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Tea is an economic shrubby plant in tropical and subtropical regions of the world. To obtain high yield in tea cultivation, chemical fertilizer application rates have generally been used. However, a large quantity of chemical fertilizer application in a long-term continuously ratooned and monoculture tea orchard can inevitably lead to soil acidification and a decline in fertility. Therefore, the restoration of soil fertility and the sustainable development of tea planting by organic ways are critical for the tea industry. In this study, field trials were conducted in the tea orchard that was continuously ratooned and mono-cultured for 20 years. Nitrogen fertilizer (NF), Laredo soybeans green manure (LF), and goat manure (GM) treatments were applied to restore optimum acidity, soil fertility, microbial activity, and the community structure of a long-term continuously monoculture tea orchard. This paper investigated that the pH value was increased from 4.23 to 4.32 in GM and LF, respectively. Similarly, the content of exchangeable acidity (EA) was decreased by 1.21 and 1.46 cmol·kg−1 in GM and LF, respectively. Available nutrient results indicated that the content of NH4+-N was increased by 3.96, 4.38, NO3−-N by 1.07, 2.16, AP by 3.46, 6.86, AK by 0.26, 0.3 mg kg−1 in GM and LF treatments, respectively. Enzyme analysis revealed that the activity of urease and sucrase was promoted by 7.98 mg·g−1·24 h−1 and 6.77 mg·g−1·24 h−1, respectively, in LF treatment. Likewise, the activity of acid phosphatase and polyphenol oxidase was sharply increased by 2.3 mg·g−1 h−1 and 63.07 mg·g−1 h−1 in LF treatments. Additionally, the activity of urease, sucrase, acidic phosphatase, polyphenol oxidase, and peroxidase were also significantly increased by applying GM treatments. Meanwhile, LF and GM treatments significantly improved soil microbial biomass as well as low weight organic acid content in degraded tea rhizosphere. Furthermore, high throughput sequence results illustrated that the relative abundance of Rhizobiaceae and Bradyrhizobiaceae families increased in LF and GM treatments, respectively, which are mostly a kind of nitrogen fixer and plant growth promoting bacteria. Taken together, the physiological traits of the new sprouts and the biochemical components of new tea leaves were also significantly improved by GM and LF treatments. From this study, it is concluded that LF and GM are good agriculture management practices, which promote plant growth, yield, and nutrient availability by maintaining and improving pH, enhancing available nutrients status, improving the secretion of low molecular weight organic acids, and balancing the microbial community structure in the long-term mono-cultured tea orchard.

There are many factors involved in the release of CO2 emissions from the soil, such as the type of soil management, the soil organic matter, the soil temperature and moisture conditions, crop phenological stage, weather conditions, residue management, among others. This study aimed to analyse the influence of these factors and their interactions to determine the emissions by evaluating the environmental cost expressed as the kg of CO2 emitted per kg of production in each of the crops and seasons studied. For this purpose, a field trial was conducted on a farm in Seville (Spain). The study compared Conservation Agriculture, including its three principles (no-tillage, permanent soil cover, and crop rotations), with conventional tillage. Carbon dioxide emissions measured across the four seasons of the experiment showed an increase strongly influenced by rainfall during the vegetative period, in both soil management systems. The results of this study confirm that extreme events of precipitation away from the normal means, result in episodes of high CO2 emissions into the atmosphere. This is very important because one of the consequences for future scenarios of climate change is precisely the increase of extreme episodes of precipitation and periods extremely dry, depending on the area considered. The total of emission values of the different plots of the study show how the soils under the conventional system (tillage) have been emitting 67% more than soils under the conventional agriculture system during the 2010/11 campaign and 25% for the last campaign where the most appreciable differences are observed.

Black soldier fly (BSF)-based bioconversion can reduce significant volumes of biosolids and other organic waste while generating high-value BSF larvae (BSFL) and frass. While the mass of frass is greater than the BSFL biomass, its end use is less explored, especially when the bioprocessed waste, such as biosolids, contains high concentrations of contaminants. We assessed the potential to use frass from bioconverted biosolids as fertiliser by analysing chemical parameters and conducting phytotoxicity germination tests. We included frass from bioconverted food waste and wheat bran as comparisons. The chemical composition and phytotoxicity of the frass was related to the type of feedstock. Frass originating from biosolids and from wheat bran had the highest phytotoxicity, which was correlated with increased NH4+-N and EC. Initially, these feedstocks had significantly higher total N compared to food waste. Frass derived from food waste showed the lowest phytotoxicity, which was related to low NH4+-N and EC. This study demonstrates that frass from BSF-based bioconversion could be used as fertiliser; however, the original feedstock will dictate how this by-product has to be used. In this study, frass from food waste was most suitable as fertiliser. Frass originating from bioconverted biosolids needs to be applied at similar rates as unconverted biosolids to avoid phytotoxicity.

