• Rural Digital Europe

The effect of nutrient status of soil on carcass quality of fish raised in earthen ponds was investigated between March and August 2016. Three soil profile pits were dug side by side three existing earthen ponds in three different geomorphological locations of Imo State at Umuagwo, Ulakwo and Uboma. Three homogenous soil horizons ( 0-20, 20-60, 60-150 cm) were identified and evaluated for nutrient composition by standard methods (USDA, 1971). Ten adults of Oreochromisniloticus of average weight of 250.0 + 5.4g randomly selected from the associated earthen ponds were chemically evaluated for carcass composition in accordance with AOAC (2005). Soil textural class for the pond at Umuagwo was dominantly sandy, sandy loam at Ulakwo and clay loam at Uboma. Soil nutrient analysis showed that the sandy soil was grossly poor in total nitrogen (0.04 – 0.08) and soil exchangeable bases, K (0.01 -0.04%), Na (0.003-0.005%) as against the clay soil which had appreciably higher reserve of total nitrogen (0.21-0.32%), organic carbon (1.22-2.50%) and exchangeable bases, K (0.06-0.18%), and Na (0.020.09%). Nutrient composition of fish carcass from the clay pond in terms of two most important nutritive factors of crude protein (32.1 + 3.0%) and fat (6.36 + 0.1%) was significantly higher (P< 0.05) than in the sandy pond (14.7+ 2.0%), 4.4. + 0.5%) and the sandy loam (14.9 + 25 %, 4.7 + 0.2 %) respectively. The implication of this in site selection of earthen ponds is discussed.

Nutrients, such as nitrogen and phosphorus, provide vital support for human life, but overloading nutrients to the Earth system leads to environmental concerns, such as water and air pollution on local scales and climate change on the global scale. With an urgent need to feed the world's growing population and the growing concern over nutrient pollution and climate change, sustainable nutrient management has become a major challenge for this century. To address this challenge, the growing body of research on nutrient budgets, namely the nutrient inputs and outputs of a given system, has provided great opportunities for improving scientific knowledge of the complex nutrient cycles in the coupled human and natural systems. This knowledge can help inform stakeholders, such as farmers, consumers, and policy makers, on their decisions related to nutrient management. This paper systematically reviews major challenges, as well as opportunities, in defining, quantifying, and applying nutrient budgets. Nutrient budgets have been defined for various systems with different research or application purposes, but the lack of consistency in the system definition and its budget terms, has hindered inter-comparison among studies and experience-sharing among researchers and regions. Our review synthesizes existing nutrient budgets under a framework with five systems (i.e., Soil-Plant system, Animal system, Animal-Plant-Soil system, Agro-Food system, and Landscape system) and four spatial scales (i.e., Plot and Farm, Watershed, National, and Global scales). We define these systems and identify issues of nitrogen and phosphorus budgets within each. Few nutrient budgets have been well balanced at any scale, due to the large uncertainties in the quantification of several major budget terms. The type and level of challenges vary across spatial scales and also differ among nutrients. Improvement in nutrient budgets will rely not only on the technological advancement of scientific observations and models, but also on better book-keeping of human activity data. While some nutrient budget terms may need decades, or even centuries, of research to be well quantified within desirable levels of uncertainties, it is imperative to effectively communicate to interested stakeholders our understanding of nutrient budgets so that scientists and a variety of stakeholders can work together to address the sustainable nutrient management challenge of this century.

Abstract The purpose of this study is to ecologically soil, reduce fertilization and maintain land productivity. In this study, the amount of nutrient elements stored in the soil is large, and the soil samples are treated with long-term constant and different water content to determine the activation amount of the solid elements in the soil. The results showed that the content of available phosphorus and available potassium released by XH6 in different water content cultures was higher than 3.89% and 10.12% of XH10, respectively. The content of nitrate nitrogen released by XH4 was higher than that of treated XH4. %. The content of ammonium released under treatment of XH10 was higher than that of treatment with XH10 of 24.11%. The release nutrients varied with the culture time, but the release of nutrients such as ammonium nitrogen, nitrate nitrogen, available phosphorus and available potassium peaked on the 14th day of culture, and stabilized in the latter culture. So, the high moisture content has a certain release and increase effect on soil available potassium and available phosphorus.

To survey and analyze soil nutrients of sugarcane field in southern Guangxi and provide basic data for reasonable land use and scientific fertilization, combining GIS technology, a total of 498 samples of topsoil of typical soil types in southern Guangxi sugarcane planting areas were collected and soil nutrients were measured. Survey results indicate that the pH value of 95% soil in southern Guangxi is lower than 6.5; acid soil is major soil type of sugarcane planting areas in southern Guangxi; the organic matter content is 6.03-44.58 g/kg; alkali-hydrolyzable N is 14.0-175.0 mg/kg; available P is 1.7-95.0 mg/kg; available K is 11.0-358.0 mg/kg; the content of most nutrients remains at medium level, and there is still a large gap with high-yield soil condition. In various trace elements, the average content of B is 0.24 mg/kg, 98% soil lacks B; the average content of available Mg is 62.34 mg/kg and 69.08% soil lacks Mg; the average content of active Ca is 592.68 mg/kg and the active Ca is relatively low in 54.84% soil; the average content of available Zn is 0.93 mg/kg, and 19.08% soil lacks Zn; the average content of available Cu is 0.65 mg/kg, and 7.02% soil lacks Cu. It is concluded that the overall soil fertility of sugarcane planting areas in southern Guangxi is not high, the organic matter is relatively low, the content of rapidly available N, P and K is at medium or low level, the content of Fe and Mn is high, and the available Cu and available Zn of most soil remain at medium level.

