Research Article

Maize Growth in Response to Beneficial Microbes, Humic Acid and Farmyard Manure Application

Izaz Hussain, Ahmad Khan* and Habib Akbar

Department of Agronomy, The University of Agriculture Peshawar, Pakistan.

Received | August 04, 2021; Accepted | September 23, 2021; Published | October 07, 2021

*Correspondence | Ahmad Khan, Department of Agronomy, The University of Agriculture Peshawar, Pakistan; Email: [email protected]

Citation | Hussain, I., A. Khan and H. Akbar. 2021. Maize growth in response to beneficial microbes, Humic acid and farmyard manure application. Sarhad Journal of Agriculture, 37(4): 1426-1435.

DOI | https://dx.doi.org/10.17582/journal.sja/2021/37.4.1426.1435

Keywords | Mineral nitrogen, Decomposition, Soil properties, Maize growth, Sustainability

Introduction

Maize (Zea mays L.) is a cereal crop grown in almost all countries of the world. It has largely used as a staple food in Pakistan as well as other developing countries of the world. In Khyber Pakhtunkhwa, it is the 2nd most important and grown crop after wheat (Triticum aestivum L.), whereas in Pakistan its rank is 3rd. Maize crop has multiple uses like it is used as food, feed and raw materials for commercial product preparation (Khan et al., 2017). Pakistan economic survey show that maize was planted on 1.40 million ha land and produced 7.88 million tons with 5121 kg ha-1 average yield (MNSF&R, 2020). In Pakistan, maize production is lower than world leading countries due to less fertility of soil, improper usage and time of fertilizer application and several other agronomic management problems. Maize is an exhaustive crop and required high amount of nitrogenous fertilizer compared to other cereal crops. Thus, soil conditioners like beneficial microbes (BM) and humic acid (HA) were utilized to decompose the added farmyard manure for nutrients availability and its impact on maize growth.

Farmyard manure (FYM) consist of animal waste products and leftover materials of farm that contains plants nutrients (Satyanarayana et al., 2002). According to an estimate of Bhattacharyya et al. (2007), the FYM production in the world and in Pakistan are up to 7 billion tons and 3.30 million tons, respectively. Huge stock of FYM could create environmental issues (Jiang and Yan, 2010), and its safe disposal is needed. FYM recycling for obtaining nutrients in farming system is widely practiced by the farmer specifically in developing countries (Khan et al., 2017; Khan et al., 2019). However, the bulky nature and high quantity requirements has minimized its usage as nutrient source (Muhammad et al., 2018) in agroecosystem. Similarly, the FYM decomposition is slow and time-consuming process for plant’s nutrients availability. Improving the nutrient release from FYM with the help of soil amendments can be considered as essential research question in soil having low soil organic matter.

Organic fertilizers like FYM is a good source of available nutrients for plant growth and production (Khan et al., 2015). Farmyard manure increases soil organic matter, soil health and fertility, microbiological activities (Bello et al., 2020), soil structure enhancement for sustainable agriculture (Luo et al., 2018), crop development and yield (Khan et al., 2017). The beneficial microorganisms (BM) are mixed cultured microbes used as inoculants for improving the microbial diversity, increase soil health and nutrients availability, thus increased crop development and yield (Azeem and Ullah, 2016). Crop production enhances by bacterial inoculation through bacterial nitrogen fixation, uptake nutrients by solubilization, hormonal activities and increases available nutrients. Similarly, humic acid (HA) consisted of mostly carbon products found in lignite coal of Pakistan (Hai and Mir, 1998). Humic acid are associated to soil biological, physical and chemical characteristics (Khattak and Muhammad, 2008). Humic acid enhances biological and physico-chemical properties of soil. Model humic acid polymer are combination of organic carbon (51-57%), total nitrogen (0.70-1.65%) and phosphorus (0.25-0.94%) (Brannon and Sommers, 1985). Beneficial microbes and humic acid combine with organic/inorganic fertilizers enhances accessibility of nutrients (Hussain et al., 1999). Humic acid acts chelating agent to boost the nutrients availability as well as to maintain soil nutrients condition. Humic acid combine with fertilizers can enhance crop growth, development and production (Bharali et al., 2017). Beneficial microorganisms associated with organic fertilizers enhances plant growth, crop yield and soil quality (Haji et al., 2014). Application of beneficial microorganism to soil enhances atmospheric nitrogen fixation, perishing organic residues and waste materials delivering important nutrients availability through nutrient cycling for plant growth, detoxifying pesticides, vanquishing of pathogens/diseases, increasing bioactive compounds (Kurepin et al., 2014).

