Next Article in Journal
Implementation of Integrated VCSEL-Based Optical Feedback Interferometry Microfluidic Sensor System with Polymer Microoptics
Previous Article in Journal
Tunable Optical Delay Line Based on a Racetrack Resonator with Tunable Coupling and Stable Wavelength
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:

Short-Term Effects of Tillage Intensity and Fertilization on Sunflower Yield, Achene Quality, and Soil Physicochemical Properties under Semi-Arid Conditions

Department of Plant Production and Genetics, Faculty of Agriculture, University of Maragheh, P.O. Box, 55181-83111 Maragheh, East Azerbaijan, Iran
National Parks of Montenegro, 81000 Podgorica, Montenegro
Department of Geography, Faculty of Philosophy, University of Montenegro, Danila Bojovica bb, 81400 Niksic, Montenegro
Faculty of Management, Comenius University in Bratislava, 820 05 Bratislava, Slovakia
Faculty of Economics and Engineering Management, University Business Academy, 21000 Novi Sad, Serbia
Authors to whom correspondence should be addressed.
Appl. Sci. 2019, 9(24), 5482;
Received: 15 November 2019 / Revised: 3 December 2019 / Accepted: 10 December 2019 / Published: 13 December 2019


Inappropriate soil management practices and specific climatic conditions in semi-arid region cause loss of soil organic matter (SOM), decline soil fertility, and trigger soil erosion processes and desertification. A two-year field study was carried out to investigate the effects of tillage intensity and fertilizer regime treatments on the productivity of sunflower (Helianthus annus L.) and soil physicochemical properties in the semi-arid highland region in northwest Iran (37°31′ north (N), 46°53′ east (E)). Five fertilizer treatments were included under conventional (CT) or reduced tillage systems (RT): F1, no fertilizer application; F2, 20 t∙ha−1 farmyard manure (FYM); F3, 40 t∙ha−1 FYM; F4: 20 t∙ha−1 FYM + 50% of the recommended dose of nitrogen–phosphorus–potassium (NPK) chemical fertilizer; F5: full dose of the recommended chemical NPK fertilizer. Results showed that utilization of FYM decreased bulk density (BD); its effects were more evident under the highest SOM content for the F2 and F3 treatments, whereas application of mineral fertilizer had no significant effect upon SOM content, and elevated levels of FYM preserved higher organic carbon contents in topsoil. The highest N, P, and K contents of the soil were obtained with FYM plus inorganic fertilizer application in the RT system. Hydraulic conductivity and soil moisture content were significantly improved by RT and FYM application. The highest root growth was observed for F3 and F4 under the RT system. The effect of fertilizer and tillage treatments was more pronounced during the second year. Traits related to growth and seed quality such as achene oil content, leaf area, and harvest index were enhanced by chemical fertilization in the CT system. The highest achene yield and oil percentage were recorded for plants grown with F3 and F4. The best option for enhancing sunflower productivity and quality in semi-arid, high-altitude environments is the application of organic fertilizers amended with reduced amounts of chemical fertilizers.

1. Introduction

About one-third of the land surface in the world is arid or semi-arid. Growing population, increasing food demand, and technological advances may soon lead to intensifying land use in semi-arid regions [1,2]. The semi-arid land represents regions of the world where the precipitation is low, irregular, and unpredictable, which is rarely sufficient for crop production and negatively affects the physical, chemical, and biological properties of soil [1,2,3,4]. Due to the mentioned climatic problems and lack of proper agricultural and soil management practices, soil organic matter (SOM) and mineral nutrient contents are very low.
Most semi-arid regions are classified as winter-dominant rainfall areas. Wheat is extremely well adapted to endure in such an environment, where its productivity and stability of production are exceeded only by barley [4]. Therefore, the dominant cultivation of semi-arid regions is often based on winter cereals with a “wheat or barley/fallow rotation”. However, it was shown that crop biodiversity has a noticeable effect on soil fertility [5]. This is a main problem in the semi-arid highlands in northwest Iran, where successive wheat or barley farming ended up reducing infiltration rates and SOM. Furthermore, inadequate vegetation and imbalanced precipitation contributed to the creation of runoffs which tend to erode the soil even more extensively [6,7,8]. Lack of interest, smallholdings, frequent dry spells, drought, low profitability, unsustainable management practices, low research commitment, and problems of complexity resulted in a shortage of low-tillage technologies for improving soil properties across semi-arid regions [9]; Poor soil and water conservation measures lead to land degradation.
Arable soils are under significant threat due to unsustainable cultivation practices. Cautious soil management is essential to obtain sustainable agricultural production especially in drought-prone areas [10]. Tilling and turning the soil layer is common practice for the preparation of seedbeds. However, the tillage intensity can greatly affect the properties of soils and the plant yield. This is especially important in soils with low organic matter, such as semi-arid regions. Conventional tillage or plowing turns over the soil completely, bringing soil materials from under the plow layer to the surface and burying materials from fertile topsoil to a lower depth. However, continuous and frequent conventional tillage can lead to degradation of soil structure, due to the gradual loss of stable aggregates, leading to soil erosion and compaction, which then result in low moisture availability for plants [11]. On the contrary, conservation tillage or reduced tillage (RT) is an agricultural management approach that aims to minimize the frequency or intensity of tillage operations. RT potentially produces benefits that result from soil C accumulation in the surface soil, such as improved infiltration, water-holding capacity, erosion reduction, nutrient cycling, and soil biodiversity. Continuous and frequent conventional tillage can significantly change the soil physical properties within a growing season [12,13].
Inorganic fertilizers play a critical role in the world’s food security; however, they do not add to or maintain soil organic matter, and their inappropriate continued use can damage the soil and endanger sustainability of production in the long term [14]. Furthermore, some studies emphasized associated problems with the inappropriate application and improper management of inorganic fertilizers, including increased consumption of fossil fuels, leach out of soil, pollution of water basins, destruction of micro-organisms and advantageous insects, increased sensitivity of the crop to diseases, and reduced soil fertility, all of which tend to impose irreparable damage to the overall system. On the other end of the spectrum, organic fertilizers seem to be capable of addressing these problems [15,16].
Apparently, a major concern in semi-arid regions is the further loss of SOM and, hence, deteriorated fertility. A number of factors contribute to reduced crop residue mulch and, hence, loss of SOM; these include overgrazing, burning the residues, termites, sparse vegetation, limited moisture, and over-ploughing [16,17].
It was revealed that surface SOM concentration is, in general, negatively correlated with aridity and positively correlated with mean annual precipitation and altitude [18]. In semi-arid regions, there are slow-cycling SOM pools, and, due to unsuitable climatic conditions, the turnover rate is low.
Tillage systems and fertilizer managements were proven to impose significant impacts on soil productivity [19,20,21,22]. Inoperative farming management decreases soil productivity to the point where many previously cultivated soils are faced with serious nutrient deficiency and can no longer naturally sustain crop productivity [23]. A combination of reducing soil tillage, mulching with crop residues, application of organic fertilizers, and crop rotation exhibit large capabilities for reversing chemical, physical, and biological processes degrading the soil [22].
However, in most semi-arid areas, reduced-tillage systems are constrained by soil densification, which decreases rainfall infiltration, thereby limiting root access to water [21,24]. Therefore, implementing low-tillage methods should be combined with other soil management options to achieve the desired result. A primary approach to preserve soil productivity is to increase SOM by simply adding OM to the soil.
As a potential supply of OM, farmyard manure (FYM, which is largely produced by the growing livestock industry in northwestern Iran) can be used to improve physical, chemical, and biological characteristics of the soil. The general aim of this study was to investigate the effects of various combinations of FYM, inorganic fertilizers, and tillage systems on selected physical and chemical properties of soil.

