Effect of Raised Flat Bed and Ridge Planting on Wheat Crop Growth and Yield under Varying Soil Moisture Depletions

Abstract

Crop yields remain significantly low in underdeveloped countries, such as Pakistan, primarily due to the prevalent use of traditional farming methods by most farmers. Resource-saving strategies, like ridge and raised flat bed systems, could boost water use efficiency and production per acre. However, further research is needed to investigate the effectiveness of these methods, along with different levels of soil moisture depletion (SMD), on wheat development in the climatic conditions of Sindh Province. Thus, field trials were undertaken at Sindh Agriculture University’s Tandojam for two years (2022 and 2023) during the wheat growing seasons. The experiment included six treatments, viz., T1 (raised flat bed method under 40% depletion), T2 (ridge method under 40% depletion), T3 (raised flat bed method under 50% depletion), T4 (ridge method under 50% depletion), T5 (raised flat bed method under 60% depletion), and T6 (ridge method under 60% depletion). The bed planter was employed to make raised flat beds, and the ridges were prepared using a ridge planter. Wheat variety (TJ-83) was sown. Under all treatments, the plant population, plant height, and seed index were statistically significant (p < 0.05), although spike length, grain spikes⁻¹, and grain weight spikes⁻¹ were non-significant at different SMD levels. To compute water saving through the ridge and raised flat methods, the recommended delta value for wheat crops under the traditional method was used as a benchmark. Both irrigation technologies conserve water compared to traditional irrigation methods. The T5 treatment conserved the most water, followed by T6. Under a 60% depletion level, the ridge approach produced the highest yield of 2175 kg ha⁻¹, compared to 601 kg ha⁻¹ with the raised flat bed method. The best crop water productivity (CWP) of 1.34 kg m⁻³ was achieved under T6, whereas raised flat beds attained the lowest CWP of 0.27 kg m⁻³ under T1. In terms of wheat grain production and CWP, the ridge furrow method outperformed the raised flat bed furrow method. Based on the results, it is recommended that farmers should use the ridge furrow method and allow a 60% depletion of soil moisture to obtain a high yield of wheat crops.

1. Introduction

Producing sufficient food and fiber with available water resources has become a challenge for developing countries like Pakistan [1,2,3]. Irrigated agriculture supplies have been limited due to rising population and competition for available water among various industries. As a result, it needs to be ensured that irrigation water is used efficiently and effectively [4,5,6]. To produce crops, water is applied at the farm level via surface irrigation systems. Several studies have found that most of the existing methods are inefficient due to a variety of managerial and design problems [7,8,9]. Consequently, the yield of crops and water use efficiency gets reduced and impacts the economy of country, in general, and farmers, in particular. Among various crops, wheat is consumed as a staple food for around 35% of the world’s population. Wheat is grown on an estimated 8.8 million hectares in Pakistan. In comparison to other countries, Pakistan’s water use efficiency (WUE) for this crop is low. The low WUE may be attributed to inadequate water availability during critical phases, along with planting and irrigation practices [10], and it can be improved using management approaches to establish safe moisture depletion levels and suitable planting irrigation techniques.

Crop yields in Pakistan are low because most farmers still practice traditional farming methods [11,12]. As a result, resource conservation strategies, such as ridge and raised flat bed planting, as well as revised planting practices, are required, which could improve water use efficiency and yield per acre [13]. Water conservation measures have been found practical and beneficial in situations where water is scarce [14].

Surface irrigation methods, such as the raised flat bed method, have been introduced to replace the conventional method of irrigation (flood) in developing countries of the world [15]. It not only enhances production but also conserves water. Raised flat bed and ridge planting consume less water and increase yields, resulting in higher WUE than flat planting in winter crops [16].

