This study aimed to evaluate the ability of the response surface methodology (RSM) approach to predict the tractive performance of an agricultural tractor during semi-deep tillage operations. The studied parameters of tractor performance, including slippage (S), drawbar power (DP) and traction efficiency (TE), were affected by two different types of tillage tool (paraplow and subsoiler), three different levels of operating depth (30, 40 and 50 cm), and four different levels of forward speed (1.8, 2.3, 2.9 and 3.5 km h⁻¹). Tractors drove a vertical load at two levels (225 kg and no weight) in four replications, forming a total of 192 datapoints. Field test results showed that all variables except vertical load, and different combinations of this and other variables, were effective for the S, DP and TE. Increments in speed and depth resulted in an increase and decrease in S and TE, respectively. Additionally, the RSM approach displayed changes in slippage, drawbar power and traction efficiency, resulting from alterations in tine type, depth, speed and vertical load at 3D views, with high accuracy due to the graph’s surfaces, with many small pixels. The RSM model predicted the slippage as 6.75%, drawbar power as 2.23 kW and traction efficiency as 82.91% at the optimal state for the paraplow tine, with an operating depth of 30 cm, forward speed of 2.07 km h⁻¹ and a vertical load of 0.01 kg.

Reducing reliance on fossil fuels with clean and sustainable alternatives is essential for mitigating climate change and global warming-related environmental concerns. Previous researchers have studied the performance of choppers and crushers as separate units powered by diesel or gasoline engines. Nowadays, an increasing interest in producing Eco-friendly machines that stand out for being dual purposes, cost-effectiveness, and with lengths suitable for feeding ruminants are imperative to achieving economic and sustainable goals. Therefore, this study aims to solve these issues and gaps by developing and evaluating a dual-purpose forage machine for chopping and crushing operations to achieve both operations more efficiently and at a lower cost. The developed forage machine's performance was evaluated for chopping operation using maize stalks with four different rotational speeds of 1200, 1400, 1600, and 1800 rpm and four different moisture contents of 22.7, 43.3, 59.8, and 74.6% (w.b.). Also, the crushing operation was evaluated using maize ears with four different crusher speeds of 1200, 1400, 1600, and 1800 rpm and three different sieves with holes' diameters of 6, 8, and 10 mm. The results concluded that the highest efficiencies with values of 94.17 and 92.85% were obtained at 1800 rpm chopper rotational speed and 22.7% moisture content for the chopper and 1200 rpm crusher rotational speed and 10 mm sieve hole diameter for the crusher, respectively. At these proper operational parameters, the machine productivity of 2.44 and 0.31 ton.hr⁻¹, the specific energy requirements of 3.22 and 4.50 kW h.ton⁻¹, and the estimated production costs of 23.56 and 121.24 EGP.ton⁻¹ (1.25 and 6.38 USD.ton⁻¹) were obtained for chopper and crusher, respectively.

Due to the recent high prices of livestock feed in the world and the new sustainable management practices of rice straw, livestock farmers are obligated to either use or purchase rice straw and cut it to desired lengths to feed ruminants. Therefore, this study aimed to construct a combined machine for collecting and chopping rice straw for lengths preferred in feeding ruminants. The combined machine comprises three main units: a picking up unit, a chopping unit, and a takeout unit. Field experiments were performed on average rice straw moisture content of 25% (w.b.) to evaluate the performance of the combined machine, under factors of 1.3, 1.6, 1.9, and 2.2 km h⁻¹ forward speeds, elevator velocities of 0.79, 0.94, and 1.10 m s⁻¹, and chopping knives rotational speeds of 1600, 2000 and 2400 rpm. The obtained results indicated that the consumed specific energy was 90.94 kWh ha⁻¹ to achieve the highest field capacity of 0.24 ha h⁻¹, with collecting efficiency of 95.30% at a forward speed of 2.2 km h⁻¹, elevator velocity of 1.10 m s⁻¹ and rotational speed of 2400 rpm for chopping knives. In order to achieve the highest chopping quality of 95%, it is recommended to operate the elevator velocity at 0.79 m s⁻¹, rotate chopping knives at 2400 rpm, and drive the tractor at a forward speed of 1.3 km h⁻¹. The total operating cost of the combined machine is lower than the traditional methods by about 49.84%.

Small-scale power weeders are an important and challenging task in many countries, where the farm size in hectare per capita is very low and is declining over time. Therefore, the development of suitable mechanized weeding methods is an imperative to meet the demand for farmers. An economical mechanical power weeder that can be used as inter and intra-row weeding method was developed and evaluated in triple hybrid 314 variety of maize. Developed power weeder consisted of engine, blades assembly and transmission system. Modified vertical blades were used with the weeder and mounted on a circular rotating element on its horizontal side; the motion was transferred to blades units by amended transmission system. The effect of weeder forward speeds, depth of operation, number of blades and soil moisture content on fuel consumption, plant damage, weeding index, effective field capacity, field efficiency, energy required per unit area and total cost were studied. Three levels of soil moisture content (7.73, 12.28 and 16.18 %), two blades arrangements (two and four vertical blades for each unit), three weeder forward speeds (1.8, 2.1 and 2.4 km/h) and two depths of operation (from 0 to 20 and from 20 to 40 mm) have been chosen. The results showed that, the minimum value of fuel consumption was 0.546 l/h and recorded by using two blades with 1.8 km/h weeder forward speed at depth of operation ranged from 0-20 mm and soil moisture content 16.18 %. The highest field efficiency was 89.88% by using two blades with 1.8 km /h weeder forward speed at depth of operation ranged from 0 to 20 mm and soil moisture content 16.18%. The minimum value of effective field capacity was 0.198 fed/h by using four blades, weeder forward speed 1.8 km/h, soil moisture content 7.73% and under depth of operation ranged from 20-40 mm. The lower value of total cost was 55.09 L.E /fed and was obtained by using two blades with 2.4 km/h weeder forward speed at depth of operation ranged from 0-20 mm and soil moisture content 16.18 %.

This study investigated the potential and sustainable use of the biomass derived from various stages of the grape drying process. A total of eleven byproducts, each containing varying organic materials, were produced and subjected to testing. Ultimate analysis, as well as analyses of heating values, chemical composition, lignocellulose composition, total solids concentration and biogas production were performed with the recommended criteria and assessment methods. The results reveal that carbon (C), nitrogen (N), hydrogen (H), and oxygen (O) levels were significantly different among the byproducts. The ash content of byproducts 5–11 ranged from 3.56 to 5.11%, which was lower than the estimated values in the other byproducts. The analysis of higher heating value showed significantly higher calorific values for byproducts 10 and 11 (22.73 ± 0.08 and 22.80 ± 0.07 MJ kg⁻¹, respectively). Byproducts 1–9 had lower sugar content than byproducts 10 and 11 (rejected raisins). Byproducts 5–9 had the lowest lignin content, and there were no significant differences in neutral detergent fiber (NDF) contents between byproducts 1–6. The highest accumulated biogas volume after 40 days was 11.50 NL L⁻¹ of substrate for byproduct group C (byproducts 10 to 11), followed by 11.20 NL L⁻¹ of substrate for byproduct group B (byproducts 5–9) and 9.51 NL L⁻¹ of substrate for byproduct group A (byproducts 1–4). It is concluded that byproducts consisting of biomass derived at different stages of raisin production may be an effective solid fuel and energy source. The amounts of volatile solids in the tested raisin processing byproducts indicated their appropriateness for pyrolysis conversion to a liquid product with high volatile content.