Legume Research
Chief EditorJ. S. Sandhu
Print ISSN 0250-5371
Online ISSN 0976-0571
NAAS Rating 6.80
SJR 0.391
Impact Factor 0.8 (2024)
Chief EditorJ. S. Sandhu
Print ISSN 0250-5371
Online ISSN 0976-0571
NAAS Rating 6.80
SJR 0.391
Impact Factor 0.8 (2024)
Effect of Irrigation Regimes and Phosphorus Fertilization on Water-use Efficiency, Phosphorus-agronomic Efficiency and Yield of Grass Pea (Lathyrus sativus L.) Ecotypes
Submitted10-12-2020|
Accepted19-04-2021|
First Online 05-08-2021|
doi 10.18805/LR-604
Descripton of study area
Field studies were conducted on grass pea two ecotypes (Lalehzar and Sharekord) cropping system during 2018-2019 in Lalehzar town (Kreman provice, Iran). The Lalehzar is located along one of Iran’s tallest mountains (Lalehzar Shah Mountains) at an altitude of over 4300 meters and has a hilltop position. The climate of the experimental area is characterized as cold and mountanous with cool summers (April to August) and very cold winters (October to March) and with (29° 29' N latitude and 56° 42'E longitude, 3000 m above mean sea level). Average annual rainfull 213.6mm and the highest maximum temperature +32°C and the lowest minimum temperature is -21°C. Physico-chemical properties of experimental soil and Chemical properties of the irrigation water before initiation of field experimentation (Table 1 and 2). Mean temperature, rainfall and evaporation at experimental site (Lalehzar, Kerman) during 2018 and 2019 (March to August) (Fig 1 and 2).
The experiment was designed as split factorial (split plot) comprised of 18 treatments replicated thrice in a randomized complete blocks design at Lalehzar during two consecutive years, 2018 and 2019. Irrigation treatments based on 3 levels of water (50, 75, 100% evaporation from Class A evaporation Pan) as main factor and 3 levels of single super phosphate fertilizer source (P2O5) (0, 60 and 120 kg ha-1) and two ecotypes (Lalehzar and Sharekord) as sub factor (Table 3).
Irrigation scheduling
The values of water with constant irrigation interval of seven days were obtained using the following formula:
Amount of water (m3 water ha-1): mm evaporation during 7 days in class A pan × 75% (class A pan coefficient) × coefficient for each treatment × 10
The amount of water per plot using water cubic meters per hectare (m3 water ha-1) and the level of each plot is specified and each treatment was provided using a discharge tube. Irrigaion treatments were carried out after plant emergence (Table 4).
Where,
Y was the yield (kg ha-1) and TWU refers to total amount of water (m3) used in a hectare.
*Total water used (TWU) was calculated by taking into consideration the total number of irrigations and water applied through irrigation (m3 ha-1) and effective rainfall during crop growth.
Agronomic efficiency of applied P
Following methodology suggested by Dordas et al., (2008) was used to calculate different efficiencies of applied phosphorus (P) in the current study:
Where,
Yp was crop yields with applied P (kg ha-1), Y0 was crop
yield (kg ha-1) in a control treatment with no P and Fp was Amount of fertilizer P applied (kg ha-1),
Statistical analysis
All the data obtained from grasspea crops for the consecutive 2 years were statistically analyzed using the MSTAT- C (1982) and the comparison of mean values was done by the use of Duncan’s new multiple range test at P≤0.05 level.
Grain yield in grass pea
The effect of drought stress reduction (50% of irrigation water) was especially evident in the no-fertilizer treatments in both ecotypes E1P0Iw50% and E2P0Iw50% (Table 5).
The data analyzed on two years mean basis data of phosphorus agronomic efficiency was tabulated in (Table 7). The effect of reducing drought stress (50% irrigation) was especially evident in the E1P0Iw50% and E2P0Iw50% (non-fertilizer treatments in both ecotypes). The highest phosphorus agronomic efficiency was obtained the E2P50%IW75% ; E2P50%IW100% there was no significant difference between these treatments. The E2P100%Iw50% exhibited the lowest phosphorus agronomic efficiency in the current study (Table 7). In a field study by Kumar et al., (2015) Influence of AM-fungi and applied phosphorus on growth indices,production efficiency, phosphorus-use efficiency and fruit-succulence in okra (Abelmoschus esculentus)-pea (Pisum sativum) cropping system in an acid Alfisol results showed that in irrigation treatment, under-irrigated conditions have increased phosphorus use efficiency and Similar magnitude of increases in PEP (partial factor productivity of applied phosphorus) both in okra and pea were also registered in treatments irrigated at 40% AWC (Available water holding capacity) in the presence or absence of AMF at varying applied phosphorus and also Overall, there was an impressive increase in phosphorus use efficiency in AMF imbedded treatments though, the response was comparatively lower at higher applied phosphorus probably due to lower efficiency of AMF at higher phosphorus (Harrier and Watson 2003). However, in pursuance of the law of diminishing returns, phosphorus use efficiency decreased as the phosphorus levels increased both in AMF inoculated and non-inoculated counterparts with every additional increment of phosphorus.
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