Effect of Organic and Inorganic Fertilizer on the Growth and Yield Components of Traditional and Improved Rice ( Oryza sativa L.) Genotypes in Malaysia

: Rice is the most important staple cereal human nutrition and consumed by 75% of the global population. Rice plants need a supply of essential nutrients for their optimal growth. Rice production has increased tremendously in Malaysia insensitive irrigation and the use of inorganic fertilizers and pesticides. However, the effect of using inorganic fertilizers resulted in contamination of ground water and decreased the productivity of soil, which in turn affected the rice production in the long term. The use of organic manure may help to regain the soil health, but that is insufﬁcient for providing the essential nutrients to achieve optimal growth. Therefore, the use of organic manure combined with inorganic fertilizers is applied to obtain optimum yields. This study aims to test the effect of organic and inorganic fertilizers on the growth and yield components of 65 rice genotypes. The pot experiment was conducted at the net house on ﬁeld 10, University Putra Malaysia, UPM, Malaysia, during the period of February to June 2019 and August to December 2019 in a randomized complete block design (RCBD) with three replications. There were three treatment combinations viz. T 1 : 5 t ha − 1 chicken manure (CM), T 2 : 2.5 t ha − 1 CM + 50% CFRR, T 3 : 100% (150 N: 60 P 2 O 5 : 60 K 2 O kg ha − 1 ) and chemical fertilizer recommended rate (CFRR). Grain and straw samples were collected for chemical analysis, and physical parameters were measured at the harvest stage. Results showed that most of the growth and yield components were signiﬁcantly inﬂuenced due to the application of organic manure with chemical fertilizer. The application of chemical fertilizer alone or in combination with organic manure resulted in a signiﬁcant increase in growth, yield component traits, and nutrient content (N, P, and K) of all rice genotypes. Treatment of 2.5 t ha − 1 CM + 50% CFRR as well as 100% CFRR showed a better performance than the other treatments. It was observed that the yield of rice genotypes can be increased substantially with the judicious application of organic manure with chemical fertilizer. The beneﬁts of the mixed fertilization (organic + inorganic) were not only the crop yields but also the promotion of soil health, the reduction of chemical fertilizer input, etc.


Introduction
Rice (Oryza sativa L.) is a widely farmed food crop that provides sustenance for more than half of the world's population. "Rice is life" is the most appropriate slogan for the world, as this grain is critical to our national food security and provides a source of income ity, and improves water-holding capacity. Chicken manure not only increases the yield of rice but can also substitute chemical fertilizers to some extent.
However, the use of organic manure alone might not meet the plant requirement due to presence of a relatively low content of nutrients. The application of organic manure with chemical fertilizer accelerates the microbial activity, increases nutrient use efficiency, and enhances the availability of the native nutrients to the plants, resulting in a higher nutrient uptake. Therefore, in order to make the soil well supplied with all the plant nutrients in the readily available form and to maintain good soil health, it is necessary to use organic manure in combination with inorganic fertilizers to obtain optimum yields.
Therefore, the present research work was undertaken to investigate the effect of the combined application of organic and inorganic fertilizers on the growth and yield of traditional and improved rice genotypes.

Plant Material
A total of 64 traditional and improved rice cultivars were evaluated in this study. The cultivars were obtained from different sources. The genotypes names and origin are presented in Table 1. First, the seeds were dried under sunlight for 8 h before soaking in a Petri dish and being placed in a dark incubator for 2 days. After that, the germinated seeds were sown in the seed tray.

Site of Experimentation
The pot experiment was conducted in a net house at the field 10, University Putra Malaysia (UPM), Malaysia. The experiment was conducted in two seasons, the first season being from February 2019 to June 2019 and the second season from August 2019 to December 2019. Geographically, the place is located at about 3 • 02 N latitude and 101 • 42 E longitude with an elevation of 31 m from the sea level, and it is characterized by a humid tropical climate. Details of the weather information are presented in Table 2. Table 2. Month-wise average of daily maximum temperature, minimum temperature, mean temperature, and rainfall at UPM during experimentation period from February to June (1st planting season) and from August to December (2nd planting season) 2019.

