Journal of Soil Science and Plant Nutrition

The objective of this study was to evaluate the influence of tetracyclines associated with swine wastewater on the enzymatic activity of soil over time, in relation to the biogeochemical cycle of the nutrients during two seasons of the year. The experiment was carried out in soil-containing pots that received two successive applications of swine wastewater treatments, in the summer and autumn seasons, corresponding to two experimental periods. The swine wastewater was applied in doses of 0.2 and 0.3 L, with or without tetracycline, chlortetracycline, and doxycycline. Soil samples were collected at 2, 4, 8, 15, 30, 45, and 75 days after treatment application to determine the activities of the enzymes dehydrogenase, β-glucosidase, acid phosphatase, and urease. During both experimental periods, there was an increase in the activities of all enzymes in the presence of swine wastewater. However, these activities decreased in the presence of the applied antibiotics. The observation of enzyme activity over time facilitated construction of longitudinal predictive models, which described the activity of enzymes over time. Our findings indicate that swine wastewater treatments led to a reduction in the bioavailability of nutrients, thereby reducing soil quality and fertility.

The elevation is a complicated environmental factor that affects the availability of light, temperature, soil nutrients, and moisture, thereby affecting the mountain ecosystem. However, it is unclear how the C:N:P ecological stoichiometry of leaf, soil, and litter changes along the altitudinal gradient, especially in the karst ecosystem in Southwest China. This work investigated the soil organic carbon (SOC), total phosphorus (TP), and total nitrogen (TN) contents, and the corresponding stoichiometric ratios of Pseudotsuga sinensis leaf, litter, and soil at an elevation range of 2127–2302 m in the northwestern Guizhou Province of China. The results indicated that altitude significantly affected the nutrient contents and stoichiometric ratios of P. sinensis in leaf, soil, and litter. The mean contents of C, N, and P in the P. sinensis forests were 473.57, 14.49, and 1.97 mg·g−1 for leaves; 422.35, 8.36, and 1.08 mg·g−1 for litter; and 40.59, 2.44, and 1.04 mg·g−1 for soil, respectively. The C, N, and P contents of soil and leaf increased significantly, whereas those in the litter decreased significantly with elevation. The average ratios of C:N, C:P, and N:P were 32.97, 244.60, and 7.42 for leaves; 51.38, 395.53, and 7.79 for litter; and 16.68, 38.84, and 2.34 for soil, respectively. The leaf C:N, N:P, and C:P ratios showed a linear decrease with an increase in altitude, whereas C:P and C:N ratios in the litter and N:P and C:P ratios in soil showed a linear increase with an increase in altitude. The resorption efficiency of both N and P of P. sinensis increased remarkably with altitude. The mean resorption efficiency of P (43.84%) was higher than that of N (40.91%). Since the N:P ratio in leaves predicts limited nutrition for plant development, we hypothesized that the N element limited the development of P. sinensis. Besides, nutrient contents were markedly related to the ratios in P. sinensis leaves, litter, and soil. The results indicate that P. sinensis had developed a favorable strategy to adapt to the high altitude and cope with unfavorable soil nutrient conditions. The N element was mainly limited to the development of P. sinensis. The P. sinensis had developed a favorable strategy to adapt to the high altitude and cope with unfavorable soil nutrient conditions. These findings highlight the relationship between the C:N:P stoichiometric ratios and altitude in plants, soils, and litters in the karst forest ecosystem, and provide insight on the better management of the karst forest ecosystems in Southwest China.

This study aims to evaluate the TiO2 nanoparticles (NPs) and soil type effect on Zea mays L. seedlings and to assess the effect of the TiO2 NPs retained in organic matter on terrestrial isopods (Armadillidium vulgare, Latreille). It was hypothesized that (i) the combined effect of soil pH and minerals, and the addition of TiO2 NPs harm maize plants, and (ii) increasing Ti’s content in organic matter (OM) causes mortality in the isopods. Under greenhouse conditions, the effects of TiO2 NPs (300 and 600 mg kg−1 dry soil) were assessed during 21 days in acid or alkaline soils, with an organic matter layer above the soil surface (3 cm). An inhibitory effect of TiO2 NPs on plant length and root size was clearly shown at 21 days in alkaline soil but not in acid soils. Besides, a higher amount of Ti was accumulated on maize tissues in alkaline soil than those grown on acid soil. An increase in TiO2 NPs caused higher Ti concentrations in the soil organic matter (SOM), which harmed the survival and weight of the terrestrial isopods when the OM is consumed. Isopods limit the consumption of NPs at high concentrations while the NPs leached toward soil deeper layers allowing a reduction in plant height and root size in Z. mays plants grown in alkaline soil. Nevertheless, further investigations on the effect of TiO2 NPs in the association of plants and terrestrial isopods in natural conditions are required.

Cardoon could be cropped for agro-environmental, industrial, and pharmaceutical purposes. The aim of this study was to assess the effects of biochar on emissions of nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4), and productivity of cardoon crop. A pot experiment was run outdoors from April to August 2018, with a cardoon plant per pot. The following four treatments, with four replicates each, were applied: control, soil only; mineral, soil amended with mineral fertilizer (2.5 g N m−2); biochar, soil amended with biochar (1 kg m−2); and mineral+biochar, soil amended with mineral fertilizer (2.5 g N m−2) and biochar (1 kg m−2). The morphological characteristics and biomass production of cardoon plants were evaluated, and the fluxes of N2O, CO2 and CH4 were measured by using the closed chamber technique. The application of biochar combined with mineral reduced N2O emissions by 36% and global warming potential (GWP) by 26% relative to mineral. However, the cumulative CO2 and CH4 emissions as well as yield-scaled GWP were not significantly different among amended soil treatments. Furthermore, the biomass production was increased by 50% by the application of biochar combined with mineral fertilizer relative to mineral. It was concluded that biochar combined with mineral fertilizer is recommended as a pathway mitigation for agro-environmental purposes, because it reduces the global warming potential and could increase the biomass production of cardoon plants.

