Drip irrigation proved to efficiently provide irrigation water and nutrients to the roots of plants, while maintaining high yield production. This research was established to study the root and nutrient distribution under drip irrigation. Faba bean and onion plants were cultivated in the experimental farm of the Faculty of Agriculture of Suez Canal University in Ismailia city with the application of normal fertilizers to soil. The data showed that soil moisture content in the soil planted with faba bean increased with the horizontal distance between drippers, contrariwise moisture content decreased with horizontal distance with the soil planted with onion. The data showed the vertical distribution of root length, root length density and specific root length of faba bean and onion decreased with increasing soil depth. The data showed that ammonium and nitrate pattern at the soil planted with the both plants increased between drippers and laterals. The peak concentration was recorded 35 mg/kg at 60 - 80 cm soil depth for faba bean and onion, indicating that the NO 3-N leaching was low by drip irrigation. Available phosphorus was higher at the surface layer than the subsurface layer at the soil planted with faba bean and onion. Available potassium tended to move both horizontally and downward under drip irrigation.
Irrigation is the artificial application of water which aims to maintain the soil moisture required for an optimum in plant growth. The crop response to irrigation methods was often different [
Drip irrigation proved to efficiently provide irrigation water and nutrients to the roots of plants, while maintaining high yield production. Modern drip irrigation has arguably become the world’s most valued innovation in agriculture since the invention of the impact of the sprinkler, which replaced flood irrigation. This is because high water application efficiencies are often possible with drip irrigation, since there is reduced surface evaporation, less surface runoff as well as minimal deep percolation [
Very significant differences in root growth exist among crops and effective rooting depths from 0.2 m to more than 1 m have been reported [
Information on root growth can also be used to design crop rotations. By placing deep-rooted crops at points in the rotation where available nutrients present in deeper soil layers, total losses can be reduced significantly. By placing shallow rooted crops only where little nutrients are available in deeper soil layers, nutrients losses after these crops can be reduced [
The aim of the present work was to study the distribution of roots and nutrients under drip irrigation system and growth parameters of faba bean and onion.
The study was conducted at the experimental site of Agricultural College of Suez Canal University during the winter season (2014/2015) at 30˚37'15.09''N and 32˚16'1.43''E. The soil of the experimental site was sandy in texture, very low in organic matter (0.3%) with pH (7.2) and EC (2.4 dSm−1). The average climate conditions of the site of the experiment during the growing season were illustrated in
To study moisture content and nutrients distribution in the soil, samples were
Months | Average temperature (C˚) | Average relative humidity (%) | Average evaporation (mm) | ||
---|---|---|---|---|---|
Max. | Mini. | Max. | Mini. | ||
November 2014 | 28.6 | 14.3 | 88.9 | 34.8 | 2.9 |
December 2014 | 26.9 | 12.0 | 89.3 | 33.8 | 2.7 |
January 2015 | 22.4 | 10.0 | 86.9 | 44.8 | 2.3 |
February 2015 | 22.9 | 9.61 | 84.6 | 31.8 | 2.3 |
March 2015 | 28.5 | 14.5 | 89.3 | 26.0 | 2.8 |
April 2015 | 29.8 | 13.3 | 87.4 | 21.2 | 3.1 |
