الفهرس 
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Abstract
The investigation in this research was extended to study the possibility to ameliorate some chemical and physical properties of compost by using plant growth promoting rhizobacteria (PGPR) for composting corn residual with Cattle manure and rock phosphate (RP) to improve the organic matter degradation and humification during the composting and increase the essential nutrients of compost, to obtained a high quality compost. The field experiment were carried out during winter season of wheat plant (2019/2020) at soils and water department farm, Faculty of Agriculture, South Valley University, Qena, Egypt. And to study the effect of different heaps application on the growth and yield parameters of wheat plants and sandy loam soil fertility.
Heap formation
Corn residues (2–3 cm length) were thoroughly mixed for homogenization purpose, and four heaps were prepared. A heap of the corn residues of 1.5 m long, 1.0 m width and 1.0 m height was made for composting process. In all heap s the moisture content was adjusted to reach about 60 % of their water holding capacity. The composting process was allowed to continue for 100 days, including maturation period. The heaps were turned for aeration every 7 days of composting time. Eventually, the heap was covered with banana leaves to prevent the fast drying of theresidues.
The study was constructed four treatments as the following:
1- Compost-1(C-1): Whereas, traditional method composting was used as a control (corn residues (5:1) + fresh cattle dung (1:5) + chemicalactivator.
2- Compost-2 (C-2): Corn residues (5:1) + cattle dung (1:5) + chemical activator+ rock phosphate @2%P.
3- Compost-3 (C-3): Corn residues (5:1) + cattle dung (1:5) + chemical activator+ rock phosphate @ 2%P + B. megatherumculture.
4- Compost-4 (C-4): Corn residues (5:1) + cattle dung (1:5) + chemical activator+ rock phosphate @ 2%P + (B.megatherum, A.lipoferum, A. chroococcum) mixedcultures.
Temperature was measured every tow day at different points of an area which could be related to the entire box spatially in the morning at a depth of 60 cm.
Compost analysis
Samples were collected from 3 points of the composting heap every 10 days and were kept in a deep freezer at 4 ºC in a refrigerator for analyses. The phsico- chemical properties of collected samples analysis including: moisture content, pH, EC, organic carbon (OC), organic matter (OM), total nitrogen (TN), C/N Ratio, Ash%, ammonical-nitrogen (NH4+ ــN), nitrate (NO3-ــN), available phosphorus, total potassium and bulk density (BD) were determined at zero time and every 10 days until 100 days of compostingtime.
phsico-chemical changes of compost heaps during composting.
In this study the temperature of all tested compost heaps was highly elevated after the second day of composting and exhibited the maximum level (54.5 ̊C to 62.2 ̊C) at 12 days at a depth of 60 cm of the heap. The heap treated with three bacterial inoculums (C-4) reached the highest peak values of 62.2°C compared to composting treatments C-1, C-2 and C-3, for which it was 54.5, 58.5 and 58.6 °C, respectively.
The Bulk densities was observed increasing on four compost heaps during composting until the end of composting, where it increased from 224 to 533 kg/m3, 310 to 765 kg/m3, 301 to 735 kg/m3 and 295 to 740 kg/m3 for composting treatment C-1, C-2, C-3 and C-4respectively.
The pH value declined to stabilize with the end result at 100 days being 6.9, 7.4, 7.1 and 7.0 for composting treatment C-1, C-2, C-3 and C-4 respectively. During the first period of composting the pH decrease forall compost piles, while in the last period of composting the pH rises above neutral.
The first values of EC for all compost heaps being 2.3, 2.08, 2.04 and 2.1 ds m-1 for composting treatment C-1, C-2, C-3 and C-4 respectively. The compost heaps showed regular increases in EC through the composting period. The composting materials conductivity rates at end of composting period were 3.48, 3.1, 3.22 and 3.32 dsm-1for treatments C-1, C-2, C-3 and C-4, respectively.
The initial values of TOC were 51.3%, 45.2 %, 45.2% and 45.2% for composting T1, T2, T3 and T4 respectively. After compost maturity the TOC reached 29.9%, 26.1%, 24.2% and 24% for treatments C-1, C-2, C-3 and C-4 respectively.
For organic matter the heap untreated (Inoculation of bacteria) C- 1(traditional method) reached the highest values of 88.5% compared to composting treatments C-2, C-3 and C-4 for which it was 77. 9, 77. 9 and 77. 9%, respectively and the final ratio values of the OM loss recorded 42.6, 45.4, 49.05 and 49.4% for composting treatment C-1, C-2, C-3 and C-4, respectively.