Low soil organic matter (< 1) of the study area could not maintain maize production in continuous cropping system (Ibrahim et al., 2020). Similarly, application of chemical fertilizer possibly enhanced crop yield (Khan et al., 2018), however its application is less profitable and hazardous to environment (Muhammad et al., 2018) as most of nitrogen is lost into environment either as nitrate polluting water bodies or ammonium. Hence, application of BM with organic fertilizers will decompose manure and enhance nutrient availability and will be more economical (Haji et al., 2014). Similarly, HA as a soil conditioner, enhance the soil richness and hence crop yield (Bharali et al., 2017). Presently, maintaining the standard of quality and quantity of agricultural commodities is the need of the day, which is only possible by utilizing organic manures for safe food, better ecosystem, minimum cost of cultivation, clean environment for better human health (Khan et al., 2018). Therefore, this research was initiated to find out the effect of BM and HA application as soil conditioner on FYM decomposition and its impact on maize growth contributing parameters.

Materials and Methods

Experimental site

Experiment was carried out at Agronomy Research Farm, The University of Agriculture in summer of 2017 and 2018. The studies were conducted to optimize beneficial microbes (BM) as effective microbes from bioaab, humic acid (HA) as soil conditioner and farmyard manure (FYM) as leftover material from

 

Table 1: Physico-chemical properties of soil, farmyard manure (FYM) and humic acid.

Physico-chemical properties	Unit	Soil	FYM	Humic acid
Organic matter	%	0.53	15.8	51.63
Total nitrogen	g kg-1	0.03	0.86	2.26
Mineral nitrogen	mg kg-1	0.68	-
pH	-	8.1	6.9	7.21
Electrical conductivity	dS m-1	0.41	3.7	2.13
Phosphorous*	mg kg-1	3.87	0.26%	4.54%
Potassium*	mg kg-1	112	0.71%	7.32%
Bulk density	g cm-3	1.23	-	-
Sand	%	20.16	-	-
Silt	%	70.21	-	-
Clay	%	9.63	-	-
Textural class	-	Silt loam	-	-

* In soil EDTA extractable

 

cattle farm for improving maize growth parameters. The soil properties of the experimental field were investigated before sowing in 2017 using standard protocols (detailed below). The research field soil was silty loam with sand (20.16%), silt (70.21%) and clay (9.63%), and classified as Ustochrept (Anonymous, 2007), and detailed in Table 1. The soil of the experimental site was alkaline with pH (8.1), SOC (0.53%), total N (0.03%), mineral N (0.68 mg kg-1 soil), electrical conductivity (0.41 dS m-1), EDTA extractable P (3.87 mg kg-1), EDTA extractable K (112 mg kg-1) and soil bulk density (1.23 g cm-3). During last five years, the experimental plots were sown with maize in summer and wheat in winter seasons with a regular maize-wheat-maize cropping pattern. The climatic data on temperature and rainfall collected in the study area is provided in Figure 1.

Materials and treatments

The experiment was conducted in RCB design with three replications. Three factors i.e. beneficial microbes (BM), humic acid (HA) and farmyard manure (FYM) along with a control were used in the studies. The BM was applied as 25 or 50 L ha-1, HA as 3, 6 or 9 kg ha-1 and FYM as 10, 15 or 20 Mg ha-1. The properties of FYM collected from the Dairy Farm of the University is given in Table 1. The analysis indicated that FYM contain OC (15.80%), total nitrogen (0.86%), pH (6.9), electrical conductivity (3.7 dS m-1), EDTA extractable P (0.26 %) and EDTA extractable K (0.71%). The humic acid was applied as “humic plus-40%” a commercial product of Al-Hameed Chemicals Pvt limited and containing OC (51.63%), total nitrogen (2.26%), pH (7.21), electrical conductivity (2.13 dS m-1), EDTA extractable P (4.54 %) and EDTA extractable K (7.32%). The application of beneficial microbes were made from “Bioabb” (as effective microbial solution) a commercial product manufactured by NFRDF-NGO in association with The University of Faisalabad-Pakistan, and consisted of Lactobacillus bacteruim, Rhodopseudomona sp, Actinomycetes, Cyanobacteria, Saccharomyces sp. (yeast) and molasses as media.

