Abstract
In present studies we have evaluated mulching impact of Jatropha curcas leaves on soil health and yield of two wheat (Triticum aestivum L.) varieties Wadan-2017 (rainfed) and Pirsabak-2013 (irrigated) under imposed water stress. Mulch of Jatropha leaves was spread on the soil surface at the rate of 0, 1, 3 and 5 Mg ha−1 after seed germination of wheat. Water stress was imposed by skipping irrigations for one month at anthesis stage of wheat maintaining 40% soil field capacity. We found a significant decline in soil microbial biomass carbon (30.27%), total nitrogen (22.28%) and organic matter content (21.73%) due to imposed water stress in non-mulch plots. However, mulch application at 5 Mg ha−1 significantly improved soil organic matter (38.18%), total nitrogen (37.75%), phenolics content (16.95 mg gallic acid equivalents/g) and soil microbial biomass carbon (26.66%) as compared to non-mulch control. Soil health indicators like soil carbonates, bicarbonates, electrical conductivity, chloride ions and total dissolved salts were decreased by 5 Mg ha−1 mulch application. We noted a decline in yield indicators like spike weight (14.74%), grain spike−1 (7.02%), grain length (3.79%), grain width (3.16%), 1000 grains weight (6.10%), Awn length (9.21%), straw weight (23.53%) and total grain yield (5.98%) of wheat due to imposed water stress. Reduction in yield traits of wheat due to water stress was higher in Pirsabak-2013 than Wadan-2017. Jatropha leaves mulch application at 5 Mg ha−1 significantly minimized the loss in yield traits of wheat crop caused by water stress. Jatropha curcas leaves mulch application at 5 Mg ha−1 is recommended for the successful establishment of wheat crop under water deficit conditions.
Subject terms: Ecology, Plant sciences
Introduction
Due to climate change, in arid and semiarid regions of the world main cause of moisture loss is evaporation from the root zone leading to the creation of water stress1. Therefore, in water stress condition plants need more water for their survival. Due to susceptibility of agricultural ecosystem to water stress food safety is threatened throughout the world. Therefore, scientists across the globe are trying to develop technologies for reducing impact of low soil moisture availability on growth and yield of economically important plants2. Mulching is one of such techniques found helpful in improving soil fertility and conservation of soil moisture3. Mulching also suppresses the weed influx4, improves soil texture5 and reduces soil erosion6. Mulch considerably increases potassium, phosphorus, nitrogen and organic carbon content of soil7. Use of organic amendments significantly decreases the toxic effects of heavy metals8, minimizes the salinity and sodicity stress effects on crops9.
Mulching increases plant productivity and conserves soil moisture content10. Mulching technique significantly reduces evaporation by modifying soil surface conditions. Due to mulching more water is available for plant use11. Organic mulch increased sesame grain yield from 147 to 250% compared to no-mulching12. Similarly rice straw mulch increased twice potato yield13. It was reported that yield of beans was increased 33% by mulch14. Straw mulch increased root yield of sugar beet from 9.40 to 11.20% and yield of sugar from 8 to 11.30%15.
Jatropha curcas is oil producing plant and belongs to family Euphorbiaceae. The seeds of Jatropha contain fibers, proteins and oil16. Jatropha is a drought-resistant plant species cultivated for controlling soil erosion and non-edible seed oil17,18. From seed oil of Jatropha varnish, medicine, lubricants, soap and biodiesel are manufactured19,20. Due to its industrial value plantation of Jatropha has been increased in tropical and sub-tropical regions of the world. Jatropha is a deciduous plant species and produces a lot of green matter which can be utilized as a source of mulch for increasing soil fertility. Jatropha leaf has been found as a rich source of minerals like Ca, Mg, K, Zn, Fe and organic matter21. However, J. curcas plantation may influence soil properties and soil microbial activities due to decomposition of its litter22. Therefore, we conducted these studies for evaluating Jatropha leaf mulch effects on soil fertility indicators and yield of wheat.
Wheat (Triticum aestivum L.) is an important food crop and can be cultivated in different environments. However, in arid regions water stress is the main ecological factor limiting the productivity of wheat crop throughout the world23. It is therefore needed of the day to protect wheat crop from water stress by using green, economical and sustainable technologies. Studies of many researchers like24–26 have reported that various mulching techniques increased grain yield of wheat by conserving soil water and improving soil microbial activity. Mineral phosphorus and organic amendments considerably increased soil fertility and yield of wheat27. In present studies we have evaluated mulching impact of Jatropha curcas leaves on soil health and yield of two wheat varieties Wadan-2017 (rainfed) and Pirsabak-2013 (irrigated) under imposed water stress.
Materials and methods
Preparation of organic mulch
Fresh leaves of Jatropha curcas were collected from 30 healthy plants (3–5 m tall) and dried in shade. The dried leaves were broken down and then sieved with the help of 2 mm mesh28.
Assessment of organic mulch potential on yield of wheat
In this study certified grains of two wheat (Triticum aestivum L.) varieties Wadan-2017 (rainfed) and Pirsabak-2013 (irrigated) were used. Details about pedigree and parentage of both the varieties are given in Table 1. Standardized size seeds of wheat were sterilized with 95% ethanol and washed with distilled water. In wheat growing season seeds were sown under natural condition during the years of 2018–2019 and 2019–2020 in District Bannu KP, Pakistan. During wheat growing season of 2018–2019 total rainfall was 284.7 mm while in 2019–2020 it was 227.4 mm. In 2018–2019 minimum and maximum average temperature was 11.02 and 24.07 °C correspondingly. Likewise during wheat growing season of 2019–2020 the average monthly minimum and maximum temperature were 11.19 and 23.29 °C respectively. Before sowing of seeds in the field recommended dose of potassium (50 kg ha−1), phosphorus (60 kg ha−1) and nitrogen (100 kg ha−1) were used. The split plot design was used for this experiment. Main treatments were control (irrigated having 100% soil field capacity) and water stress having (40% soil field capacity). Water stress was imposed by skipping irrigation for one month at anthesis stage of wheat. Application of irrigation during wheat growing season of 2018–2019 are given in Table 2. The plot size was 1 × 1 m2, having three replicates per treatment. The seeds were sown 10 cm apart and 5 cm deep in soil. Mulch of Jatropha leaves was spread on the soil surface at the rate of 0, 1, 3 and 5 Mg ha−1 after germination of wheat29.
Table 1.
Pedigree/parentage of wheat varieties used in the study.
| Variety | Pedigree/parentage | Province of release | Year of release | Moisture regime |
|---|---|---|---|---|
| Pirsabak-2013 |
CMSS97M04005T-040Y-020Y-030M-020Y-040M-28Y-3M0Y CS/TH.SC//3*PVN/3/MIRLO/BUC/4/MILAN/5/TILHI |
Khyber Pakhtunkhwa | 2013 | Irrigated |
| Wadan-2017 |
CMSA04Y00649S-028CRE1Y-010M-3SY-03CRE1Y-010M-03Y-0B YAV79//DACK/RABI/3/SNIPE/4/AE.SQUARROSA |
Khyber Pakhtunkhwa | 2017 | Rainfed |
Table 2.
