Publications

Abstract To meet the increasing challenges for food security, agricultural management should aim to maximize grain yield and export from the field while improving soil fertility. However, the effects of different straw incorporation on soil aggregates, grain yield and soil C and N contents as well as their potential linkages remain poorly understood. In this study in China, we simultaneously investigated soil aggregates, SOC and TN and grain yield. The three treatments: (i) no straw (CK, the local traditional practice), (ii) straw plowed into the soil (SP), and (iii) ammoniated straw plowed into the soil (ASP, straw with low C/N ratios). The SOC content in the macro-aggregates (> 5 mm) and the micro-aggregates (≤ 0.25 mm) differed among the CK, SP, and ASP plots after 5 growing years, i.e., ASP > SP > CK. In addition, the ASP treatment had the highest grain yield, 5-year mean grain yield and aboveground biomass compared with CK and SP treatments. The ASP treatment significantly increased SOC and TN content in topsoil layers, relative to CK and SP treatments. These results suggest that we could potentially shape soil structure, increase yield stability, soil C and N content under ASP treatment. Our results highlight the importance of optimal crop straw returning on soil structure, grain yield and SOC and TN content, whereas long-term continuous measurements and observations are still required to have a good understanding of sustainable agriculture.

Arsenic (As) is identified by the EPA as the third highest toxic inorganic contaminant. Almost every 9th or 10th human in more than 70 countries including mainland China is affected by As. Arsenic along with other toxins not only affects human life but also creates alarming situations such as the deterioration of farm lands and desertion of industrial/mining lands. Researchers and administrators have agreed to opt for phytoremediation of As over costly cleanups. Boehmeria nivea L. can soak up various heavy metals, such as Sb, Cd, Pb, and Zn. But the effect of As pollution on the biology and metabolism of B. nivea has been somewhat overlooked. This study attempts to evaluate the extent of As resistance, chlorophyll content, and metabolic changes in As-polluted (5, 10, 15, and 20 mg L(-1) As) B. nivea in hydroponics. Toxic effects of As in the form of inhibited growth were apparent at the highest level of added As. The significant changes in the chlorophyll, electrolyte leakage, and H2O2, significant increases in As in plant parts, catalase (CAT), and malondialdehyde (MDA), with applied As revealed the potential of B. nivea for As decontamination. By employing the metabolic machinery of B. nivea, As was sustainably removed from the contaminated areas.

Particulate plastic fragments (micro and nano-plastics) in aquatic environments provide abundant solid substrates, which serve as an important habitat for a variety of microorganisms. Surfaces of microplastics (MPs) exhibit hydrophobicity that facilitate the adsorption of dissolved organic carbon (DOC) in the aquatic environment. Furthermore, MPs act as substrata, as well as a carbon source including the readily bioavailable DOC, which promote the formation of microbial biofilms. These biofilms have varied metabolic actions that govern the subsequent succession of micro- and meso-organisms habitation of MPs. The assemblage of ecosystems colonising the plastic environment is often referred to as the “plastisphere”. Polymer type, environmental conditions, including nutrient status, salinity, and season, affect the microbial composition of the biofilm. Microbial habitation accelerated by biofilm formation on particulate plastics enables the movement of microorganisms, especially in the aquatic environment, and impacts the transport and toxicity of contaminants associated with these particulate plastic fragments. This review paper describes the processes of microbial habitation and subsequent biofilm formation, the factors affecting biofilm formation, and the implications of biofilm formation on the mobility of microorganisms, degradation of MPs, and the bioavailability of contaminants associated with MPs.