Preparation of treatments and its application

The experimental plots of 4×4.5 m dimension were prepared and separated with small bund (5-7 cm high). The FYM was added to the soil as per proposed rates on dry weight basis, whereas the humic acid was applied to the soil as a mixture of proposed rate with one kg soil to each plot. The proposed rates of BM as 2% solution was mixed with one liter of distilled water, well shaken, and sprayed as saturated liquid on the soil, where FYM and HA were already applied. After application of the treatments, plots were ploughed single time with common field cultivator to incorporate all these materials of the treatments to a depth of 15 cm. The application of BM, FYM and HA was carried out about one month before sowing each year. A total of two irrigation, 1st after 10 days and 2nd after 20 days of treatment incorporation was provided for proper and effective decomposition of treatment and to maintain plots at proper field capacity level before sowing.

Field operations and methodology

One month after treatment imposition, the field was ploughed two times using common field cultivator at proper field capacity level in each year. The field cultivator was followed by rotavator in the respective plots for proper seed bed preparation. The plots were rebuilt and separated with 10-15 cm high and 30 cm wide bunds between two plots. However, the replication-to-replication distance was 1 m. Maize (cv. Azam) was sown at the seed rate of 30 kg ha-1 in plots of 18 m2 having 6 rows of 4 m length and spaced 75 cm. The sowing of maize was made on July 8, 2017 for the first year and July 7, 2018 for the 2nd year on the same plots with same treatment procedure. However, general wheat was grown between two maize crops and provided with recommended amount of 120 kg N ha-1 and 90 kg P ha-1 as a gap crop. The wheat was planted in 2nd week of October 2017 and harvested in 3rd week of April 2018. Basal dose of mineral nitrogen (90 kg ha-1) applied in three equal splits i.e. ⅓ each at first, third and fourth irrigation along with basal phosphorus (60 kg ha-1) at the time of sowing was applied to all plots for maize cultivation. Field was irrigated six times during both 2017 and 2018 as flood irrigation at critical stages (after emergence, three leaves stages, knee height, tasseling/silking, grain development and grain filling). Weeds were controlled manually by hoeing after 2nd irrigation, and no herbicides were used. However, borers were controlled through Furadan (Carbofuran 3%) applied at the rate of 20 kg ha-1 after 2nd irrigation i.e. three leaves stage.

Observations and measurements

Composite soil samples were collected from experimental field from 20 cm depth before planting maize crop in 2017. However, three samples were collected from 20 cm depth in each plot after maize harvesting in 2017 and 2018 and combined to make a composite sample (from the same plots established in 2017 and 2018). Both before and after sowing, the composited samples were cleaned, grounded to 2 mm mesh size and stored for determination of soil total N or freshly process for soil mineral N as per the procedure given below. Samples were also collected from farmyard manure and humic acid, and analyzed for carbon, nitrogen, phosphorous and potash concentration as well as pH and electrical conductivity.

Plant growth parameters

Plants (m-2), ear length, leaves plant-1, leaf area plant-1, leaf area index and plant height were worked out to know the growth response of maize in response to three types of treatments. The plants were counted across a single meter long row at three locations in each plot and converted to plants m-2. Five ears were detached from plants in each plot and ears length was measured with common scale and averaged to find out the ear length. All leaves in five plants were counted at tasseling stage and were averaged to report leaves plant-1 data. Three leaves from top, middle and bottom, respectively were randomly detached from plants, and the width and length of all those leaves were measured using ordinary scale and averaged. The leaf area plant-1 was calculated as the product of leaf length, width, factor (0.69) and leaves plant-1.

Soil analysis

Soil samples taken prior to experiment were used for determination of soil physical properties. Soil water suspension (1:5) was prepared by taking 10 g of dry soil and 50 ml of distilled water. The suspension was shaked for 1 hour on mechanical shaker, left for 30 minutes and then filtered. The filtrate was used for determination of soil pH using pH meter calibrated with 4 and 7 buffers. The soil EC was also determined using the same soil suspension with the help of soil EC meter following the procedure out lined by Rhoades (1996). The soil mineral nitrogen content was determined following the steam distillation procedure as reported by Keeney and Nelson (1982). The soil total nitrogen was determined as per the procedure of Bremner and Mulvaney (1982).