2. Materials and Methods

2.1. Site Characteristics

The experiments were conducted in Kharajoo District, between Maragheh and Hashtroud, northwestern Iran (longitude: 46°53′ east (E), latitude: 37°31′ north (N), altitude: 1780 m) during the 2015–2016 growing seasons (two years). The site was covered by a fine mixed, mesic, typical cacixerepts soil, exhibiting a xeric moisture regime [25]. This regime is the typical moisture regime of Mediterranean climates, where winters are moist and cool, and summers are warm and dry. Annual average precipitation is 310 mm with a maximum in April, and one-third of the precipitation falls as snow, and about 78% of the precipitation occurs during the growing seasons [26].
Before the initiation of the experiments a wheat–fallow rotation was applied as a common rotation system in the region. Being adjacent to Sahand Mountains, the area is known to experience long cold winters. The average slope across the study site was measured at 5%–6%. Table 1 shows the monthly average evaporation, relative humidity, temperature, and precipitation across the study area during the growing seasons experienced in this research.

2.2. Experimental Design and Farm Management

The soil was clay/loam texture and contained 3.82 g∙kg−1 organic matter, 0.64 g∙kg−1 total N, 11.75 mg∙kg−1 available phosphorus (P), and 182.31 mg∙kg−1 available potassium (K) in the 0–20-cm soil layer [27,28,29]. Organic matter content of the soil was low (<0.5%) at the initiation of the experiment [30]. The study site was left uncultivated for three years prior the experiments. A randomized complete blocked design with four replications was adopted based on a split plot arrangement. Main plot size was set to 40 m × 6 m and sub-plot size was set to 6 m × 6 m. Sunflower (cv. Azargol) was cultivated in a particular site during the wet season (April–August) for two successive years.
Two tillage systems, namely, (a) moldboard ploughing (into an average depth of 30 cm) + two shallow disc harrowing (herein referred to as conventional tillage: CT), and (b) chisel ploughing + disc (herein referred to as reduced tillage: RT), were implemented onto the main plots. The subplots were allocated to five fertilizer treatments including F1: control (no fertilizer application), F2: FYM (20 Mg∙ha−1), F3: FYM (40 Mg∙ha−1), F4: FYM (20 Mg∙ha−1) + 50% of the recommended dose of chemical 100 kg∙ha−1 N + 50 kg∙ha−1 P + 50 kg∙ha−1 K, and F5: full recommended dose of chemical fertilizers (100:50:50, that is, 200 kg∙ha−1 N + 100∙kg ha−1 P + 100 kg∙ha−1 K).
Farmyard manure was applied annually, and tillage operations were performed every March. Planting dates were 10 April 2015 and 15 April 2016. Sunflower seeds were sown manually in rows 0.75 m apart with a plant-to-plant distance in the row of 0.20 m. This resulted in a plant density of approximately 5–7 m−2. Dates of harvesting were 21 August 2015 and 14 August 2016. Chemical fertilizers were added after layout preparation in the form of urea (CH4N2O, N 46%), triple superphosphate (Ca(H2PO4)2·H2O), and potassium sulfate (K2SO4).
Each year, farmyard manure was applied, and a tillage operation was performed in March. Then, the planting phase was undertaken a month after the tillage manure application by planting sunflower seeds manually along rows of 75-cm row spacing, at a plant-to-plant distance of 20 cm.
Chemical fertilizers were used in three splits including 1/3 N + full P + full K as basal, 1/3 N as top dressing at the vegetative stage (V4), and 1/3 N as top dressing at the reproductive stage (R2). Each year, following tillage operation, the surface layer of the soil was provided with decayed farmyard manure and mixed to a depth of 15 cm by spade to achieve a uniform mix. In order to arrange the experimental plots into ridges and furrows, soil was piled on either side of rows, so that inter-row areas defined the furrows. The furrow was used to irrigate or drain the plot. In the course of this preparation process, large amounts of FYM and soil were piled along the ridges.
The used farmyard manure was dominantly composed of wheat straw and cow dung—what is normally used for bedding in cowsheds. Containing C at 16.9%, N at 0.52%, P at 0.19%, and K at 0.43%, the FYM was applied on the basis of dry weight. Six rounds of irrigation via furrows were performed during the growing season to provide the plants with water. Composite samples of soil were collected from the top 10–20 cm of the soil layer across each subplot.