May 2015 | 35.1 | 18.5 | 86.4 | 21.1 | 4.3 |
collected according to [
To study root distribution, root length, root length density and specific root length in the field, soil cores were removed using a 20 cm tall auger with an internal diameter of 10 cm. The cores were washed to collect the deep to 80 cm and one every 20 cm. Samples were collected at the end of the experiment. A similar method was obtained by [
Parameters assessments: After physiological maturity, ten plants from each of faba bean and onion were taken at random select for measuring plant height (cm), number of branches, number of pods, pods dry weight of plant, 100 seed weight (g) and seed yield of faba bean and number of leaves, bulb diameter (mm), bulb height (mm) and bulb fresh weight (g) of onion. The plant samples of faba bean and onion dried at 70˚C after that the samples were grinding and stored for analysis. Mineral content (N, P, K) of faba bean and onion plants were evaluated by [
The distribution of the water in the soil occurs along the hydraulic gradient between the wet and the dry soil, laterally by means of capillary action and vertically due to gravitation. In sand soil, the water moves more vertically than horizontally [
The moisture distribution of the soil planted with faba bean was increased with the horizontal distance between drippers at the surface layer 0 - 20 cm. The peak value of the soil moisture was 12% at the 60 cm horizontal distance at 40 - 60 cm depth. The moisture distribution at depths 0 - 20, 20 - 40, 40 - 60, 60 - 80 cm closed to be uniform, and the same trend observed at the vertical distance illustrated at
For the soil planted with onion, the soil moisture content decreased with horizontal distance (2.9% to 2.0%) at 60 cm and fluctuated with depth but it could be described as the moisture content remain constant with depth. At the vertical distance, the percentage of soil moisture increased from 1.30% to 1.7% at 30 - 60 cm (
The data in the
Soil depth (cm) | Horizontal distance (cm) | Vertical distance (cm) | |||
---|---|---|---|---|---|
0 | 30 | 60 | 0 - 30 | 30 - 60 | |
0 - 20 | 5.27 | 3.43 | 3.64 | 2.50 | 3.32 |
20 - 40 | 4.95 | 2.83 | 3.60 | 3.33 | 2.83 |
40 - 60 | 4.42 | 3.67 | 12.3 | 3.40 | 2.43 |
60 - 80 | 4.45 | 3.83 | 3.96 | 3.73 | 3.85 |
Soil depth (cm) | Horizontal distance (cm) | Vertical distance (cm) | |||
---|---|---|---|---|---|
0 | 30 | 60 | 0 - 30 | 30 - 60 | |
0 - 20 | 2.9 | 2.3 | 2.0 | 1.3 | 1.7 |
20 - 40 | 3.2 | 3.1 | 1.9 | 3.0 | 3.1 |
40 - 60 | 3.0 | 3.4 | 3.2 | 3.4 | 2.2 |
60 - 80 | 2.9 | 3.2 | 3.0 | 3.1 | 2.9 |
Plant | Soil depth (cm) | Root length density | Specific root length | |
---|---|---|---|---|
(cm∙cm−3) | % | cm∙g−1 root dry weight | ||
Faba bean | 0 - 20 | 0.59 ± 0.012 | 72 | 18.41 ± 1.83 |
20 - 40 | 0.23 ± 0.008 | 28 | 7.3 ± 0.52 | |
40 - 60 | - | - | ||
Onion | 0 - 20 | 0.37 ± 0.015 | 71 | 35.12 ± 3.7 |
20 - 40 | 0.152 ± 0.02 | 29 | 14.44 ± 2.5 | |
40 - 60 | - | - | - |
The root length density and specific root length decreased with increasing soil depth and the spatial distribution of roots was the basis for determining soil moisture changes at different soil depths. This results because of the close association of crop root growth with soil water. Similar reports were reported by [
Under drip irrigation, 72% of root length density of faba bean was found at 0 - 20 cm layer and 28% of root length density was at 20 - 40 cm and below this depth, the roots disappeared from the 40 - 60 cm depth. Specific root length in the upper layer 0 - 20 cm was higher (18.41 cm∙g−1 root dry weight) than the subsurface layer (20 - 40 cm).
