Effect of humic acid, calcium and poultry waste on growth and yield of broccoli

A field experiment aimed to investigate the effect of humic acid, calcium spraying on the plant and poultry waste on growth and yield of broccoli in Abu Ghraib area within the Horticultural Department during 2019 season. The study utilized a randomized complete block design (RCBD). Humic acid to the soil at two levels (0 and 40 L ha−1), poultry manure at two levels (0 and 12 Mg ha−1), nitrogen at 96 kg N ha−1, phosphorous at 184 kg P ha−1, potassium added at 100 kg K ha−1. Calcium sprayed on the plants in the form of CaCl2 and CaSO4 at two levels (0 and 10 g L−1). Results showed effects of humic acid, incorporating poultry manure, plant calcium spraying, their interactions, on N, P and K in flowering leaves number, and plant yield. Nitrogen concentration in the flowering tablets reached 3.04%, phosphorus concentration in the flowering tablets was 0.47%, and potassium concentration in the flowering discs was 3.23%. Additionally, there was a notable increase in leaves number per plant (41.47 leaf plant−1) and plant yield reached 30.07 Mg ha−1, representing a remarkable of 143.87% compared to control.


Introduction
Iraqi soils are typically by a low organic matter and pH that tends to be alkaline and contain high carbonate minerals.These factors lead to a reduction in nutrient availability in the soil.Therefore, incorporation of organic fertilizers can enhance nutrient in the soil, providing a continuous and gradual release of nutrients due to their slow decomposition.This process helps maintain a balanced nutrient, supporting the ongoing nutritional requirements of plants [1].
Humic acids constitute the primary component of decomposed organic matter in the soil, exerting biological and chemical influences on plant growth.They can be directly applied to plants and serve as an effective source of carbon, enhancing microbial activity and enhances nutrient availability.This is enhancement occurs through chelation of nutrients and the formation of complex and chelating compounds, ultimately freeing ions are liberated, increasing the chance of uptake in plant [2].
Organic matter serves as a crucial and beneficial source for providing plants and soil microorganisms with nutrients essential for plant growth.It enhances microbial and enzymatic activity in the soil, regulates water movement, promotes air circulation, and facilitates gas exchange.Additionally, organic matter contributes to improved soil moisture retention, an increase CEC, and a reduction in soil pH.This, in turn, enhances nutrient availability through the release of organic acids and CO2 gas during decomposition.The impact of these processes extends to the dissolution of minerals containing essential nutrients, such as calcium [8].Calcium plays numerous physiological roles crucial for plant and development.It plays to building the structure of plant cells, serving as the primary component of the middle lamina in the form of calcium pectates.Additionally, calcium is essential for processes such as cell division, chromosome stability, mitochondria production, hydrolysis, and cell expansion [3].
Broccoli is a member of the cruciferous family (Brassicaceae), holds significant nutritional and therapeutic value.It is rich in various, including vitamin A, C, carotenoids, folic acid, niacin, and riboflavin.Additionally, broccoli contains essential like sodium, iron, calcium, phosphorus, and potassium [4].

Materials and methods
Field experiment was implementing during season of 2019 at Department of Research and Studies, Horticulture Department, Abu Ghraib.Soil samples were gathered from the surface layer to physical, chemical, and fertility analyses (Table 1).Experiment employed with three replications.Field underwent plowing, smoothing, and leveling operations, divided into three blocks, each further divided into six lines.The spacing between lines was set at 0.8 m, with a 2 m distance between blocks.Each line comprised three replicates, and each experimental unit consisted of four rows, leaving 1 m between all experimental units and 2 m between sectors.On 20/9/2019, broccoli seedlings (Jassmine F1 of Dutch origin) were planted.
Humic acid was added to the soil with two levels (0, 40) L ha -1 symbolized as H0 and H1, and poultry waste was incorporated at 0 and 12 Mg ha -1 symbolized as M0 and M1, and its characteristics are shown in table (2).Nitrogen was applied at 96 kg N ha -1 , phosphorus was applied at 184 kg P ha -1 , potassium at 100 kg K ha -1 .Calcium sprayed on the plant in the form of CaCl2 and CaSO4 at 0 and 10 g L -1 , designated as Ca1 and Ca2, with a control treatment denoted as Ca0 .