In this study, three japonica rice varieties—Nanjing 9108, Jiahua 1 and Wuyunjing 29—were supplied with different levels of nano-foliar selenium fertilizers (0, 40 and 80 kg Se ha−1) under field conditions. Their rice yield and absorption, accumulation, transportation and utilization of selenium were studied to find suitable selenium-rich rice cultivars and optimal selenium supply levels, while providing references for the development of selenium-rich rice. On an average basis, the Nanjing 9108, Jiahua 1 and Wuyunjing 29 yielded 8755 ± 190, 8200 ± 317 and 9098 ± 72.7 kg ha−1, respectively. The selenium content in polished rice of the three rice varieties is between 0.210 and 0.933 mg kg−1. When 40 g Se ha−1 nano-selenium fertilizer was used, the selenium accumulation in the shoots of Nanjing 9108, Jiahua 1 and Wuyunjing 29 was, respectively, 11.4 g Se ha−1, 12.3 g Se ha−1 and 12.2 g Se ha−1, and when 80 g Se ha−1 selenium fertilizer was applied, the total selenium accumulation of three rice varieties was, respectively, 2.45, 1.75 and 2.40 times that of 40 g Se ha−1 selenium fertilizer. No evident diversity was observed in the selenium transport coefficient and the apparent utilization rate of selenium among the three varieties. The three rice varieties in this experiment had a strong selenium enrichment capacity, and they could be planted as selenium-enriched and high-yield rice varieties. Further, the amount of selenium fertilizer should not exceed 40 g Se ha−1.

Traceability technologies have great potential to improve sustainable performance in cold food supply chains by reducing food loss. In existing approaches, traceability technologies are selected either intuitively or through a random approach, that neither considers the trade-off between multiple cost–benefit technology criteria nor systematically translates user requirements for traceability systems into the selection process. This paper presents a hybrid approach combining the fuzzy Analytic Hierarchy Process (AHP) and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) with integer linear programming to select the optimum traceability technologies for improving sustainable performance in cold food supply chains. The proposed methodology is applied in four case studies utilising data collected from literature and expert interviews. The proposed approach can assist decision-makers, e.g., food business operators and technology companies, to identify what combination of technologies best suits a given food supply chain scenario and reduces food loss at minimum cost.

Due to an increase in international demand, quinoa production has boomed tremendously in the Andes since the early 2010s. This has led to significant investments into developing improved varieties for large-scale agribusinesses, but breeding programs are not tailored to the needs of smallholders. In this paper, we study farmers’ preferences and willingness to pay for improved quinoa varieties in the Junín region in Peru. We use data from a choice experiment among 458 smallholders and estimate generalized multinomial logit models to control for preference and scale heterogeneity. We find that farmers generally prefer improved varieties over traditional varieties, with mildew-resistance as the most important crop trait. In general, farmers prefer varieties that are characterized by larger grain sizes, higher yield levels, lower levels of saponin, and a reduced maturation period. Yet, food-insecure farmers are found to be indifferent to early maturity and a larger grain size, which can be explained by a lower degree of commercialization among these farmers. Our results imply that developing mildew-tolerant and higher-yielding varieties with a medium to low saponin content is a priority if investments in quinoa technologies are to benefit small-scale and food insecure farmers in the Andean highlands of Peru.

Slurries are one of the main NH3 emission sources. Nitrogen losses impact air quality, and they constrain the sustainability of farming activities. In a rainfed Mediterranean agricultural system, the aim was to quantify NH3 emissions at a time when plants do not yet cover the soil surface and according to fertilization practices. One treatment was slurry from fattening pigs (PSF) applied before cereal sowing and incorporated into the soil; two treatments were PSF or from sows (PSS) applied at the cereal tillering stage (topdressing); and two more treatments received slurries twice, before sowing and as topdressing. Ammonia emissions were quantified with semi-static chambers during 145 h (before sowing) and 576 h (at cereal tillering) after slurry application. Before sowing, tillage after slurry application controlled NH3-N emissions, but they accounted for 14% of the total NH4-N applied. At tillering, average NH3-N emissions also accounted for ca. 14% of total NH4-N applied as PSF or PSS, respectively. Slurry dry matter from 84 kg m−3 (PSS) up to 127 kg m−3 (PSF), combined with low soil moisture content (below 30% of water holding capacity) at application time, helped in NH3 emission control. Slurry applications before sowing did not enhance later NH3-N emissions at topdressing.