Application of irrigation during 2018–2019 wheat growing season.
| Irrigation | Start | End | Duration of days |
|---|---|---|---|
| 1 | 12 November 2018 | 02 December 2018 | 20 |
| 2 | 07 December 2018 | 01 January 2019 | 25 |
| 3 | 05 January 2019 | 02 February 2019 | 28 |
| 4 | 07 February 2019 | 09 March 2019 | 30 |
| 5 | 12 March 2019 | 5 April 2019 | 24 |
When the seeds of wheat become fully matured and plants turned yellow, then they were harvested and yield parameters were determined. Thousand seed weight, spike weight, straw weight and yield per plot were determined with digital balance. Straw weight and grain yield of wheat was converted into kg/ha. By digital Vernier Caliper length and width of wheat seeds were determined. Number of grains per spike was counted in each treatment. Awn length of wheat spike was measured with the help of common measuring scale.
Assessment of organic mulch on soil fertility
After crop harvest soil samples were collected and effect of mulch and water stress on soil fertility was determined. Soil E.C and pH was determined according to standard methods of Richards and Mclean30,31. Carbonates, bicarbonates, total dissolved salts, chloride ion, calcium and magnesium were analyzed in soil by the method of Richards30. Soil organic matter was determined by the method of Walkley32. By the method of Singleton et al.33 soil phenolics content were measured. Soil microbial biomass carbon was determined by the method of Vance et al.34. Total nitrogen was determined according to the method of Bremner and Mulvaney35.
Statistical analysis
The data of soil parameters was analyzed by one way ANOVA while the data of yield parameters of wheat was analyzed by two way ANOVA. By LSD test means of control and treatment were compared36. Pearson correlation was calculated between soil fertility indicators and grain yield of wheat.
Complies with international, national and/or institutional guidelines
Experimental research and field studies on plants (either cultivated or wild), comply with relevant institutional, national, and international guidelines and legislation. Experimental studies were carried out in accordance with relevant institutional, national or international guidelines or regulation.
Permissions or licenses
The experiment was started, after taking permission from University of Science and Technology Bannu, Khyber Pakhtunkhwa, Pakistan.
Identification of the plant material
Before collection, the plant was identified by Dr. Zahid Ullah (Taxonomist), using the standard protocol at the Department of botany, University of Swat, Pakistan.A voucher specimen of this material has been deposited in a publicly available herbarium.
Ethics approval and consent to participate
We all declare that manuscripts reporting studies do not involve any human participants, human data, or human tissue. So, it is not applicable.
Results
Jatropha leaves mulch effect on soil fertility
The effects of Jatropha leaves mulch were investigated on the following indicators of soil fertility status.
Soil organic matter and nitrogen content
Mulch application significantly improved soil organic matter and nitrogen % as compared to non-mulch control (Table 3). Highest content of organic matter and nitrogen % was found in soil of plots applied with mulch at 5 Mg ha−1. Water stress decreased soil organic matter and nitrogen % as compared to irrigated and non-mulch control. However, mulch treated plots exposed to water stress exhibited higher contents of soil organic matter and nitrogen %.
Table 3.
Effect of Jatropha curcas leaves mulch on nitrogen%, organic matter, phenolics content, soil microbial biomass carbon and electrical conductivity under water stress.
| Treatments | Organic matter (%) | Nitrogen (%) | Phenolics content (mg gallic acid eq./gram of extract) | Soil microbial biomass carbon (mg/kg) | Electrical conductivity (µS cm−1) |
|---|---|---|---|---|---|
| Control (unmulched and irrigated) | 0.3833 ± 0.01f | 0.0193 ± 0.00f | 46.00 ± 0.05h | 20.350 ± 0.07d | 249.67 ± 2.60d |
| Mulch (1 Mg ha−1) + irrigated | 0.4900 ± 0.00c | 0.0247 ± 0.00c | 49.10 ± 0.08g | 23.670 ± 0.16b | 166.67 ± 10.14e |
| Mulch (3 Mg ha−1) + irrigated | 0.5200 ± 0.01b | 0.0263 ± 0.00b | 50.65 ± 0.21f | 23.967 ± 0.05b | 156.67 ± 4.91e |
| Mulch (5 Mg ha−1) + irrigated | 0.6200 ± 0.01a | 0.0310 ± 0.00a | 55.39 ± 0.13e | 27.747 ± 0.16a | 132.67 ± 6.49f |
| Water stress (40% soil field capacity) | 0.3000 ± 0.01g | 0.0150 ± 0.00g | 74.23 ± 0.15d | 14.190 ± 0.10f | 384.00 ± 10.21a |
| Mulch (1 Mg ha−1) + water stress | 0.4100 ± 0.01e | 0.0207 ± 0.00e | 106.26 ± 0.06c | 16.730 ± 0.11e | 354.00 ± 4.58b |
| Mulch (3 Mg ha−1) + water stress | 0.4500 ± 0.00d | 0.0227 ± 0.00d | 111.20 ± 0.12b | 21.113 ± 0.08c | 303.33 ± 9.28c |
| Mulch (5 Mg ha−1) + water stress | 0.5100 ± 0.01bc | 0.0257 ± 0.00bc | 113.19 ± 0.12a | 23.690 ± 0.08b | 243.33 ± 8.82d |
Means with similar English letter are not statistically different. LSD values for nitrogen%: Treatments = 1.223, organic matter: Treatments = 0.0240, phenolics content: Treatments = 0.3738, soil microbial biomass carbon: Treatments = 0.3178, electrical conductivity: Treatments = 22.857.
Soil phenolics content
The plots supplemented with Jatropha mulch showed considerable increase in soil phenolics content as compared to non-mulch control (Table 3). Maximum phenolics content was found in plots applied with Jatropha mulch at 5 Mg ha−1. We observed that water stress increased soil phenolics content over irrigated and non-mulch control. However, water stress treated plots applied with mulch showed highest amount of soil phenolics. We noted that soil phenolics content was improved by mulch both under non-stress and water stress conditions.
Soil microbial biomass carbon
Application of mulch improved soil microbial biomass carbon as compared to non-mulch control (Table 3). Plots treated with 5 Mg ha−1 showed highest content of soil microbial biomass carbon. However, water stress significantly decreased soil microbial biomass carbon. The decrease in soil microbial biomass carbon was overcome by application of mulch under water stress conditions.
Soil electrical conductivity
We examined that electrical conductivity of soil was decreased in plots supplemented with mulch than non-mulch control (Table 3). Water stress treated plots without mulch has high value of electrical conductivity over irrigated and non-mulch control. The mulch application decreased electrical conductivity of soil in plots exposed to water stress. It is stated that application of mulch completely reversed the increase in soil electrical conductivity both in irrigated and water stress treated plots.