Statistical analysis

The data was analyzed as per the procedure of RCB design and means were compared using least significant differences (LSD) test at P ≤ 0.05 upon significant F-test (Jan et al., 2009). The correlation analyses were carried out to understand the positive and negative relationship of soil properties with maize growth parameters. The statistical analysis was carried out using statistical software Statistix ver. 8.1 (Analytical software, Florida) and graphs by Sigma plot ver. 14 (Systat. Software Inc., Chicago, IL).

 

Table 2: Maize growth parameters in response to beneficial microbes (BM, L ha-1), humic acid (HA, kg ha-1) and farmyard manure (FYM, Mg ha-1) during 2017 and 2018.

Treatments	Leaves plant-1	Leaf area (cm-2)	Leaf area index	Ear length (cm)	Plant height (cm)
	2017
25-BM	12.6	3712 b	2.4 b	15.6 b	189 b
50- BM	12.6	3932 a	2.5 a	16.6 a	196 a
Significance	NS	**	*	**	**
3-HA	12.6	3658 c	2.3 b	16.1 ab	185 c
6-HA	12.6	3810 b	2.4 b	15.7 b	193b
9-HA	12.7	3998 a	2.5 a	16.6 a	199 a
LSD0.05	NS	145	0.1	0.67	4.2
10-FYM	12.3 b	3542 c	2.2 c	15.5 b	186 b
15-FYM	12.6 ab	3858 b	2.5 b	16.1 ab	192 b
20-FYM	12.9 a	4067 a	2.6 a	16.7 a	199 a
LSD0.05	0.4	145	0.1	0.7	4.2
Control	12.0 b	2251 b	1.4 b	12.9 b	160 b
Treated plots	12.6 a	3822 a	2.4 a	16.1 a	192 a
Significance	NS	**	**	**	**
	2018
25-BM	12.7	3755 b	2.4 b	15.9 b	192 b
50- BM	13.0	4121 a	2.7 a	16.8 a	199 a
Significance	NS	**	**	**	**
3-HA	12.7	3745 b	2.4 b	15.9 b	187 c
6-HA	12.8	3969 a	2.5 b	16.5 a	194 b
9-HA	13.1	4100 a	2.7 a	16.6 a	204 a
LSD0.05	NS	131	0.1	0.5	5.7
10-FYM	12.1 c	3648 b	2.3 b	15.5 c	186 b
15-FYM	13.0 b	4057 a	2.6 a	16.3 b	197 a
20-FYM	13.5 a	4109 a	2.7 a	17.3 a	202 a
LSD0.05	0.4	131	0.1	0.5	5.7
Control	11.5 b	2136b	1.3 b	13.5 b	169 b
Treated plots	12.9 a	3938 a	2.5 a	16.3 a	195 a
Significance	**	**	**	**	**

*, **, NS mean significant at P ≤ 0.05, 0,01, and non-significant, respectively; Means of the same category followed by different letters are significantly different from each other at p ≤ 0.05 using LSD test.

 

Results and Discussion

Maize growth response to BM, HA and FYM

The application of BM had no effects on leaves plant-1 but significantly increased the leaf area plant-1 (7.8%) and leaf area index from 2.4 to 2.6 based on two years data (Table 2). Similarly, the HA application had no significant effects on leaves plant-1 but had increased the leaf area (9.3%) and leaf area index both in 2017 and 2018 (Figure 2). The application of FYM at the rate of 15 Mg FYM ha-1 had more leaves plant-1 (13.2), but 20 Mg FYM ha-1 had maximum leaf area plant-1 (4088 cm-2), and leaf area index (2.6) averaged over two-year data (Table 2). This indicates that doubling the amount of FYM from 10 to 20 Mg FYM ha-1 had increased leaves plant-1 by one leaf, leaf area plant-1 by 13.7% and leaf area index by 13% over two years data.