2.3. Evaluation of Soil Properties and Plant Growth

Soil samples were collected in mid-June of each year to assess physical and chemical properties. Accordingly, mean emergence time (MET) was evaluated as follows: MET = (Σn × g)/N, where n is the number of seedlings emerging per day, g is the required number of days for emergence, and N is total number of emerged seeds [31].
Bulk densities (BDs) were evaluated from oven-dried (at 105 °C for 24 h) soil sample weights and the soil corer volume, and they were further used to determine total porosity by assuming a particle density of 2.65 cm−3. BD of the soil was calculated for a depth interval of 0–15 cm using the core method [32]. A gravimetric method was devised to record soil moisture at 55 DAS at a depth of 20 cm between sunflower rows across each plot. The moisture content of soil was recorded five days after each round of irrigation. BD multiplied by the gravimetric moisture content gave volumetric soil moisture. The Blanco-Canqui method [33] was followed to obtain saturated hydraulic conductivity (Ksat). Core samples were taken from a depth of 0–15 cm along rows and across inter-row areas. Root depth was evaluated according to Shirani et al. [20].
Chlorophyll was evaluated with the Minolta SPAD-502 hand-held device in fully expanded upper leaves at the flowering stage. Leaf area measurements were performed upon termination of the flowering stage. Observations on 10 plants selected at random were recorded to check for the impacts of different tillage systems and fertilizer treatments on phenological development of plants until maturity. Physiological maturity stage was targeted for harvesting the plants, as indicated by the color alteration of the back of the head (from green to yellow) and bracts (to brown). As far as harvesting was concerned, 10 plants were sampled at random from each replicate for each treatment before being quantified in terms of yield and yield components. Oil contents of the samples were extracted by a small expeller press and were further extracted by the Soxhlet extraction method where hexane served as the solvent [34]. Crop and soil properties were subjected to analysis of variance as described by Gomez and Gomez [35]. The procedure was implemented utilizing SAS Software (SAS Institute, Cary, NC, USA). The F-test was devised to indicate whether or not effects of the treatments were significant, while significance of the difference between means of the two treatments was evaluated by least significant difference (LSD) at 5% probability. We assessed the factor year and found no significant tillage × year × fertilizer type interactions.

3. Results

3.1. Physical Properties

Results of one-way ANOVA were indicative of significance of effects of tillage system, fertilizer treatment, and their interaction on Ksat (Table 2), which represents soil infiltration. The comparison between mean values showed an increase in the value of Ksat upon applying FYM, particularly in the second year, while different FYM levels exhibited the same effect. By comparison of mean values of Ksat over each year, a decrease in Ksat was noted in the CT system during the second year, even upon applying FYM.
Based on bulk density (BD) evaluations, BD was found to be significantly influenced by both fertilizer treatment and tillage system. On the other hand, FYM was seen to lower BD, such that maximum and minimum BDs were observed in the control plot (the one with no fertilization) and that onto which FYM was applied at the maximum level, respectively. In the meantime, a further decrease in BD in response to the application of FYM was observed in the first and second years in the CT and RT systems, respectively (Figure 1).
However, the effect of FYM was more prominent in second year. These findings indicate the gentle trend through which FYM may work in RT systems, such that it may take a long time for positive effects of the application of FYM on physical characteristics of soil to emerge. Results were indicative of a negative correlation between BD and OM (r = −0.87 and −0.84; Table 3).
Evaluation of soil moisture during the first year showed that, upon applying FYM, soil moisture enhanced significantly, with the enhancement being more evident in the RT system rather than the CT system (Table 2). Here, 50% and 33% increases in soil moisture (over control) were obtained upon applying FYM at 20 and 40 t∙ha−1, respectively. Different levels of FYM resulted in significant differences by the first year, while the same result was obtained with different FYM application rates during the second year.

3.2. Chemical Properties

Based upon OM measurement results, application of FYM was observed to enhance SOM under both tillage systems (Figure 1). A comparison of mean values among different fertilizer treatments showed significantly different organic matter content (p < 0.05) with different rates of FYM application. In the meantime, FYM exhibited more remarkable impacts under the RT system than the CT system. Maximum SOM was obtained when FYM was applied at 40 t∙ha−1 in the RT system (27 and 41 g∙kg−1 in the first and second years, respectively). A small increase in SOM was observed with chemical fertilization, as compared to control.
Nitrogen content measurements indicated that, irrespective of NPK fertilizer dose, application of NPK fertilizer enhanced the nitrogen content of the soil. Generally speaking, higher nitrogen contents were obtained with the RT system than the CT system. The highest nitrogen content was achieved in the second year when 50% of the recommended dose of chemical fertilizer was applied in combination with FYM in the RT system (Table 2). Commonly, the nutrient content of plots subjected to CT was more perceptible, partly because of the deficit in substantial soil displacement and mixing. Maximum K and P contents were observed when FYM was applied in combination with chemical fertilizer in the RT system (Table 2). Maximum K content in the RT system was 13% higher than that in the CT system. Applying FYM in combination with chemical fertilizer in the CT and RT systems enhanced K content by 48% and 59% over the control, respectively. Although the soils of semi-arid areas are known to contain relatively high K contents, the use of FYM and an RT system can improve the content of K available to the plant, thereby increasing its resistance to abiotic stresses.
P content measurements made it clear that maximum P contents in the CT and RT systems were achieved with chemical fertilization and combined FYM/chemical fertilizer application, respectively. The results indicated that further organic P was available in the RT system than the CT system.

