Agrotechnology

Effect of Alternate Furrow Irrigation with Different Irrigation Intervals on Yield, Water Use Efficiency, and Economic Return of Green Cob Maize (Zea mays) Production at Wayu Tuka and Diga Districts, Western Oromia

Adisu Tadese^* and Lema Teklu Bako Agricultural Research Centre, Kenya
^*Correspondence: Adisu Tadese, Bako Agricultural Research Centre, Kenya, Email:

Received: 02-Dec-2021 Published: 23-Dec-2021

Introduction

Irrigated agriculture is the main solution to produce crop to feed and achieve the different needs for an ever-increasing world population. However, a Growing competition for water from domestic and industrial sectors reduced its availability for irrigation. In this regards irrigation only based on crop water requirement is not an option especially in areas where water resource is limited. Much of an increase in the irrigated area had come because of the expansion of small-scale irrigation in the country. Yet, the existing irrigation development in Ethiopia, as compared to the resources the country has, is negligible. Irrigation water management implies the application of suitable water to crops in right amount at the right time. Salient features of any improved method of irrigation is the controlled application of the required amount of water at desired time, which leads to minimization of range of variation of the moisture content in the root zone, thus reducing stress on the plants. Many investigations have been conducted to gain experiences in irrigation of crops to maximize performance, efficiencies and profitability. However, investigation in water saving irrigation still is continued [2].

Satisfying crop water requirements, although it maximizes production from the land unit, does not necessarily maximize the return per unit volume of water. The target crop maize is the one of the major crop in Ethiopia with is the top crop by the number of farming community engaged and next to teff it is the highest in area coverage in the country. The study area is at Western Ethiopia where crop production in wet season by rain fall and during dry season is unexpected without irrigation. Moreover, it is characterized by having highly variable initial and conditional probability of threshold limit of 30 mm per decade rainfall in the main rainy season. To improve crop production to feed the ever increasing population under limiting water resource condition, strategies that conserve moisture in the soil and efficient irrigation techniques should be identified and practiced [3]. Different works have been done on irrigation water management for maize in different part of the world that revealed that yield and water productivity of maize enhanced through different irrigation water management methods like conventional furrow, alternate furrow and water conservation methods like application of straw and plastic mulching.

Application of irrigation water through conventional furrow method that irrigate all the neighbouring furrow in two consecutive irrigation time leads to maximize yield under different crops including maize. However, productivity of irrigation water is maximized through deficit irrigation practice using different techniques like alternate furrow method by irrigating only one of the neighbouring two furrows during the consecutive irrigation time. For example, reported that maximum maize yield was obtained under conventional furrow irrigation with irrigation water application of 100% crop water requirement than the alternate and fixed furrow irrigation method. The same research revealed that with comparable yield penalty, alternate furrow irrigation method maximized water use efficiency of maize. According to that reported alternate partial root-zone irrigation improves water use efficiency of okra plant than the conventional furrow condition under different soil moisture depletion levels. Based on their findings, they concluded that alternate furrow irrigation as a way to save water and maize production relies heavily on repeated irrigation [4].

Alternate furrow irrigation (AFI) is considered to be one of the most effective tools to minimize water application and irrigation costs and produce a higher crop yield. The AFI method is a way to save irrigation water, improve irrigation efficiency, and increase corn yield. Using Alternate furrow irrigation with appropriate irrigation interval can save irrigation water without yield reduction. Little works were done on irrigation interval of Alternate furrow irrigation. Found that corn grain yield of AFI at 7-d intervals was lower than every-furrow irrigation (EFI) at 10-d intervals. In addition, found that alternate partial root-zone and fixed partial root-zone irrigation techniques led to a higher reduction of transpiration than photosynthesis and thus increased corn leaf water use efficiency (WUE). Beside this, found that AFI at 14-d intervals seemed to not significantly decrease yield, whereas yield increased under AFI at 7-d intervals as compared with the EFI method. Therefore, in an effort to improving water productivity through Alternate furrow irrigation with appropriate irrigation interval is an interest of the study done on maize crop [5].

The objective of this research study was to investigate the effects of alternate furrow irrigation with different irrigation intervals on corn yield, irrigation water productivity, and economic return as compared with EFI (conventional method).

Materials and Methods

Description of the Study Area

This experiment was conducted in Dida and Wayu Tuka Districts of western Oromia. The study sites are Lelisa Dimtu from Diga District and Xaxo from Wayu Tuka. Diga and Wayu Tuka districts were located at 338 and 325km from Addis Ababa respectively. The district has three agro ecologies Dega, Weyna and Kola (Figure 1).