 

Increasing the BM levels from 25 to 50 L ha-1 had significantly increased the ear length of maize by 6.4% in 2017 and 5.7% in 2018 and 6.4% when the data was analyzed combined over two years (Table 2). The application of 6 kg HA ha-1 had resulted in 15.7 cm ear length as compared to 16.6 cm ear length measured with 9 kg HA ha-1 in 2017. However, in 2018 increasing the HA from 3 to 9 kg ha-1 had increased the maize ear length from 15.9 to 16.6 cm, respectively. Increasing the HA levels by three times i.e. from 3 to 9 kg ha-1, the ear length of maize over two years average data increased by 0.6 cm. The data indicates that increasing FYM from 10 to 20 Mg ha-1 had increased the ear length by 7.8% in 2017 as compared to 11.61% in 2018. The maize ears were lengthier for 20 Mg FYM ha-1 (17.0 cm) and shorter with 10 Mg FYM ha-1 (15.5 cm). Plant tallness increased by 7.3 cm (2018) with increasing BM from 25 to 50 L ha-1 (Table 2). Similarly, increasing the HA levels by three times i.e. from 3 to 9 kg ha-1, the plant height of two years average data increased by 15.6 cm. The tallest plants (204.0 cm) were in 2018 when 20 Mg FYM ha-1 were incorporated in soil, as compared to dwarf plants been measured with 10 Mg FYM ha-1 (187.3 cm) in 2017. Similarly, increasing the FYM from 10 to 20 Mg ha-1 in 2018, the plant height of maize was increased by 16 cm. The average of two years data showed that doubling the levels of FYM i.e. up to 20 Mg FYM ha-1, the plant height increased by 14.5 cm (Table 2). It was further noted that application of 20 Mg FYM ha-1 produced tallest plants (200.7 cm), followed by 15 Mg FYM ha-1 (194.2 cm) and shortest plant were measured with 10 Mg FYM ha-1 (186.2 cm).

The treated plots when compared to control had increased the number of leaves from 11.8 to 12.7, leaf area plant-1 from 2194 to 3880 cm-2 and leaf area index from 1.4 to 2.5, plant tallness by 29.3 cm, and ear length by 2.9 cm. (Table 2). The interaction between HA×FYM (Figure 2) indicated that increasing the levels of FYM had increased the ear length both in 2017 and 2018 when 3 kg HA ha-1 was applied. However, with application of HA greater than 3 kg ha-1 the increased FYM had no significant differences for ear length in 2017 and 2018. The interactive response of BM×HA showed that plant tallness increased with increasing level of HA both in 2017 and 2018 across both levels of BM (Figure 3). However, the increases in plant tallness were prominent with 50 L ha-1 over 25 L ha-1 over both year data average.

Maize growth contributing parameters like plant height, leaves plant-1, ear length, leaf area and leaf area index was greater with 50 L BM ha-1 compared to 25 L BM ha-1. The increased growth contributing parameters might be related to the improved individual plant performance (Khan et al., 2014) as a result of greater mineral N availability due to higher decomposition of manure in the presence of microbes (Khan et al., 2019). The increased mineral N is directly related to the increased growth contributing parameters of maize (Khan et al., 2014), and hence the crop growth increased. Other possible mechanisms could be the improved moisture availability (Jia et al., 2013), soil condition (Singh et al., 2015), crop stand (Ibrahim and Khan, 2017). These findings are in agreement with earlier researcher who obtained improved growth parameters of maize due to microbes’ addition (Haji et al., 2014). Increasing HA application three times from 3 to 9 kg ha-1 had increased the maize leaves plant-1, ear length, leaf area and leaf area index both in 2017 and 2018. The increased growth parameters could be related to the improved soil properties as a result of chelating properties of HA (Mackowiak et al., 2001). The chelating properties of HA had enhanced the nutrients availability (Mackowiak et al., 2001) which might have been increased the plant photosynthesis capability and hence the growth of maize crop.

 

The application of 20 Mg FYM ha-1 had increased leaves plant-1, leaf area, leaf area index, plant height, and ear length of maize. The increased leaves plant and associated leaf area as well as plant height might be related to the improved permeability of soil (Jat et al., 2019), water storage capacity of soil and optimized soil temperature (Jia et al., 2013). These results are in line with the finding of Khan et al. (2009), who reported increased growth and biomass of maize due to the application of FYM when compared to control plots. Similarly, when the higher amount of FYM was added mineral nitrogen availability increased (Khan et al., 2019) as a result of increased decomposition of FYM (Bowles et al., 2014). The direct addition of FYM is considered as addition of nutrients which prolong the vegetative period of maize (Khan et al., 2014) and thus might have improved the increased maize growth. These results agree with the findings of earlier researchers like Khan et al. (2009), who documented increases in growth in response to higher usage of FYM i.e. 20 Mg FYM ha-1 to either lower levels or control plot.

