phosphorus (P), and potassium (K) and organic matter from the littoral zone of Lake Pleasant, Pennsylvania, were highly variable. Only organic matter and total N were correlated with depth, however. This result suggests the existence of more complex environmental gradients than the prevailing paradigm of monotonic changes in sediment characteristics with increasing depth. The spatial heterogeneity of submersed aquatic plant communities was significantly correlated with depth, and available N and P. Canonical correspondence analysis demonstrated that these three factors explained 38% of the variance in community structure. Other sediment characteristics (available K, organic matter, and total N, P and K) were not significant by themselves, but all variables combined explained 63% of community-structure variance. Cluster analysis identified species or groups of species typical of endpoints on the depth versus nutrient axes. Myriophyllum exalbescens was typical of deep sites with relatively nutrient-rich sediments, whereas deep nutrient-poor sites were dominated by Vallisneria americana and Megalodonta beckii. Shallow nutrient-rich sites were dominated by several species of Potamogeton and Elodea canadensis, and shallow nutrient-poor sites were dominated by Heteranthera dubia and Najas flexilis. These results demonstrate the importance of sediment characteristics in determining macrophytes' community structure within lakes.

scholarly journals Foliar Zn Spraying Simultaneously Improved Concentrations and Bioavailability of Zn and Fe in Maize Grains Irrespective of Foliar Sucrose Supply

Agronomy ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 386 ◽  
Author(s):  
Haiyong Xia ◽  
Weilin Kong ◽  
Lan Wang ◽  
Yanhui Xue ◽  
Wenlong Liu ◽  
...  
Keyword(s):  
Agronomic Traits ◽  
Application Rate ◽  
Deionized Water ◽  
Control Treatment ◽  
Agricultural Practice ◽  
N Application ◽  
Application Rates ◽  
N Application Rate ◽  
Maize Grain ◽  
Sucrose Supply

Zinc (Zn) deficiency is a global nutritional problem that is reduced through agronomic biofortification. In the current study, the effects of foliar spraying of exogenous ZnSO4·7H2O (0.2% in Quzhou and 0.3% in Licheng, w/v) and/or sucrose (10.0%, w/v) on maize (Zea mays L.) agronomic traits; concentrations of Zn, iron (Fe), calcium (Ca), total phosphorus (P), phytic acid (PA) P, carbon (C), and nitrogen (N); C/N ratios; and Zn and Fe bioavailability (as evaluated by molar ratios of PA/Zn, PA × Ca/Zn, PA/Fe and PA × Ca/Fe) in maize grains were studied under field conditions for two years at two experimental locations. The results confirmed that there were no significant differences in maize agronomic traits following the various foliar treatments. Compared with the control treatment of foliar spraying with deionized water, foliar applications of Zn alone or combined with sucrose significantly increased maize grain Zn concentrations by 29.2–58.3% in Quzhou (from 18.4–19.9 to 25.2–29.6 mg/kg) and by 39.8–47.8% in Licheng (from 24.9 to 34.8–36.8 mg/kg), as well as its bioavailability. No significant differences were found between the foliar spraying of deionized water and sucrose, and between Zn-only and “sucrose + Zn” at each N application rate and across different N application rates and experimental sites. Similar results were observed for maize grain Fe concentrations and bioavailability, but the Fe concentration increased to a smaller extent than Zn. Foliar Zn spraying alone or with sucrose increased maize grain Fe concentrations by 4.7–28.4% in Quzhou (from 13.4–17.1 to 15.2–18.5 mg/kg) and by 15.4–25.0% in Licheng (from 24.0 to 27.7–30.0 mg/kg). Iron concentrations were significantly and positively correlated with Zn at each N application rate and across different N application rates and experimental locations, indicating that foliar Zn spraying facilitated the transport of endogenous Fe to maize grains. Therefore, foliar Zn spraying increased the Zn concentration and bioavailability in maize grains irrespective of foliar sucrose supply while also improving Fe concentrations and bioavailability to some extent. This is a promising agricultural practice for simultaneous Zn and Fe biofortification in maize grains, i.e., “killing two birds with one stone”.

Crop rotation and N application rate affecting the performance of winter wheat under deficit irrigation

2018 ◽  
Vol 210 ◽  
pp. 330-339 ◽  
Author(s):  
Wenli Qin ◽  
Xiying Zhang ◽  
Suying Chen ◽  
Hongyong Sun ◽  
Liwei Shao
Keyword(s):  
Winter Wheat ◽  
Crop Rotation ◽  
Deficit Irrigation ◽  
Application Rate ◽  
N Application ◽  
N Application Rate

scholarly journals Nitrous oxide emission and fertiliser nitrogen efficiency in a tropical sugarcane cropping system applied with different formulations of urea

Soil Research ◽  
2016 ◽  
Vol 54 (5) ◽  
pp. 572 ◽  
Author(s):  
Weijin Wang ◽  
Glen Park ◽  
Steven Reeves ◽  
Megan Zahmel ◽  
Marijke Heenan ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Yield Loss ◽  
N Uptake ◽  
Management Strategies ◽  
Application Rate ◽  
Sugar Yield ◽  
N2o Emissions ◽  
N Application ◽  
N Application Rate ◽  
Coated Urea

Nitrous oxide (N2O) emissions from sugarcane cropped soils are usually high compared with those from other arable lands. Nitrogen-efficient management strategies are needed to mitigate N2O emissions from sugarcane farming whilst maintaining productivity and profitability. A year-long field experiment was conducted in wet tropical Australia to assess the efficacy of polymer-coated urea (PCU) and nitrification inhibitor (3,4-dimethylpyrazole phosphate)-coated urea (NICU). Emissions of N2O were measured using manual and automatic gas sampling chambers in combination. The nitrogen (N) release from PCU continued for >5–6 months, and lower soil NO3– contents were recorded for≥3 months in the NICU treatments compared with the conventional urea treatments. The annual cumulative N2O emissions were high, amounting to 11.4–18.2kg N2O-Nha–1. In contrast to findings in most other cropping systems, there were no significant differences in annual N2O emissions between treatments with different urea formulations and application rates (0, 100 and 140kgNha–1). Daily variation in N2O emissions at this site was driven predominantly by rainfall. Urea formulations did not significantly affect sugarcane or sugar yield at the same N application rate. Decreasing fertiliser application rate from the recommended 140kgNha–1 to 100kgNha–1 led to a decrease in sugar yield by 1.3tha–1 and 2.2tha–1 for the conventional urea and PCU treatments, respectively, but no yield loss occurred for the NICU treatment. Crop N uptake also declined at the reduced N application rate with conventional urea, but not with the PCU and NICU. These results demonstrated that substituting NICU for conventional urea may substantially decrease fertiliser N application from the normal recommended rates whilst causing no yield loss or N deficiency to the crop. Further studies are required to investigate the optimal integrated fertiliser management strategies for sugarcane production, particularly choice of products and application time and rates, in relation to site and seasonal conditions.

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