Nitrogen in flower tablets %
Results from Table 4 show effects of poultry manure on nitrogen in the flowering tablets, as M1 achieved 2.73 % with an increase 35.14 % compared to M0 which gave of 2.02 %, this is attributed to release of N from poultry waste compost when the it added to the soil by decomposition it and the C/N ratio decreases, as well as it contains compounds that are easy to decompose by microorganism of soil, enhancing nitrogen availability in the soil.This, in turn, facilitates increased nitrogen absorption by the plant and its accumulation in the fruit parts [5-7], results agree to [8][9][10][11][12].
Results showed effects of humic acid on nitrogen, as H1 achieved 2.66 %, with an increase 26.66 % compared to H0, which gave of 2.10 %, the reason is attributed to that humic acid contains nutrients such as nitrogen that is readily absorbed by plant roots, humic acid is a complex substance enhances the activity of organisms involved in nitrogen fixation in the soil and is a source of nitrogen and reduces nitrogen loss from the soil, the role of humic acid in stimulating organism activities within the plant contributes to increased vegetative growth, which increases its absorption from the soil and increases nitrogen in the flowering tablets, results agree to [13].Results show effects of spraying calcium on plant on nitrogen concentration, Ca2 achieved 2.57 % with an increase 16.81 % compared to Ca0, which gave of 2.20 %, the reason is attributed to that spraying calcium with its various sources and appropriate concentrations improved the nutritional status by increasing the nitrogen in flowering tablets [14].
The results from Tables (4) show effects of triple interaction between organic manure, humic acid and spraying with calcium on concentration of nitrogen, as M 1 H 1 Ca 2 achieved 3.04 %, with an increase 132.06 % compared to M0H0Ca0 which gave 1.31 %, results agree to [15][16][17].

Phosphorus in flower tablets %
Results of Table (5) show effects of poultry manure on phosphorus concentration in the flowering tablets, as M1 achieved 0.33 %, with an increase 50.00 % compared to M0, which gave 0.22 %, the reason is attributed to poultry waste contains phosphorous in its composition, in addition the decomposition of poultry waste reduces pH in the rhizosphere [15,16], results are agree for [18,19].Results showed effects of humic acid on phosphorus, as H1 achieved 0.31 % with an increase 24.00 % compared to H0, which gave 0.25 %, the reason is attributed to P content in humic acid, in addition to its role in reducing soil pH subsequently dissolving some compounds containing phosphorus and it will be available into the soil solution, and absorbing it by plant roots, in addition to its chelating behavior that reduces sedimentation reactions of phosphorus in the soil [20].
Results show effects of spraying calcium on phosphorus concentration, as Ca2 achieved 0.34 % with an increase 47.82 % compared to Ca0 which gave 0.23 %, this indicates however, spraying calcium fertilizers on plants with its various sources and at appropriate concentrations by increase phosphorus concentration in the flowering tablets [21].Results showed effects of triple interaction between organic manure, humic acid, spraying with calcium on concentration of nitrogen, as M1H1Ca2 achieved 0.47 % with an increase 213.33 % compared to M0H0Ca0, which gave 0.15 %, results agree to [22].

Potassium in the flower tablets %
Results from Table (6a dan 6b) show effects of poultry manure on potassium concentration in the flowering tablets, as M1 achieved 2.84%, with an increase 47.91% compared to M0 which gave 1.92%, the reason is attributed to poultry waste content of potassium, in addition, the addition of poultry manure to the soil contributes, upon its decomposition by the action of soil microorganisms [23].Results showed effects of humic acid on potassium, as H1 achieved 2.71 % with an increase 32.19 % compared to H 0 , which gave 2.05 %, It is indicated that humic acid added to the soil works to increasing absorption of major nutrients, especially potassium, from the soil by plant roots, and thus increase its concentration in the flowering tablets.Results showed effects of spraying calcium on the plant on potassium concentration as Ca2 achieved 2.59 % with an increase 18.80 % to Ca0 which gave 2.18 % this indicates that spraying calcium on plants and its various sources improved the nutritional status of plants by increasing potassium concentration in the flowering discs of broccoli.Results showed effects of triple interaction between organic manure, humic acid, spraying with calcium on potassium, as M1H1Ca2 achieved 3.23% with increase 190.99% compared to M0H0Ca0, of 1.11%.