Experimental Design and Treatments
The experiment was conducted following a randomized complete block design with three replication on each treatment. Twenty-day-old seedlings of each test genotypes were transplanted, and two seedlings were used per hill in 45 cm diameter and 52 cm height plastic pot with 15 kg soil and 20 cm spacing between hills. There were three (3) treatment combinations with chicken manure (CM) and chemical fertilizer recommended rate (CFRR) for high goal (HYG) as follows-T 1 : CM (5 t ha −1 ), T 2 : CM (2.5 t ha −1 ) + 50% CFRR (NPK) and T 3 : 100% CFRR (NPK).

Application of Fertilizer and Operational of Intercultural
Organic fertilizer was incorporated into the soil before crop establishment, while a compound fertilizer (NPK 2.16:1.89:0.79) was applied at the rate of 5 t ha −1 . Triple super phosphate and muriate of potash were applied during final pot preparation, and urea was applied in two split doses at 25 days after seeding (DAS) and at 55 DAS, to supply total recommended nutrient of 150 N: 60 P 2 O 5 : 60 k 2 O kg ha −1 . Both organic fertilizer and chemical fertilizer were applied as prescribed by the treatments. Weeding and other management practices were performed as and when required. Irrigation was also conducted whenever required.

Soil Analyses
Initial soil samples were taken from the surface to a depth of 0-15 cm. The samples were air-dried and crushed to pass through a 2 mm (10 meshes) sieve after being free of weeds, plant roots, stubbles, and stones. After that, the samples were placed in clean plastic bags to be analyzed chemically and mechanically. Standard procedures were used to assess the physical and chemical qualities of the initial and postharvest soil samples in Table 3. The textural class was calculated by projecting the values for percent sand, percent silt, and percent clay to the Marshall's Triangular Coordinate following the USDA methodology, and the particle size analysis of the soil was performed by hydrometer method [15]. Organic matter was determined by Walkley and Black method [16], soil pH (1:2.5 soil-water) by glass electrode pH meter method [17], total N by semi-micro Kjeldahl method [18], available P by Olsen method [19], exchangeable K by flame photometer after extraction with 1N NH 4 OA c at pH 7.0 [20], available S by extracting soil samples with CaCl2, solution (0.15%), and by measuring turbidity by spectrophotometer [21] method and CEC by sodium saturation method [15].

Plant Tissue Analyses
After harvest, plant samples were collected from each treatment, and the samples were separated into the shoot (above ground plant parts excluding the grains), root, and grain, after which they were oven-dried at 70 • C for 72 h. Oven-dried samples were ground in the laboratory using a Wiley hammer mill with 1 mm mesh size. The samples were analyzed for total nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg). The nutrients were determined using acid wet digestion method [22]. For the digestion process, ground samples of 0.25 g were transferred to clean 100 mL digestion flask, and 5 mL of concentrated sulfuric acid (H 2 SO 4 ) was added to each flask. The samples were allowed to stand for 2 h, after which 2 mL of 50% hydrogen peroxide (H 2 O 2 ) was added. The flasks were heated for 45 min at 285 • C and then allowed to cool. This process was repeated twice to let the digestion be clear (colorless). The flasks were then removed from the digestion block, cooled to room temperature, and made up to 100 mL with distilled water filtered through filter paper (Whatman no. 1). The digested samples were stored in plastic vials before analysis for N, P, K, Ca, and Mg. Nitrogen and potassium were determined with auto analyzer (AA) (Lachat instrument, Milwaukee, WI, USA), while potassium, calcium, and magnesium were determined using automatic absorption spectrometer (ASS) (Perkin Elmer, 5100, Waltham, MA, USA).

Obtaining the Data
The data on morphological, physiological, and yield characteristics were collected in this study, which includes the quantitative characters that can be counted or measured using specific measuring tools such as plant height (PH, cm), total number of tiller per plant (NT, no.), total number of panicle per plant (NP, no.), panicle length (PL, cm), number of filled grains per panicle (NFG, no), number of unfilled grains per panicle (UNFG, no), 1000 grain weight (TGW, g), grain yield per plant (YP, g), straw yield per plant (SY, g), harvest index (HI,%), and nutrient content (N, P, and K) of grain and straw samples.

