Ling Zhang

By Ling Zhang and Xiaojun Liu

Nitrogen (N) is one of the most important plant nutrient, and its availability and transformations are vital for net primary production. Soil N transformations include mineralization, nitrification and denitrification processes. Nitrogen mineralization transforms organic N into inorganic N, providing available N for crops. Both nitrification and denitrification are microbe-driven processes associated with nitrous oxide (N2O) emissions. N2O emissions from agricultural soils decrease N fertilization efficiency and potentially induce global warming. The mitigation of soil N2O emissions in agricultural practice is essential for sustainable development of agriculture considering the environmental effect of N2O. Various strategies have been proposed for the mitigation of N2O emissions. Nitrification inhibitors have been demonstrated to be useful in decreasing soil N2O emissions, including the application of nitrification inhibitors, such as dicyandiamide (DCD) and 3,4-dimethylpyrazole phosphate (DMPP). Recently, biological nitrification inhibitors have also attracted researchers’ attention, which may be more environment-friendly. In addition, biochar commonly used as soil ameliorant to improve soil quality and C sequestration could also mitigate soil N2O emissions. Once all effective strategies would be widely implemented, more environment-friendly agriculture could be expected.

Part of the book: Nitrogen in Agriculture

By Nasir Shad, Ling Zhang, Ghulam Mujtaba Shah, Fang Haifu, Muhammad Ilyas, Abbas Ali and Salman Ali Khan

Nitrogen (N) is a key factor for any ecosystem and has been found limited for biomass production. More N in forest ecosystem and their efficient utilization will contribute to the maximization in their growth, competition, and reproduction. Invasive plants capture and utilize more N than native plants and accelerate N cycles through altering the structure and community of soil microbes and the litter decomposition rates, under microclimate conditions, resulting in an increase of N availability. All these factors are promoting the invasiveness of plants and cause further ecological and economic damage and decline in native biodiversity. Plant invasions affect soil microbial community, soil physiochemical properties, and litter decomposition rates, promoting N cycle and releasing more nitrous oxide (N2O) into the atmosphere, further facilitating global warming, causing changes in the geographic ranges of some invasive species. Also, a better understanding of the mechanism, affecting factors, impacts, and control of the invasive species will lead to proper forest management. Proper and effective management will ensure the control of invasive species which includes invasive plant inventory, early deduction and rapid response, management plan and implication, and government support.

Part of the book: Advances in Forest Management under Global Change

By Bangliang Deng and Ling Zhang

Camellia oleifera Abel. is one of the four woody edible oil trees around the world, which is also an important economic species in subtropical China. It is mainly cultivated in subtropical region, where the soil constrains the yield of C. oleifera oil due to its low fertility and pH. Thereby, intensive management including fertilization practice, especially intensive nitrogen (N) input, has been developed as a vital way to enhance oil yield in C. oleifera plantations. However, excessive nitrogen input increases soil nitrous oxide (N2O) emissions and soil acidification, limiting sustainable development of economic forests. As one of the important greenhouse gases, N2O is 265 times greater than carbon dioxide in global warming potential on 100-year scale. To mitigate soil N2O emissions and soil acidification, soil amelioration, including applications of biochar, nitrification inhibitors, and urease inhibitors, played an important role in sustainable management of C. oleifera plantations. This chapter reviewed soil nitrogen cycling, N2O emissions, and soil amelioration in C. oleifera plantations, which will benefit the sustainable management of C. oleifera plantations and hence the development of C. oleifera industries.

Part of the book: Advances in Forest Management under Global Change

By Nasir Shad, Zohra Nasheen, Rabia Afza and Ling Zhang

Litter decomposition plays an important role in the biogeochemical cycling of elements in ecosystems. Plant trait differences especially between invasive and native species lead to changes in litter decomposition rates. The litter decomposition rate is influenced by climatic factors such as seasonal variations, humidity, temperature, and rainfall, where species litter may have different responses. This review aims to better understand how litter decomposes in ecosystems associated with plant invasion and global changes. It also reviews the effects of various factors on litter degradation as well as how quickly invasive litter decomposes and contributes to greenhouse gases (GHGs) emissions. Single species litter or only aboveground litter studies may not sufficiently represent ecosystem dynamics; therefore, the co-determination of above- and belowground litter in a mixture of species diversity is required in different biomes interaction with global change factors. As a result, comprehensive litter degradation studies must be conducted in order to understand the turnover rate of nutrients and other elements in these sensitive ecosystems.

Part of the book: Resource Management in Agroecosystems