Cordyline is one of the most important indoor pot plants and has a high request in the global market. As a bio-stimulant, chitosan could be used to enhance the plant growth and productivity, despite the variation in growth analysis and phenotypic plasticity of several plant species in response to chitosan supplement. Cordyline seedlings were foliar sprayed with five concentrations of oligo-chitosan (0, 25, 50, 75, and 100 mg L−1) for 4 months. Oligo-chitosan induced rapid growth of cordyline seedlings, in terms of larger specific leaf weight (SLW) and higher relative growth rate (RGRA), as well as improving the efficiency of plant photosynthesis (high net assimilation rate (NAR) or low specific leaf area (SLA)). Root growth rate (RGRR) has also increased by 89.13% with the application of 50 mg L−1 oligo-chitosan, which reflected on higher plant biomass (BM) in comparison to the control. Consequently, root biomass (RM) showed the greatest plasticity index (PPI) that enhanced growth, productivity, and quality as well as the marketability of cordyline seedlings. Foliar spray of 50 mg L−1 oligo-chitosan improved plant growth, root development, and plasticity index, resulted in increased quality and marketability of cordyline seedlings.

The present study was carried out to analyze physico-chemical characteristics of agricultural soil samples of Amritsar, India, under wheat cultivation and their genotoxic and anti-oxidative enzyme responses in Allium cepa test system. Physico-chemical parameters of soil samples, total protein content, crude lipid content, and activity of different anti-oxidative enzymes in A. cepa under the exposure of different soil samples were investigated using standard protocols. The genotoxicity of agricultural soil samples was assessed by employing Allium cepa root tip chromosomal aberration assay. The genotoxicity studies in A. cepa showed induction of various physio-logical and clastogenic aberrations dominated by delayed anaphase/s followed by stickiness, C-mitosis, and chromatin bridges. Eastern zone (EW2) soil sample (26.21%) showed induction of highest percent chromosomal aberrations, while central zone (CW1) soil sample (16.33%) showed lowest percent as compared to control (5.96%) in in situ treatment. Root dip treatment revealed highest percent aberrations in EW2 sample (30.28%), whereas southern zone (SW4) showed lowest percentage (28.43%) of chromosomal aberrations at highest concentration of soil extract used, i.e., 100%. Biochemical studies on onion bulbs treated with agricultural soil samples indicated a significant reduction in the contents of crude lipids, while variation in total protein contents as compared to control was insignificant. The activities of superoxide dismutase and ascorbate peroxidase were reduced, while the activities of glutathione-S-transferase and dehydro-ascorbate reductase were enhanced in treated bulbs as compared to control bulbs. Pearson correlation analysis reported significant negative correlation between magnesium ion concentration and in situ soil genotoxicity. Other physico-chemical parameters also showed significant correlations with enzymes and biochemical molecules. The study clearly depicted significant genotoxic potential of agricultural soils along with their effects on the activities of anti-oxidative enzymes which could be attributed to indiscriminate use of chemical fertilizers and pesticides.

Tác động của việc sử dụng kết hợp giữa dinh dưỡng vô cơ và hữu cơ cùng với phun lá kẽm ở dạng nano lên cây lúa chưa từng được nghiên cứu đến nay. Giả thuyết cho rằng sự kết hợp này có thể đảm bảo sự tăng trưởng và năng suất tốt hơn trong Inceptisols thông qua việc cải thiện khả năng có sẵn của dinh dưỡng cũng như hoạt động sinh học của đất. Tám sự kết hợp điều trị (mức độ thay đổi của liều nitơ khuyến nghị (RDN), từ phân chuồng (FYM) và/hoặc kẽm nano) đã được thử nghiệm trên cây lúa (var. Shatabdi (IET 4786)). Các thông số tăng trưởng và năng suất tiêu chuẩn, phân tích sắc tố, trạng thái dinh dưỡng đất có sẵn, nồng độ và hấp thụ của thực vật, tình trạng vi sinh vật trong đất và hoạt động enzym dehydrogenase đã được phân tích. Năng suất hạt tối đa (5,06 t ha−1) thu được từ sự kết hợp 75% RDN từ phân bón hóa học thương mại + 25% RDN từ FYM + xử lý phun kẽm nano cho thấy số lượng cành tối đa m−2 và số hạt nhiều hơn per cành, tăng mức năng suất hạt lên 8,82% so với 100% RDN từ phân bón hóa học (4,65 t ha−1). Việc ứng dụng kẽm dạng nano một mình đã dẫn đến năng suất hạt 4,01 t ha−1, cải thiện 17,6% so với đối chứng. Dân số vi sinh vật tốt hơn trong đất được đảm bảo nhờ việc cải thiện hoạt động enzym dehydrogenase trong các ô đất được xử lý bằng FYM so với 100% liều phân bón khuyến nghị ở tất cả các giai đoạn tăng trưởng của cây lúa. Việc áp dụng kẽm ở dạng nano trong hệ thống INM không chỉ nâng cao năng suất của cây lúa và hiệu quả sử dụng kẽm mà còn cải thiện sức khỏe của đất bằng cách cải thiện các tính chất hóa học và sinh học của đất.