Statistical Analysis
All evaluated data were analyzed by pooled statistical analysis software (SAS) version 9.4 to test for significant differences using the analysis of variance (ANOVA) procedure and least significant differences (LSD) (p ≤ 0.001, 0.05) to compare among the significant characteristics mean using the Duncan's new multiple range test (DNMRT) [23]. Prior to running ANOVA, data were tested for normal distribution and homogeneity of variance. These were used to determine the level of variation of all observed traits, which was brought about by genotypes, seasons, treatments, genotypes by treatments, genotypes by seasons, and genotypes by treatments by seasons to determine the level of variations.

Number of Filled Grains and Number of Unfilled Grains per Panicle
The number of filled and unfilled grains had a significant difference (p ≤ 0.01) among the rice genotype, treatment, genotype by treatment, and genotype by season (combination of genotype and season) as presented in Table 4. Results indicated that the application of T 2 (2.5 t ha −1 CM + 50% CFRR) was significantly higher on number of filled grains panicle  Table 8.

Discussion
The results of this experiment revealed that there is a high correlation between plant height and rice plant productivity or growth rate. During the developing stages of rice plants, they grow and flourish to a specific height [24]. Phenotype refers to the process of measuring the basic and complicated traits of a rice species, which include plant height. Organic fertilizer has a positive impact on the growth and production of various crops [25,26]. Plant height is also a major agronomic characteristic that indirectly affects rice plant yields. Traditionally, rice genotypes are tall in stature, are susceptible to loading at maturity, respond poorly to nitrogen fertilizer, and, therefore, produce low yields. For high-yielding varieties, moderate plant heights are desirable. Approximately half of the recommended chemical fertilizer is saved, according to the findings of this study. It differs from the findings of Chandini et al. [13], who discovered that organic fertilizers could potentially replace 50% of needed nitrogen and phosphorus fertilizers by improving. They examined the efficacy of suggested nitrogen and phosphorus fertilizers and lowering chemical fertilizer costs while also preventing environmental contamination from widespread use. Chemical N and P application can be reduced by 50%, while rice yield is boosted with the addition of 5 t ha −1 organic fertilizer [27]. However, when organic fertilizers were used in conjunction with a half dose of inorganic fertilizer on lettuce (Lactuca sativa), twenty-five percent (25%) more growth was achieved than when only chemical fertilizer was used, and at least fifty percent (50%) of chemical fertilizer was saved by using organic fertilizer [28]. The enhanced vegetative growth and additional nitrogen contribution that occurs in response to the recommended fertilizer dose could be the primary reason for the increase in plant height [29]. The availability of main nutrients was equated to the variance in plant height caused by nutrient sources. Chemical fertilizers provide nutrients that are easily soluble in soil solutions and hence available to plants almost immediately. Microbial action and increased soil physical condition contribute to nutrient availability from organic sources. Bargaz et al. [30] agreed with these conclusions. Variations in the availability of key nutrients were thought to be the cause of plant height variation caused by nutrition source. Setiawati et al. [31] reported similar results in rice crops.
Tillering is a crucial feature for grain production and, as a result, a significant factor in rice output. Siavoshi et al. [32] found that different fertilizer mixes increased the number of tillers in rice plants. According to them, the increased number of tillers per square meter could be related to increased nitrogen availability, which is important for cell division. Organic sources provide plants with a better balanced diet, particularly micronutrients, which have a good impact on the number of tillers in plants [33]. The number of productive tillers (tillers that carry panicles) is more important than the overall number of tillers in determining rice plant productivity. The considerable difference in the number of tiller and panicle plant −1 seen in this study can be attributed to genetic differences in their ability to use fertilizers, partition photosynthesis, and accumulate dry matter. The number of panicles grew with increasing nitrogen rates [34,35], and the number of panicles plant −1 increased with increasing NPK rates. Organic manure and chemical fertilizers produced the most prolific tillers, which could be attributed to the nutrient availability in the soil. The availability of nutrients from organic sources, on the other hand, is attributed to microbial action and improved soil physical conditions. The excessive application of inorganic fertilizers is not required to generate good tillers if organic manures are supplemented, which also helps to provide vital micronutrients to the plants [36,37]. In rice crops, Mirza et al. [38] found similar findings.