&lt;p&gt;Rainfall intensity and duration directly affect the process of soil nutrient loss. In this paper, long-term, low-intensity rainfall (LL) (58.4mm rainfall, 605min duration) and short-term, high-intensity rainfall (SH) (59.2mm rainfall, 287min duration) were selected to study the pathway for soil nitrogen and phosphorus loss and load differentiation under different rainfall modes by using a slope experiment plot. The results indicated that: (1) The difference between the runoff duration of LL (3410min) and that of SH (410min) was obvious, and the runoff rate was 14.44% and 28.55%, respectively; (2) There were different nutrient concentration distributions. On one hand, the concentration of TN in the surface flow was lower than that in the interflow. The average TN concentration in the surface flow of LL and SH was 13.7 and 16.94 mg&amp;#183;L&lt;sup&gt;-1&lt;/sup&gt;, respectively. The average TN concentration in the interflow of LL and SH was 59.25 and 50.89 mg&amp;#183;L&lt;sup&gt;-1&lt;/sup&gt;, respectively. On the other hand, the concentration of TP in the surface flow was higher than that in the interflow. The concentration of TP ranged from 0.42 to 1.44 mg&amp;#183;L&lt;sup&gt;-1&lt;/sup&gt; in the surface flow, and from 0.21 to 0.91 mg&amp;#183;L&lt;sup&gt;-1&lt;/sup&gt; in the interflow; (3) The interflow is the main pathway of nitrogen loss, while the surface flow is the main pathway of phosphorus loss. The respective TN load of LL and SH runoff was 4.04 and 8.49 kg&amp;#183;hm&lt;sup&gt;-2&lt;/sup&gt;, of which the contribution rate of the interflow was 88.49% and 85.54%, respectively. Additionally, the respective TP load of LL and SH runoff was 0.11 and 0.33 kg&amp;#183;hm&lt;sup&gt;-2&lt;/sup&gt;, of which the contribution rate of the surface flow was 65.79% and 70.67%, respectively; (4) The amount of rainfall was almost the same but its intensity was different. High intensity rainfall would cause greater soil nutrient loss. The amount of total nitrogen and phosphorus loss in a sloppy land due to SH rainfall was 2-3 times higher than that due to LL rainfall.&lt;/p&gt;

SARGINCI, Murat/0000-0002-2263-9003; Esen, Derya/0000-0003-4175-758X WOS: 000273364500005 PubMed: 20648809 Fire is a long-standing and poorly understood component of the Mediterranean forestlands in Turkey. Fire can alter plant composition, destroy biomass, alter soil physical and chemical properties and reduce soil nutrient pools. However, fire can also promote productivity of certain ecosystems by mineralizing soil nutrients and promoting fast growing nitrogen fixing plant species. Fire effects on soils and ecosystems in Turkey and Mediterranean regions are not well understood. This study, uses a retrospective space-for-time substitution to study soil macro-nutrient changes on sites which were burned at different times during the last 8 years. The study sites are in the Fethiye Forest Management Directorate in the western Mediterranean Sea region of Turkey Our samples show 40% less Soil C, and cation exchange capacity (CEC) at 0-20 cm soil depth two weeks after the fire, Soil C and CEC appear to recover to pre-fire level in one year Concentrations of Mg were significantly lower on new-bum sites, but returned to pre-fire levels in one year Total soil N concentrations one and two years after fire were 90% higher than other sites, and total P was 9 times higher on new-bum site than averages from other sites. Some implications of these results for forest managers are discussed.

In the North Western Himalayas, particularly Jammu region, where 85% of people depend on agriculture and allied sectors, 70% of agriculture is rain-fed. Various factors, especially land use pattern and variations in climatic conditions affect the soil fertility and nutrient contents. However, information on essential nutrients in the soil across the region is meager. An attempt has been made to study the soil nutrient status under different agro-climatic zones of Jammu region. Seven hundred seventy surface soil samples (0-15 cm) from sub-tropical, intermediate and temperate zones of Jammu region were collected and analyzed for soil texture, pH, electrical conductivity (EC), organic carbon (OC), CaCO3, CEC, available macro nutrients (N, P, K, S) and micronutrients (Fe, Cu, Zn, Mn). The results indicated large variation within the soils of each zone. The amount of all the available nutrients was more in the soils of temperate zone than those of other zones. The soils of sub-tropical zones were low in available N, P, S and Zn and to some extent in K. Organic matter content, clay and silt content of the soil vis-à-vis cation exchange capacity were found to be the main factors controlling the available nutrient content of the studied soils.