Maize growth in response to soil properties

The correlation analysis of soil total as well as mineral nitrogen contents with maize growth parameters like plant m-2, leaves plant-1, leaf area, LAI, grain yield and grain N contents is provided in Figure 4. It was observed from the correlation analysis that grain yield positively correlated with soil mineral N, plant height, ear length, leaves plant-1, leaf area and leaf area index. However, the relationship of grain yield with soil total N and plants m-2 was found non-significant. Similarly, most of maize growth parameter were positively correlated with each other, except plants m-2. Among these relationships, the relationship among the growth parameters of maize i.e. leaf area and leaf index with grain yield was stronger than the relationship of grain yield with ear length, and leaves plant-1. It was further observed that mineral N had strong effects on growth of maize whereas total N had no effects on maize growth parameters.

 

The low soil organic matter (Khan et al., 2019) of the experimental site is the main obstacle for lower growth of maize and associated soil fertility indices. Therefore, the direct addition of FYM from external source may provide nutrients (Khan et al., 2015) to the soil, which could be made available due to the improved microbiological properties (Odlare et al., 2008) of soil in the presence of BM and HA, and thus might have improved the maize growth as documented by positive and significant relationship in the current studies. The increased BM can improve the decomposition (Ma et al., 2020) of added FYM, which was further facilitated as a result of soil chelating properties (Mackowiak et al., 2001) by HA addition and the energy provision by FYM for microbes (Zhou et al., 2019), and thus had a positive impact on maize growth.

Conclusions and Recommendations

Doubling the beneficial microbial solution increased maize growth. The addition of humic acid has positive effects on maize growth in term of plant height, leaves plant-1, leaf area and leaf area index. Grain yield was positively correlated with soil mineral N, leaves plant-1, leaf area, leaf area index, plant height and ear length. Based on the conclusion and results of the studies, it is recommended, that application of 50 L ha-1 beneficial microbes should be applied with 6-9 kg HA ha-1 and 20 Mg FYM ha-1 for improving the mineral N availability and hence the maize growth in the studied area.

Acknowledgements

The authors acknowledge the research facilities provided by the Department of Agronomy, the University of Agriculture Peshawar. The authors also acknowledge, the anonymous reviewers and editor for the sparing their time and provision of very constructive comments and suggestion.

Novelty Statement

Increasing beneficial microbes, humic acid and farmyard manure levels had increased the maize growth in term of plant height, leaf area and leave plant. The grain yield was positively correlated with soil mineral N, leaves plant-1, leaf area/index, plant height an dear length.

Author’s Contribution

Izaz Hussain: Carried out research & drafted the manuscript.

Ahmad Khan: Analyzed the data, carried out tabulations/figures of data, and did overall supervision during research.

Habib Akbar: Conceived the idea and helping in designing of experiment

Conflict of interest

The authors declared no conflict of interest.

References

Anonymous. 2007. Soil Survay of Pakistan. Land resource inventory and agricultural land use plan of Peshawar district. National agriculural land use plan. In Soil Survay of Pakistan. Land resource inventory and agricultural land use plan of Peshawar district. National agriculural land use plan, Lahore Pakistan.

Azeem, K. and I. Ullah. 2016. Physiological indices of spring maize as affected by integration of beneficial microbes with organic and inorganic nitrogen and their levels. Comm. Soil Sci. Plant Anal., 47: 2421-2432. https://doi.org/10.1080/00103624.2016.1228951

Bello, A., Y. Han, H. Zhu, L. Deng, W. Yang, Q. Meng, Y. Sun, U.U. Egbeagu, S. Sheng, X. Wu, X. Jiang and X. Xu. 2020. Microbial community composition, co-occurrence network pattern and nitrogen transformation genera response to biochar addition in cattle manure-maize straw composting. Sci. Total Environ., 721: 137759. https://doi.org/10.1016/j.scitotenv.2020.137759

Bharali, A., K.K. Baruah, P. Bhattacharyya and D. Gorh. 2017. Integrated nutrient management in wheat grown in a northeast India soil: Impacts on soil organic carbon fractions in relation to grain yield. Soil Tillage Res., 168: 81-91. https://doi.org/10.1016/j.still.2016.12.001

Bhattacharyya, R., S. Chandra, R. Singh, S. Kundu, A. Srivastva and H. Gupta. 2007. Long-term farmyard manure application effects on properties of a silty clay loam soil under irrigated wheat–soybean rotation. Soil Tillage Res., 94: 386-396. https://doi.org/10.1016/j.still.2006.08.014