Soil carbonates and bicarbonates
Our results showed that application of mulch significantly decreased soil carbonates and bicarbonates contents as compared to non-mulch control (Table 4). The lowest content of carbonates and bicarbonates was found in plots applied with mulch at 5 Mg ha−1. Interestingly water stress treated plots showed significantly higher content of carbonates and bicarbonates as compared to non-mulch and irrigated control. We concluded that Jatropha mulch decreased soil carbonates and bicarbonates content both under normal and water stress conditions.
Table 4.
Effect of Jatropha curcas leaves mulch on carbonates, bicarbonates, calcium and magnesium, chloride ion and total dissolved salts under water stress.
| Treatments | Carbonates (meq/L) | Bicarbonates (meq/L) | Ca + Mg (meq/L) | Chloride ion (meq/L) | Total dissolved salts (mg/L) |
|---|---|---|---|---|---|
| Control (unmulched and irrigated) | 0.9000 ± 0.03b | 2.1933 ± 0.02d | 6.0600 ± 0.07d | 0.9000 ± 0.02e | 174.77 ± 1.82d |
| Mulch (1 Mg ha−1) + irrigated | 0.8067 ± 0.03c | 2.1000 ± 0.02e | 7.5000 ± 0.12b | 0.7900 ± 0.02f | 116.67 ± 7.10e |
| Mulch (3 Mg ha−1) + irrigated | 0.5033 ± 0.02e | 2.0267 ± 0.01f | 8.0533 ± 0.07a | 0.7000 ± 0.02g | 109.67 ± 3.44e |
| Mulch (5 Mg ha−1) + irrigated | 0.2567 ± 0.03f | 1.6333 ± 0.02g | 8.5000 ± 0.12a | 0.5000 ± 0.02h | 92.87 ± 4.54f |
| Water stress (40% soil field capacity) | 0.9767 ± 0.03a | 4.0000 ± 0.03a | 5.3333 ± 0.33e | 2.8933 ± 0.02a | 268.80 ± 7.15a |
| Mulch (1 Mg ha−1) + water stress | 0.6500 ± 0.03d | 3.7033 ± 0.03b | 6.2267 ± 0.15cd | 2.7967 ± 0.02b | 247.80 ± 3.21b |
| Mulch (3 Mg ha−1) + water stress | 0.5267 ± 0.03e | 3.0000 ± 0.02c | 6.5000 ± 0.12cd | 2.2000 ± 0.02c | 212.33 ± 6.50c |
| Mulch (5 Mg ha−1) + water stress | 0.3250 ± 0.02f | 2.0267 ± 0.01f | 6.6667 ± 0.09c | 2.0267 ± 0.01d | 170.33 ± 6.17d |
Means with similar English letter are not statistically different. LSD values for carbonates: Treatments = 0.0724, bicarbonates: Treatments = 0.0686, Ca + Mg: Treatments = 0.4645, chloride ion: Treatments = 0.0561, Total dissolved salts: Treatments = 16.000.
Soil calcium and magnesium
We observed that soil calcium and magnesium content was increased by mulch application as compared to non-mulch control (Table 4). Highest value of calcium and magnesium content was found in plots applied with mulch at 5 Mg ha−1. Water stress decreases the content of calcium and magnesium in soil as compared to irrigated and non-mulch control. The decrease in calcium and magnesium content was reversed by mulch application under water stress. Most effective dose of mulch was 5 Mg ha−1.
Soil chloride ions and total dissolved salts
We found that the content of chloride ions and total dissolved salts were lower in plots supplemented with mulch as compared to non-mulch control (Table 4). The plots exposed to water stress and not applied with mulch had higher content of chloride ions and total dissolved salts over irrigated control. The mulch application decreased chloride ions and total dissolved salts in plots exposed to water stress. It is worthy to mention that mulch application at 5 Mg ha−1 completely reversed increase in the content of chloride ions and total dissolved salts of water stress treated plots as compared to non-mulch and irrigated control.
Jatropha leaves mulch effect on wheat yield
Grain spike−1
Data of treatment means in Table 5 showed useful effect of Jatropha mulch on grain spike−1 of wheat. Highest number of grain (16.25%) was recorded for plants supplemented with 5 Mg ha−1 of mulch. We noted severe decrease (7.02%) in grain number due to water stress, however, percent decrease in grain number was higher in Pirsabak-2013 (9.77%) than Wadan-2017 (4.81%). It is noted that decreasing effect of water stress on grain number was decreased by Jatropha mulch particularly at 5 Mg ha−1 mulch.
Table 5.
Effect of Jatropha curcas leaves mulch on grain per spike and thousand grain weight of wheat under water stress.
| Treatments | Grain spike−1 (No) | Thousand grain weight (g) | ||||
|---|---|---|---|---|---|---|
| V1 (Wadan-2017) | V2 (Pirsabak-2013) | Mean | V1 (Wadan-2017) | V2 (Pirsabak-2013) | Mean | |
| Control (unmulched and irrigated) | 55.33 ± 1.45bc | 44.333 ± 0.33e | 49.833c | 51.517 ± 0.82b−d | 46.850 ± 0.35gh | 49.183c |
| Mulch (1 Mg ha−1) + irrigated | 56.667 ± 1.45b | 45.000 ± 0.58e | 50.833c | 52.050 ± 0.65a−c | 47.050 ± 0.35f–h | 49.550bc |
| Mulch (3 Mg ha−1) + irrigated | 57.667 ± 1.45b | 49.333 ± 1.20d | 53.500b | 53.233 ± 0.37ab | 48.083 ± 0.47 fg | 50.658ab |
| Mulch (5 Mg ha−1) + irrigated | 66.000 ± 1.53a | 53.000 ± 0.58c | 59.500a | 53.817 ± 0.38a | 48.783 ± 0.15ef | 51.300a |
| Water stress (40% soil field capacity) | 52.667 ± 1.45 cd | 40.000 ± 1.15f | 46.333d | 49.983 ± 0.80de | 42.383 ± 1.05i | 46.183d |
| Mulch (1 Mg ha−1) + water stress | 55.667 ± 1.20bc | 42.667 ± 1.45ef | 49.167c | 51.083 ± 0.58 cd | 42.583 ± 0.50i | 46.833d |
| Mulch (3 Mg ha−1) + water stress | 57.333 ± 1.45b | 43.000 ± 1.00ef | 50.167c | 52.767 ± 1.19a−c | 45.783 ± 0.81h | 49.275c |
| Mulch (5 Mg ha−1) + water stress | 58.000 ± 1.53b | 52.333 ± 1.45cd | 55.167b | 53.533 ± 0.15a | 46.233 ± 0.40h | 49.883bc |
| Mean | 57.417a | 46.208b | 52.248a | 45.969b | ||
Means with similar English letter are not statistically different. LSD values for grain spike−1: Treatments = 2.5687, Varieties = 1.2843, T × V = 3.6327: LSD values for thousand grain weight: Treatments = 1.2927, Varieties = 0.6463, T × V = 1.8281.