Leaves number (leaf plant -1 )
Results from Table (7) show effects of poultry manure on leaves number of broccoli, as M1 achieved 34.70 leaf plant -1 , with an increase 39.13 % compared to M0, which gave 24.94 leaf plant -1 , reason is that poultry waste contains nutrients such as NPK, which are released into the soil solution upon its decomposition by the action of soil microbiology continuously and increase its availability in the soil.Results showed effects of humic acid on leaves number, as H1 achieved 31.92leaf plant -1 , with increases 15.15 % compared to H0, which gave 27.72 leaf plant -1 , reason is impact humic acid, which influences photosynthesis, protein synthesis, and enhances enzymatic reactions leading to increased nutrient absorption, Moreover, it contributes to the production of substances, leading to increases number of leaves.Additionally, humic acid improving and promoting overall root growth, resulting in increased root fragmentation and branching, thereby enhancing vegetation and leaf count in the plant Results showed effects of spraying calcium on the plant on leaves number, as Ca2 achieved 33.77 leaf plant -1 , with an increase 26.19 % compared to Ca0, which gave 26.76 leaf plant -1 , reason is importance of calcium in growth, as the availability of suitable amounts of it is important for cell division, and it also activates a number of important enzymes such as arginine kinase and adenosine triphosphates.
Results showed effects of triple interaction between organic manure, humic acid, spraying with calcium on leaves number, as M1H1Ca2 achieved 41.47 leaf plant -1 with increase 106.42 % compared to M0H0Ca0.

Plant yield
Results from Table (8) show effects of poultry manure on plant yield, as M1 achieved 23.82 Mg ha -1 , with an increase 62.15 % compared to the M0, which gave 14.69 Mg ha -1 , the reason is attributed to that poultry waste in lowering soil pH and increasing the nutrients availability, which was reproduced and increasing the yield of flowering tablets of the broccoli plant, in addition to the effects of poultry remnants fertilizer on mineral ions, thus increasing the amount of nutrients absorption from soil, Additionally the addition of poultry waste fertilizer has resulted in an integrated nutritional balance during the plant's vegetable and floral growth stages, the results is agree with [24].Results showed effects of humic acid on plant yield, H 1 achieved 21.48 Mg ha -1 , with an increase 26.20 % compared to H 0 , which gave 17.02 Mg ha -1 , reason is attributed to that humic acid is include nutrients such as N, and this results in enhanced growth characteristics and an overall increase in the yield of the broccoli plant, Furthermore, humic acids contribute to an elevation subsequently resulting in heightened and an increase in formation of materials [20].Results showed effects of spraying calcium on the plant-on-plant yield as Ca2 achieved 21.32 Mg ha -1 , with an increase 26.67% compared to Ca0, which gave 16.83 Mg ha -1 , reason is to spraying calcium fertilizers on plants with its various sources improved the nutritional status of broccoli plant.Results showed effects of triple interaction between organic manure, humic acid, spraying with calcium on plant yield, as M1H1Ca2 achieved 30.07 Mg ha -1 , with an increase 143.87 % compared to M0H0Ca0, which gave 12.33 Mg ha -1 , the reason is attributed to that poultry waste in improving the nutrient in the soil [25].

Conclusions
Results showed effects of poultry manure, humic acid, spraying calcium on plants, their interactions on NPK concentration in flowering tablets, number of leaves and plants yield.The treatment of interaction between organic manure (poultry waste), humic acid to the soil and spraying with calcium gave N, P, K concentration in the flowering tablets of broccoli, higher leaves number plant and the highest yield plant of flowering tablets of broccoli, The reason attributed to that poultry waste in improving soil nutrients, in addition to that the fertilizer played a role in preserving the survival of microorganisms.

Referecnces
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Table 1 .
Physical, fertility and chemical analyses of soil.

Table 3 .
Characteristics of humic acid.

Table 4 .
Effect of humic acid, calcium and poultry waste on nitrogen in flowering tablets %.

Table 5 .
Effect of humic acid, calcium and poultry waste on phosphorus in flowering tablets %.

Table 6a .
Effect of humic acid, calcium and poultry waste on potassium in flowering tablets %.

Table 6b .
Effect of humic acid, calcium and poultry waste on potassium in flowering tablets %.

Table 7 .
Effect of humic acid, calcium and poultry waste on leaves number (leaf plant -1 ).

Table 8 .
Effect of humic acid, calcium and poultry waste on Plant yield (Mg ha -1 ).