PERFORMANCE EVALUATION OF SEED DRILL-FERTILIZER UNDER TWO DIFFERENT FARMING SYSTEMS AND TRACTOR PRACTICAL SPEEDS

This study was aim to investigate performance of seed drill - fertilizer (GIL-SAX multisem18) was evaluated under two different farming systems (till and no-till) and tractor speeds (5.28, 7.76 and 8.30 km.h -1 ). The characteristics were measured including draft force, wheel slip, seed delivery rate, and germination rate. The experiment was organized as a randomized complete block design (RCBD). The significant difference was examined using the least significant difference tests at a P≤0.05. The results showed a minimum draft force and wheel slip under the till system and tractor speed of 5.28 km.h -1 interaction. The lowest seed delivery rate was found when no-till was practiced with a speed of 5.28 km.h -1 . Adopting the no-till system with the speed of 7.76 km.h -1 achieved the highest germination rate. The till system achieved the lowest fuel cost in economic analysis 8395 IQD. ha -1 at a speed of 8.30 km.h -1 , while the no-till system achieved the lowest cost of seeds 65066 IQD. ha -1 and sowing operation cost 36079 IQD. ha -1 at speed 5.28 km.h -1 . Irrigation and agronomy indicators should be addressed in the further work.


INTRODUCTION
Finding new ways to increase the yield of cereal crop production is a global ambition (1,18,27). For instance, identifying new techniques to reduce the impact of pests (2,9,13,26,28). In Iraq, wheat represents the most crucial strategic food crop. This crop's importance relies on the fact that it is profitable and growing in all Iraqi provinces and contributes to maximizing the national income (39). In addition, the crop plays a role in employing approximately 20% of the Iraqi population (7,39). This is because wheat is suited to Iraqi conditions such as climate circumstances, soil characteristics and water availability (21). Due to the sustainable improvement of farming systems, sowing methods are the dominant factor affecting seeding efficiency and crops performance (32,36,46). Farming systems can be categorized in cultivation practices, field traffic, crops, machines utilized for sowing (16,45). One of the ways to improve crop yields and minimise field inputs is to adopt a farming system that reduces the number of machineries used and traffic (14). In terms of tillage practices, the farming systems employed by wheat farmers globally are broadly classified as either conventional tillage (CT) or no-till (17). Under the CT systems, primary and secondary tillage are used to remove soil compaction, prepare the appropriate seedbeds and provide better seed germination and root growth (13,37). However, intensive use of primarily tillage equipment (e.g., moldboard, chisel plough, and sub-soiler) can lead to erosion and damage in the soil structure (31). The no-till system was practiced globally with about 111 million hectares since 2009 and continued to increase until it rapidly reached 155 million hectares in 2014 (23). This practice was applied in Northern Iraq to improve wheat crops and sustainability in the rainfed crops since 2005 (21). The key advantages of no-till are to improving water quality, reducing fuel and time and labour saving (6 ,33). However, notill has been a relatively recent introduction in Iraq, and its adoption rate and effects are still relatively low (20). Several techniques of wheat seeding methods are available worldwide; the wheat drills are typically designed with different operating widths and rows to cover a wider area and provide a uniform plant population on the farm (44). The main advantages of using seed drills are to saving seeds, effort, covering seeds faster, reducing farm input and saving time, and planting seeds at a uniform depth (43). However, the efficiency of drills is significantly affected by the conditions such as tractor speed and the physical properties of the seeds (30). Thus, this paper attempted to evaluate the performance of GIL seed drillsfertilizer under two different farming systems and three -level tractor speeds under Iraqi conditions. The characteristics were measured including draft force, wheel slip, seed delivery rate, and germination rate. The findings of this research may provide significant information for farmers to be more specific in their applications of wheat growing which can be potentially translated to savings in finances and time.

MATERIALS AND METHODS Site description A typical site was selected in Abu Ghraib
Research Station/ Office of Agricultural Research/ Baghdad (33°19'33.01" N 44°13'21.58" E, 34.1 m above sea level) during the growing season 2021/2022. This site was located about 38 km from the center of Baghdad. In addition, the area was used for cropping wheat maize in rotation. The soil texture was silty clay. The variety of wheat (Mawada) is grown yearly in this district due to water availability and suitability of the soil. According to the Agro-meteorological center/ Iraqi Ministry of Agriculture (2021), the location has a moderate climate. Wheat was planted and irrigated on December, 5 th , 2021. Flood irrigation was applied in this study.