The raised flat bed sowing method has been widely used by farmers for a very long time in many parts of the world [17]. The farmers are using this method to minimize the adverse effect of excess water on crop production or to apply irrigation to crops in arid and semi-arid regions where water is in low quantity [18]. Raised flat beds are widely used in the agriculture sector in developed countries and have proven to be an excellent option for wheat crops [19]. The raised flat bed planting method could prevent waterlogging, control the weeds, and save up to 50% of the water and 20–25% of the yield over the conventional method. The modified planting techniques provide favorable conditions for maximum yield because of optimum moisture levels in the root zone and proper seed germination and emergence [15,20]. In Pakistan, modified planting methods, like the raised flat bed and ridge planting methods, have been practiced for the last few years. Apart from the irrigation/planting method, the irrigation scheduling also affects crop production. In dry and semi-arid climates, irrigation scheduling can affect root development, crop growth, and yield. Wheat is extremely sensitive to changes in irrigation scheduling; water stress during critical periods significantly reduces grain production [15]. Several studies have been conducted to determine the impact of modified irrigation/planting strategies [14,15,17,18,19,20].

However, there is a lack of comprehensive research on the comparative effectiveness of these methods under varying soil moisture depletion (SMD) levels in the specific climatic conditions of Sindh Province. This research gap necessitates a thorough investigation into the impact of the raised flat bed and ridge planting methods on wheat crop growth and yield. It is critical to understand how different levels of soil moisture depletion affect these planting methods to provide evidence-based recommendations for farmers. Without this knowledge, farmers in the region may continue to use suboptimal farming practices, leading to continued low yields and inefficient water usage, exacerbating food security challenges and resource scarcity.

Therefore, this study aims to evaluate the performance of the raised flat bed and ridge planting methods under different SMD levels, specifically focusing on plant population, plant height, seed index, spike length, grains per spike, grain weight per spike, water conservation, yield, and crop water productivity. The ultimate goal is to identify the most effective planting method and optimal soil moisture depletion level to maximize wheat crop yield and water use efficiency in Sindh Province. This study is beneficial for wheat growers to obtain the maximum out of the minimum available resources.

2. Materials and Methods

2.1. Study Area

This research study was conducted during the wheat growing season for two consecutive years (2022 and 2023) at the experimental station of the Department of Irrigation and Drainage, Sindh Agriculture University, Tandojam. It is located at 25.42460° N and 68.54066° E. The soil characteristics including soil texture, dry bulk density, porosity, and field capacity of the experimental site were determined for the depth of 0–20, 21–40, and 41–60 cm, and their averages are present in

Table 1. Soil and irrigation water properties of the experimental site.

S. No.	Properties	Reference	Values
1.	Soil texture	[21]	% Clay	% Sand	% Silt
			27.8	24.7	47.5
			Clay loam
2.	Dry bulk density	[21]	1.23 g cm−3
3.	Field capacity	[22]	34%
4.	Porosity	[22]	48%
5.	ECW (dS/m)	[23]	0.9
6.	pH of water	[23]	7.5

. The source of irrigation water in this study is canal water. Irrigation water quality indicators, viz., EC and pH values, are also presented in Table 1. This depicts that the quality of irrigation water was good. Hence, it was not considered as an influencing factor in this study. The climate of the study area is arid and has a mean annual rainfall of 50 mm.

2.2. Treatments and Experimental Setup

The experiment was conducted in a randomized complete block design (RCBD) with three replications, as demonstrated in Figure 1. The experiment comprised two irrigation methods (raised flat bed and ridge planting method) and three SMD levels, including 40, 50, and 60% of the field capacity of the soil. The raised flat bed has a raised flat and bed, while the ridge has slanted sides. The details of the experiment factors are described below.

• Factor A: irrigation methods (M) = 2
• M1 = raised flat bed method
• M2 = ridge method
• Factor B: soil moisture depletion (SMD) levels (D) = 3
• D₁ = 40% of F.C
• D₂ = 50% of F.C
• D₃ = 60% of F.C
• Treatment combinations
• T1 = M1D1
• T2 = M2D1
• T3 = M1D2
• T4 = M2D2
• T5 = M1D3
• T6 = M2D3

The plot size for each treatment was kept at 3 by 3 m. The total number of plots in all replications was 18 with a total area of 220 m² as illustrated in Figure 2a,b, which was inclusive of the water channel area. The disc plow was used at the experimental site to plow the soil. Then, the soil was stirred using a cultivator. Finally, the land was leveled with a conventional leveler. The bed planter was employed to make raised flat beds, and the ridges were prepared using a ridge planter. The dimensions of irrigation methods laid out in the field are illustrated in Figure 3a,b.