Figure 1: Map of Study area

Treatments and Experimental Design

Irrigation treatments were: 1, Farmer practice (FP); 2, Conventional irrigation method (EFI), every furrow was irrigated at CROPWAT irrigation interval; 3, Alternate furrow irrigation at CROPWAT irrigation interval (AFI_norm); 4, Alternate furrow irrigation at Reduced CROPWAT irrigation interval (AFI_reduced); and 5, Alternate furrow irrigation at extended CROPWAT irrigation interval (AFI_extended The adopted treatments were assessed with randomized complete block design (RCBD) with three replicates. The experimental plot size was 45m² (10m wide × 4.5m long). Each treatment included 7 furrows and 6 planting ridges (rows). Furrow spacing was 0.75 m. Space between plots been 1m and between replication 1.5 m. Space between rows 0.75m and 0.35cm between the plants was used [6]. The experimental plot was pre-irrigated one day before planting. Before the commencement of treatment, two to three common light irrigations was supplied to all plots at two to three days interval to ensure better plant establishment ( Table 1).

Table 1: Treatment set-up.

Agronomic Practices

Agronomic practices maize seeds (BH-546) were planted during 2018/19 and 2019/20 growing seasons at the rate of 25kgha-1. Two seeds were planted per hole with a plant spacing of 0.35m. All plots were irrigated immediately after planting (planting irrigation). Recommended fertilizer of 100kg/ha NPS and half of 200kg/ha UREA was applied prior to the second pre-treatment irrigation [7]. Thinning was carried out after the second pre-treatment irrigation and the remains half UREA was applied after 35 days of planting. All other agricultural operations, including pesticide and hand weeding, were applied uniformly and simultaneously for all treatments. Experimental treatments were implemented after the second pre-treatment irrigation in both seasons.

Crop Water Requirement and Irrigation Schedule

The estimate of the water requirement and irrigation scheduling of crops under this study is based on the atmospheric conditions of the environment by using a model. A computer program called “CROPWAT version 8.0” was used to determine reference evapotranspiration, crop water requirements, and irrigation schedule by utilizing metrological data as an input. For estimation of water irrigation requirements, climatic, crop and soil data have been utilized as an input. This calculation has been done by using the FAO Penman-Monteith method. In this experiment, the reference evapotranspiration (ETo) and crop water requirement (ETc) were estimated from long term climatic data collected from Ethiopia Metrological Agency [8].

Irrigation water was conveyed to the experimental plots through Parshall Flume having appropriate opening diameter of three inch (3") and a length of 2 m. The amount of water for each application was added through Parshall Flume by recording time of water flow through furrows. Time is then recorded with a stopwatch to estimate the amount of water applied to each plot [9]. Furrows subjected to irrigation were close-ended; then, water cannot exceed the edge of the plot because all were closed-ended. The water in the channel was controlled to maintain a constant head to provide an adequate inflow rate during irrigation events with a close ended [10].

Data Collection

Climatic Data

Before the start of the experiment, secondary data such as climatic data of 30 years on rainfall (R.F.) min and max temperature, relative humidity (RH), wind speed (WS) and sunshine hours (SH) were collected from the National meteorological agency. Irrigation efficiency for furrow irrigation, root depth of maize crop, maize crop growth stages and their respective length of period data were also collected from previous records and FAO guidelines [11].

Soil Physical Properties

Four soil profiles were randomly made in the experimental site to measure soil physical properties. Soil texture was determined using the volumetric method at 0-5, 5-10, 10-15 and 15-20cm depths of the soil profiles. Bulk density was determined by the core method for each sampling depth. Soil water content was determined from soil samples taken at the same locations using the gravimetric method [12]. The soil basic infiltration rate was determined in the field using double-ring infiltrometer method in two separate sites in the experimental area as described (Table 2).

Table 2: Soil physical characteristics of the experimental sites.

Yield and Yield Components

Yield (green cob) data, were collected from each plot size of 10 *4.5m and extrapolated to a hectare basis. Green Cobs of maize were categorized as small, medium and large based on the size of cobs and data were collected in number and weight basis from each plot at both locations [13]. Stand count data was also collected from all plots at maturity stage (Table 3).

Water Productivity

Water productivity (WP) Water productivity was determined by dividing grain yield by total applied irrigation water and is expressed as follows:

WP = GY/Wa

Where GY is grain yield (kg ha^-1) and Wa is irrigation applied water (m3 ha^-1).

Data Analysis

The collected data was subjected to analysis of variance (ANOVA) and least significant difference (LSD) was used to separate means at p<0.05 probability levels of significance (Table 4).