Bowles, T.M., V. Acosta-Martínez, F. Calderón and L.E. Jackson. 2014. Soil enzyme activities, microbial communities, and carbon and nitrogen availability in organic agroecosystems across an intensively-managed agricultural landscape. Soil Bio. Biochem., 68: 252-262. https://doi.org/10.1016/j.soilbio.2013.10.004

Brannon, C.A. and L.E. Sommers. 1985. Preparation and characterization of model humic polymers containing organic phosphorus. Soil Bio. Biochem., 17: 213-219. https://doi.org/10.1016/0038-0717(85)90117-8

Bremner, J. and C. Mulvaney. 1982. Nitrogen-total. . In: Method of soil analysis, Part II. 2nd edition. A.L. Page and D.R. Keeney (eds), Pp: 595-624. Soil Science Society of America Inc, Madison, Wisconsin USA, Madison. WI. https://doi.org/10.2134/agronmonogr9.2.2ed.c31

Hai, S. and S. Mir. 1998. The lignitic coal derived humic acid and the prospective utilization in Pakistan’s agriculture and industry. Sci. Tech. Dev., 17: 32-40.

Haji, M., A. Zaman, S.K. Khalil and Z. Shah. 2014. Effect of beneficial microbes (BM) on the efficiency of organic and inorganic N fertilizers on wheat crop. Sarhad J. Agric., 30: 7-14.

Hussain, T., T. Javaid, J. Parr, G. Jilani and M. Haq. 1999. Rice and wheat production in Pakistan with effective microorganisms. Am. J. Alternat. Agric., 14: 30-36. https://doi.org/10.1017/S0889189300007980

Ibrahim, M. and A. Khan. 2017. Phenology and maize crop stand in response to mulching and nitrogen management. Sarhad J. Agric., 33: 426-434. https://doi.org/10.17582/journal.sja/2017/33.3.426.434

Ibrahim, M., A. Khan, W. Ali and H. Akbar. 2020. Mulching techniques: An approach for offsetting soil moisture deficit and enhancing manure mineralization during maize cultivation. Soil Tillage Res., 200: 104631. https://doi.org/10.1016/j.still.2020.104631

Jan, M.T., P. Shah, P.A. Hollington, M.J. Khan and Q. Sohail. 2009. Agriculture research: design and analysis: A Monograph. 85-91. Department of Agronomy, The Univesity of Agriculture, Peshawar

Jat, S.L., C.M. Parihar, A.K. Singh, H.S. Nayak, B.R. Meena, B. Kumar, M.D. Parihar and M.L. Jat. 2019. Differential response from nitrogen sources with and without residue management under conservation agriculture on crop yields, water-use and economics in maize-based rotations. Field Crops Res., 236: 96-110. https://doi.org/10.1016/j.fcr.2019.03.017

Jia, Z.K., X. Wang, L. Liang and S. Kang. 2013. Effect of manure management on the temporal variations of dryland soil moisture and water use efficiency of maize. J. Agric. Sci. Tech., 15: 1293-1304.

Jiang, Y. and J. Yan. 2010. Effects of land use on hydrochemistry and contamination of Karst groundwater from Nandong underground river system, China. Water Air Soil Pollut., 210: 123-141. https://doi.org/10.1007/s11270-009-0229-z

Keeney, D.R. and D.W. Nelson 1982. Nitrogen-inorganic form. In: Method of soil analysis. Part 2. A.L. Page, Miller and D.R. Keeney (eds), Pp: 643-698. American Society of Agronomy, Madison. WI, USA. https://doi.org/10.2134/agronmonogr9.2.2ed.c33

Khan, A., M.Z. Afridi, M. Airf, S. Ali and I. Muhammad. 2017. A sustainable approach toward maize production: Effectiveness of farmyad manure and urea nitrogen Ann. Biol. Sci., 5: 8-13. https://doi.org/10.21767/2348-1927.1000103

Khan, A., N. Ali and S.I. Haider. 2018. Maize productivity and soil carbon storage as influenced by wheat residue management. J. Plant Nutri., 41: 1868-1878. https://doi.org/10.1080/01904167.2018.1463384

