The conversion of natural forests to tea plantations largely affects soil nitrous oxide (N₂O) emissions and soil microbial communities. However, the impacts of this conversion on the contribution of fungi to N₂O emission and on fungal community structure remain unclear. In this study, we determined the soil N₂O emission rate, N₂O production by fungi, associated fungal community diversity, and related ecological factors in chronological changes of tea crop systems (3, 36 and 105 years old tea orchards named T3, T36 and T105, respectively), and in an adjacent soil from a natural forest. The results indicate that the tea plantations significantly enhanced soil N₂O production compared with the forest soil. Tea plantations significantly decreased soil pH and C/N ratio, but increased soil inorganic nitrogen (N). Furthermore, they increased the fungal contribution to the production of soil N₂O, but decreased the bacterial counterpart. We also observed that fungal community and functional composition differed distinctly between tea plantations and forest. Additionally, most of the fungal groups in high N₂O emission soils (T36 and T105) were identified as the genus Fusarium, which were positively correlated with soil N₂O emissions. The variation in N₂O emission response could be well explained by NO₃⁻-N, soil organic carbon (SOC), C/N, and Fusarium, which contributed to up to 97% of the observed variance. Altogether, these findings provide significant direct evidence that the increase of soil N₂O emissions and fungal communities be attributed to the conversion of natural forest to tea plantations.

Land use in east China tends to change from paddy rice to vegetables or other high-value cash crops, resulting in high input rates of organic manures and increased risk of contamination with both heavy metals (HMs) and antibiotics. This investigation was conducted to determine the accumulation, distribution and risks of HMs and tetracyclines (TCs) in surface soils and profiles receiving different amounts of farmyard manure. Soil samples collected from suburbs of Hangzhou city, Zhejiang province were introduced to represent three types of land use change from paddy rice to asparagus production, vineyards and field mustard cultivation, and divided into two portions, one of which was air-dried and sieved through 2-, 0.3- and 0.149-mm nylon mesh for determination of pH and heavy metals. The other portion was frozen at -20 °C, freeze-dried and sieved through a 0.3-mm nylon mesh for tetracyline determination. HM and TC concentrations in surface soils of 14-year-old mustard fields were the highest with total Cu, Zn, Cd and ∑TCs of 50.5, 196, 1.03 mg kg(-1) and 22.9 μg kg(-1), respectively, on average. The total Cu sequence was field mustard > vineyards > asparagus when duration of land use change was considered; oxytetracycline (OTC) and doxycycline were dominant in soils used for asparagus production; OTC was dominant in vineyards and chlortetracycline (CTC) was dominant in mustard soils. There were positive pollution relationships among Cu, Zn and ∑TCs, especially between Cu and Zn or Cu and ∑TCs. Repeated and excessive application of manures from intensive farming systems may produce combined contamination with HMs and TCs which were found in the top 20 cm of the arable soil profiles and also extended to 20-40 cm depth. Increasing manure application rate and cultivation time led to continuing increases in residue concentrations and movement down the soil profile.

Intercropping of arsenic (As) hyperaccumulator Pteris vittata and cash crop Morus alba could improve the As concentration in the hyperaccumulator but decrease As concentration in the intercropped crop. The effects of several amendments on the transfer of As were investigated to determine an enhancement strategy for the intercropping system of P. vittata and M. alba. Phosphorus, in the form of Ca(H₂PO₄)₂, promoted the release of As to the soil solution and apparently increased the As removal from the soil by 42% compared with the untreated variant. The addition of FeSO₄ and CaCO₃ decreased As concentration in the soil solution and the uptake of As by both plant species. The As levels in the mulberry leaves remained under the threshold limits of feedstuffs in China. Intercropping was confirmed as an applicable strategy to manage contaminated soil. Hence, under the condition that all treatments produced safe mulberry leaves, Ca(H₂PO₄)₂ was the appropriate amendment to achieve the highest As removal rate, whereas FeSO₄ could lower the risk of As to further migrate to another medium.

The expansion of land being used for cash crop cultivation has threatened wildlife in recent decades. Tea has become the dominant cash crop in southwestern China. Unfortunately, tea plantations may threaten Asian elephant (Elephus maximus) populations via habitat loss and fragmentation. Identifying areas of suitable habitat for tea plant cultivation, and where this habitat overlaps with Asian elephant distribution, is vital for planning land use, managing nature reserves, shaping policy, and maintaining local economies. Here, we assess the potential impact of tea plantations on Asian elephants in southwestern Yunnan province, China. We used MaxEnt modeling with bioclimatic and environmental variables to identify suitable habitat for tea plant cultivation under the current climate scenario, and then overlapped this habitat with 9 known Asian elephant distribution areas (G1–G9) to determine “threatened areas.” Our results showed that (1) annual precipitation (48.1% contribution), temperature constancy (29 % contribution), and slope (8.7 % contribution) were key in determining suitable habitat for tea plants; (2) the cumulative area of suitable habitat for tea plants was 13,784.88 km², mainly distributed in Menghai (3934.53 km²), Lancang (3198.67 km²), and Jinghong (2657.74 km²); (3) the distribution area of elephants was 943.75 km², and these areas overlapped with suitable tea plant habitat primarily located in G4 (379.40 km²), G3 (251.18), and G7 (168.03 km²); and (4) threatened areas in G1 and G7 were predominately located along the periphery of current nature reserves. Win-win solutions that work for elephant conservation and economic development include rescoping nature reserve boundaries, strengthening management on the periphery of nature reserves, establishing ecological corridors and new nature reserves within regions where elephants are currently distributed, planting alternative cash crops, and financial subsidies to farmers. This study improves understanding of human-elephant coexistence, and will assist in guiding land use policy for the future conservation outcomes seeking to promote responsible and profitable cash crop farming and elephant conservation.