2.3. Sowing of Seeds and Fertilizer Application

Wheat seeds (TJ-83) were applied at a rate of 125 kg ha⁻¹ [24]. The seeds were sown on the raised flat bed and ridge using a bed planter and driller, respectively. There were two rows on ridges and four rows on the raised flat methods. The spacing between rows was kept equal to 0.12 m. Fertilizers were applied at the recommended rate of 120–60–60 NPK kg ha⁻¹ to the wheat crop under each replication of the treatment [6]. The NPK was applied in the form of the urea, Di-ammonium phosphate, and sulfate of potash, respectively. The P and K with half N were applied during the preparation of land. The remaining half N was applied during the 2nd, 3rd, and 4th irrigations [25,26].

2.4. Irrigation Plan and Scheduling

Irrigation to the wheat crop was applied when the SMD reached 40, 50, and 60% of field capacity. Soil moisture was monitored by tensiometers. Tensiometers were calibrated in the laboratory before use. The tensiometers were installed at 20 cm and 60 cm depths considering active root zone depth for wheat crops. The tensiometer shows the reading in centibars. In the study area for clay loam soils, the reading of 22 centibars is considered as the field capacity. The readings for 40, 50, and 60% depletion levels were taken as 30, 33, and 35 centibars respectively. As soon as the tensiometers attained the corresponding reading, irrigation was applied. The flow rate of the field channel was measured using a flow meter. The following relation was invoked to compute water depth:

$$D=\frac{\left(Cf-\mathit{Cm}\right)}{100}\times {\rho }_b\times d_{r }$$

(1)

where D = water application depth (cm), Cf = soil field capacity (%), Cm = pre-irrigation moisture content of the soil (%), ρ_b = dry bulk density (g cm⁻³), and d_r = crop root depth (cm).

The relation used to compute the time to apply the required irrigation depth is given below, as discussed earlier by [6].

$$\mathit{QT}=28\times A\times D$$

(2)

where T = irrigation application time (hour), A = area to be irrigated (hectare), and Q = discharge required (LPS). The average time to irrigate a plot of 3 m × 3 m was 2.25, 2.85, and 3.38 min for 40, 50, and 60% depletion levels, respectively. The discharge of the stream was 20 lps.

2.5. Harvesting of Crops

Harvesting wheat crops was performed at crop maturity under each replication of the treatment. The wheat crop was harvested manually and threshed manually. Spikes were separated from the straw, and grains were weighed by weighing balance to record the grain yield (kg m⁻²). Then, the yields were converted to (kg ha⁻¹) by dividing the yield by a conversion factor of 10⁴ [6].

2.6. Sampling, Measurements, and Analyses

The plant population was determined during the experimental period. At physiological maturity, in an area of 1 by 1 m in the middle of each replicate plot, the plants were harvested manually and divided into biomass and grains. The plant height (cm), spike length (cm), grain spikes⁻¹, grain weight spikes⁻¹ (g), seed index (1000 grain weight, g), and grain yield (kg ha⁻¹) were recorded. Irrigation water, rainfall, and SMD in each treatment were utilized to compute the total water consumed throughout the study period. Crop yield was divided by total water utilized to calculate crop water productivity (CWP). The water saving for wheat crops under the raised flat bed and ridge planting methods over conventional irrigation methods were calculated using the following relations [27]:

$$W{S}_{RBM40\%}=\frac{\left(W_a-W_b\right)}{W_a}\times 100$$

(3)

$$W{S}_{RBM50\%}=\frac{\left(W_a-W_c\right)}{W_a}\times 100$$

(4)

$$W{S}_{RBM60\%}=\frac{\left(W_a-W_d\right)}{W_a}\times 100$$

(5)

