In most Asian countries, farmers have smallholdings ranging from one to two hectares. The tractor-mounted boom sprayers cannot practically be used in small size farms with divided plots and complex terrain. To cope with these issues, a prototype self-propelled crop sprayer was developed, including a 20-hp engine, 300 L liquid tank, and hydraulically-controlled spray boom with eight hollow cone nozzles. The spray symmetry of the hollow cone nozzle was evaluated under four pressures (2.5, 3, 3.5, and 4 bar) in the laboratory. The operating parameters of the sprayer, such as forward speed (4, 6, and 8 km h⁻¹), spray height (40, 55, and 70 cm), and pressure (3, 5, and 7 bar) were optimized by measuring three spray characteristics including droplet density, coverage percentage, and Volume Median Diameter (VMD) in the cotton field. The results revealed that the nozzle spray was symmetrical at 2.5 and 3 bar pressure as the R² value was higher than 0.96. The field test result showed that in all treatments, treatments T14 (6 km h⁻¹, 55 cm, 5 bar) and T22 (8 km h⁻¹, 55 cm, 3 bar) were suitable for spraying medium-to-low concentration solution (post-emergence herbicides and fungicides) and high concentration solution (insecticides and pre-emergence herbicides), respectively. The spray characteristics at treatments T14 and T22 were 64.7 droplets cm⁻², 26.7%, 230 µm, and 39 droplets cm⁻², 14.9%, and 219.8 µm respectively. The field efficiency of the sprayer was 61%. The spraying cost per unit area was 55–64% less compared to manual labor cost. In conclusion, a prototype self-propelled crop sprayer is an efficient and environment-friendly technology for small farms. Operating the sprayer at the optimal parameters also saves operational costs and time.

Cotton is a global cash crop with a significant contribution in the world economy. Optimum nutrient and water supply are most important for sustainable cotton production under warmer and dry environments. Field experiments were carried out to evaluate the cumulative impacts of various nitrogen doses and mulches on sustainable cotton production under semi-arid conditions during 2018 and 2019. Four nitrogen doses; 0, 70, 140, and 210 kg ha⁻¹ and three types of mulch: control (without mulch), natural mulch (5 tons/ha wheat straw), and chemical mulch (methanol (30%). Nitrogen 210 kg ha⁻¹ with natural mulching increased 40.5% gunning out turn, 30.0% fiber length, 31.7% fiber strength, 32.6% fiber fineness, 20.8% fiber uniformity, and 34.0% fiber elongation. Shoot nitrogen, phosphorous, potassium, calcium, and magnesium contents were maximum where 210 kg ha⁻¹ nitrogen and mulch was applied. Natural mulch reduced the soil temperature as compared to chemical and no mulch conditions. The soil temperature was 0.5 to 1.8 ℃ lower in mulching treatments as compared to the control. Maximum economic yield was around 90% higher in natural mulch with the 210 kg ha⁻¹ nitrogen application. It is concluded that optimum nitrogen application with natural mulch not only enhanced plant growth and development but also induced sustainability in quality cotton production under semi-arid conditions.

Energy and the environment are among the top global issues of this era. Environmental degradation specifically due to consumption of fossil fuels in conventional energy generation systems has become a critical challenge for the whole world. With the introduction of advance industrial processes and operations, the air quality deterioration has also become very complex. There is a dire need to replace the conventional energy systems with alternative energy resources for reducing air pollutants. Renewable energy systems generate clean energy with less environmental footprints. This chapter will highlight the latest trends and future strategies in clean and renewable energy supply systems to mitigate air pollution for environmental sustainability.

Atmosphere is polluted for all living, non-living entities. Concentrations of atmospheric pollutants like PM2.5, PM10, CO, CO2, NO, NO2, and volatile organic compounds (VOC) are increasing abruptly due to anthropogenic activities (fossil fuels combustion, industrial activities, and power generation etc.). These pollutants are causing soil (microbial diversity disturbance, soil structure), plants (germination, growth, and biochemistry), and human health (asthma, liver, and lungs disorders to cancers) interventions. All the effects of these pollutants on soil, plants, animals, and microbes needed to be discussed briefly. Different strategies and technologies (HOPES, IOT, TEMPO and TNGAPMS) are used in the world to reduce the pollutant emission at source or when in the atmosphere and also discussed here. All gaseous emissions control mechanisms for major exhaust gases from toxic to less toxic form or environmental friendly form are major concern. Heavy metals present in dust and volatile organic compounds are converted into less toxic forms and their techniques are discussed briefly.