Thousand grains weight
Jatropha mulch at 5 Mg ha−1 considerably increased thousand grains weight by 4.13% as compared to well irrigated and non-mulch control (Table 5). Thousand grains weight was decreased (6.10%) by water stress as compared to well irrigated and non-mulch control. On the other hand, use of mulch at 3 and 5 Mg ha−1 significantly reversed decrease in thousand grain weights caused by skipped irrigations. Treatment × variety interaction showed that in sensitive variety Pirsabak-2013 percent decrease in thousand grain weights was higher than tolerant Wadan-2017. Both the varieties have better reaction to mulch at 5 Mg ha−1.
Grain length
Treatment means indicated that under well watered conditions Jatropha mulch at 5 Mg ha−1 considerably increased grain length by 7.47% over well irrigated and unmulched control (Table 6). As compared to well irrigated and unmulched control skipped irrigation decreased grain length by 3.79%. However, decrease in seed length was significantly overcome by application of mulch at 3 and 5 Mg ha−1. Treatment × variety interaction showed that skipped irrigation highly decreased grain length of sensitive variety Pirssbak-2013 (4.36%) than tolerant Wadan-2017 (3.28%).
Table 6.
Effect of Jatropha curcas leaves mulch on grain length and grain width of wheat under water stress.
| Treatments | Grain length (mm) | Grain width (mm) | ||||
|---|---|---|---|---|---|---|
| V1 (Wadan-2017) | V2 (Pirsabak-2013) | Mean | V1 (Wadan-2017) | V2 (Pirsabak-2013) | Mean | |
| Control (unmulched and irrigated) | 6.8100 ± 0.06b–d | 6.1167 ± 0.12fg | 6.4633cd | 3.3400 ± 0.05e–h | 3.2967 ± 0.01f–i | 3.318de |
| Mulch (1 Mg ha−1) + irrigated | ***6.8967 ± 0.24a–c | 6.2400 ± 0.20e–g | 6.5683c | 3.4067 ± 0.03b–e | 3.3500 ± 0.03d–g | 3.3783cd |
| Mulch (3 Mg ha−1) + irrigated | 6.9300 ± 0.16a–c | 6.4333 ± 0.17d–f | 6.6817bc | 3.4900 ± 0.02b | 3.4500 ± 0.03b–d | 3.4700b |
| Mulch (5 Mg ha−1) + irrigated | 7.2267 ± 0.13a | 6.7433 ± 0.14b–d | 6.9850a | 3.6367 ± 0.00a | 3.4867 ± 0.01b | 3.5617a |
| Water stress (40% soil field capacity) | 6.5867 ± 0.11c–e | 5.8500 ± 0.03g | 6.2183d | 3.2467 ± 0.03h–j | 3.1800 ± 0.01j | 3.2133f |
| Mulch (1 Mg ha−1) + water stress | 6.6500 ± 0.25c–e | 6.4200 ± 0.12d–f | 6.5350cd | 3.2967 ± 0.03f–i | 3.2033 ± 0.03ij | 3.2500ef |
| Mulch (3 Mg ha−1) + water stress | 6.7700 ± 0.08b–d | 6.4700 ± 0.04d–f | 6.6200bc | 3.3767 ± 0.06c–f | 3.2667 ± 0.03g–j | 3.3217de |
| Mulch (5 Mg ha−1) + water stress | 7.1133 ± 0.06ab | 6.6900 ± 0.05cd | 6.9017ab | 3.4567 ± 0.02bc | 3.3967 ± 0.08b–f | 3.4267bc |
| Mean | 6.8729a | 6.3704b | 3.4062a | 3.3288b | ||
Means with similar English letter are not statistically different. LSD values grain length: Treatments = 0.2847, Varieties = 0.1423, T × V = 0.4026: LSD values for grain width: Treatments = 0.0729, Varieties = 0.0364, T × V = 0.1031.
It is noted that Wadan-2017 had taller seed length (7.31%) than Pirsabak-2013. Both varieties showed good response to mulch at 5 Mg ha−1.
Grain width
Treatment means data in Table 6 indicated that Jatropha mulch has favorable effect on grain width of wheat. Highest seed width (3.56 mm) was noted for plants treated with 5 Mg ha−1 of mulch over irrigated and unmulched control (3.32 mm). Grain width was significantly decreased (3.16%) by skipped irrigation. However, as compare to Wadan-2017 skipped irrigation highly decreased grain width in Pirsabak-2013. It is noted that skipped irrigation effects was minimized by Jatropha mulch. As compared to other mulch treatments 5 Mg ha−1 mulch was more effective.
Spike weight
Application of mulch at 3 and 5 Mg ha−1 considerably increased spike weight (13.36% and 17.33%) respectively (Table 7). Major reduction (14.74%) occurred in spike weight due to skipped irrigation. Percent decrease in spike weight was higher in Pirsabak-2013 (17.53%) as compared to Wadan-2017 (12.42%) due to skipped irrigation. However, skipped irrigation does not significantly effects the spike weight of plants treated with Jatropha mulch. It is noted that application of mulch at 5 Mg ha−1 significantly increase spike weight of wheat both under skipped irrigated and well irrigated conditions.
Table 7.
Effect of Jatropha curcas leaves mulch on spike weight and awn length of wheat under water stress.
| Treatments | Spike weight (g) | Awn length (cm) | ||||
|---|---|---|---|---|---|---|
| V1 (Wadan-2017) | V2 (Pirsabak-2013) | Mean | V1 (Wadan-2017) | V2 (Pirsabak-2013) | Mean | |
| Control (unmulched and irrigated) | 3.2467 ± 0.24cd | 2.7000 ± 0.03ef | 2.9733cd | 6.3333 ± 0.44b–e | 6.3333 ± 0.33b–e | 6.3333bc |
| Mulch (1 Mg ha−1) + irrigated | 3.3433 ± 0.03bc | 2.9000 ± 0.03cf | 3.1217bc | 6.6667 ± 0.33a–c | 6.5000 ± 0.29a–d | 6.5833ab |
| Mulch (3 Mg ha−1) + irrigated | 3.7867 ± 0.01ab | 3.0767 ± 0.01c–e | 3.4317ab | 6.8333 ± 0.17ab | 6.6667 ± 0.17a–c | 6.7500ab |
| Mulch (5 Mg ha−1) + irrigated | 3.9433 ± 0.02a | 3.2500 ± 0.02cd | 3.5967a | 7.0000 ± 0.00a | 6.8333 ± 0.17ab | 6.9167a |
| Water stress (40% soil field capacity) | 2.8433 ± 0.24d–f | 2.2267 ± 0.01g | 2.5350e | 6.0000 ± 0.00d–f | 5.5000 ± 0.03f | 5.7500d |
| Mulch (1 Mg ha−1) + water stress | 2.9633 ± 0.09c–f | 2.5500 ± 0.13fg | 2.7567de | 6.1667 ± 0.17c–e | 5.9000 ± 0.03ef | 6.0333cd |
| Mulch (3 Mg ha−1) + water stress | 3.0033 ± 0.30c–f | 2.8900 ± 0.09c–f | 2.9467cd | 6.6667 ± 0.17a–c | 6.4000 ± 0.06b–e | 6.5333ab |
| Mulch (5 Mg ha−1) + water stress | 3.7133 ± 0.36ab | 2.9733 ± 0.29c–f | 3.3433ab | 6.8333 ± 0.17ab | 6.5333 ± 0.03a–d | 6.6833ab |
| Mean | 3.3554a | 2.8208b | 6.5625a | 6.3333b | ||
Means with similar English letter are not statistically different. LSD values spike weight: Treatments = 0.3216, Varieties = 0.1608, T × V = 0.4548: LSD values for awn length: Treatments = 0.4177, Varieties = 0.2088, T × V = 0.5907.
Awn length
Data of treatment means in Table 7 showed that as compared to well irrigated and unmulched control awn length of wheat spike was significantly increased (8.43%) by Jatropha mulch at 5 Mg ha−1 under well irrigated conditions. Awn length was decreased (9.21%) by skipped irrigation than unmulched control and well irrigated. Moreover, decrease in awn length was significantly overcome by 3 and 5 Mg ha−1 mulch. Decrease in awn length was higher in sensitive variety Pirssbak-2013 (13.15%) than tolerant Wadan-2017 (5.26%) due to skipped irrigation. It is noted that variety Wadan-2017 has higher awn length than Pirsabak-2013.
Straw weight
Treatment means data showed that mulch at 3 and 5 Mg ha−1 respectively increase straw weight (35.01% and 45.79%) in non stressed groups (Table 8). Skipped irrigation significantly decrease (23.53%) straw weight. Straw weight was considerably decreased in Pirsabak-2013 (29.29%) as compared to Wadan-2017 (18.89%) by skipped irrigation. Moreover, straw weight treated with Jatropha mulch was not affected by skipped irrigation. It is examined that both under skipped irrigated and well irrigated conditions straw weight of wheat was increased by application of mulch at 5 Mg ha−1. Wadan-2017 had high straw weight (20.05%) than Pirsabak-2013.
Table 8.
Effect of Jatropha curcas leaves mulch on straw weight and grain yield of wheat under water stress.
| Treatments | Straw weight (kg ha−1) | Grain yield (kg ha−1) | ||||
|---|---|---|---|---|---|---|
| V1 (Wadan-2017) | V2 (Pirsabak-2013) | Mean | V1 (Wadan-2017) | V2 (Pirsabak-2013) | Mean | |
| Control (unmulched and irrigated) | 12.000 ± 0.289de | 9.900 ± 0.058gh | 10.950e | 4200.0 ± 5.8ef | 3883.3 ± 44.1h | 4041.7e |
| Mulch (1 Mg ha−1) + irrigated | 18.500 ± 0.289b | 10.500 ± 0.289f–h | 14.500c | 4750.0 ± 28.9d | 4050.0 ± 28.9f–h | 4400.0d |
| Mulch (3 Mg ha−1) + irrigated | 22.000 ± 0.764a | 11.683 ± 0.428d–f | 16.842b | 5483.3 ± 8.8ab | 4950.0 ± 28.9c | 5216.7a |
| Mulch (5 Mg ha−1) + irrigated | 22.940 ± 0.266a | 17.450 ± 0.770b | 20.195a | 5620.0 ± 11.5a | 5083.3 ± 44.1c | 5351.7a |
| Water stress (40% soil field capacity) | 9.747 ± 0.087h | 7.000 ± 0.289i | 8.373f | 4000.0 ± 11.5gh | 3600.0 ± 28.9i | 3800.0f |
| Mulch (1 Mg ha−1) + water stress | 11.043 ± 0.275e–g | 9.500 ± 0.173h | 10.272e | 4130.0 ± 43.6fg | 4100.0 ± 28.9fg | 4115.0e |
| Mulch (3 Mg ha−1) + water stress | 11.260 ± 0.167ef | 14.667 ± 0.167c | 12.963d | 4996.7 ± 57.8c | 4350.0 ± 28.9e | 4673.3c |
| Mulch (5 Mg ha−1) + water stress | 12.757 ± 0.884d | 15.350 ± 0.176c | 14.053c | 5400.0 ± 28.9b | 4700.0 ± 115.5d | 5050.0b |
| Mean | 15.031a | 12.006b | 4822.5a | 4339.6b | ||
Means with similar English letter are not statistically different. LSD values straw weight: Treatments = 0.8442, Varieties = 0.4221, T × V = 1.1939: LSD values for grain yield: Treatments = 135.03, Varieties = 67.515, T × V = 190.96.
Grain yield
Table 8 indicated that 5 Mg ha−1 Jatropha mulch significantly increased (24.48%) grain yield of wheat as compared to unmulched and irrigated control. Skipped irrigation considerably decreased (5.98%) grain yield of wheat as compared to unmulched and irrigated control. The percent decrease due to skipped irrigation in grain yield of wheat was higher in Pirsabak-2013 (7.30%) compared to Wadan-2017 (4.7%). However, the decrease in grain yield of wheat was overcome by leaves mulch of Jatropha. Comparably Wadan-2017 had high grain yield (10.01%) than Pirsabak-2013.
Pearson’s correlation coefficient (r)
Heat map analysis (Fig. 1) revealed that grain yield was significantly positive correlated with soil N content (r = 0.9895), soil organic matter (r = 0.9951), soil phenolics (r = 0.9294), soil microbial biomass carbon (r = 0.9955), thousand grains weight (r = 0.9946), and soil Ca + Mg (r = 0.9961). Soil N content was significantly positive correlated with organic matter (r = 0.9914), soil phenolics (r = 0.9026), soil microbial biomass carbon (r = 0.9897), and thousand seed weight (r = 0.9770). Soil organic matter content was significantly positive correlated with soil phenolics (r = 0.9101), soil microbial biomass carbon (r = 0.9979), and thousand seeds weight (r = 0.9846). Soil microbial biomass carbon was considerably positively correlated with thousand seed weight (r = 0.98610).
Figure 1.
Pearson’s Correlation Coefficient (r) shown by heatmap for the soil fertility indicators and yield related traits of wheat under water stressed condition. Blue color is indicator of negative correlation whereas, peach to maroon colors indicate positive correlation. The color allotted to a specific point in the heat map is indicator of the strength of correlation between two specific traits.
Discussion
Jatropha mulch showed positive effects on soil organic matter content. A soil organic matter contains organic compounds released from dead and decaying of living organisms37 and improves soil health38. Soil organic matter improves water holding capacity of soil and this is the major reason that organic mulches minimize water stress effects on the establishment of crops39. Organic matter resulting from microbial degradation of mulch releases nutrients to the soil and thus improving soil fertility40.
We recorded improvements in soil total nitrogen (%) due to Jatropha mulch application. Mulching improves nutrients cycle in cultivated lands41 leading to better establishment of crops42. Nitrogen content was high in the plots supplemented with maize straw mulch43. Studies have shown impact of mulches on soil N and C pools44. Organic mulching materials of oak (Quercus fabri), cogon grass (Imperata cylindrica), bracken fern (Pteridium aquilinum) and Chinese coriaria (Coriaria nepalensis) increased soil nitrogen content which was directly proportional to the decaying rate and nutrients content of the mulching material45.
We reported that water stress decreased soil microbial biomass in non-mulch plots; however, Jatropha mulch improved soil microbial biomass both under non-stress and water stress conditions. Microbial biomass shows considerable response to the climatic conditions and soil micro environment. Changing pattern of rainfall and global warming effects the reproduction and growth of soil microbes46–48. Therefore, in soil ecosystem degradation, microbial biomass carbon content acts as an early warning indicators49. Many researchers have reported that with the increase of drought stress soil microbial activity becomes damaged50–52 and decreased up to 39%53. Our studies indicated that Jatropha leaves mulch improved soil microbial biomass which assisted in better establishment of wheat crop under low soil moisture availability.
Phenolics concentration was higher in plots supplemented with Jatropha mulch. Studies of Stoklosa et al.54 showed that phenolics concentration was higher in soil provided with rye and oat mulch. Higher content of phenolics in plots applied with mulch may be because that Jatropha leaves contained a reasonable amount of phenolics. Although phenolics are highly reactive having phytotoxicity yet they are degraded either by soil microbes or by oxidation limiting their allelopathic potential in mulching trials55.
We noted a severe decrease in yield related traits of wheat due to imposed water stress. Water stress considerably minimized the yield of wheat56. This reduction in grain yield of wheat under water stress may be due to leaf senescence acceleration, degeneration of photosynthesis and sink restrictions56. In our studies Jatropha mulch minimized water stress negative impact on grain yield of wheat. Furthermore, decrease in grain number per spike was due to reduction in spikelets number per spike of wheat57. Studies have shown that black plastic mulch and rice straw mulch significantly increased straw yield, thousand seed weight and seed yield of wheat respectively29. Deng et al.58 have also described the benefits of mulching on yield of wheat. Water stress reduced the grain and straw yield as compared to well watered treatments. Application of Jatropha mulch on grain yield may be majorly due to its improving effects on soil organic matter and soil nitrogen content as reported earlier59. Our results are also in confirmation with those of60 that dual transparent plastic film + straw mulching and dual black plastic film + straw mulching considerably improved soil temperature, biomass, soil water storage potential, total nitrogen, soil organic carbon and grain yield of wheat. Arbuscular mycorrhizal fungi significantly increased water use efficiency, soil microbial biomass carbon/nitrogen ratio and crop productivity of non-irrigated wheat61.
Conclusion
Application of Jatropha mulch improved soil microbial activity, total N, organic matter and phenolics content as compared to non-mulch and irrigated control. Water stress restricted microbial biomass production, decreased soil nitrogen content and grain yield of wheat. The application of Jatropha curcas leaves mulch reversed negative effects of water stress on grain yield and soil fertility status. Findings of our research are novel in the sense that Jatropha leaves mulch was beneficial on soil microbial biomass and soil phenolics which might contribute in the reduction of disease attacks on wheat crop. Moreover, phenolics present in mulch have made a way of diffusion into the soil which might have assisted in the water stress resistance of wheat varieties. It was found that both the wheat varieties showed similar response to Jatropha mulch application irrespective of their tolerance level to water deficit stress.
Acknowledgements
The authors are grateful to the Deanship of Scientific Research, King Saud University for funding through Vice Deanship of Scientific Research Chairs.
Author contributions
Conceptualization, S.F.; F.U.; Data curation, M.I., F.U.; Formal analysis, S.M., A.A.A.-H., H.M.A., M.H.S.; Investigation, M.I.; Methodology, S.S.; A.A.A.-H.; K.D.; Project administration, K.D.; Resources, A.A.A.-H.; S.D., R.D.; Supervision, S.F.; Validation, K.D.; Writing—original draft, F.U.; Writing—review and editing, S.F.; A.A.A.-H.
Data availability
The datasets generated and/or analysed during the current study are not publicly available, but are available from the corresponding author on reasonable request.
Competing interests
The authors declare no competing interests.
Footnotes
Publisher's note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Contributor Information
Faizan Ullah, Email: drfaizanwazir@gmail.com.
Asma A. Al-Huqail, Email: aalhuqail@ksu.edu.sa
Shah Fahad, Email: shah_fahad80@yahoo.com.
Shah Saud, Email: saudhort@gmail.com.
References
- 1.Khamraev ShR, Bezborodov YuG. Results of research on the reduction of physical evaporation of moisture from the cotton fields. Sci. World. 2016;2(33):86–93. [Google Scholar]
- 2.Khan AU, et al. Production of organic fertilizers from rocket seed (Eruca sativa L.), chicken peat and Moringa oleifera leaves for growing linseed under water deficit stress. Sustainability. 2021;13(1):1–19. [Google Scholar]
- 3.Patil Shirish S, Kelkar Tushar S, Bhalerao Satish A. Mulching: A soil and water conservation practice. Res. J. Agric For. Sci. 2013;1(3):26–29. [Google Scholar]
- 4.Matkovic A, et al. Mulching as a physical weed control method applicable in medicinal plants cultivations. J. Lekovite Sirovine. 2015;35:37–51. doi: 10.5937/leksir1535037M. [DOI] [Google Scholar]
- 5.Nawaz A, Lal R, Shrestha RK, Farooq M. Mulching affects soil properties and greenhouse gas emissions under long-term no-till and plough-till systems in alfisol of Central Ohio. Land Degrad. Dev. 2016;28(2):673–681. doi: 10.1002/ldr.2553. [DOI] [Google Scholar]
- 6.Brant V, et al. Splash erosion in maize crops under conservation management in combination with Shallow Strip-tillage before Sowing. Soil Water Res. 2017;12(2):106–116. doi: 10.17221/147/2015-SWR. [DOI] [Google Scholar]
- 7.Kumar R, et al. Effect of plant spacing and organic mulch on growth, yield and quality of natural sweetener plant Stevia and soil fertility in western Himalayas. Int. J. Plant Prod. 2014;8(3):311–334. [Google Scholar]
- 8.Seleiman MF, Kheir AMS. Maize productivity, heavy metals uptake and their availability in contaminated clay and sandy alkaline soils as affected by inorganic and organic amendments. Chemosphere. 2018;204:514–522. doi: 10.1016/j.chemosphere.2018.04.073. [DOI] [PubMed] [Google Scholar]
- 9.Seleiman MF, Kheir AMS. Saline soil properties, quality and productivity of wheat grown with bagasse ash and thiourea in different climatic zones. Chemosphere. 2018;193:538–546. doi: 10.1016/j.chemosphere.2017.11.053. [DOI] [PubMed] [Google Scholar]
- 10.Chakraborty D, et al. Effect of mulching on soil and plant water status, and the growth and yield of wheat (Triticum aestivum L.) in a semi-arid environment. Agric. Water Manag. 2008;95(12):1323–1334. doi: 10.1016/j.agwat.2008.06.001. [DOI] [Google Scholar]
- 11.Ahmad ZI, Ansar M, Iqbal M, Minhas NM. Effect of planting geometry and mulching on moisture conservation, weed control and wheat growth under rainfed conditions. Pak. J. Bot. 2007;39(4):1189–1195. [Google Scholar]
- 12.Teame G. Effect of organic mulches and land preparation methods on soil moisture and sesame productivity. Afr. J. Agric. Res. 2017;12(38):2836–2843. doi: 10.5897/AJAR2017.12478. [DOI] [Google Scholar]
- 13.Lehar L, Wardiyati T, Moch Dawam M, Suryanto A. Influence of mulch and plant spacing on yield of Solanum tuberosum L. cv. Nadiya at medium altitude. Int. Food Res. J. 2017;24(3):1338–1344. [Google Scholar]
- 14.Arash K. The evaluation of water use efficiency in common bean (Phaseolus vulgaris L.) in irrigation condition and mulch. Sci. Agric. 2013;2(3):60–64. [Google Scholar]
- 15.Artyszak A, Gozdowski D, Kucińska K. The yield and technological quality of sugar beet roots cultivated in mulches. Plant Soil Environ. 2014;60(10):464–469. doi: 10.17221/428/2014-PSE. [DOI] [Google Scholar]
- 16.Brittaine, R. & Lutaladio, N. Jatropha: A Smallholder Bioenergy Crop. The Potential for Pro-poor Development Integrated Crop Management, Vol. 8 (IFAD/FAO, 2010). http://www.fao.org
- 17.Elbehri, A., Segerstedt, A. & Liu, P. Biofuels and the sustainability challenge: A global assessment of sustainability issues, trends and policies for biofuels and related feedstocks. Food and Agric. Organ. United Nations (FAO) xvi-174 (2013).
- 18.King AJ, et al. Potential of Jatropha curcas as a source of renewable oil and animal feed. J. Exp. Bot. 2009;60(10):2897–2905. doi: 10.1093/jxb/erp025. [DOI] [PubMed] [Google Scholar]
- 19.Raheman, H. 14 Jatropha. Handbook of Bioenergy Crop Plants, 315–345 (2012).
- 20.Ullah F, Bano A, Nosheen A. Sustainable measures for biodiesel. Effects. 2014;36(23):2621–2628. [Google Scholar]
- 21.Irshad M, et al. Evaluation of Jatropha curcas L. leaves mulching on wheat growth and biochemical attributes under water stress. BMC Plant Biol. 2021;21(1):1–12. doi: 10.1186/s12870-021-03097-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 22.Dieye T, et al. The effect of Jatropha curcas L. leaf litter decomposition on soil carbon and nitrogen status and bacterial community structure (Senegal) J. Soil Sci. Environ Manag. 2016;7(3):32–44. doi: 10.5897/JSSEM15.0528. [DOI] [Google Scholar]
- 23.Kafi M, Salehi M. Kochia scoparia as a model plant to explore the impact of water deficit on halophytic communities. Pak. J. Bot. 2012;44:257–262. [Google Scholar]
- 24.Yang YM, Liu XJ, Li WQ, Li CZ. Effect of different mulch materials on winter wheat production in desalinized soil in Heilonggang region of North China. J. Zhejiang Univ. Sci. B. 2006;7(11):858–867. doi: 10.1631/jzus.2006.B0858. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 25.Xie ZK, Wang YJ, Li FM. Effect of plastic mulching on soil water use and spring wheat yield in arid region of northwest China. Agric. Water Manag. 2005;75(1):71–83. doi: 10.1016/j.agwat.2004.12.014. [DOI] [Google Scholar]
- 26.Khan RH, Anwar-ul-Haq K, Sajjad MR. Effect of different types of mulches on grain yield and yield components of wheat (Triticum aestivum) under rainfed condition. J. Biol. Agric. Healthc. 2014;4(12):85–91. [Google Scholar]
- 27.Weidhuner A, Afshar RK, Luo Y, Battaglia M, Sadeghpour A. Particle size affects nitrogen and carbon estimate of a wheat cover crop. Agron. J. 2019;111(6):3398–3402. doi: 10.2134/agronj2019.03.0164. [DOI] [Google Scholar]
- 28.Ding Z, et al. The integrated effect of salinity, organic amendments, phosphorus fertilizers, and deficit irrigation on soil properties, phosphorus fractionation and wheat productivity. Sci. Rep. 2020;10(1):1–13. doi: 10.1038/s41598-019-56847-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 29.Rummana S, Amin AKMR, Islam MS, Faruk GM. Effect of irrigation and mulch materials on growth and yield of wheat. Bang. Agron. J. 2018;21(1):71–76. doi: 10.3329/baj.v21i1.39362. [DOI] [Google Scholar]
- 30.Richard, L. A. Diagnosis and improvement of saline and alkaline soils. Handbook No. 60 (US Depart. Agric., 1954).
- 31.McLean, E. O. Soil pH and lime requirement. Methods of Soil Analysis: Part 2 Chemical and Microbiological Properties, Vol. 9, 199–224 (1983).
- 32.Walkley A. A critical examination of a rapid method for determining organic carbon in soils—Effect of variations in digestion conditions and of inorganic soil constituents. Soil Sci. 1947;63:251–264. doi: 10.1097/00010694-194704000-00001. [DOI] [Google Scholar]
- 33.Singleton VL, Orthofer R, Lamuela-Raventos RM. Analysis of total phenols and other oxidation substrates and antioxidants by means of Folin–Ciocalteu reagent. Methods Enzymol. 1999;299:152–178. doi: 10.1016/S0076-6879(99)99017-1. [DOI] [Google Scholar]
- 34.Vance ED, Brookes PC, Jenkinson DS. An extraction method for measuring soil microbial biomass C. Soil Biol. Biochem. 1987;19:703–707. doi: 10.1016/0038-0717(87)90052-6. [DOI] [Google Scholar]
- 35.Bremner JM, Mulvaney CS. Nitrogen-total. In: Page AL, Miller RH, Keeney DR, editors. Methods of Soil Analysis. Part 2. Chemical and Microbiological Properties. Soil Sci. Society America; 1982. pp. 595–624. [Google Scholar]
- 36.Steel RGD, Torrie JH, Dickey DA. Principles and Procedures of Statistics: A Biometrical Approach. 3. McGraw-Hill; 1997. p. 246. [Google Scholar]
- 37.Brady NC, Weil RR. Soil colloids: Seat of soil chemical and physical acidity. Nat. Prop. Soils. 2008;5(13):311–358. [Google Scholar]
- 38.Scharenbroch BC, Lloyd JE. Particulate organic matter and soil nitrogen availability in urban landscapes. Arboricul. Urb. For. 2006;32(4):180–191. doi: 10.48044/jauf.2006.024. [DOI] [Google Scholar]
- 39.Bhadha, J. H., Capasso, J. M., Khatiwada, R., Swanson, S. & LaBorde, C. Raising soil organic matter content to improve water holding capacity. UF/IFAS 1–5 (2017).
- 40.Chalker-Scott L. Impact of mulches on landscape plants and the environment—A review. J. Environ. Hortic. 2007;25(4):239–249. doi: 10.24266/0738-2898-25.4.239. [DOI] [Google Scholar]
- 41.Liu Z, Fu B, Zheng X, Liu G. Plant biomass, soil water content and soil N:P ratio regulating soil microbial functional diversity in a temperate steppe: A regional scale study. Soil Biol. Biochem. 2010;42(3):445–450. doi: 10.1016/j.soilbio.2009.11.027. [DOI] [Google Scholar]
- 42.Bai SH, Blumfield TJ, Reverchon F. The impact of mulch type on soil organic carbon and nitrogen pools in a sloping site. Biol. Fertil. Soils. 2014;50(1):37–44. doi: 10.1007/s00374-013-0829-z. [DOI] [Google Scholar]
- 43.Yang H, et al. The combined effects of maize straw mulch and no-tillage on grain yield and water and nitrogen use efficiency of dry-land winter wheat (Triticum aestivum L.) Soil Tillage Res. 2020;197:104485. doi: 10.1016/j.still.2019.104485. [DOI] [Google Scholar]
- 44.Li XJ, et al. Abscisic acid pretreatment enhances salt tolerance of rice seedlings: Proteomic evidence. Biochim. Biophys. Acta (BBA) Proteins Proteomics. 2010;1804(4):929–940. doi: 10.1016/j.bbapap.2010.01.004. [DOI] [PubMed] [Google Scholar]
- 45.Fang S, Xie B, Liu D, Liu J. Effects of mulching materials on nitrogen mineralization, nitrogen availability and poplar growth on degraded agricultural soil. New For. 2011;41(2):147–162. doi: 10.1007/s11056-010-9217-9. [DOI] [Google Scholar]
- 46.Houghton, J. T. Climate Change 2001: The Scientific Basis 419–470 (2001).
- 47.Johnson D, et al. Plant community composition affects the biomass, activity and diversity of microorganisms in limestone grassland soil. Eur. J. Soil Sci. 2003;54(4):671–678. doi: 10.1046/j.1351-0754.2003.0562.x. [DOI] [Google Scholar]
- 48.Johnson MJ, Lee KY, Scow KM. DNA finger printing reveals links among agricultural crops, soil properties, and the composition of soil microbial communities. Geoderma. 2003;114:279–303. doi: 10.1016/S0016-7061(03)00045-4. [DOI] [Google Scholar]
- 49.Nielsen NM, Winding A, Binnerup S. Microorganisms as Indicators of Soil Health. Ministry of the Environment, National Environ. Res. Inst.; 2002. pp. 15–16. [Google Scholar]
- 50.Wilkinson SC, et al. PLFA profiles of microbial communities in decomposing conifer litters subject to moisture stress. Soil Biol. Biochem. 2002;34(2):189–200. doi: 10.1016/S0038-0717(01)00168-7. [DOI] [Google Scholar]
- 51.Drenovsky RE, Vo D, Graham KJ, Scow KM. Soil water content and organic carbon availability are major determinants of soil microbial community composition. Microb. Ecol. 2004;48(3):424–430. doi: 10.1007/s00248-003-1063-2. [DOI] [PubMed] [Google Scholar]
- 52.Liu YY, Yao HY, Huang CY. Influence of soil moisture regime on microbial community diversity and activity in a paddy soil. Acta Pedol. Sin. 2006;43:828–834. [Google Scholar]
- 53.Jensen KD, Beier C, Michelsen A, Emmett BA. Effects of experimental drought on microbial processes in two temperate heathlands at contrasting water conditions. Appl. Soil Ecol. 2003;24(2):165–176. doi: 10.1016/S0929-1393(03)00091-X. [DOI] [Google Scholar]
- 54.Stoklosa A, Hura T, Stupnicka-Rodzynkiewicz E, Dabkowska T, Lepiarczyk A. The influence of plant mulches on the content of phenolic compounds in soil and primary weed infestation of maize. Acta. Agron. Bot. 2008;61(2):205–219. [Google Scholar]
- 55.Ohno T. Oxidation of phenolic acid derivatives by soil and its relevance to allelopathic activity. J. Environ. Qual. 2001;30(5):1631–1635. doi: 10.2134/jeq2001.3051631x. [DOI] [PubMed] [Google Scholar]
- 56.Farooq S, Shahid M, Khan MB, Hussain M, Farooq M. Improving the productivity of bread wheat by good management practices under terminal drought. J. Agric. Crop Sci. 2015;201(3):173–188. doi: 10.1111/jac.12093. [DOI] [Google Scholar]
- 57.Madani A, Rad AS, Pazoki A, Nourmohammadi G, Zarghami R. Wheat (Triticum aestivum L.) grain filling and dry matter partitioning responses to source: Sink modifications under postanthesis water and nitrogen deficiency. Acta Sci. Agron. 2010;32:145–151. doi: 10.4025/actasciagron.v32i1.6273. [DOI] [Google Scholar]
- 58.Deng XP, Shan L, Zhang H, Turner NC. Improving agricultural water use efficiency in arid and semiarid areas of China. Agric. Water Manag. 2006;80(1–3):23–40. doi: 10.1016/j.agwat.2005.07.021. [DOI] [Google Scholar]
- 59.Athar HR, Khan A, Ashraf M. Inducing salt tolerance in wheat by exogenously applied ascorbic acid through different modes. J. Plant Nutr. 2009;32:1799–1817. doi: 10.1080/01904160903242334. [DOI] [Google Scholar]
- 60.Luo, et al. Dual plastic film and straw mulching boosts wheat productivity and soil quality under the El Nino in semiarid Kenya. Sci. Total Environ. 2020;738:139808. doi: 10.1016/j.scitotenv.2020.139808. [DOI] [PubMed] [Google Scholar]
- 61.Duan, et al. Improvement of wheat productivity and soil quality by arbuscular mycorrhizal fungi is density-and moisture-dependent. Agron. Sustain. Dev. 2021;41(1):1–12. doi: 10.1007/s13593-020-00659-8. [DOI] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
The datasets generated and/or analysed during the current study are not publicly available, but are available from the corresponding author on reasonable request.