$$W{S}_{RM40\%}=\frac{\left(W_a-W_e\right)}{W_a}\times 100$$

(6)

$$W{S}_{RM50\%}=\frac{\left(W_a-W_f\right)}{W_a}\times 100$$

(7)

$$W{S}_{RM60\%}=\frac{\left(W_a-W_g\right)}{W_a}\times 100$$

(8)

where WS = water saving (%), W_a = crop water requirement for wheat in a conventional irrigation system, and the value was taken from the literature, i.e., 375 mm [26], W_b = total water used under the raised flat bed method at 40% depletion, W_c = total water used under the raised flat bed method at 50% depletion, W_d = total water used under the raised flat bed method at 60% depletion, W_e = total water used under the ridge method at 40% depletion, W_f = total water used under the ridge method at 50% depletion, and W_g = total water used under the ridge method at 60% depletion. Only water saving through the ridge and raised flat methods have been compared with the traditional practices. In water saving computations, the delta value recommended for wheat crops by the agriculture ministry of Pakistan has been used as a benchmark.

2.7. Statistical Analysis

The data were analyzed using the SPSS program version 21.0 for analysis of variance (ANOVA). Duncan’s multiple range test was used to determine whether the differences between treatments were significant at the 0.05 level.

3. Results

A strong association between the two-year (2020 and 2021) trial results was observed, as depicted by an R² (coefficient of determination) equal to 0.98. Therefore, the average results for two years are reported and discussed in the subsequent paragraphs.

3.1. Plant Population

The results pertaining to plant population (m⁻²) obtained from experimental units are demonstrated in Figure 4. The results indicate that raised flat beds under 40% depletion (T1) gave a minimum number of plants (58 m⁻²), while the ridge method under 40% depletion (T2) gave a maximum number of plants (85 m⁻²), which was 31.7% higher than T1. Similarly, raised flat beds under 50% depletion (T3) gave a minimum number of plants (71 m⁻²), while the ridge method under 50% depletion (T4) gave a maximum number of plants (77 m⁻²), which was 7.8% higher than T3. In the same way, raised flat beds under 60% depletion (T5) gave a minimum number of plants (55 m⁻²), while the ridge method under 60% depletion (T6) gave a maximum number of plants (92 m⁻²), which was 40.2% higher than T5, respectively. These results imply that plant population (m⁻²) response under the ridge method under all depletion levels was higher compared to the raised flat bed method. The reason is that the maximum plant population (m⁻²) under T6 could be the uniform lateral distribution of water through the ridge.

3.2. Plant Height

The analysis of data concerning plant height (cm) is illustrated in Figure 4. The results showed that in the raised flat bed method under 40% depletion (T1), a minimum plant height of 71 cm was recorded, while in the ridge method under 40% depletion, (T2) a maximum of 79 cm was recorded, which was 10.1% higher than T1. Similarly, for raised flat beds under 50% depletion (T3), a plant height of 76 cm was recorded, and it was 79 cm for the ridge method under 50% depletion (T4), which was 3.8% higher than T3. The plant height for raised flat beds under 60% depletion (T5) was recorded at 70 cm, and for the ridge method under 60% depletion (T6), it was recorded at 80 cm, which was 12.5% higher than T5. From these findings, it was concluded that the maximum plant height was recorded in the ridge method (T6) against the lowest in T5.

3.3. Spike Length

The analysis of data regarding spike length (cm) is presented in Figure 4. The results revealed that in the raised flat bed method under 40% depletion (T1), a minimum spike length of 10.6 cm was recorded, while in the ridge method under 40% depletion (T2), a maximum of 11.0 cm was recorded, which was 3.6% higher than T1. Similarly, for raised flat beds under 50% depletion (T3), a spike length of 10.4 cm was recorded, and it was also the same (10.4 cm) for the ridge method under 50% depletion (T4). Similarly, the spike length for raised flat beds under 60% depletion (T5) was recorded (10.2 cm), and for the ridge method under 60% depletion (T6), it was recorded as 11.3 cm, which was 9.7% higher than T5, but there is a non-significant difference under all treatments.