Experiment design
The field trial was organised as a random complete block design (RCBD) (2*3) with three replications were followed (5). This design allows for identifying the influence of factors and their interactions. The field was divided into two blocks. The first block was employed for conventional tillage and the second was used for no-till. The length of each block was 200 m, while the width was 13.5 m. Each block had 18 treatments. The treatment dimensions were 20 m in length and 3 m in width to correspond to the working width of the seed drill -fertilizer. The treatments were also randomly selected in each block to reduce the chance of biased outcomes. Transects were left between treatments for tractor stability and field measurements were followed (4). The dimensions of the transect (15 m * 3 m). The independent variables were farming system (till and no-till) and tractor speeds (5.28, 7.76 and 8.30 km.h -1 ). The dependent variables were a draft force, wheel slip, seed delivery rate, and germination rate. Field work and research studied parameter Draft force (DF) As reported above, two tractors were employed in this research. The measurement of DF was done by attaching a dynamometer between two tractors. The first tractor (Renault 630) was used as a pulling tractor, while the second (Valtra 6400) was used as a neutral. As well, the GIL seed drill -fertilizer was attached to the second tractor. A distance of 20 m aligned with the study area was selected for measuring rolling resistance force. The rolling resistance force was obtained when the tractors and drill (furrow openers lifted) passed the distance assigned under three levels of machinery speeds (5.28, 7.76, and 8.30 km. h -1 ). Furthermore, the pulling force of the machinery unit (tractors & seed drill) was also measured during the sowing operation for all treatments and replications assigned in the study area underneath tractor speeds (5.28, 7.76 and 8.30 km. h-1). The draft force was calculated by using the following equation (29) ). Furthermore, the lowercase letters (a, b and c) in the figures refer to statistical differences between treatments (P≤0.05).

RESULTS AND DISCUSSION Draft force
The interaction between farming systems and tractor speeds also showed significant differences in DF (Figure 1). The lowest DF was found at 3.33 kN under the till system when the tractor speed was 5.28 km. h -1 , while the speed of 8.30 km. h -1 under the no-till system showed the highest DF (9.28 kN)(1).

Figure 1. Effect of farming systems and speed tractor on draft force Wheel slip
The interaction between farming systems and tractor speeds also a significantly impacted on wheel slip (Figure 2). The lowest wheel slip was found at 5.34 % under the till system when the tractor speed was 5.28 km. h -1 , whilst, the speed of 8.30 km. h -1 under the no-till system showed the highest wheel slip (11.53%). This suggests that working depth and speed are the dominant factors that effectively influence slippage, regardless of the system used (35). ). This may suggest that a precision seeding rate was achieved under uniform field conditions, particularly when planting at fast forward speeds (12,40).

Figure 3. Effect of farming systems and tractor speed on seed delivery rate Germination rate
The interaction between farming systems and tractor speeds also showed a significant difference in GR (Figure 4). The highest GR was 88% at a speed of 7.76 km. h -1 under the no-till system, while the lowest was 77% under the till system at 5.28 km. h - 1 . This suggests that farming systems and sowing depth are the dominant factors that significantly impact seeding efficiency and germination rate (15). The interaction between farming systems and tractor speeds also revealed a significant difference in fuel costs ( Figure 5). The lowest fuel cost was 8395 IQD. ha -1 under the till system when the tractor speed was 8.30 km. h -1 , while the speed of 5.28 km. h -1 under the notill system showed the highest fuel cost (14567 IQD. ha -1 ). These are due to the reduction in the input costs of fuel, labor, tillage machinery, and energy consumed by machinery (23). Thus, a farming system can be efficient when it consumes a minimum number of inputs and provides the maximum outputs by reducing the variable costs (34).

Figure 5. Effect of farming systems and tractor speed on fuel costs Seed costs (SC)
The interaction between farming systems and tractor speeds also significantly impacts SC (Figure 6). The lowest SC was 65066 IQD. ha -1 under the no-till system when the tractor speed was 5.28 km. h -1 , while the speed of 8.30 km. h -1 under the till system showed the highest SC (84044 IQD. ha -1 ).

Figure 6. Effect of farming systems and tractor speed on seed cost Sowing operation cost
The interaction between farming systems and tractor speeds also revealed differences in sowing operation costs (Figure 7). The lowest costs were 36079 IQD. ha -1 under the no-till system when the tractor speed was 5.28 km. h -1 , whereas the speed of 8.30 km. h -1 under the till system showed the highest sowing operation costs (140467 IQD. ha -1 ). This research showed that no-till achieved the lowest sowing operation costs compared to the till farming system at all treatments. This implies farmers who are practicing no-till are superior economically and have a higher net return, as well production costs can reduce compared to conventional tillage farmers (10). germination rate at a speed of 7.76 km.h -1 . These outcomes improve farming systems used for growing wheat crop and may provide better information and knowledge to farmers in regarding saving energy and reducing costs.