Table 4: Number of irrigation events and depth of applied water for each irrigation event under different irrigation treatments for both seasons at Wayu Tuka.

Result and Discussion

chemical parameters were measured in the field and laboratory. The laboratory results of the average chemical properties of the experimental site were presented in table 3. The result of the soil analysis from the experimental site showed that the top soil surface had bulk densities were of 1.34gm/cm3 and 1.31gm/cm3 at sites respectively. In general, the average soil bulk density (1.31gm/m3) is below the critical threshold level (1.4g/cm3) and was suitable for crop root growth. Average moisture content at field capacity of the experimental sites soils were 61.72% and 52.6% at Xao and Lelisa Dimtu sites respectively, and permanent wilting point the sites were 50.18% and 34.87% at Xaxo and Lelisa Dimtu respectively. Soil pH was found to be at slightly acidic value (5.7 averages of all treatments) at both sites for maize and other crops [14]. Therefore, the soils of the study area are normal soils. The weighted average organic matter content of the soil was 5.3 and 5.6% at Xaxo and Lelisa Dimtu respectively.

Table 3: Soil chemical properties characteristics of the experimental sites.

Depth of Applied Water

The irrigation events and amount of applied water (Wa) for each treatment at Wayu Tuka district of Lega Xaxo site are shown in Table 4. The AFI_Redu (Altenat Furrow irrigation with reduced irrigation interval) treatment was more frequent (11 irrigation events) than CFI and AFI_Norm (eight irrigation events) for both seasons. The mean of the two seasons were amounted to 415mm (415m³ha^-1), 346mm (346m³ha^-1), 173mm (173m³ha^-1), 135mm (135m³ha^-1) and 208mm (208m³ha^-1) for FP, CFI, AFI_Norm, AFI_Extend and AFI_Redu, respectively.

This indicates that the AFI_Extend and AFI_Norm alternate furrow irrigation treatments saved water by approximately 60% and 50% (two-season means), respectively, as compared to conventional CFI. Regardless of irrigation intervals, the lowest amount of applied water (Wa) under AFI_Norm, treatments as compared with CFI might be due to the great reduction of wetted surface in AFI_Norm; almost half of the soil surface is wetted in AFI_Norm as compared with CFI. This result supports the outcome obtained by, who found that AFI methods can supply water in a way that greatly reduces the amount of wetted surface, which leads to less evapotranspiration and less deep percolation [15].

The irrigation events and amount of applied water (Wa) for each treatment at Diga district of Lalisa Dimtu site are shown in Table 5. The AFI_Redu (Altenat Furrow irrigation with reduced irrigation interval) treatment was more frequent (11 irrigation events) than CFI and AFI_Norm (eight irrigation events) for both seasons. Based on the output of the CROPWAT 8 model, the optimum seasonal irrigation requirement in the area for maize was found to be mean of the two seasons were amounted to 471mm (471m³ha^-1), 402mm (402m³ha^-1), 229mm (229m³ha^-1), 178mm (178m³ha^{- 1}) and 283mm (283m3ha-1) for FP, CFI, AFI_Norm, AFI_Extend and AFI_Redu, respectively. This indicates that the AFI_Extend and AFINorm alternate furrow irrigation treatments saved water by approximately 55.7% and 43.6% (two-season means), respectively, as compared to conventional CFI. Amount of water saved under AFI_Extend and AFINorm at Lelisa Dimtu site was relatively low as compared to Lega Xaxo Site. Amount of water applied under alternate furrow irrigation also agrees with the conclusion that says that alternate furrow irrigation is commonly applied as part of a deficit irrigation program because it does not require the application of more than 50–70% of the water used in a conventional furrow irrigation method.

Table 5: Number of irrigation events and depth of applied water for each irrigation event under different irrigation treatments for both seasons at Diga.

Yield (Green Cobs) and Stand Count

At maturity stage of the crop numbers of cobs were counted for all plots and categorized to three groups (small, medium and large) based on the size of cobs. Based this, Number of cobs categorized as small , medium and large size were collected from each plot was significantly affected by the irrigation treatments and had the same trend in both seasons (Table 6).

Table 6: Average number of cobs (green cobs) under different irrigation treatments at Lelisa Dimtu during 2018/19 and 2019/20.

