Leaching loss of dissolved organic nitrogen from cropland ecosystems

2020 ◽  
Author(s):  
Hao Liang ◽  
Songjuan Gao ◽  
Zhiming Qi ◽  
Kelin Hu ◽  
Junzeng Xu

While widely studied in grassland and forest ecosystems, dissolved organic nitrogen (DON), an important form of N lost through leaching, has received little attention in cropland ecosystem research. A global literature review and partial least squares path modeling (PLS-PM) were adopted to assess the quantity and composition of N leaching loss under different cropping systems, soil types, and management practices, as well as to identify the major factors controlling DON leaching. Annual total dissolved nitrogen (TDN, organic + inorganic N) leaching under different cropping systems ranged from 4.0 to 383.2 kg N ha-1. Vegetable and rice production systems showed the greatest and least TDN leaching, respectively. Across different cropping systems, DON accounted for 4.7%–34.9% of TDN in leachate. The NH_4^+ N form of N leaching is negligible in most upland cropping systems (< 2.3%), but not so in lowland rice systems. The largest ratio of DON leaching to TDN leaching was found in a rice-wheat rotation (34.9%). Cropping systems in which animal manure or plant compost was applied or lowland rice was included showed a relatively high DON leaching ratio. Accordingly, in investigating DON leaching, more attention should be focused on cropping systems with manure application or lowland rice systems. Compared to climatic conditions and soil properties, field management practices (irrigation, chemical N input, and manure amendments) proved to be the factors most strongly influencing DON leaching. This suggests that optimizing water and N management practices is the most effective way of reducing the risk of DON leaching and increasing N use efficiency, particularly for vegetable and rice production systems.

1993 ◽  
Vol 28 (3-5) ◽  
pp. 691-700 ◽  
Author(s):  
J. P. Craig ◽  
R. R. Weil

In December, 1987, the states in the Chesapeake Bay region, along with the federal government, signed an agreement which called for a 40% reduction in nitrogen and phosphorus loadings to the Bay by the year 2000. To accomplish this goal, major reductions in nutrient loadings associated with agricultural management practices were deemed necessary. The objective of this study was to determine if reducing fertilizer inputs to the NT system would result in a reduction in nitrogen contamination of groundwater. In this study, groundwater, soil, and percolate samples were collected from two cropping systems. The first system was a conventional no-till (NT) grain production system with a two-year rotation of corn/winter wheat/double crop soybean. The second system, denoted low-input sustainable agriculture (LISA), produced the same crops using a winter legume and relay-cropped soybeans into standing wheat to reduce nitrogen and herbicide inputs. Nitrate-nitrogen concentrations in groundwater were significantly lower under the LISA system. Over 80% of the NT groundwater samples had NO3-N concentrations greater than 10 mgl-1, compared to only 4% for the LISA cropping system. Significantly lower soil mineral N to a depth of 180 cm was also observed. The NT soil had nearly twice as much mineral N present in the 90-180 cm portion than the LISA cropping system.


2016 ◽  
Vol 8 (1) ◽  
pp. 284-289
Author(s):  
S. Kanimoli ◽  
K. Kumar

The present study was carried out to evaluate the nitrogen fixing ability of diazotrophs isolated from the rhizosphere soils of rice which were grown in three different rice growing systems. A total of hundred and ten isolates obtained were subjected to Acetylene Reduction Assay (ARA) and ninety eight isolates recorded significant amount of nitrogenase activity in a range of 185.73 to 3794.55 nmoles of ethylene mg of protein-1 h-1. The highest nitrogenase activity was recorded by Derxia (3794.55 nmoles of ethylene mg of protein-1 h-1) isolated from Trichy (lowland). Among the three different rice production systems, isolates obtained from lowland rice (Derxia – 3794.5 nmoles of ethylene mg of protein-1 h-1) recorded higher nitrogenase activity followed by Aerobic (Pseudomonas - 2194.89 nmoles of ethylene mg of protein-1 h-1) and SRI (Azotobacter - 1971.85 nmoles of ethylene mg of protein-1 h-1) rice isolates. The results revealed marked variation in the ARA of the diazotrophic isolates obtained from lowland, SRI and Aerobic rice. The nitrogenase activity of diazotrophs from rice fields have been reported earlier but the nitrogenase activity of diazotrophs from three different rice production systems from various parts of Tamil Nadu is reported for the first time from India.


Soil Research ◽  
2002 ◽  
Vol 40 (2) ◽  
pp. 317 ◽  
Author(s):  
H. J. Di ◽  
K. C. Cameron

The leaching of nitrate (NO3–) in intensive agricultural production systems, e.g. dairy pastures, is a major environmental concern in many countries. In this lysimeter study we determined the amount of NO3– leached following the application of urea, dairy effluent, urine returns, and pasture renovation to a freedraining Lismore stony silt loam (Udic Haplustept loamy skeletal) growing a mixture of perennial ryegrass (Lolium perenne) and white clover (Trifolium repens) pasture. The study showed that NO3–-N leaching losses ranged from 112 to 162 kg N&sol;ha per year, depending on the amount and forms of N applied and pasture conditions. Nitrate leaching under the urine patches was the main contributor to the N leaching loss in a grazed paddock. Nitrate leaching losses were lower for urine applied in the spring (29&percnt; of N applied) than for urine applied in the autumn (38–58&percnt;). The application of urea or dairy effluent only contributed a small proportion to the total NO3– leaching loss in a grazed paddock. Pasture renovation by direct-drilling may also have caused an increase in NO3– leaching (c. 31 kg N&sol;ha) in the first year. Modelled annual average NO3–-N concentrations in the mixed recharge water in the acquifer were significantly lower than those measured under the rooting zone due to dilution effects by recharge water from other sources (3.9 v. 13–27 mg N&sol;L). Herbage nitrogen offtake and dry matter yield were higher in the urine treatments than in the non-urine treatments. groundwater, denitrification, mineralisation, grazing, forage.


2021 ◽  
Vol 13 (19) ◽  
pp. 11123
Author(s):  
Olfa Gharsallah ◽  
Claudio Gandolfi ◽  
Arianna Facchi

The intensification of agricultural production is connected to the increased use of fertilizers, pesticides, irrigation water, and energy. Among all cropping systems, rice cultivation is considered to be one of the most significant sources of environmental harm due to the flooding conditions in which rice normally grows; at the same time, rice has important economic and social implications, especially in areas where it is a staple food. In the last 20 years, sustainable development of agricultural production has become a priority for scientific research and policy programs. Several studies proposed methodological frameworks to assess the impacts of different management practices adopted in agro-ecosystems and to identify strategies to mitigate the negative effects of agricultural intensification. Such methodologies are based on the use of particular indicators, which are increasingly seen as crucial tools in impact assessment studies and for decision making. This paper aims to review and analyze the most significant methodological frameworks developed to assess the sustainability of agricultural production systems, with a particular focus on rice cultivation. The analysis includes highlighting which dimensions of sustainability (economic, environmental, social, and governance) are covered by each method and identifying which indicators are used to describe the different dimensions. The spatial scale of the application of the indicators, their typology, the data needed for their implementation, and the criteria for formulating the overall sustainability judgment were then examined. The analysis highlighted the scarce availability of clear operational data for the calculation of the indicators and the often-limited involvement of stakeholders in the development and implementation of the methodologies. The exceptions to these limitations are represented by a few methodologies developed under the umbrella of important international organizations to promote sustainability and research efficiency in specific agricultural production systems, such as the SRP (sustainable rice platform) for rice. Finally, the analysis shows that there is a need to develop methodologies that are applicable not only to an individual farm or group of farms, but also at larger spatial scales (district, watershed, region), which are often those of greatest interest to decision makers.


HortScience ◽  
2011 ◽  
Vol 46 (3) ◽  
pp. 481-486 ◽  
Author(s):  
Yingqian Lin ◽  
Alexa R. Wilson ◽  
Pascal Nzokou

High rates of inorganic fertilizers are used in conventional intensive production systems such as Abies fraseri (fraser fir) cropping systems for Christmas trees. Groundcovers can be used as green mulches, help reduce the use of farm chemicals, and provide several environmental benefits. We investigated the performance of a low-input cropping system by combining two legume cover crops [Dutch white clover (Trifolium repens) and alfalfa (Medicago sativa)] in combination with low rates of inorganic fertilizers as a step toward a more sustainable production system. The randomized block design comprised one cover crop and one of three applications of reduced rate inorganic fertilizer (75%, 50%, and 25% of the recommended rate). A conventional system using herbicides for weed control and the 100% rate of inorganic fertilizer was used as a control. Parameters measured included tree morphology, foliar nitrogen concentration, soil mineral nitrogen, and nitrate-N leaching below the root zone. A significant positive growth response (height and diameter) was obtained in all alfalfa-based cropping systems. This was accompanied by foliar nutrient concentrations similar to conventional plots and a reduction in nitrate-N leaching. However, in white clover-based cropping systems, the growth response was reduced (both height and diameter), suggesting competition for soil resources. In addition, the total nitrate-N leaching was higher in this system, suggesting an imbalance between mineral nitrogen availability and use in white clover-based cropping systems. We conclude that if the potential competition between cover crops and trees can be properly managed, legume cover crops can be effectively used to make intensive production tree-based systems more sustainable. Further studies related to mineralization and macronutrient flows are needed before any definite recommendation can be made about the use of these systems in large-scale production systems.


Sign in / Sign up

Export Citation Format

Share Document