3.4. Number of Grain Spikes⁻¹

The magnitude of the sink capacity of the wheat spike is determined by the number of grains per spike produced. The analysis of data concerning grain spikes⁻¹ is portrayed in Figure 4, and the results evidenced that in the raised flat bed method under 40% depletion (T1), the minimum number of grain spikes⁻¹ (54.07) was recorded, while in the ridge method under 40% depletion (T2), the maximum number of grain spikes⁻¹ was recorded (57.33), which was 5.69% higher than T1. Similarly, for raised flat beds under 50% depletion (T3), the number of grain spikes⁻¹ (53.7) was recorded, and it was 54.20 for the ridge method under 50% depletion (T4), which was almost the same in both treatments. In the same way, for raised flat beds under 60% depletion (T5), the minimum number of grain spikes⁻¹ was recorded (48.87), and for the ridge method under 60% depletion (T6), it was recorded as the maximum (58.87), which was 17% higher than T5. From these findings, it was concluded that the maximum number of grain spikes⁻¹ was recorded in the ridge method (T6) at 60% SMD. However, the minimum number of grains per spike was recorded in T5 in the raised flat bed method. The results of the higher number of grains might be due to relatively healthy spikes in the above-mentioned treatments.

3.5. Grain Weight Spikes⁻¹ (g)

The analysis of data concerning the weight of the grain spike⁻¹ is shown in Figure 4. The results indicate that in the raised flat bed method under 40% depletion (T1), a minimum grain weight of 1.78 g was recorded, while in the ridge method under 40% depletion (T2), the maximum grain weight was recorded as 2.00 g, which was 11% higher than T1. Similarly, for T3 raised flat beds under 50% depletion, a grain weight of 1.95 g was recorded, and it was 1.97 g for the ridge method under 50% depletion (T4), which was almost the same. In the same way, for raised flat beds under 60% depletion, the T5 grain weight was recorded as a minimum (1.76 g), and for the ridge method under 60% depletion, the T6 the maximum grain weight was recorded (2.18 g), which was 19.2% higher than T5. These results revealed that the highest grain weight was recorded in T6, followed by T2. The results for the highest grain weight were due to healthy spikes.

3.6. Seed Index

The results regarding the seed index (g) are also provided in Figure 4. The results depict that the minimum 1000 grain weight of 33 g was recorded in the raised flat bed method under 40% depletion (T1), while in the ridge method under 40% depletion (T2), the maximum 1000 grain weight was recorded (38 g). Similarly, for raised flat beds under 50% depletion (T3), a minimum 1000 grain weight of 33 g was recorded, and it was almost the same (35 g) for the ridge method under 50% depletion (T4). In the same way as raised flat beds under 60% depletion (T5), grain weight was recorded (31 g), and for the ridge method under 60% depletion (T6), the maximum 1000 grain weight was recorded (38 g). From these findings, it was concluded that the ridge technique gave maximum weight (38, 35, and 38 g) under treatments T2, T4, and T6, respectively, which were 13.2, 5.7, 13.15, and 18.42% higher than T1, T3, and T5.

3.7. Grain Yield

Grain yield under all six treatments under different SMDs was recorded. The data regarding grain yield kg ha⁻¹ are shown in

Table 2. Effect of the raised flat bed and ridge planting methods and soil moisture depletions on crop water productivity (kg m⁻³) under all treatments.

Treatments	Grain Yield (kg ha−1)	Vol. of Water Applied cu. m per ha	CWP
T1	880	3265	0.27
T2	2071	4054	0.51
T3	1294	2097	0.62
T4	1701	2603	0.65
T5	601	1305	0.46
T6	2175	1620	1.34

. The results indicate that a minimum grain yield of 880 kg ha⁻¹ in the raised flat bed method under 40% depletion (T1) was achieved, while in the ridge method under 40% depletion (T2), the maximum grain yield was recorded (2071 kg ha⁻¹), which was 54% higher than T1. Similarly, for T3, the raised flat bed under 50% depletion, a minimum grain yield of 1294 kg ha⁻¹ was recorded, and it recorded a maximum of 1701 kg ha⁻¹ for the ridge method under 50% depletion (T4), which was 23.93% higher than T3. In the same way, for raised flat beds under 60% depletion, T5 grain yield was recorded (601 kg ha⁻¹), and for the ridge sowing method under 60% depletion (T6), the grain yield was recorded as a maximum of 2175 kg ha⁻¹, which was 72.4% higher than T5. This means the investigated factors, irrigation methods, and SMD levels significantly affect the wheat grain yield.

