Land use effect on nitrogen and phosphorus fluxes into and from soil

Eurasscience Journals Eurasian Journal of Forest Science (2017) 5(1): 8-12 LAND USE EFFECT ON NITROGEN AND PHOSPHORUS FLUXES INTO AND FROM SOIL H. Barış TECİMEN1,2 1Istanbul University, Faculty of Forestry, Soil Science and Ecology Dept. 34473, Bahçeköy – İstanbul – Türkiye 2Indian River Research and Education Center, Institute of Food and Agriculture Science, University of Florida, 34945, 2219 South Rock Road, Fort Pierce, FL-USA Abstract Land use is recently being taken in consider among ecologists thus the global imbalances of biological and mineral aspects on earth raised and have been retaining since last century with births of undescribed and introduced problematic issues. One of the most threatening effect of those global problems is extinction of food and water resources. Soil utilization, land management practices, source (land properties containing above and below ground resources) based features are the main marks of land use issue. Within this study, (i) what extend does the land use change effect the nitrogen content in soil and freshwater systems, (ii) microbial agents’ effects on phosphorus sources, (iii) environmental threatens and anxieties of improper land use are questioned. The results revealed that, both nitrogen and phosphorus elemental cycles are interrupted by abrupt changes at land uses, while, sustainability of resource management and controls at microbial level might highly be subsidiary to solution of land use sourced degradations. Keywords: Land use, nitrogen, phosphorus, soil. Özet Küresel ölçekte meydana gelen biyolojik dengenin bozulması ve madde dolaşımındaki anormallikler ve son yüzyılda rastlanan yeni ve tanımlanamayan problemlerden ötürü, arazi kullanımı, ekolojiyle ilgilenen bilim insanları tarafından mercek altına alınmaya başlamıştır. Bu küresel problemler arasındaki en büyük problem, su ve besin kaynaklarının yok olmasıdır. Toprağın kullanımı, arazi yönetimi uygulamaları, toprak altı ve toprak üstü özelliklerinden oluşan arazi kaynağı, arazi kullanımının en önemli hususlarını oluşturmaktadır. Bu çalışmada, (i) arazi kullanımının toprak ve tatlısulardaki azot içeriğine etkileri, (ii) mikroorganizmaları fosfor kaynakları üzerine etkileri, (iii) yanlış arazi kullanımının çevre için doğurduğu tehditler ve stresler sorgulanmıştır. Çalışma sonucunda, azot ve fosfor döngülerinin, arazi kullanımı değişiminden dolayı şiddetli bir şekilde sekteye uğradığı ve mikroorganizma düzeyinde yürütülecek olan sürdürülebilir kaynak yönetimi uygulamaları, arazi kullanımından ve/veya arazi kullanımı değişiminden kaynaklanan sorunların çözümüne yardımcı olacağı anlaşılmaktadır. Anahtar kelimeler: Arazi kullanımı, azot, fosfor, toprak. INTRODUCTION Nitrogen and phosphorus are crucial elements for plant nutrition and also highly used by fertilizers at agricultural fields. Land use change in advantage of agricultural lands, conversion of forest lands and wetlands to agricultural lands causes higher fertilizer receiving in soil. Growth of population resulted to increased food source creating an impulse to over loading soil with fertilizers. After nutrient elements absorbed by plants at a sufficient amount, the excess of the labile macronutrients move from soil to freshwater systems by either underground crack structure or surface water flow. Pollution of freshwater by eutrophication, decrease in oxygen amount in water, extinction of wetlands creates strong influence on global climate. This is supported by negative feedback cycle in the sequence of disappearance of wetlands – increased temperature – temperature induced 8 Eurasian Journal of Forest Science 5(1):8-12 (2017) evaporation – loss of wetland water (Lloret et al. 2008). Besides wetlands are both highly sensitive to global climate change and have a regulatory role on climate change. Since floodplains, mangroves, seagrasses, saltmarshes, arctic wetlands, peatlands, freshwater marshes and forests are very diverse habitats, with different stressors and hence different management and restoration techniques are needed (Erwin 2009) in terms of both protection from pollutants and itself freshwater source. The symptoms of eutrophication, such as noxious and harmful algal blooms, reduced water quality, loss of habitat and natural resources, and severity of hypoxia (oxygen depletion) and its extent in estuaries and coastal waters will increase and global climate changes will likely result in higher water temperatures, stronger stratification, and increased inflows of freshwater and nutrients to coastal waters in many areas of the globe (Rabalais et al. 2009). Land use is under the influences of actual utilization status of a land (land use type such as forest, agriculture or pasture), geographical position, microclimate caused by land, exposed climatic effects, change of function of a land and further management strategies. Thus the effects of land use on nitrogen and phosphorus elements should be taken in considered from the point of this view. Limitations and obligations imposed by the governmental agents suppress the use of fertilizer or pesticide use to prevent pollutant effects the natural resources. The most prominent outcomes of land use change or land use management type consist from artificial effects by farmers as chemical substrates or remaining the land as a pasture or forest land with its natural but more complex relations. Though, unintended effects of nitrogen and phosphorus fertilizers’ soluble or dissolved compounds create significant changes at worldwide level. Thus, in this article the fate of derivatives and by products of excess nitrogen and phosphorus caused from land use and management strategies have been criticized. The issues questioned are; (i) what extend does the land use change effect the nitrogen content in soil and freshwater systems, (ii) microbial agents’ effects on phosphorus sources, (iii) environmental threatens and anxieties of improper land use. LAND USE DISTRIBUTION IN THE WORLD Two major land use types consist from agricultural lands and forest lands, whereas account up to 65% of global terrestrial ecosystems and the rest of the terrains show a variety of land uses such as; wetlands, deserts, prairies, tundra, savannas, pasturelands and glacials. The highest agricultural activities approximately 30% of world’s total surface area is being conducted at temperate, tropical and subtropical regions of the world (Fig. 1 and 2). Figure 1. Wordlwide distribution of agricultural lands. (Center for Sustainability and the Global Environment (SAGE) at University of Wisconsin-Madison. 2003) Figure 2. Forestlands distribution in the world (https://myweb.rollins.edu/jsiry/WhereTheWor ld%20are_.html) However, the conversion of land use under the forces of urbanization, agricultural aims and other socio-economic factors have influent impact on natural resources. The main conclusion of land use is deterioration of a given land itself either irreversibly or requiring a long t (...truncated)