3.3. Plant Growth Properties

According to root depth measurements, the deepest root was recorded in the CT system where FYM was applied at a high level. Based on the obtained values of mean emergence time (MET), the application of FYM lowered the MET significantly in both tillage systems, such that minimum MET was recoded for plots receiving 40 t∙ha−1 FYM (Figure 2). Comparing mean values of MET between the two tillage systems revealed that there were similar MET values in both systems. A further comparison of MET between FMY-treated and fertilized subplots indicated that F2, F3, F4, and F5 had MET values of 32%, 44%, 41%, and 19%, respectively. The effects of fertilizers on MET were much more prominent in RT systems than in CT systems. Given the soil compaction in RT systems, the application of FYM could largely address this problem and enhance the seedling emergence rate, thereby improving seedling establishment even further. Further confirming this fact, a positive association was identified between BD and MET (Table 3). Moreover, MET was found to be inversely related to OM, as well as nutrient concentration (Table 3). According to the results, a further improvement in soil physical properties can raise seedling emergence rate. Table 4 reports the impacts of the two tillage systems and fertilized treatments on growth parameters and achene yield. The results showed that chlorophyll index was originally not affected by the tillage system; however, an increase by 43% was observed in the chlorophyll index upon the combined application of FYM and 50% of the recommended dose of chemical fertilizer.
The largest leaf area was recorded with F3 and F4 in the RT systems. A positive relationship was observed between leaf area and OM, moisture content, root depth, and P, K, and N contents (Table 3). An investigation on the obtained values of achene yield indicated that, although the two tillage systems had no significant difference in the first year, the highest achene yield in the second year occurred in the RT system (Figure 2). Maximum yield in either year was obtained across F3 and F4 subplots. Surprisingly, a positive significant correlation was detected between achene yield as Ksat, OM content, soil moisture, and nutrient concentration (Table 3).

4. Discussion

The increased Ksat upon adding FYM to inorganic fertilizer might be related to the enhanced structural stability of soil, increased OM, and improved surface soil biological activity. Farmyard manure and a balanced chemical fertilizer seem to contribute to better aggregation, thereby increasing effective pore volume. Given the dependence of soil permeability on effective pore volume, one may suggest a direct impact in terms of improved pore volume upon applying FYM on the Ksat of soil [34]. According to the results, the RT system with combined FYM + 50% of the recommended dose chemical NPK fertilizer application could increase Ksat significantly, possibly because of decreased density. Hydraulic conductivity is significantly affected by soil pore volume, and our findings showed that the application of FYM and choosing a suitable tillage (RT) can affect flow and transport through the soil matrix by improving the pores. These factors are very important in semi-arid regions, and they can determine the effective rain ratio for plants. the application of RT without the application of organic fertilizers will lead to failure in the short term.
Our results showed that there was a significant negative correlation between BD and OM. Given that potential factors determining soil density are mostly mineral and chemical, the organic contents of FYM can affect these factors, mainly by influencing the charges on colloid surfaces [35]. Furthermore, differences in tillage systems could be responsible for more extensive soil structure degradation and structure changes in the CT system. Following the same approach explained for soil tillage, machine traffic tends to deteriorate soil porosity, thereby increasing BD. A difference observed between the years can be related to the accumulated effects of fertilizer and aridity of the first year. The significant correlation of FYM and tillage effects with BD showed that the soil organic matter and carbon levels are now below their critical level in the studied site, and this status was noticeable under the RT system. Our findings demonstrate that the combined effects of tillage and fertilizer should be considered in soil management; however, the effect of FYM was more prominent than other treatments.
These results demonstrate that, in RT systems, it is necessary to apply significant amounts FYM or adopt proper crop residue management. The resultant increase in SOM can be attributed to the increased macro-aggregate stability of clay soils, possibly because of promoted microbial populations and the aggregation of clay- and silt-sized particles to form macro-aggregates using the microbe-produced mucilage [36,37,38]. Studies showed that the distribution of dominant populations of microorganisms is affected by tillage system, thereby highlighting differences among various tillage systems. However, generally, microbial activities follow slower trends in RT systems than in CT systems where OM is supplied to the soil. Likewise, incorporating farmyard manure into the soil and RT reportedly increased the OM content of the soil, protected the soil against erosion, and resulted in enhanced porosity and aggregation of the soil, which enhanced the water retention and infiltration characteristics of the soil while reducing its mechanical impedance.
Soil moisture was considerably increased by FYM application under RT in the second year. The soil had very low SOM before the application of farmyard manure. Under the mentioned conditions, due to the unsuitable physical conditions, water retention capacity in the soil was very low, and a small part of the provided water from rainfall or irrigation could penetrate into the effective depth of the soil, and most of the water was either runoff from the plant surface or temporarily stored in the surface layers and evaporated from the soil immediately. The application of FYM by reducing bulk density, and increasing porosity, water infiltration rate, saturated hydraulic conductivity, and other factors improved the capillary water holding capacity. The improvement of permeability, increased water holding capacity in the soil, and reduced evaporation were among the factors contributing to the improvement of water content in these conditions. The volume of moisture stored in the soil is a function of total precipitation, which was, as a matter of fact, higher in the second year than in the first year. The observed outcome was possibly a result of the cumulative effect of FYM. Moreover, a comparison between the two tillage systems showed significant differences, with the RT system exhibiting the maximum moisture content. These results further confirmed those of Zibilske and Bradford [39]. The subplot subjected to chemical fertilization showed the minimum soil moisture, possibly due to promoted foliage growth and accelerated moisture depletion through transpiration. As another observation, CT was often seen to increase soil temperature. The relatively high soil moisture–OM content correlation coefficient could be explained by these factors (r = 0.91 and 0.88; Table 3). Also, an increase in soil moisture was recorded for the second year. In this regard, some previous studies also suggested that inorganic fertilization can indirectly increase SOM by improving the root biomass compared to control plots [34,35].
Irrespective of the applied tillage system, the minimum OM contents were observed either without using any fertilizer or upon using chemical fertilization. Indeed, despite the original presumption that chemical fertilizers can contribute to increased soil OM by promoting root development by extending the population of microorganisms, our results showed the non-sustainability and insignificance of this mentioned assumption in the studied semi-arid region. Hence, taking into account the specific set of dominant conditions across semi-arid areas, such as high temperature, low rainfall, and inadequate straw return, chemical fertilizers may fail to enhance SOM appropriately.
For most part, the soil surface exhibits the highest nutrient content, with the content degrading upon moving to further depths. This is because nutrients are commonly applied at the surface where crop residues also decay. Rainfall is thought to accelerate the loss of residual N. However, the gradual release of elements from FYM largely inhibits the losses, such that high levels of N can be preserved by applying FYM. The higher amount of N in plots receiving NPK was due to faster N release from urea, which enabled maximum N availability only up to 30 days, coinciding with the stem elongation stage. In addition to NPK, FYM also supplied appropriate quantities of N, P, K, Mn, Zn, and Fe, thus conferring a distinctive advantage in terms of the continued balanced supply of major and micro-nutrients for a prolonged period, thereby mitigating the chance of nutrient stress. An adequate supply of N and other nutrients through FYM was the main reason for their better performance. The difference in P content between the tillage systems could be attributed to corresponding differences in the physicochemical properties and moisture content of soil. It is advantageous to compare this figure to that presented by Rotta et al. [40], who suggested a reduction in P content with soil disturbance in CT.
The highest root depth was recorded for CT. It should be, however, noted that over-compaction in the reduced tillage system imposes adverse impacts on soil water, soil nutrient pools, and root growth, thereby limiting the explored volume of soil by roots. This can then degrade the plant’s ability to provide itself with nutrients and water. These outcomes are in agreement with those of other researchers who pointed out that the compaction of deeper soil layers in an RT system inhibits the proper development of roots [19]. However, long-term application of FYM was found to significantly reduce soil compaction and density.
The highest chlorophyll content and leaf area were recorded for plants grown with an integrated application of FYM and NPK fertilizer. Given the key roles played by nitrogen and magnesium in the synthesis of chlorophyll, this improved index could partly be attributed to increased availability of these elements. Leaf area and chlorophyll index are determinant factors for photosynthesis rate and source strength in a plant, and they take key part in determining the supply of photo assimilates. The results indicate that crop yield can be enhanced through improving soil conditions by adjusting sink–source relationships and by increasing the strength and size of the source. Biological yield and achene oil content also followed similar trends. The improvements in photosynthetic vegetative organs strengthen the source capacity in plants and ultimately result in higher achene yield and improved oil yield.
The statistically significant correlation coefficient between growth characteristics and soil properties showed that even a small improvement in physical and chemical properties of soil through proper management can end up increasing the yield. The maximum harvest index in the first and second years was seen with chemically fertilized and combined FYM/chemically fertilized subplots in the RT system, respectively. The superior effect of FYM in the second year was largely due to cumulative effects of OM and the gradual release of nutrients. Our findings emphasized that, in semi-arid regions such as the studied location, the successive application of FYM and chemical fertilizer under reduced tillage (RT) can achieve sustainable conditions where the effects of chemical fertilizer will be more realistic.