Abstract Land use and land cover change (LULCC) directly affect the temporal and spatial change of soil erosion. As a typical governance watershed in the hilly and gully area of the Loess Plateau, the Jiuyuangou watershed has experienced significant LULCC in the past 10 years due to conversion of farmland to forests, economic construction, and cropland abandonment. However, the evolution process of soil erosion change and LULCC in the watershed is unclear, as is the relationship between the two. This study used satellite images to extract information on LULCC in the watershed and the Chinese soil loss equation (CSLE) model to evaluate the temporal and spatial evolution of soil erosion in the watershed from 2010 to 2020. The main results showed that (1) the continuous vegetation restoration project in the watershed reduced soil erosion from 2010 to 2015; however, the increased frequency of extreme rainfall events after 2015 reduced its impact. The annual average soil erosion modulus decreased from 10.85 t ha −1 year −1 in 2010 to 8.03 t ha −1 year −1 in 2015 but then increased to 10.57 t ha −1 year −1 in 2020; (2) the main land use and land cover (LULC) type in the Jiuyuangou watershed is grassland, accounting for 62% of the total area, followed by forestland, cropland, buildings, and water. Cropland has the largest multi‐year average soil erosion modulus, followed by grassland and buildings, with forestland having the smallest; (3) significant spatial correlations occurred between soil erosion change and LULCC for common ‘no change’ and common ‘gain’ in the settlements, roads, and areas near the human influences with good soil and water conservation, but not other regions due to the influence of climatic factors (heavy rain events). Thus, we should repair terraces, control dams in the watershed, and actively conserve water and soil. This study provides a scientific reference for planning and managing water and soil conservation and ecological environment construction in the watershed.

Abstract Background Aims Conservation tillage benefited soil aggregate function—essential for soil nutrient cycling and plant growth. Nevertheless, little is known about tillage practices' impact on soil particle aggregation, particularly soil nutrients and distribution of enzymes and microbes among different-sized aggregates, and their possible later influence upon other soil functions and processes. Methods We conducted a long-term experiment with maize ( Zea mays L.) in a region of oasis farming in Northwest China, in which tillage was applied in four treatments: no-tillage, minimal tillage, fold-tillage, and sub-tillage. Soil aggregates were categorized as follow: <0.25 mm (‘micro’), 0.25–2 mm (‘small’), and > 2 mm (‘macro’), whose corresponding nutrient contents, enzymatic activity and stoichiometry were measured, as well as the structure of soil microbial community of those fraction, along with crop productivity. Results The no-tillage treatment increased the amount of N, P, and C in soil, the biomass of microbiota, and the availability P and N within micro-aggregates and bulk soil. It also augmented enzymatic activity for acquiring C- and P as well the enzymatic ratio of C: N but decreased that of N: P in micro-aggregates, and promoted crop productivity compared with conventional tillage. Additionally, microbial community structure differed under the four tillage regimes and between the aggregate fractions, especially under conventional tillage, but the tillage system did not affect alpha diversity. Conclusions Our results showed that no-tillage restructured the soil microbial community composition of aggregate fractions. Thus, long-term conservation tillage promotes soil functioning and crop productivity by changing soil aggregates in oasis farmland ecosystems.

The coordination/trade-off among below-ground strategies for phosphorus (P) acquisition, including root morphology, carboxylate exudation and colonisation by arbuscular mycorrhizal fungi (AMF), is not well understood. This is the first study investigating the relationships between root nodulation, morphology, carboxylates and colonisation by an indigenous community of AMF under varying P levels and source. Two chickpea genotypes with contrasting amounts of rhizosheath carboxylates were grown in pots at six P levels (from 0 to 160 μg g^-1 ) as KH₂ PO₄ (KP, highly soluble) or FePO₄ (FeP, sparingly soluble), with or without AMF (±AMF) treatment. Under both FeP and KP, the presence of AMF inhibited shoot growth and shoot branching, decreased total root length and specific root length, increased mean root diameter and root tissue density and reduced carboxylates. However, the role of AMF in acquiring P differed between the two P sources, with the enhanced P acquisition under FeP while not under KP. Co-inoculation of AMF and rhizobia enhanced nodulation under FeP, but not under KP. Our results suggest that the effects of AMF on shoot branching were mediated by cytokinins as the reduced shoot branching in FeP40 and KP40 under +AMF relative to -AMF coincided with a decreased concentration of cytokinins in xylem sap for both genotypes.

