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Abstract Hydrothermal liquefaction (HTL) is a promising technology for converting organic-rich waste biomass such as swine manure (SM) and sewage sludge (SS) into energy-dense bio-crude. Until now, one of the major challenges associated with HTL is the pumpability of high dry-matter containing fibrous feedstocks for continuous processing. In this context, this batch scale study presents a suitable approach for enhancing the pumpability of the fibrous material, specifically SM, by co-processing with SS. Obtained results showed that SM was not pumpable itself due to its fibrous nature, but became pumpable by the addition of SS at overall 25 % dry matter content. It was highlighted that the sample mixture containing ~80 % of the SM was smoothly pumped with 20 % SS. Subsequently, HTL experiments were carried out on samples mixed under the ratios SM:SS (100:0, 0:100, 50:50, 80:20, and 20:80). The highest bio-crude yield (42.38 %) via maximum synergistic effect was obtained from the sample SM/SS (50:50) at ratio 1:1 with the best HHV of 36 MJ/kg. Almost 60–70 % mass of all bio-crudes contained volatiles at 350 °C. ICP-AES measurements revealed that the majority of the inorganic elements were concentrated into the solid phase, while 40–50 % of the potassium and sodium were transferred to the aqueous phase. In conclusion, using SS as a co-substrate with SM not only enhances the pumpability of SM, but its co-liquefaction has demonstrated beneficial synergistic effects on improving the energy recovery of the bio-crude.

Many studies have examined the impact of climatic variability on agricultural productivity, although an understanding of these effects on farmland values and their relationship to farmers’ decisions to adapt and modify their land-use practices remains nascent in developing nations. We estimated the impacts of the deviation in our study year's (2012) temperature and precipitation patterns from medium-term (1980–2011) climatic patterns on farmland values in Pakistan. This was accomplished by employing a modified form of a Ricardian regression model. We also examined farmers’ perceptions of climate change during this period, as well as their perceptions of climate change impacts on farm productivity, in addition to past and anticipated farm adaptation strategies. Our results indicate that positive temperature deviation from the medium-term mean – indicative of climatic change – affects farmland values in Pakistan. Deviation in annual cumulative precipitation conversely appears to have no significant impact. Estimates of the marginal impact of temperature deviation suggested a slight but negative linear relationship with farmland values. The location of farms in areas where farmers can avail financial or extension services conversely had a positive impact on farmland values, as did the availability of irrigation facilities. Our analysis of farmers’ perceptions of climate change and their consequent adaptation behavior indicated a relatively high degree of awareness of climatic variability that influenced a number of proactive and future anticipated farm adaptation strategies. Examples included increased use of irrigation and farm enterprise diversification, as well as land-use change, including shifting from agriculture into alternative land uses. National policy in Pakistan underscores the importance of maintaining a productive rural agricultural sector. Our findings consequently highlight the importance of appropriate adaptation strategies to maintain both farm productivity and farmland values in much of Pakistan. The implications of increased extension and financial services to enhance farmers’ potential for climate change adaptation are discussed.

Climate change, soil degradation, and depletion of natural resources are becoming the most prominent challenges for crop productivity and environmental sustainability in modern agriculture. In the scenario of conventional farming system, limited chances are available to cope with these issues. Relay cropping is a method of multiple cropping where one crop is seeded into standing second crop well before harvesting of second crop. Relay cropping may solve a number of conflicts such as inefficient use of available resources, controversies in sowing time, fertilizer application, and soil degradation. Relay cropping is a complex suite of different resource-efficient technologies, which possesses the capability to improve soil quality, to increase net return, to increase land equivalent ratio, and to control the weeds and pest infestation. The current review emphasized relay cropping as a tool for crop diversification and environmental sustainability with special focus on soil. Briefly, benefits, constraints, and opportunities of relay cropping keeping the goals of higher crop productivity and sustainability have also been discussed in this review. The research and knowledge gap in relay cropping was also highlighted in order to guide the further studies in future.