Pakistan is placed among the most vulnerable countries with relation to climate change and its impacts on agricultural productivity. Cotton is staged as the cash crop of the country and the main source of raw material for textile, oil, and feed industry. Varying environmental attributes have significant effects on the duration of vegetative and reproductive stages of cotton crop. To evaluate the potential impacts of varied temperatures regimes in different sowing times, field experiments were carried out throughout the cotton growing areas of Pakistan from Faisalabad in Central Punjab to RYK in Southern Punjab and Sakrand in Sindh to Dera Ismail Khan in Khyber Pakhtunkhwa (KPK) Province. Crop was sown on six different sowing dates starting from 1st March towards 15th May with 2-week intervals for two crop seasons (2016 and 2017). The timing of phenological events like emergence, squaring, flowering, and boll opening was recorded on calendar days and cumulative heat units (GDDs) were calculated for flowering and boll opening stages. Heat use efficiency for these sowing times was estimated. Data regarding yield-related parameters like opened bolls per plant, average boll weight, and seed cotton yield were also recorded during the study. Results revealed that duration of the growth stages was significantly affected by variation in mean thermal kinetics in varied sowing times in all four different environments. Seed cotton yield and heat use efficiency were also varied among the locations and sowing dates. The maximum seed cotton yield was recorded in Sakrand location at 15th April sowing date. The dependence of the phenological advancement on temperature and negative impacts of higher thermal stress on cotton productivity were also confirmed throughout the cotton growing zone of Pakistan.

Plastic films have previously displayed tremendous potential to increase water use efficiency in farmland and the yield of cash crops; however, long-term use of plastic film in soils can influence soil physiological and biochemical characteristics and change its biota. The present study aimed to investigate the effects of residual plastic film pollution on soil microbe community structure and fertility in Xinjiang province, China. Residual plastic film-contaminated soil and non-contaminated soil in Xinjiang farmland were selected for this study. The results indicated that residual plastic film pollution changed the structure of the soil biological community by significantly decreasing and increasing the abundance of Actinomycetes and Proteobacteria, respectively; further, the pollution decreased soil organic matter and inorganic nitrogen content by downregulating microbial genes related to soil carbon and nitrogen cycles and decreasing related enzymatic activities. The present results indicated that long-term residual plastic film exposure (more than 10 years) in farmland significantly decreases soil fertility and alters the microbial community structure.

Cadmium (Cd) is a widespread toxic heavy metal trace pollutant worldwide. The ability of Cd absorption and accumulation highly varies among different species and varieties. In order to screen oilseed rape cultivars which are appropriate for cultivation and application in Cd-contaminated soils, we conducted the field trial of 32 oilseed rape varieties in Shifang County of Chengdu Plain. The various biomass, Cd accumulation, and distribution patterns were investigated via determining the Cd concentration in different plant tissues. Moreover, the food safety risks of rapeseeds were finally assessed. The results indicated diverse responses to Cd stress appeared in various tested varieties, including plant biomass, seed yield, Cd concentration, and proportion in different tissues. And most Cd were concentrated in non-edible parts. Through cluster analysis, we found that Nanchongjie, Pengzhoubai, and J-25 belong to high-biomass and high-Cd-accumulated groups in experimental cultivars, which indicated that they could possess more biomass and gather higher Cd content in overground part, so they could be great materials for phytoremediation in Cd-polluted area. Besides, combined with the risk assessment of food safety in rapeseeds, cultivars 72A and 47 with the traits of high yield, low-Cd concentration, and low food safety risk can be considered as suitable materials to widely plant as cash crop. These results provide valuable reference for practical planting and application of oilseed rape in Cd-polluted areas.