3.8. Crop Water Productivity

The data regarding CWP is given in Table 2. It indicates that CWP in the raised flat bed method under 40% depletion (T1) was a minimum of 0.27 kg m⁻³, while CWP obtained a maximum of 0.47 kg m⁻³ for the ridge method under 40% depletion (T2), which was 42.5% higher than T1. Similarly, for the raised flat bed method under 50% depletion (T3), 0.62 kg m⁻³ was obtained, while for the ridge method under 50% depletion (T4), the CWP has a maximum of 0.65 kg m⁻³ with a minor difference, which was 4.6% more than T3. In the same way, raised flat beds under 60% depletion (T5) had a minimum of 0.46 kg m⁻³. For the ridge method under 60% depletion (T6), CWP was obtained a maximum of 1.34 kg m⁻³, which was 65.7% higher than T5. It is apparent from the above results that the maximum CWP was obtained in the T6 ridge irrigation method under 60% SMD. This means that modified irrigation methods and SMD significantly affect CWP.

3.9. Irrigation Water Saving

The results for water saving (%) for wheat crops in the raised flat bed method and ridge method under different SMDs over the conventional irrigation method are shown in

Table 3. Effect of the raised flat bed and ridge planting methods and soil moisture depletions on water savings under all treatments.

Treatments	Irrigation Water Used (m3 ha−1)		Water Savings (%)
	Furrow Irrigation Systems (m3 ha−1)	Conventional Irrigation System (m3 ha−1)
T1	3265	3750	13
T2	4054		−8
T3	2097		44
T4	2603		30.6
T5	1305		65.2
T6	1620		56.8

. The water requirement for wheat crops under a conventional irrigation system is 375 mm, which is 3750 m³ ha⁻¹. The results reveal that there is a significant difference among all treatments. The maximum water saved is under T5 followed by T6, while in T2, more water than recommended was consumed. A minimum amount of water was conserved under T1.

4. Discussion

The evaluation of modified planting methods, like the raised flat bed and ridge methods, is critical for a subsequent recommendation. Thus, the presented study was conducted to determine the best sowing technique for wheat under different SMDs to overcome water shortage problems in the future. The findings of this study are discussed in the subsequent paragraphs.

The grain yield and plant growth parameters were plant population (m⁻²), plant height (cm), spike length (cm), number of grain spikes⁻¹, grain weight spike⁻¹ (g), seed index (g), grain yield (kg ha⁻¹), and harvest index under all treatments, viz., T1 = the raised flat bed method and T2 = the ridge method under 40% SMD. Similarly, T3 and T4 under 50% SMD and T5 and T6 under 60% SMD were measured at the crop maturity stage for designed treatments. Wheat plants germinated at m⁻² were higher in the ridge method. These findings are in line with the study by Meng et al. (2020), who reported that an increase in the number of plants germinated from the millet crop was recorded in the ridge sowing technique [28]. The maximum spike length was recorded in the ridge method. These results were confirmed by Mushtaq et al. (2012), who reported that the ridge method increased spike length due to better soil moisture conditions [29]. Grain spikes⁻¹ were higher in the ridge method, and similar results were reported earlier [30]. Thousand grain weight (g) and grain yield (kg ha⁻¹) were higher under the ridge method. Meng et al. (2020) and Memon et al. (2021) also attest to these results [6,28]. This may be attributed to the reality that the ridge method provides good soil tilth conditions for proper root development and lodging control, ensuring efficient use of irrigation water and nutrients to the soil for proper growth and development [31]. The raised flat bed method resulted in the lowest grain yield and negatively affected growth parameters compared to the ridge method. This outcome can be attributed to the wide size of the raised flat beds, which caused slow lateral wetting in the center of these beds. Consequently, the central areas of the raised flat beds did not receive sufficient moisture, leading to suboptimal growth conditions for the wheat crop. In contrast, the ridge method facilitated better water distribution and availability, promoting healthier crop growth and higher yields. These results are confirmed by Akbar et al. (2016), who reported that wide-size raised flat beds can save only water by reducing water losses and improving land utilization efficiency [32]. However, there is a reduction in the yield of wheat since lateral water infiltration to the middle part of the raised flat beds is not achieved for different types of soils. Several vegetable crops can be grown on the raised flat bed, viz., cauliflower, tomatoes, cabbage, and bitter gourd, specifically during heavy rainfall and high temperatures. As far as cereal grain crops like wheat are concerned, the ridge system is not favorable.