The total nitrogen increase ratio was 32.9 %, 29%, 26.9% and 28.9 % for treatments C-1, C-2, C-3 and C-4, respectively. Enrichment of compost by B.megatherum (C-3) and A. lipoferum + A. chroococcum + B.megatherum (C-
4) run to increases in nitrogen content like compared to the C-2 treatment.
The initial C/N ratio was 46.6, 46.2, 46.2 and 46.2/1 for composting treatments C-1, C-2, C-3 and C-4 respectively, and the final values of total C/N ratio after the 100 days were 15:1, 14:1, 12:1 and 10:1 for composting treatments C-1, C-2, C-3 and C-4 respectively.
The ash content gradually increases in all treatments during the composting process. The final ash content reached 48.45%, 55%, 58.28% and 58.63% for treatments C-1, C-2, C-3 and C-4 respectively.
For available phosphorus, at the end of first period (before Inoculation of bacteria) the treatments reached 1.21, 1.32, 1.48 and 1.3 g/kg compost for heaps C-1, C-2, C-3 and C-4 respectively. While, at the end of the composting period the treatments increased after Inoculation of bacteria at ratio 33.1%, 47.4 %,
52.7 % and 54.6% for heaps C-1, C-2, C-3 and C-4 respectively.
The amount of increase in TK was in the range of 62.7-75.9% during the composting period, the TK increase in prepared compost was in the order: C-1>C-4>C-3>C-2.
Field experiments
A field experiment was conducted during the winter season of (2019) at the Experimental Research Farm of the Faculty of Agriculture, South Valley University. This experiment carried out to study the effect of application of preparing enriched composts alone or combination with mineral-N on wheat growth and yield, nutrients status and some soil physical and chemical properties. The experiment included the followingtreatments:
T1: recommended dose of NP fertilizers (100% RDF) T2: Compost (C-1) 100%N
T3: Compost (C-1) 50 %N +50 % (mineral-N) T4: Compost (C-1) 25%N + 75 % (mineral-N) T5: Compost (C-2) 100%N
T6: Compost (C-2) 50%N + 50 % (mineral-N) T7: Compost (C-2) 25 %N + 75% (mineral-N) T8: Compost (C-3) 100 % N
T9: Compost (C-3) 50 %N +50 % (mineral-N) T10: Compost (C-3) 25 %N + 75 % (mineral-N) T11: Compost (C-4) 100 % N
T12: Compost (C-4) 50 %N +50 % (mineral-N) T13: Compost (C-4) 25 %N + 75 % (mineral-N)
Growth:
Significant increase for different application rates of composts and their combinations on plant height, number of tillers, fresh and dry weight of wheat plants. The highest values of plant height, number of tillers, fresh and dry weight were recorded in T12 (50% C-4 + 50% mineral-N and P) followed by T9 (50% C-3 + 50% mineral-N and P). The most simulative treatment T12 (50% C- 4 + 50% mineral-N and P), on all of the measured plant growth parameters, scoring the following increases in ; plant height, number of tillers, fresh and dry weight making 17.35 %, 60% , 17.60 % and 10.73 %, respectively, compared with the treatment T1 (100% recommended dose of N and Pfertilizers).
Yield:
Significant increase (p≤0.05) effect of mineral-N and enriched composts application and their combinations of wheat plants. The highest
values of spike length (cm), weight of grain of spike (g) and 1000- Grains weight (g) were recorded in T12 (50% C-4 + 50% mineral-N and P) followed by T9 (50% C-3 + 50% mineral-N and P). The most stimulative treatment T12 (50% C-4 + 50% mineral-N and P), on all of the measured yield parameters, scoring the following increases in ; spike length, weight of grain of spike and 1000- Grains weight making 25.70 %, 26.51 % and 22.65 %, respectively, compared with the treatment T1 (100% recommended dose of N and P fertilizers).
Grain, straw and biological yields of wheat plants t/fed:
Addition of compost C-4 + 50% mineral-N and P (T12) yielded significant increases in grain, straw and biological yields (2.39, 2.81 and 5.20 t/fed.) respectively compared to the T1 ((100% recommended dose of N and P fertilizers). Also, T9 (50% C-3 + 50% mineral-N and P) was recorded 2.38, 2.75 and 5.13 t/fed, respectively for grain, straw and biological yields of wheat plants. The previous results, indicate there is no significant difference between treatment T12 andT9.