Excessive nitrogen (N) discharge from agriculture causes widespread problems in aquatic ecosystems. Knowledge of spatiotemporal patterns and source attribution of N pollution is critical for nutrient management programs but is poorly studied in headwaters with various small water bodies and mini-point pollution sources. Taking a typical small watershed in the low mountains of Southeastern China as an example, N pollution and source attribution were studied for a multipond system around a village using the Hydrological Simulation Program-Fortran (HSPF) model. The results exhibited distinctive spatio-seasonal variations with an overall seriousness rank for the three indicators: total nitrogen (TN) > nitrate/nitrite nitrogen (NOₓ⁻-N) > ammonia nitrogen (NH₃-N), according to the Chinese Surface Water Quality Standard. TN pollution was severe for the entire watershed, while NOₓ⁻-N pollution was significant for ponds and ditches far from the village, and the NH₃-N concentrations were acceptable except for the ponds near the village in summer. Although food and cash crop production accounted for the largest source of N loads, we discovered that mini-point pollution sources, including animal feeding operations, rural residential sewage, and waste, together contributed as high as 47% of the TN and NH₃-N loads in ponds and ditches. So, apart from eco-fertilizer programs and concentrated animal feeding operations, the importance of environmental awareness building for resource management is highlighted for small farmers in headwater agricultural watersheds. As a first attempt to incorporate multipond systems into the process-based modeling of nonpoint source (NPS) pollution, this work can inform other hydro-environmental studies on scattered and small water bodies. The results are also useful to water quality improvement for entire river basins.

Assessing the current farm-level efforts of climate change adaptation is essential to distinguish their usefulness and implying policy level advance measures for future. The present study investigated cotton farmers’ climate change adaptation and its impact on increasing cotton productivity and net cotton income in Punjab province of Pakistan. A pretested and well-structured questionnaire was used for data collection of 480 cotton farmers from three major cotton-producing divisions of cotton-wheat zone of Punjab, Pakistan. Logistic regression analysis approach was used in this study to find out the factors of adaptation and propensity score matching method employed to identify connecting adaptation impact on cotton productivity and cotton income. Empirical estimates of this study indicated as owing to some external and internal constraint farmers were limited focused on adaptation while conscious about adverse effects of climate change. Usage of required and recommended types of fertilizer, variation in planting dates, and changing varieties of crop were main adaptation strategies implemented by cotton farmers. Cotton farmers’ adaptation decision was significantly influenced by some major factors as weather forecasting, market information, easy access to agricultural extension services, farming experience, and education of cotton farmer. Farm-level increase in cotton productivity and net cotton crop income was direct while overall increases in national output and improving rural area farmer well-being were indirect and significant outcomes of implementing climate change adaptation of cotton farmers. Cotton farmers were using various combinations of adaptation strategies and achieving more benefits regarding their crop productivity and net returns. Findings of the study suggest need for larger investment in farm-level extension services, farmers’ schooling, and develop climate change institutional setup for enhancing farmers’ adaptation capability to increasing cotton productivity, improving well-being of farming community, and securing agriculture from future climatic uncertainties. Future policies must deal with farm-level limitations of advanced adaptation measures like making available information and sustaining sponsoring soil conservation practices, launching climate smart varieties and advanced adaptation measures based on various agro-ecological zones.

Tea tree (Camellia sinensis) is a valuable and popular cash crop widely planted in tropical and subtropical areas of China. To increase tea yield and quality, high rates of chemical fertilizer and pesticide application have generally been used; however, increasing usage of fertilizers and pesticides does not always proportionally increase tea yield. Indeed, excessive nutrient inputs may cause serious agricultural non-point source pollution. A pilot study on dual reduction in fertilizers and pesticides was conducted in a green tea plantation in Shaoxing, Zhejiang Province, to explore the environmental effects of different fertilizer and pesticide managements (e.g., changes in soil properties and nutrient accumulation, nutrient inputs in runoff water) and to reveal the potential effects of the interaction of these two managements on tea yield and quality. Traditional formulas and rates of chemical fertilizers and pesticides were used as the baselines (100% usage); replacement with different proportions of organic fertilizer (i.e., 20%, 50% and 80%) and direct pesticide reductions of 30%, 50%, and 80% were tested. The results showed that proper management with organic fertilizer replacement can effectively mitigate soil acidification and nutrient deficiency in tea plantations, increase soil organic matter (OM) and ammonium nitrogen (NH₄-N) contents, and promote tea yield and quality. Moreover, managements with organic fertilizer replacement can markedly reduce the inputs of ammonium nitrogen (NH₄-N), nitrate nitrogen (NO₃-N), total phosphorus (TP), and total potassium (TK) in runoff water. Soil nutrient accumulation was the highest while the runoff nutrient input was the lowest at 20% organic fertilizer replacement. Experimental spraying of bifenthrin and chlorfenapyr revealed that these pesticides were mainly trapped by the tea leaves and rarely entered the soil or water bodies. Although pesticide reduction treatments can effectively decrease pesticide residues in tea leaves, differences in pesticide residue between various treatments were not obvious due to the rapid degradation of pesticides. Multivariate analysis of variance showed that 50% of the variation in tea yield, bud density, polyphenols, and caffeine can be explained by interactions between fertilizers and pesticides. Combinations of 20% or 50% organic fertilizer replacement and 30% or 50% pesticide application reduction are appropriate for both mitigating nutrient loss and balancing tea yield and quality, especially the combination of 50% organic fertilizer replacement and 50% pesticide reduction, which produced the best results. This study demonstrates the feasibility of dual reductions in fertilizers and pesticides for mitigating environmental hazards while maintaining the yield and quality of tea.