Khan, A., S. Fahad, A. Khan, S. Saud, M. Adnan, F. Wahid, M. Noor, W. Nasim, H.M. Hammad, H.F. Bakhat, S. Ahmad, M. Habib ur Rehman, D. Wang and O. Sönmez. 2019. Managing tillage operation and manure to restore soil carbon stocks in wheat–maize cropping system. Agron. J., 111: 2600-2609. https://doi.org/10.2134/agronj2019.02.0100

Khan, A., M.T. Jan, M. Afzal, I. Muhammad, A. Jan and Z. Shah. 2015. An integrated approach using organic amendments under a range of tillage practices to improve wheat productivity in a cereal based cropping system. Int. J. Agric. Biol., 17: 467-474. https://doi.org/10.17957/IJAB/17.3.13.248

Khan, A., M.T. Jan, A. Jan, Z. Shah and M. Arif. 2014. Efficiency of dry matter and nitrogen accumulation and redistribution in wheat as affected by tillage and nitrogen management. J. Plant Nutri., 37: 723-737. https://doi.org/10.1080/01904167.2013.867989

Khan, A., M.T. Jan, K.B. Marwat and M. Arif. 2009. Organic and inorganic nitrogen treatments effects on plant and yield attributes of maize in a different tillage systems. Pak. J. Bot., 41: 99-108.

Khattak, R. and D. Muhammad. 2008. Increasing crop production through humic acid in salt affected soils in Kohat division (NWFP). Pak-Us Collaborative Research Endeavor, ALP Project, PARC, Islamabad.

Kurepin, L.V., M. Zaman and R.P. Pharis. 2014. Phytohormonal basis for the plant growth promoting action of naturally occurring biostimulators. J. Sci. Food Agric., 94: 1715-1722. https://doi.org/10.1002/jsfa.6545

Luo, G., L. Li, V.P. Friman, J. Guo, S. Guo, Q. Shen and N. Ling. 2018. Organic amendments increase crop yields by improving microbe-mediated soil functioning of agroecosystems: A meta-analysis. Soil Bio. Biochem., 124: 105-115. https://doi.org/10.1016/j.soilbio.2018.06.002

Ma, Q., Y. Wen, J. Ma, A. Macdonald, P.W. Hill, D.R. Chadwick, L. Wu and D.L. Jones. 2020. Long-term farmyard manure application affects soil organic phosphorus cycling: A combined metagenomic and 33P/14C labelling study. Soil Bio. Biochem., 149: 107959. https://doi.org/10.1016/j.soilbio.2020.107959

Mackowiak, C., P. Grossl and B. Bugbee. 2001. Beneficial effects of humic acid on micronutrient availability to wheat. Soil Sci. Soc. Am. J., 65: 1744-1750. https://doi.org/10.2136/sssaj2001.1744

MNSF&R. 2020. Ministry of national food security and reserach, Agriculture statistic of Pakistan. In Ministry of national food security and reserach, Agriculture statistic of Pakistan, Islamabad.

Muhammad, I., F. Khan, A. Khan and J. Wang. 2018. Soil fertility in response to urea and farmyard manure incorporation under different tillage systems in Peshawar, Pakistan. Int. J. Agric. Biol., 20: 1539-1547.

Odlare, M., M. Pell and K. Svensson. 2008. Changes in soil chemical and microbiological properties during 4 years of application of various organic residues. Waste Manage., 28: 1246-1253. https://doi.org/10.1016/j.wasman.2007.06.005

Rhoades, J. 1996. Salinity: Electrical conductivity and total dissolved solids. Meth. Soil Anal. Part 3 Chem. Meth., 5: 417-435. https://doi.org/10.2136/sssabookser5.3.c14

Satyanarayana, V., P. Vara Prasad, V. Murthy and K. Boote. 2002. Influence of integrated use of farmyard manure and inorganic fertilizers on yield and yield components of irrigated lowland rice. J. Plant Nutri., 25: 2081-2090. https://doi.org/10.1081/PLN-120014062

Singh, B.B., J. Singh, G. Singh and G. Kaur. 2015. Effects of long term application of inorganic and organic fertilizers on soil organic carbon and physical properties in maize–wheat rotation. Agron., 5: 220-238. https://doi.org/10.3390/agronomy5020220

Zhou, G., X. Qiu, J. Zhang and C. Tao. 2019. Effects of seaweed fertilizer on enzyme activities, metabolic characteristics, and bacterial communities during maize straw composting. Bioresourc. Technol., 286: 121375. https://doi.org/10.1016/j.biortech.2019.121375