Macronutrients uptake (mg plant-1)
Regarding uptake of N, P and K in wheat plants grown on sandy loam soil as affected by residual effect, the results showed that the highest significant differences increase in N, P and K uptake was found in treatment (T12) when compost C-3 was applied along with 50% of mineral N and P recommended rate. Application compost C-4 + 50% mineral-N and P (T12) recorded significant increases in N, P and K (121.10, 24.90 and 75.70 mg Plant-1) respectively compared to the T1 (100% recommended dose of N and P fertilizers), which recorded 105.40, 15.20 and 63.96 mg Plant-1 of N, P and K uptake,respectively.
Soil chemical properties
Soil pH: The different level of compost materials caused a significant decrease in soil pH compared to the control received beginning level compost (T1). The decrease in soil pH was mostly correlated with the increase of application level. The treated soil with C-4 50 %N +50 % mineral-N and P (T12) gave the lowest values of soil pH which amounted to 7.55 after 70 days from planting wheat plants in sandy loamsoil.
Cation Exchange Capacity (CEC): the application of compost increased soil CEC compared to the control (beginning addition). Also, the data elucidated that a positive correlation between total carbon and CEC.at beginning time, the treated soil with (Compost (C-2) 100%N T5) gave the highest values of soil CEC which amounted to 53.05 Cmol(+) kg-1soil. Moreover, after 70 days from wheat cultivation, the treated soil with (Compost (C-1) 100%N T2) gave the highest values of soil CEC which amountedto
43.93 Cmol (+) kg-1soil.
Organic matter (OM %) content in soil: the application of compost increased soil organic matter compared to the control (beginning addition). Also, the data elucidated that organic matter increased progressively by increasing the compost levels. (Compost (C-2) 100%N T5) of compost treatments yielded greater organic matter contents than other treatments which amounted to (3.22%) at 70 days from wheatcultivation.
Total nitrogen (mg kg-1) in soil: at beginning time, the maximum values of total nitrogen were recorded with treatment T12 (C-4 50 %N +50 % mineral- N and P) giving 0.74% total N. While treatment T4 (C-1 25 %N +75 % mineral- N and P) recorded the lowest soil N content giving 0.32 % total N. This result may be attributed to the highly content of N in compost4(C-4).
Available phosphorus (mg kg-1) in soil: The highest values of available– P were obtained when soil treated with compost at the levels of (C-4 50 %N
+50 % mineral-N and P) T12 which recorded (55.75 and 35.43) mg kg-1 at beginning time and after 70 days respectively. On the contrary, the lowest values of available–P were obtained at the control treatment (beginning level) compost amounted to (17.16 and 13.89) mg kg-1 at beginning time and after 70 days respectively.
Available potassium (mg kg-1) in soil: available-K in soil increased significant with compost application at beginning time and after 70 of wheat planting compared to the control (T1). The highest values of available–K obtained when soil treated with C-4 100%N (T11), which recorded 0.68 and
0.18 g kg-1 at beginning time and after 70 days respectively. These increments in available–K were mostly correlated with the levels ofapplication.
Soil physical properties:
Soil bulk density (g cm-3): the application of compost as organic amendments significantly decreased soil bulk density (BD) compared to the uncomposted soil which recorded the highest. The reduction in values of soil bulk density was mostly correlated with the level of application. The lowest value of soil bulk density was obtained in the T8 (C-3 100 %N) the value of soil bulk density amounted to 1.11 g cm-3 at 70 days .The difference between chemical fertilizer (100% NP) and mixed fertilizer concerning bulk density (BD) was significant at0.05.
Soil particle density (g cm-3): at beginning time the application of different compost levels insignificantly decreased soil particle density compared to the uncomposted soil (T1). The relative value of soil particle density was mostly correlated with the levels of application. Also at 70 days soil particle density decreased compared to the uncomposted soil (T1). The lowest value of soil particle density was obtained in the T4 the value of soil particle density amounted to 2.23 gcm-3.
Field capacity (FC %): the treating sandy loam soil with compost significantly increased its moisture retention at FC as compared to the untreated soil treatment (T1), and this increase were proportional to the increase in application levels. The highest value of F.C (17.08%) was recorded in the T5 (Compost (C-2) 100%N), while the lowest value (9.29%) was recorded in the T1 (control).