5. Conclusions

Our findings revealed that best sunflower performance was obtained with the integrated application of FYM and chemical fertilizer. The application of FYM improved soil organic matter, soil moisture, and nutrient concentration while decreasing bulk density. Also, the choice of tillage system strongly affected particular soil characteristics (e.g., the CT system caused a dramatic drop in soil quality). Integrating soil fertility management with RT resulted in larger root growth and maximized nutrient use efficiency, as well as enhanced access of the plant to soil nutrients and stored moisture. After two years of applying FYM across this region, the soil exhibited higher productivity, particularly in the RT system. The advantages of FYM were more evident in the second year. The results reflected that, to achieve an acceptable result in the short term, both organic and inorganic fertilizers should be considered. It was further shown that achene oil content significantly responded to soil management and nutrition supply, especially under the RT system. To sum up, soil preservation practices including RT and combined FYM/chemical fertilizer application can help enhance the efficiency of crop production systems and soil structure in the long run.

Author Contributions

Conceptualization, M.N., V.S., and G.S.; methodology, M.N., G.S., and B.D.; formal analysis, M.N., V.S., G.S., and B.D.; investigation, M.N., V.S., and G.S.; data curation, M.N., V.S., and G.S.; writing—original draft preparation, M.N., V.S., G.S., B.D., and M.G.; writing—review and editing, M.N., V.S., G.S., B.D., and M.G.; supervision, V.S. and B.D.; project administration, M.N., B.D., and M.G.; funding acquisition, M.N., B.D., and M.G.


This research received no external funding and the APC was funded by the Faculty of Management, Comenius University in Bratislava, Slovakia.


The authors wish to sincerely acknowledge the technical assistance provided by Askari, Kuchak-Khani, and Amanzadeh in the field sampling, lab analysis, and data analysis during the study period. Financial support for the research study was provided by the University of Maragheh, Iran and it is highly appreciated. Also, the authors would like to thank experts of the Central Laboratory (part of the Laboratory Network of Strategic Technologies) for their assistance.

Conflicts of Interest

The authors declare no conflicts of interest.