Wheat (Triticum aestivum) is a dominant and staple crop around the globe; hence, a large portion of the population depends on this crop for their daily food consumption. However, wheat faces several environmental stressors in its surroundings that elicit a devastating effect on its productivity and yield. Therefore, wheat relies on several tolerance strategies to enhance its survival and yield capacity under sudden environmental perturbations, including salt stress. Wheat root systems respond to salt stress contact by coordinating regulatory actions that impact growth, physiology, and yield tolerance. The root systems-mediated signaling networks could be considered as salt tolerance messengers, as they pivotally control and lower salt-induced oxidative toxicities in wheat plants. In response to salt stress exposure, the root system induces adaptive modifications in their morphological, physiological, and metabolic well-being to overcome salt severity to a greater extent. These mechanisms are pivotal in maintaining the equilibrium between the antioxidant metabolisms, providing relief from salt-mediated ionic, osmotic, and oxidative disorders. This can be further enhanced through biotechnological interventions encompassing omics strategies to finely tune root behavior, aiming to promote and protect the wheat productivity in response to salt environments. Thus, the present chapter highlights and focuses on the effects of salt stress on wheat plants and explains how root systems can help ameliorate plant morbidities. With a comprehensive understanding of root-mediated salt acclimatization, researchers could augment wheat defense mechanisms associated with the current and future concern for transgenic development to improve food security standards and crop nutrition values.

Salt stress is a widespread environmental constraint that impairs crop growth, development, and productivity, reducing seed germination and seedling growth. Plants respond to salinity by modulating physiological and molecular processes, but these responses are inefficient, with salinity issues rapidly escalating worldwide. Salicylic acid (SA) is the most important signal molecules. that protects plants from the damaging effects of salt. This study examined the tolerance potential of 10-day-old Capsicum annuum L. Pusa Sadabahar seedlings against various concentrations of salt stress (0, 25, 50, 75, 100, and 150 mM NaCl) with or without 1 mM salicylic acid (SA) to understand how SA could help Capsicum annuum avoid salt toxicity. The results showed that physiochemical attributes such as seed germination, were higher in the control (0 mM NaCl) and low to medium NaCl (50 and 75 mM) concentrations compared to the high NaCl (150 mM) concentration, which inhibited seed germination, shoot (180.75%) and root (507.20%) lengths, fresh and dry weights, % moisture content, tolerance index, vigor index, chlorophyll content and α-amylase, but increased enzymatic antioxidants like superoxide dismutase (SOD, 37.50%), peroxidase (POX, 62.21%), catalase (CAT), ascorbate peroxidase (APX, 30%), glutathione reductase (GR, 40.46%), glutathione-s-transferase (GST), glutathione peroxidase (GPX), glyoxalase I (Gly I, 44.37%) and glyoxalase II (Gly II, 34.58%) activities, non-enzymatic antioxidants, ascorbate (AsA, 48.51%), carotenoids, phenolics, proline (71.85%), hydrogen peroxide (H 2 O 2) , malondialdehyde (MDA, 60.05%), and protein contents. The exogenous SA treatment enhanced all studied parameters except AsA , H 2 O 2 , and MDA, protecting the cells from lipid peroxidation and stimulating the ascorbate-glutathione (AsH-GSH) cycle, glyoxalase system, and proline accumulation, which helped to alleviate salt-induced ionic and oxidative damage. Overall, the study highlighted the potential of SA in aiding Capsicum annuum ’s resistance to salt stress and reducing its harmful effects. • Salinity stress leads to reduced growth and development of Capsicum annuum . • Exogenous application of salicylic acid boosts AsA-GSH cycle to manage oxidative damage. • Salicylic acid induced the accumulation of proline content thus marking recovery from salinity stress. • Seed priming with SA protects plant growth and developmental processes during early growth stages.