With regard to the root length density of onion at the top layer was 71% of the total root length density with the soil depth. In this respect, [
Irrigation introduces water rate into the soil along with salts dissolved in it. During irrigation, water with micro and macro elements is spread on the surface of the field. At drip irrigation, water is applied in one spot [
Nitrogen is the most important determinant nutrient for plant growth and crop yield. The behavior of N in the soil system is complex, yet an understanding of the basic N processes, is essential for a more efficient N management program. Major N processes in the soil are: mineralization, immobilization, denitrification and nitrification, and leaching. The most efficient way is to understand processes that contribute to N losses in soil and how can mineralization and nitrification be harnessed to improve N content in the soil. In coarse-textured soil, leaching is a dominant process that results in N losses. Nitrate-nitrogen (NO3-N) is soluble and moves readily with soil water becoming a potential source of ground water pollution. Ammonium Nitrogen is less subjected to leaching from the soil compared to nitrate because of its adsorption in the Cation Exchange Capacity. However, losses of ammonium nitrogen through leaching occur in a coarse- textured soil with a low Exchange Capacity. Leaching is major N loss mechanism in coarse textured soil. Therefore, a proper understanding of N movement in coarse-textured soils can reduce N losses through leaching in the soil [
At the end of the season, ammonium availability was studied at the soil planted with faba bean under drip irrigation (
Soil depth (cm) | Horizontal distance (cm) | Vertical distance (cm) | |||
---|---|---|---|---|---|
0 | 30 | 60 | 30 | 60 | |
0 - 20 | 14 | 18 | 14 | 18 | 21 |
20 - 40 | 21 | 21 | 18 | 18 | 18 |
40 - 60 | 14 | 28 | 14 | 14 | 25 |
60 - 80 | 14 | 14 | 25 | 35 | 28 |
concentration was increased up to 30 cm at all depths at the horizontal distance. The highest available
With regard to the soil planted with onion, the ammonium distribution illustrated in
With regarding to the
Soil depth (cm) | Horizontal distance (cm) | Vertical distance (cm) | |||
---|---|---|---|---|---|
0 | 30 | 60 | 0 - 30 | 30 - 60 | |
0 - 20 | 28.0 | 35.0 | 20.0 | 42.0 | 35.0 |
20 - 40 | 17.5 | 31.5 | 35.0 | 21.0 | 35.0 |
40 - 60 | 14.0 | 17.5 | 21.0 | 7.00 | 35.0 |
60 - 80 | 7.00 | 17.5 | 14.0 | 7.00 | 14.0 |
respectively. The data in
Nitrate movement at soil planted with onion showed at
Soil depth (cm) | Horizontal distance (cm) | Vertical distance (cm) | |||
---|---|---|---|---|---|
0 | 30 | 60 | 0 - 30 | 30 - 60 | |
0 - 20 | 14 | 14 | 7.0 | 7.0 | 14 |
20 - 40 | 11 | 18 | 11 | 7.0 | 18 |
40 - 60 | 11 | 14 | 11 | 11 | 18 |
60 - 80 | 11 | 11 | 18 | 35 | 14 |
Soil depth (cm) | Horizontal distance (cm) | Vertical distance (cm) | |||
---|---|---|---|---|---|
0 | 30 | 60 | 0 - 30 | 30 - 60 | |
0 - 20 | 35.0 | 28.0 | 21.0 | 21.0 | 28.0 |
20 - 40 | 35.0 | 21.0 | 35.0 | 28.0 | 24.5 |
40 - 60 | 14.0 | 14.0 | 35.0 | 28.0 | 21.0 |
60 - 80 | 28.0 | 24.5 | 28.0 | 14.0 | 21.0 |
Phosphorus is one of the most important nutrients for plant growth so in most cases applied P fertilizer can lead to higher yield. Phosphorus transport in both vertical and lateral directions was too slow for the average rate of root growth into the soil [
At the end of the season, data showed that phosphorus availability at the soil planted with faba bean was higher in the surface layer than the subsurface layers between drippers and laterals (
Phosphorus pattern at the soil planted with onion is illustrated in
At the end of the experiment, potassium availability was determined at the soil planted with faba bean under drip irrigation.