  1. Verheye, W.H. Soils of arid and semi-arid areas. Land Use Land Cover Soil Sci. 2009, 7, 67–95. [Google Scholar]
  2. Lucke, B.; Nikolskii, I.; Bäumler, R. Soils in arid and semiarid regions: The past as key for the future. In Developments in Soil Classification, Land Use Planning and Policy Implications; Springer: Dordrecht, Germany, 2013; pp. 269–284. [Google Scholar]
  3. Spalevic, V.; Lakicevic, M.; Radanovic, D.; Billi, P.; Barovic, G.; Vujacic, D.; Sestras, P.; Khaledi Darvishan, A. Ecological-Economic (Eco-Eco) modelling in the river basins of Mountainous regions: Impact of land cover changes on sediment yield in the Velicka Rijeka in Montenegro. Not. Bot. Horti Agrobot. Cluj Napoca 2017, 45, 602–610. [Google Scholar] [CrossRef][Green Version]
  4. Spalevic, V.; Barovic, G.; Fikfak, A.; Kosanovic, S.; Djurovic, M.; Popovic, S. Sediment yield and Land use changes in the Northern Montenegrin Watersheds: Case study of Seocki Potok of the Polimlje Region. J. Environ. Prot. Ecol. 2016, 17, 990–1002. [Google Scholar]
  5. Tubeileh, A.; El-Dessougi, H.; Thomas, R.J. Soil System Management under Arid and Semi-Arid Conditions. In Biological Approaches to Sustainable Soil Systems; CRC Press: Boca Raton, FL, USA, 2006; pp. 50–64. [Google Scholar]
  6. Botterill, L.C. Wheat Marketing in Transition: The Transformation of the Australian Wheat Board; Springer: Berlin, Germany, 2012. [Google Scholar]
  7. Di Falco, S.; Zoupanidou, E. Soil fertility, crop biodiversity, and farmers’ revenues: Evidence from Italy. Ambio 2017, 46, 162–172. [Google Scholar] [CrossRef] [PubMed][Green Version]
  8. Vaezi, A.R.; Bahrami, H.A.; Sadeghi, S.H.R.; Mahdian, M.H. Spatial variability of soil erodibility factor (K) of the USLE in North West of Iran. J. Agric. Sci. Technol. 2010, 12, 241–252. [Google Scholar]
  9. Kumar, H.; Pani, P. Effects of soil erosion on agricultural productivity in semi-arid regions: The case of lower Chambal valley. J. Rural Dev. 2013, 32, 165–184. [Google Scholar]
  10. Houshyar, E.; Esmailpour, M. The impacts of tillage, fertilizer and residue managements on the soil properties and wheat production in a semi-arid region of Iran. J. Saudi Soc. Agric. Sci. 2018. [Google Scholar] [CrossRef]
  11. Ordoñez-Morales, K.D.; Cadena-Zapata, M.; Zermeño-González, A.; Campos-Magaña, S. Effect of Tillage Systems on Physical Properties of a Clay Loam Soil under Oats. Agriculture 2019, 9, 62. [Google Scholar] [CrossRef][Green Version]
  12. Busari, M.A.; Kukal, S.S.; Kaur, A.; Bhatt, R.; Dulazi, A.A. Conservation tillage impacts on soil, crop and the environment. Int. Soil Water Conserv. Res. 2015, 3, 119–129. [Google Scholar] [CrossRef][Green Version]
  13. Haddaway, N.R.; Hedlund, K.; Jackson, L.E.; Kätterer, T.; Lugato, E.; Thomsen, I.K.; Jørgensen, H.B.; Isberg, P.E. How does tillage intensity affect soil organic carbon? A systematic review. Environ. Evid. 2017, 6, 30. [Google Scholar] [CrossRef][Green Version]
  14. Johns, C. The Management of Soil Nutrients: Chemical Fertilizers or Not? Strategic Analysis Paper: Future Directions International Pty Ltd., 2017. Available online: (accessed on 17 September 2015).
  15. Parama, V.R.; Munawery, A. Sustainable soil nutrient management. J. Indian Inst. Sci. 2012, 92, 1–16. [Google Scholar]
  16. Liverpool-Tasie, L.S.O.; Omonona, B.T.; Sanou, A.; Ogunleye, W.O. Is increasing inorganic fertilizer use for maize production in SSA a profitable proposition? Evidence from Nigeria. Food Policy 2017, 67, 41–51. [Google Scholar] [CrossRef] [PubMed][Green Version]
  17. Fuentes, M.; Govaerts, B.; De Leónc, F.; Hidalgo, C.; Dendooven, L.; Sayre, K.D.; Etchevers, J. Fourteen years of applying zero and conventional tillage, crop rotation and residuemanagement systems and its effect on physical and chemical soil quality. Eur. J. Agron. 2009, 30, 228–237. [Google Scholar] [CrossRef]
  18. Göl, C. Assessing the amount of soil organic matter and soil properties in High Mountain forests in Central Anatolia and the effects of climate and altitude. J. Forest Sci. 2017, 63, 199–205. [Google Scholar]
  19. Kanchikerimath, M.; Singh, D. Soil organic matter and biological properties after 26 years of maize-wheat-cowpea cropping as affected by manure and fertilization in a Cambisol in semiarid region of India. Agric. Ecosyst. Environ. 2001, 86, 155–162. [Google Scholar] [CrossRef]
  20. Shirani, H.; Hajabbasi, M.A.; Afyuni, M.; Hemmat, A. Effects of farmyard manure and tillage systems on soil physical properties and corn yield in central Iran. Soil Tillage Res. 2002, 68, 101–108. [Google Scholar] [CrossRef]
  21. López-Fando, C.; Dorado, J.; Pardo, M.T. Effects of zone-tillage in rotation with no-tillage on soil properties and crop yields in a semi-arid soil from central Spain. Soil Tillage Res. 2007, 95, 266–276. [Google Scholar] [CrossRef]
  22. Rong, Y.; Su, Y.Z.; Tao, W.; Qin, Y. Effect of chemical and organic fertilization on soil carbon and nitrogen accumulation in a newly cultivated farmland. J. Integr. Agric. 2016, 15, 658–666. [Google Scholar]
  23. Ultra Jr, V.U.; Tan, G.M.; Lao, F.U.; Punsalan, M.R.O.; Galo, E.A. Nutrient Availability and Biological Properties of Paddy Soils Under Rainfed Traditional “Payatak” Farming Systems in Catubig Valley, Philippines. J. Agric. Sci. Tech. 2017, 19, 1631–1645. [Google Scholar]