The highest number of cobs 483 per plot (107333 per hectare) and 487 per plot (108222 per hectare) were recorded from AFINorm for both seasons respectively followed by AFI_Redu at Lelisa Dimtu Site. Numbers of cobs recorded from AFI_Norm were higher than for CFI with 9111 to 9333 numbers per hectare in both seasons. Beside this, statistical analysis showed that stand count of maize had not affected by the application of different irrigation systems with different irrigation intervals (p<0.05). The lowest number of cobs per plant 438 per plot (97333 per hectare) and 441 per plot (98000 per hectare) were recorded from FP for both seasons respectively at Lelisa Dimtu site. Numbers of cobs AFI_Extend were higher than CFI for in both seasons. When comparing CFI and AF_Norm, the latter increased number of green cobs by approximately 667/ha and 889 in the first and second seasons respectively.

Statistical analysis also showed significance influence (p<0.005) due to the adoption of both different furrow irrigation methods as well as irrigation intervals on weight of cobs per plot. Highest weights of cobs per plot were recorded from AFI norm 130.2 kg per plot (28933 kgha-1) and 135.3 kg per plot (30067 kgha-1) for both seasons respectively at Lelisa Dimtu Site respectively. However, the lowest weight of cobs 93kg per plot (20689kgha-1) and 97 kg per plot (21578 kgha-1) were recorded from FP for both seasons respectively.

Highly significant (p<0.005) difference was observed on number cobs per plot due to different irrigation methods with different irrigation intervals during both the study season. The higher number of cobs per plot 452 (100444 per hectare) and 459 (102000 per hectare) were obtained from AFINorm and statistically superior to other irrigation method during both season. The lower number of cobs per plot 439 (97556 per hectare) and 446 (99111 per hectare) were observed from FP treatment during both season respectively.

Application of Alternate furrow irrigation with normal irrigation interval (irrigation interval produced by CROPWAT Model) for maize improved number of cobs than convectional furrow irrigation and other irrigation methods. Beside this, statistical analysis showed that stand count of maize had not affected by the application of different irrigation systems with different irrigation intervals (p<0.05). On the other hand, statistically insignificant difference was observed between AFI norm and AFI extended regarding in number of cobs during both seasons.

This implies at Xaxo Site, under AFI norm and AFI extended treatments similar green cob yield was observed with less amount of water applied for AFIextended during both seasons. When comparing CFI and AFnorm, the latter increased number of green cobs by approximately 1555/ha in the first and second seasons. This result shows the same trend as reported Shifting irrigation practice from conventional irrigation (CFI) to alternate furrow increased corn yield to 8.9% (0.5 ton/ha).

The analysis of means and both season data also revealed that different irrigation methods with different irrigation interval on maize had a highly significant (p<0.05) influence on weight of cobs per plot. Moreover, weight of cobs (green cob) of maize was significantly (p<0.05) affected by different types irrigation methods with different irrigation interval at Lega Xaxo site for both seasons. Maximum weight of cobs per plot 126 (28044kgha-1) and 129 (28711kgha-1) were observed from AFI norm treatment during both season respectively. The maximum weight of cobs obtained from AFI norm was statistically superior to both treatments which followed Alternate furrow irrigation condition. Moreover, the minimum weight of cobs per plot 89 (19822 kgha-1) and 93 (20711kgha-1) were obtained from FP treatment were statistically inferior to other treatments during both seasons respectively.

Water Productivity (WP)

Water productivity was significantly (p<0.05) influenced due to application of different irrigation method with different irrigation intervals at Diga (Lelisa Dimtu site) and Wayu Tuka (Xaxo site) for both seasons. Results indicated that the water productivity of maize was higher under AFI_Norm next to AFI_Extended treatment during both seasons as compared with conventional and other treatments. Maximum water productivity values were 3.42 kg/m3, 3.45 kg/m3,3.55 kg/m3 and 3.30 kg/m3 observed from AFIExtended and statistically superior to AFINorm and other treatments for both seasons respectively. Statistically there was significant difference between Water productivity values of AFI_Norm and AFI_Extended at both locations and seasons. However, there was no statistical difference between AFI_Norm and AFI_Reduced on water productivity values for both location and seasons. This implies that more amount of water was applied under AFI_Reduced at both sites than AFI_Norm produces similar water productivity values. The minimum water Productivity values were 1.04kg/m3, 1.05kg/m3,1.03kg/m3 and 1.05kg/m3 s observed at both locations from FP respectively and this was statistically inferior to other treatments. These results indicated that AFIExtended and AFI_Norm were appropriate to increase WP because they allow applying less irrigation water for maize production.

The high WP values for AFI could be due to the small amount of applied water for AFI as compared with the EFI treatment. Reported similar results. In addition, concluded that the AFI system generally increases crop yield and WP. Clearly, WP depends on total applied water. This finding agrees with results obtained by Ibrahim and Emara (2010), who reported that an adverse relationship was found between the amount of applied irrigation water and WP.

