The term ‘Hydroponics’ was derived from Greek word ‘hydro’ means water and ‘ponos’ mean labor. Hydroponics is a modern agriculture technique that uses nutrient solution rather than soil for crop production. Humans need water, food and living habitat to endure. As population increases the food demand also increases. The worry is that the existing system of agriculture will not be able to meet the food requirement near future as this system is facing many challenges. The objectives of this review paper are to discuss the hydroponic greenhouse technologies, impact of environmental factors on hydroponic greenhouse cultivation, advantages and challenges of hydroponic greenhouse system. This study revealed that hydroponic greenhouse cultivation is better option in the sense of utilization of inputs and improved crop production.

The number of spray deposits plays an important role in effective and efficient spraying. The spraying equipment is one of the most significant factors that affect the number of spray deposits. Therefore, the study was focused on the parameter optimization of a newly developed self-propelled variable height crop sprayer. Response surface methodology (RSM) along with Box–Behnken design (BBD) was used to study the effect of the independent variables (forward speed, spray height, and spray pressure) on response variables such as droplet density, coverage per-centage, and Volume Median Diameter (VMD). The experiment was conducted in the cotton field. Additionally, the RSM model was validated in this research. The results revealed that the coefficient of determination (R2) values was good for all response variables in the quadratic polynomial model. The optimized parameters were 6.5 km/h, 60 cm, 4 bar for fungicide application, and 8 km/h, 70 cm, 3 bar for insecticide and herbicide application. The predicted response variable values at the optimal conditions were 60.4 droplet/cm², 27%, 230 µm for fungicides and 37.8 droplet/cm², 19.1%, 225.4 µm for insecticide and herbicides application. The model validation is confirmed by the mean of actual response variable values at the optimal condition for insecticide and herbicides application, which was 41.35 ± 3.67 droplet/cm², 21.10 ± 1.72%, 227.43 ± 1.22 µm, and the prediction error was 8.46%, 9.2%, and 0.9% for droplet density, coverage percentage, and VMD, respectively. This study can provide support for further optimizing the parameters of the sprayer.

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.

The spray is the primary method to apply pesticides to the crops. To provide enough coverage and deposition on target surfaces, the drop size produced during spray application must be precisely calibrated; nevertheless, it must not be too tiny to cause the undesirable phenomena known as “spray drift”. Spray drift is the movement of droplets in the atmosphere during or after spraying. The negative effect of spray drift can harm human health, livestock, and adjacent crops or can cause environmental pollution. To address this problem, a lot of work has been done. Previous studies on spray drift reduction approaches including factors promoting drift, drift measuring technologies, drift prediction models, and drift reduction technologies, were reviewed in this paper. Based on the literature review, future research and developments are projected. This review may provide guidance and reference to researchers for further development and improvement in drift reduction technologies.

Drying is the taking away of water from agricultural product thus at the same time provide extended period of shelf life. In this study, an innovative solar sustained maize dryer along with screw conveyor for unloading the grain and central air perforated duct (throughout aeration chamber length) has been developed. High drying rate was achieved due to central air distribution model of the dryer during the drying process. Using 758-kg of freshly harvested maize at moisture content 24% (wet basis), dryer was evaluated. The average aeration rate of the solar sustained maize dryer was 3.67 kilogram per hour. 60% saving in drying time was also achieved by using the solar sustained maize dryer. From 24% to 13% moisture content for drying the whole maize, solar sustained maize dryer took 27 hours. It is economical and environment friendly drying method. Cost analysis was also done and it was found by using this drying method, at very low cost we can dehydrated better quality maize. At community level, marketable size of the solar sustained maize dryer can be better and formed for revolution of agriculture in the country-side areas.