  24. Mirleau-Thebaud, V.; Dayde, J.; Scheiner, J.D. The influence of soil compaction and conservation tillage on sunflower’s (Helianthus annuus L.) below ground system. Phyton Int. J. Exp. Bot. 2016, 86, 53–67. [Google Scholar]
  25. Mavi, K.; Demir, I.; Matthews, S. Mean germination time estimates the relative emergence of seed lots of three cucurbit crops under stress conditions. Seed Sci. Technol. 2010, 38, 14–25. [Google Scholar] [CrossRef]
  26. Salehi, M.H.; Eghbal, M.K.; Khademi, H. Comparison of soil variability in a detailed and a reconnaissance soil map in central Iran. Geoderma 2003, 111, 45–56. [Google Scholar] [CrossRef]
  27. Kottek, M.; Grieser, J.; Beck, C.; Rudolf, B.; Rubel, F. World map of the Köppen-Geiger climate classification updated. Meteorol. Z. 2006, 15, 259–263. [Google Scholar] [CrossRef]
  28. Okalebo, J.R.; Gathua, K.W.; Woomer, P.L. Laboratory Methods of Soil and Plant Analysis: A Working Manual, 2nd ed.; The Soil Fertility and Biology Programme: Nairobi, Kenya, 2002. [Google Scholar]
  29. Okoth, P.; Okoth, S.; Jefwd, J.M. The Conservation and Use of Micro-Organisms and Invertebrates in Root Crop-Based Systems: State of Knowledge, Trends and Future Prospects; University of Nairobi Research Archive: Nairobi, Kenya, 2013. [Google Scholar]
  30. Olsen, S.R.; Cole, C.V.; Watanabe, F.S.; Dean, L.A. Estimation of Available Phosphorus in Soils by Extraction with Sodium Bicarbonate; United States Department of Agriculture: Washington, DC, USA, 1954; pp. 939–948.
  31. Walkley, A.; Black, I.A. An examination of the effect of the digestive method for determining soil organic matter and the proposed odification of the chromic acid titration method. Soil Sci. 1934, 37, 29–38. [Google Scholar] [CrossRef]
  32. Hirmas, D.R.; Furquim, S.A.C. Simple modification of the clod method for determining bulk density of very gravelly soils. Commun. Soil Sci. Plant Anal. 2006, 37, 899–906. [Google Scholar] [CrossRef]
  33. Blanco-Canqui, H.; Gantzer, C.J.; Anderson, S.H.; Alberts, E.E.; Ghidey, F. Saturated hydraulic conductivity and its impact on simulated runoff for clay pan soils. Soil Sci. Soc. Am. J. 2002, 66, 1596–1602. [Google Scholar] [CrossRef]
  34. Aguirre, M.R.; Velasco, J.; Ruiz-Méndez, M.V. Characterization of sunflower oils obtained separately by pressing and subsequent solvent extraction from a new line of seeds rich in phytosterols and conventional seeds. OCL 2014, 21, D605. [Google Scholar] [CrossRef][Green Version]
  35. Gomez, K.A.; Gomez, A.A. Statistical Procedures for Agricultural Research-An IRRI Book; John Wiley and Sons: New York, NY, USA, 1984. [Google Scholar]
  36. Zhang, J.B.; Yang, J.S.; Yao, R.J.; Yu, S.P.; Li, F.R.; Hou, X.J. The effects of farmyard manure and mulch on soil physical properties in a reclaimed coastal tidal flat salt-affected soil. J. Integr. Agric. 2014, 13, 1782–1790. [Google Scholar] [CrossRef][Green Version]
  37. Huang, P.M.; Li, Y.; Sumner, M.E. Handbook of Soil Sciences: Resource Management and Environmental Impacts; CRC Press: Boca Raton, FL, USA, 2011. [Google Scholar]
  38. Okoth, S.A.; Siameto, E. Evaluation of selected soil fertility management interventions for suppression of Fusarium spp. in a maize and beans intercrop. Trop. Subtrop. Agroecosyst. 2011, 13, 73–80. [Google Scholar]
  39. Zibilske, L.M.; Bradford, J.M. Soil aggregation, aggregate carbon and nitrogen, and moisture retention induced by conservation tillage. Soil Sci. Soc. Am. J. 2007, 71, 793–802. [Google Scholar] [CrossRef][Green Version]
  40. Rotta, L.R.; Paulino, H.B.; Anghinoni, I.; Souza, E.D.D.; Lopes, G.; Carneiro, M.A.C. Phosphorus fractions and availability in a haplic plinthosol under no-tillage system in the brazilian cerrado. Ciênc. Agrotec. 2015, 39, 216–224. [Google Scholar] [CrossRef][Green Version]
Figure 1. Effect of nutrient management practices and tillage systems on soil organic matter content (OM: columns) and bulk density (BD: dashed line) during the years 2015 and 2016. The error bars indicate standard deviation. C: conventional tillage, R: reduced tillage, F1: control, F2: farmyard manure (FYM) at 20 Mg∙ha−1, F3: FYM at 40 Mg∙ha−1, F4: 50% of the recommended dose of chemical nitrogen–phosphorus–potassium (NPK) + FYM at 20 Mg∙ha−1, F5: full recommended dose NPK fertilizer.
Figure 1. Effect of nutrient management practices and tillage systems on soil organic matter content (OM: columns) and bulk density (BD: dashed line) during the years 2015 and 2016. The error bars indicate standard deviation. C: conventional tillage, R: reduced tillage, F1: control, F2: farmyard manure (FYM) at 20 Mg∙ha−1, F3: FYM at 40 Mg∙ha−1, F4: 50% of the recommended dose of chemical nitrogen–phosphorus–potassium (NPK) + FYM at 20 Mg∙ha−1, F5: full recommended dose NPK fertilizer.
Applsci 09 05482 g001
Figure 2. Effect of nutrient management practices and tillage systems on sunflower (Helianthus annuus L.) achene yield (AY: columns) and on the mean emergence time of seedling (MET: dashed line) during the years 2015 and 2016. The error bars indicate standard deviation. C: conventional tillage, R: reduced tillage, F1: control, F2: FYM at 20 Mg∙ha−1, F3: FYM at 40 Mg∙ha−1, F4: 50% of the recommended dose of chemical NPK + FYM at 20 Mg∙ha−1, F5: full recommended dose NPK fertilizer.