The results showed that the CWP of wheat for ridge planting is higher compared to the raised flat bed method under all treatments. These results were in close agreement with Akbar et al. (2015), who reported that the wider beds can save water but affect raised flat bed performance due to slow lateral wetting into the center of wide beds, which may reduce the wheat grain yield in the bed’s middle compared to the ridge planting method [33]. Jat et al. (2011) also reported that wheat grain yield was about 16.6% higher with nearly 50% less irrigation water in the ridge planting method compared to the raised flat bed and conventional irrigation methods [34]. Hussain et al. (2015) recommended that farmers adopt the ridge planting method, particularly in clayey soils, to increase wheat grain yield and enhance crop water productivity [35].

Water saving (%) for wheat crops in the raised flat bed and ridge planting methods under different SMDs were determined. The results suggested that the raised-flat bed method saves more water compared to the ridge planting and conventional irrigation methods [36]. The water savings under 50% and 60% depletion for raised flat beds were 44% and 65.2%, and for the ridge method, they were 30.6% and 56.8%, respectively. These results are also confirmed by Soomro et al. (2017), who concluded that under 50% to 60% SMD levels, the water saving was 50.73% in the furrow bed irrigation method [37]. These findings are supported by Naresh et al. (2012), who reported that the furrow-irrigated raised flat bed technique not only saves resources, like water, but also saves higher labor costs [38]. Similarly, Karrou et al. (2012) found that water can be saved in an amount of 1500 m³ ha⁻¹ in wheat under the raised flat bed irrigation method [39]. Similarly, for the present research study, water saving for the raised flat bed method under a 50% SMD level was 1671 m³ ha⁻¹, which was 44%. These results are supported by Hassan et al. (2001), who found that the raised flat bed planting method could fend off waterlogging and save irrigation water up to 50% over the conventional irrigation method [19]. Jat et al. (2011) and Halli et al. (2021) also reported that the ridge furrow irrigation method can save nearly 50% of irrigation water compared to other flooding irrigation methods [34,40]. The results closely matched the findings of Hobbs and Gupta (2003) and Madhu (2022), who reported that the raised flat bed planting method of crops all over the world is one of the best and improved techniques for water saving over other old traditional methods [41,42]. The ridge planting method demonstrated superior performance in terms of both yield and crop water productivity. The higher yield and efficient water use can be attributed to better lateral water movement, which provides more uniform moisture distribution to the plants. Although the raised flat bed method showed greater water savings, it did not translate to higher yields due to inadequate water distribution in the wider beds, affecting the growth parameters negatively.

5. Conclusions

The present study was conducted to assess the effect of different irrigation methods and depletion levels on the grain yield and water productivity of wheat crops. The ridge planting method gave a better overall performance with respect to an increase in yield and yield components of wheat and CWP. The performance of the ridge method is due to the maximum lateral movement of water. It is also deduced that the frequency of irrigation should be set at the 60% level since the readily available water for wheat crops is up to this level. Thus, it is suggested that the wheat crops should be planted and irrigated through the ridge method, and irrigation should be applied at a 60% moisture depletion level to obtain maximum water productivity and yield.