Soil depth (cm) | Horizontal distance (cm) | Vertical distance (cm) | |||
---|---|---|---|---|---|
0 | 30 | 60 | 0 - 30 | 30 - 60 | |
0 - 20 | 35.5 | 47.7 | 35.3 | 32.5 | 22.7 |
20 - 40 | 27.5 | 39.1 | 26.0 | 21.0 | 17.4 |
40 - 60 | 21.7 | 22.1 | 8.3 | 15.6 | 9.8 |
60 - 80 | 23.2 | 18.7 | 13.4 | 9.8 | 8.6 |
Soil depth (cm) | Horizontal distance (cm) | Vertical distance (cm) | |||
---|---|---|---|---|---|
0 | 30 | 60 | 0 - 30 | 30 - 60 | |
0 - 20 | 20.67 | 11.85 | 16.89 | 16.64 | 20.2 |
20 - 40 | 14.88 | 6.56 | 15.38 | 14.12 | 19.6 |
40 - 60 | 11.09 | 7.06 | 10.60 | 10.33 | 9.80 |
60 - 80 | 10.42 | 11.09 | 8.83 | 13.11 | 8.83 |
Soil depth (cm) | Horizontal distance (cm) | Vertical distance (cm) | |||
---|---|---|---|---|---|
0 | 30 | 60 | 0 - 30 | 30 - 60 | |
0 - 20 | 100 | 107 | 115 | 100 | 100 |
20 - 40 | 109 | 118 | 114 | 105 | 103 |
40 - 60 | 127 | 119 | 114 | 80.0 | 75.0 |
60 - 80 | 122 | 119 | 108 | 100 | 75.0 |
surface to the subsurface layers. The potassium moves both horizontally and downward under drip irrigation, resulting more uniform distribution of the available potassium in the wetted soils. With regard to the vertical distance between laterals, the movement of potassium is declined with the distance from 0 - 30 and 30 - 60 cm and with the depth. At the top layer 0 - 20 cm, the available potassium remains constant with vertical distance (100 mg/kg). These results in agreement with that obtained by [
Potassium pattern at the soil planted with onion under drip irrigation showed at
Soil depth (cm) | Horizontal distance (cm) | Vertical distance (cm) | |||
---|---|---|---|---|---|
0 | 30 | 60 | 0 - 30 | 30 - 60 | |
0 - 20 | 112 | 108 | 112 | 115 | 119 |
20 - 40 | 112 | 112 | 106 | 108 | 112 |
40 - 60 | 100 | 108 | 90.0 | 106 | 72.2 |
60 - 80 | 106 | 100 | 112 | 112 | 108 |
Data presented in
The understanding of plant root distributions and nutrient distribution pattern had become very important to develop the environmental practices including high frequency irrigation. This study was conducted in the experimental site of Agricultural College of Suez Canal University during the winter season. The data showed that soil moisture distribution was more uniformity under drip irrigation than surface and sprinkler irrigation. The distribution of root length density of faba bean roots was spread at the top layer under drip irrigation more than sprinkler and surface irrigation. The same result was observed for the distribution of onion’s roots. Also, it observed that ammonium concentration was higher at the surface irrigation than drip and sprinkler irrigation, respectively. Most of the available nitrates were found in the top layer of soil at the sprinkler and drip irrigation as compared with surface irrigation in which more amounts
Plant | Dry weight of plant (g) | Plant height (cm) | No. of Branches | No. of pods | Pods dry weight of plant (g) | 100 seed weight (g) | Seed yeild | Nutrient content (g∙kg−1) | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
leaves | Stems | Roots | Seeds | ||||||||||||||||
N | P | K | N | P | K | N | P | K | N | P | K | ||||||||
Faba bean | 75.02 | 151.3 | 7 | 38.7 | 183.7 | 48.8 | 1102.4 | 27.7 | 1.2 | 37.1 | 10.4 | 0.89 | 13.1 | 21.2 | 1.7 | 7.8 | 42.6 | 3.6 | 13.2 |
Plant length (cm) | No. of leaves | Bulb | Nutrient content (g∙kg−1) | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Diameter (mm) | Height (mm) | Fresh Weight (g) | Leaves | Bulbs | Roots | ||||||||
N | P | K | N | P | K | N | P | K | |||||
58 | 9.75 | 59.67 | 48.14 | 93.46 | 11.3 | 1.5 | 13 | 11.5 | 1.8 | 10.7 | 11.2 | 3.32 | 15.97 |
soil planted with faba bean was higher at the surface layer under drip irrigation but at the soil planted with onion, the highest concentration of available phosphorus was at surface irrigation. The potassium of the soil planted with faba bean and onion moves both horizontally and downward under drip irrigation. At the soil planted with onion, potassium decreased with increasing in soil depth.
Mahgoub, N.A., Mohamed, A.I., El Sikhary, E.S.M. and Ali, O.M. (2017) Roots and Nutrient Distribution under Drip Irrigation and Yield of Faba Bean and Onion. Open Journal of Soil Science, 7, 52-67. https://doi.org/10.4236/ojss.2017.72004