Figure 2. Effect of nutrient management practices and tillage systems on sunflower (Helianthus annuus L.) achene yield (AY: columns) and on the mean emergence time of seedling (MET: dashed line) during the years 2015 and 2016. The error bars indicate standard deviation. C: conventional tillage, R: reduced tillage, F1: control, F2: FYM at 20 Mg∙ha−1, F3: FYM at 40 Mg∙ha−1, F4: 50% of the recommended dose of chemical NPK + FYM at 20 Mg∙ha−1, F5: full recommended dose NPK fertilizer.
Applsci 09 05482 g002
Table 1. Monthly average evaporation, relative humidity, temperature, and precipitation of Kharajoo region during growing seasons of sunflower.
Table 1. Monthly average evaporation, relative humidity, temperature, and precipitation of Kharajoo region during growing seasons of sunflower.
Temperature (°C)Evaporation (mm)Relative Humidity (%)Precipitation (mm)
Table 2. Analysis of variance (ANOVA) on the effects of tillage (T), fertilizer type (F), and their interaction on soil physicochemical properties and sunflower root depth for two years.
Table 2. Analysis of variance (ANOVA) on the effects of tillage (T), fertilizer type (F), and their interaction on soil physicochemical properties and sunflower root depth for two years.
Statistical Significance
Tillage (T)*******NS**
Fertilizer (F)************
T × F**NSNSNS****
CT: conventional tillage, RT: reduced tillage, F1: control, F2: farmyard manure (FYM) at 20 Mg∙ha−1, F3: FYM at 40 Mg∙ha−1, F4: 50% of the recommended dose of chemical nitrogen–phosphorus–potassium (NPK) + FYM at 20 Mg∙ha−1, F5: full recommended dose NPK fertilizer. Ksat: saturated hydraulic conductivity (cm∙h1), VM: volumetric moisture (%), N: nitrogen concentration (%), P: phosphorus concentration (ppm), K: potassium concentration (ppm), RD: root depth (cm). The columns sharing the same letter are not significantly different from each other (least significant difference (LSD), p < 0.05). NS: p > 0.05, * p ≤ 0.05, ** p ≤ 0.01.
Table 3. Correlation coefficients among some physicochemical properties of soil and morphological traits of sunflower.
Table 3. Correlation coefficients among some physicochemical properties of soil and morphological traits of sunflower.
OM −0.870.96−0.840.910.640.830.470.780.160.540.750.380.900.59−0.03
BD−0.84 −0.790.80−0.87−0.57−0.72−0.50−0.86−0.09−0.71−0.77−0.27−0.99−0.37−0.09
Ksat0.84−0.67 −0.830.850.690.840.460.730.170.520.730.480.820.56−0.12
MET−0.910.87−0.77 −0.77−0.73−0.85−0.51−0.77−0.27−0.66−0.92−0.23−0.81−0.34−0.25
VM0.88−0.640.95−0.78 0.360.590.160.870.140.410.570.350.880.27−0.15
N0.66−0.670.87−0.760.76 0.790.770.310.200.560.790.480.610.570.13
K0.92−0.830.86−0.950.840.82 0.720.670.230.790.930.120.750.690.32
P0.31−0.570.32−0.490.230.550.57 0.16−0.090.660.710.160.520.710.35
RD0.61−0.800.41−0.750.330.580.590.37 0.250.670.71−0.020.820.130.19
LA0.91−0.810.81−0.940.850.790.940.580.62 −0.070.21−
CHL0.81−0.750.58−0.830.600.530.870.650.520.84 0.85−0.150.650.350.44
AY0.75−0.730.81−0.800.700.870.900.730.570.860.81 0.010.760.450.49
BY0.57−0.450.48−0.620.520.430.750.680.090.680.840.69 0.320.25−0.75
DM0.81−0.980.62−0.820.620.610.750.540.770.780.700.660.38 0.460.06
OIL0.60−0.630.67−0.660.680.780.660.620.500.810.550.750.410.68 0.01
Critical values of correlation p < 0.05 and p < 0.01 are 0.65 and 0.85, respectively. The coefficients above the diagonal line are related to the first year and the numbers below the diagonal line are related to the second year. Ksat: saturated hydraulic conductivity, VM: volumetric moisture, N: nitrogen concentration, P: phosphorus concentration, K: potassium concentration, RD: root depth, CHL: chlorophyll content, LA: leaf area, DM: day to maturity, BY: biological yield, OIL: achene oil percentage, HI: harvest index.
Table 4. Effect of FYM and chemical fertilizers on plant growth parameters under different tillage systems for two years.
Table 4. Effect of FYM and chemical fertilizers on plant growth parameters under different tillage systems for two years.
Statistical significance
Tillage (T)NS**NSNS**
Fertilizer (F)***********
T × FNS********NS
CT: conventional tillage, RT: reduced tillage, F1: control, F2: FYM at 20 Mg∙ha−1, F3: FYM at 40 Mg∙ha−1, F4: 50% of the recommended dose of chemical NPK + FYM at 20 Mg∙ha−1, F5: full recommended dose NPK fertilizer. CHL: chlorophyll content (SPAD unit), LA: leaf area (cm2), DM: day to maturity, BY: biological yield (kg∙ha−1), OIL: achene oil percentage, HI: harvest index (%). The columns sharing the same letter are not significantly different from each other (LSD, p < 0.05). NS: p > 0.05, * p ≤ 0.05, ** p ≤ 0.01.

Share and Cite

MDPI and ACS Style

Nouraein, M.; Skataric, G.; Spalevic, V.; Dudic, B.; Gregus, M. Short-Term Effects of Tillage Intensity and Fertilization on Sunflower Yield, Achene Quality, and Soil Physicochemical Properties under Semi-Arid Conditions. Appl. Sci. 2019, 9, 5482.

AMA Style

Nouraein M, Skataric G, Spalevic V, Dudic B, Gregus M. Short-Term Effects of Tillage Intensity and Fertilization on Sunflower Yield, Achene Quality, and Soil Physicochemical Properties under Semi-Arid Conditions. Applied Sciences. 2019; 9(24):5482.

Chicago/Turabian Style

Nouraein, Mojtaba, Goran Skataric, Velibor Spalevic, Branislav Dudic, and Michal Gregus. 2019. "Short-Term Effects of Tillage Intensity and Fertilization on Sunflower Yield, Achene Quality, and Soil Physicochemical Properties under Semi-Arid Conditions" Applied Sciences 9, no. 24: 5482.

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop