Influence of nitrogen fertilization on lettuce yields (Lactuca sativa L.) using the 15N isotope label

M. Amirouche¹*, L. Zella² and D. Smadhi³

¹National High School, Department of Rural Engineering, El–Harrach, DZ16004 Algiers, Algeria
²University of Saad Dahlab, Faculty of Nature and life sciences, Department of biotechnology, Ouled Yaïch, DZ09000 Blida, Algeria
³Division of Bioclimatology and Agricultural Hydraulic, National Institute for Agricultural Research, El–Harrach, DZ16004 Algiers, Algeria
*Correspondence: mawhoub.amirouche@gmail.com

Abstract:

Nitrogen fertilization plays an important role in the growth of market gardening and the improvement of yields. Its efficiency of use is imperative for the preservation of the agricultural environment. An experiment is carried out over three consecutive years (2014/2015), (2015/2016) and (2016/2017), in a sub humid climate. The methodology adopted focuses on the variation of optimal nitrogen doses and their effects on the evolution of lettuce cultivation (Lactuca sativa L.), which has a socio-economic impact. The approach takes into account the isotopic marking technique, ¹⁵N. The experimental device adopted is of the complete random block type, with four (04) levels: 0 (control), 60, 120 and 180 kg N ha^-1 with four (04) repetitions. These levels are used to diagnose the effect of different doses on biomass (dry matter) and yield. It has been shown those doses between 0 and 120 kg N ha^-1 increase significantly (p < 0.05), yields and dry matter with values of 18.32, 45.49 to 57.93 t ha^-1 and 4.32, 5.52 to 9.77 t ha^-1, respectively. The rate of 120 kg N ha^-1, is shown statistically, as the efficient rate to cover the nitrogen needs of lettuce. This efficiency reaches 74.48%. Beyond that, nitrogen is not valorized by the crop. These results contribute to the realization of a technical reference system for lettuce cultivation, for an efficient use of nitrogen.

Key words:

Fertilizer use efficiency impact on GHG emissions in the Latvian crop sector

A. Lēnerts¹, D. Popluga¹*, K. Naglis-Liepa¹ and P. Rivža²

¹Latvia University of Agriculture, Faculty of Economics and Social Development,
Institute of Economics and Regional Development, Svetes street 18, LV-3001, Jelgava,
Latvia
²Latvia University of Agriculture, Faculty of Information technologies, Liela street 2,
LV-3001, Jelgava, Latvia
*Correspondence: dina.popluga@llu.lv

Abstract:

Within increasing production activity Latvian agricultural sector has become one of the main sources of greenhouse gas emissions (GHG) in Latvia. In 2013, agricultural sector contributed 21.0% of the total GHG emissions originated in Latvia (2310.1 Gg CO₂eq). Analysis of agricultural GHG emissions by sources shows that direct N2O emissions from agricultural soils through the usage of synthetic fertilizers are one of the most significant GHG source in Latvia. The usage of synthetic fertilizers is one of the most common widespread agricultural practices in Latvian cropping systems and according to statistical data usage of synthetic fertilizers is constantly increasing, for example, in 2013 it increased by 6.9% if compared with 2012. Taking into account that over-fertilization can lead to negative economic and environmental consequences, such as high production costs, depletion of energy resources, and increased GHG emissions, this research aims to estimate how effective usage of synthetic fertilizers are in Latvian crop farms. In order to achieve the set aim an N fertilizer usage were estimated in four crop farms by giving insight into N balance and N use efficiency (NUE) rate in these farms. Research results suggest that improved N efficiency can be selected as GHG mitigation measure as it reduces N surpluses and the use and production of mineral fertiliser while maintaining yield levels. It was also concluded that improved N efficiency reduces direct N₂O emissions from fertilized soils and indirect N₂O emissions that occur by the release of NH₃.

Key words:

emissions., GHG, Latvia, nitrogen use efficiency