Conclusion and Recommendation

The effort of this study was to determine the effect of alternate furrow irrigation with different irrigation interval on maize green cob production by comparing with farmer practice and convectional furrow irrigation. Beside this, maximum number of green cobs and green cob weight were obtained by applying alternate furrow irrigation with normal irrigation interval throughout the growing season at both locations and during 2018/19 and 2019/20 growing seasons. Crop water productivity (WP) is highest for alternate furrow irrigation with extended irrigation interval when comparing with Alternate furrow irrigation with normal irrigation interval and other treatments at both study area. Higher water productivity can be obtained by stressing maize crop by extending irrigation interval under alternate furrow irrigation. However, extending irrigation interval under alternate furrow irrigation showed yield reduction when comparing with applying Alternate furrow irrigation with normal irrigation interval.

Alternate-furrow irrigation with appropriate normal irrigation interval (irrigation interval produced by CROPWAT software) can be used as an efficient method for maize n production during dry season when production depends heavily on irrigation. It could be concluded that alternate-furrow irrigation with normal irrigation interval can improve crop water productivity without the risk of yield reduction. Generally in all parameters alternative furrow system with full irrigation application has shown the good mean results in contrasts to other treatments under normal irrigation water quality.

Therefore, it is recommended that if the cost of available water is not high and excess water delivery to the field does not require any additional expense, then the alternate furrow irrigation with normal irrigation interval will essentially be the best choice under the conditions of the study area.

REFERENCES

1. Abdel-Maksoud HH, Othman SA, El-Tawil AY. Improving water and N-use utilization for field crops via alternate furrow irrigation technique 1-Maize crop. Mansoura University Journal of Agricultural Sciences Mansoura University. 2002;27:8761-9.
2. El-Halim A. Impact of alternate furrow irrigation with different irrigation intervals on yield, water use efficiency, and economic return of corn. Chilean journal of agricultural research. 2013 Jun;73(2):175-80.
3. Blake GR, Hartge KH. Methods of Soil Analysis. Bulk Density, Part 1. Agronomy. 1986;9:363-75.
4. Debaeke P, Aboudrare A. Adaptation of crop management to water-limited environments. European Journal of Agronomy. 2004 Dec 1;21(4):433-46.
5. El-Beltagy AT, Abo-Hadeed AF. The main pillars of the National Program for maximizing the water-use efficiency in the old land. The Research and Development Council. MOALR.(in Arabic). 2008;30.
6. Kashiani P, Saleh G, Osman M, Habibi D. Sweet corn yield response to alternate furrow irrigation methods under different planting densities in a semi-arid climatic condition. African Journal of Agricultural Research. 2011 Feb 18;6(4):1032-40.
7. Lambisso R. Assessment of design practices and performance of small scale irrigation structures in south region.2008
8. Mebrahtu Y. Response of onion to deficit irrigation under different furrow irrigation water management techniques in Raya valley, northern Ethiopia (Doctoral dissertation, HAWASSA UNIVERSITY). 2017
9. Nasri M, Khalatbari M, Farahani HA. The effect of alternate furrow irrigation under different nutritional element supplies on some agronomic traits and seed qualitative parameters in corn (Zea mays L). Journal of cereals and oilseeds. 2010 Dec 31;1(2):17-23.
10. Nelson DJ, Al-Kaisi MM. Agronomic and economic evaluation of various furrow irrigation strategies for corn production under limited water supply. Journal of soil and water conservation. 2011 Mar 1;66(2):114-21.
11. Oweis T, Pala M, Ryan J. Stabilizing rainfed wheat yields with supplemental irrigation and nitrogen in a Mediterranean climate. Agronomy Journal. 1998 Sep;90(5):672-81.
12. Oweis T, Zhang H, Pala M. Water use efficiency of rainfed and irrigated bread wheat in a Mediterranean environment. Agronomy journal. 2000 Mar;92(2):231-8.
13. Penman HL. Natural evaporation from open water, bare soil and grass. Proc R Soc Lond A. Mathematical and Physical Sciences. 1948 Apr 22;193(1032):120-45.
14. Rafiee M, Shakarami G. Water use efficiency of corn as affected by every other furrow irrigation and planting density. World Applied Science Journal. 2010;11(7):826-9.
15. Sepaskhah AR, Khajehabdollahi MH. Alternate furrow irrigation with different irrigation intervals for maize (Zea mays L). Plant production science. 2005 Jan 1;8(5):592-600.