Rice genotypes differed considerably in panicle length and grain yield. These findings are thought to be attributable to the rice plant receiving extra nutrients as a result of the soil amendment. The application of organic manure and chemical fertilizers resulted in a considerable increase in panicle length [1]. Similar findings were reported by [39,40].
In comparison to fertilizers, manure had a stronger effect in increasing the quantity of grains panicle −1 . It is possible that this owes to the manure's higher nutrient availability. The application of organic materials as fertilizers provided growth-regulating substances that helped better grain filling and improved the physical, chemical, and microbial properties of the soil in this study, and the organic manure and chemical fertilizer had a significant effect because the application of organic materials as fertilizers provides growth-regulating substances that helped better grain filling and improved the physical, chemical, and microbial properties of the soil [41]. The use of organic manures and chemical fertilizers resulted in a considerable increase in grains per panicle [12]. These findings are also supported by Iqbal et al. [42].
The combined application of organic manure and artificial fertilizer resulted in statistically significant change in the weight of 1000 seeds. The combined use of organic manure and artificial fertilizers enhanced the 1000-grain weight of rice [43]. The use of organic manure and artificial fertilizer enhanced the 1000-grain weight of rice [44]. Hoque et al. [45] also found that combining organic manure with chemical fertilizers improved grain weight by 1000 grains. Geng et al. [46] reported that the availability of nutrients throughout the reproductive stage resulted in improved grain filling and thus increased grain weight.
The addition of organic manure to chemical fertilizers enhanced grain output significantly in all genotypes. This was due to the effect of organic and chemical fertilizers on encouraging growth and, as a result, increasing yields. The various fertilizers aided tiller growth and helped spikelet formation, resulting in a higher yield. Wang et al. [34] supported these findings. The fact that it improves soil quality, soil health, and crop output could explain this. The observations of [10] backed up this theory. It was demonstrated that applying organic manure can boost photosynthetic efficiency and nutrient availability [9]. Ye et al. [47] suggested the use of organic manure and chemical fertilizers enhanced grain output considerably. Organic manure and chemical fertilizers boosted rice straw yields [48]. These assumptions are supported by [40,49]. Increasing cropping intensity, the use of modern varieties (high-yielding varieties and hybrids), cultivation of high-biomass-potential crops, nutrient leaching, and unbalanced fertilizer application, with no or little addition of organic manure, have resulted in nutrient mining from the soils. To stop nutrient mining, it is not justified to increase the use of only inorganic fertilizers, but the use of organic sources of plant nutrients viz. cow dung, chicken manure, compost, and green manure should be also considered. In this study, nutrient contents of grain and straw of all genotypes showed that the highest N, P, and K contents were recorded in T 2 (2.5 t ha −1 CM+ 50% CFRR). These findings are partially similar to these of [50,51], who obtained higher contents of nutrient elements such as N, P, and K in rice by applying chicken manure with inorganic fertilizers. The use of a combination of organic manures and inorganic fertilizers clearly aided plant vegetative growth, resulting in higher straw yield.

Conclusions
From the above results, it may be concluded that organic fertilizers in the form of chicken manure have the potential to increase the growth parameters, yield components, and nutritional quality of rice. The use of chicken manure as an organic fertilizer for rice also had positive effects on growth, yield, and nutrient content in the crop. All of the treatments had a significant impact on rice genotypes growth and production. In the current study, it was discovered that 2.5 tons of chicken manure per hectare, combined with 50% of the prescribed chemical fertilizer, resulted in a higher grain yield than the other treatments. From a financial standpoint, producers can employ a combination of organic fertilizer and a lower amount of inorganic fertilizer to increase rice yields while also maintaining and improving soil health.