EFFECT OF AMENDMENT RESIDUE ON SOIL CHEMICAL PROPERTIES, YIELD POTENTIAL AND PROTEIN CONTENT IN SOYBEAN (GLYCINE MAX (L.) MERR)

1. Master Student of Agroecotechnology, Faculty of Agriculture UniversitasSyiah Kuala, Banda Aceh, Indonesia 23111. 2. Department of Soil Science, Faculty of Agriculture UniversitasSyiah Kuala, Banda Aceh, Indonesia 23111. 3. Department of Agrotechnology, Faculty of Agriculture UniversitasSyiah Kuala, Banda Aceh, Indonesia 23111. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History Received: 25 January 2020 Final Accepted: 27 February 2020 Published: March 2020


ISSN: 2320-5407
Int. J. Adv. Res. 8(03), 1082-1091 1083 of the sources of vegetable protein for diversification in order to support the national food security program (Hasanuddinet al., 2005). The crude protein content in plants can be increased due to the presence of large amounts of soil fauna such as earthworms which can play a role in the removal of deciduous leaves so as to increase soil nitrogen. Another factor that can increase levels of crude protein in plants is the ability of plants to absorb nitrogen (Wilson et al., 1990). Plants grown under shade have lower crude fiber content due to an increase in N elements. Crude protein has the understanding of the amount of nitrogen (N) contained in feed ingredients then multiplied by a protein factor of 6,25% (plant-based feed) or 5,56% (animal feed). Figures 6,25% and 5,56% are obtained assuming that protein contains 16% nitrogen (Fathul, 2014).
This research is the third planting season from the previous research, namely in the first planting season (water spinach plants), the second planting season (corn) and in the third planting season using soy plants planted on land with residual soil amendment in the previous planting season, to see how much influence the residual soil amendment has on the chemical properties of the soil, and is there any effect on the yield potential and protein content of the soybeans. This research is expected to add insight into the effect of soil amendments residues on soil chemical properties, yield potential and protein content in soybean plants.

Method:-
The research was conducted at the Experimental Garden of the Faculty of Agriculture, Syiah Kuala University at coordinates 05 ° 17'05.2 "N and 95 ° 28'13.1" E, analysis of soil chemical properties was carried out at the Soil and Plant Laboratory of the Aceh Agricultural Technology Assessment Center and the Soil Chemical Laboratory of the Faculty of Agriculture Syiah Kuala University, and analysis of protein content was carried out at the Laboratory of Animal Nutrition Science, Department of Animal Husbandry, Faculty of Agriculture, Syiah Kuala University.
The materials used are NPK phonska fertilizer, Urea and KCl, Rhizobium sp. (Agrisoy) and Dena 1 variety soybean seed, as well as materials used for chemical analysis of soil and protein in the Laboratory. The tools used are scales, soil drill and other laboratory tools that support analysis. The design used in this study was a non-factorial randomized block design with 2 replications consisting of 30 plots and 15 treatments.
This study is a continuation of previous studies, namely in the first planting season the application of soil amendment to water spinach plants and in the second planting season, the effect of residues and the addition of soil amendment in corn plants. The combination of treatments in the first and second growing seasons can be seen in Table 1.  (Hardjowigeno, 2003). According to Kartikaet al., (2018) the application of biochar increases soil pH but does not affect cation exchange capacity (CEC), and the availability of major soil nutrients.
In addition to cow manure residues, residues from rice husk biochar can also raise soil pH from pH conditions in the second growing season which averaged 6,57 from all treatments. As explained in the study of Nisa (2010) soils treated with biochar treatment can increase the soil pH value from the initial condition of 6,78 to 7,40 or an increase of 9,14% from the initial soil condition. Furthermore, Xieet al (2016) added that biochar works well in terms of increasing soil pH and soil organic carbon. Based on statistics, there is a significant difference in the effect of soil 1085 amendment residues on the pH value of the soil, but it is not significant, because based on the criteria for soil properties, all are in the neutral category.

C-organic:
Organic carbon in the soil has a role in maintaining soil fertility from various aspects both-physical, chemical and biological soil. In this study, the effects of two types of soil amendments, namely residues from biochar rice husks and cow manure, were given in the previous two planting seasons. The results of the C-organic analysis in the third growing season from the residues of soil amendment given in the first and second growing seasons can be seen in Table 3. Table 3:-Average C-organic effects of Soil amendment Residues at the Third Planting Period.

Total Nitrogen:
Nitrogen fertilization is needed by plants, this is because nitrogen is only absorbed in the form of anion nitrate (NO 3 -) or ammonium cation (NH 4 + ), but the ammonium cation is very quickly oxidized to nitrate by bacteria in the soil, while nutrients in the anion form will be easy washed by negative soil particles and organic matter, making N difficult to be available to plants (Lakitan, 2012).
The results of the analysis of total N soil in the third planting season from the residual soil amendment given in the first and second growing season can be seen in Table 4.
In Table 4 shows the total N content is not statistically different, when viewed based on the criteria of soil properties, the condition of this soil is almost entirely at very low criteria if it is at a value <0,10 %. The effect of the residue in the third planting season can significantly increase the total nitrogen value of the soil both without addition of doses or by adding a dose of soil amendment from the total N value of the soil in the initial conditions of the land which is 0,05 %. Rahmi and Biantary research (2014) states that vegetation that grows above the ground and its decomposition rate are factors that cause changes in N content in the soil. Furthermore Singh et al (2018) stated that the application of biochar made from rice husk can also significantly increase soil N, P and C content. The same thing was conveyed by Yunilasari (2019), the total N-content in the soil increased, but the amount was 1086 still in a very low criterion, the low increase in the total N-total soil could be due to adsorption by biochar and also absorption by plants better.

Treatment
N-total (%) R1 (Control (NPK 0 %)) 0,12 R2 (Control (N and K)) 0,09 R3 (Control (NPK 50 % recommendation)) 0,10 R4 (Biochar rice husk10 ton ha -1 + NPK 0 %) 0,09 R5 (Biochar rice husk10 ton ha -1 + N and K) 0,09 R6 (Biochar rice husk10 ton ha -1 + NPK 50 % recommendation) 0,10 R7 (Biochar rice husk 5 ton ha -1 + NPK 0 %) 0,08 R8 (Biochar rice husk 5 ton ha -1 + N and K) 0,09 R9 (Biochar rice husk 5 ton ha -1 + NPK 50 % recommendation) 0,09 R10 (Cow manure10 ton ha -1 + NPK 0 %) 0,09 R11 (Cow manure10 ton ha -1 + N and K) 0,08 R12 (Cow manure10 ton ha -1 + NPK 50 % recommendation) 0,07 R13 (Cow manure20 ton ha -1 + NPK 0 %) 0,07 R14 (Cow manure20 ton ha -1 + N and K) 0,09 R15 (Cow manure20 ton ha -1 + NPK 50% recommendation) 0,08 P Available: In addition to nitrogen, phosphorus nutrients (P) are also absolutely needed by plants. Yunilasari (2019) said, the amount of P in the soil is usually more than the amount of N, however the P element is difficult to be absorbed by plants because it is difficult to dissolve and fixated by soil particles. The results of the P analysis are available in the third growing season from the residual soil amendment that has been given in the first and second growing seasons can be seen in Table 5. 45,54 f Description: Numbers followed by the same letters in the same column are not significantly different at the 0,05 test level (DMRT) Table 5 shows the value of P in the post-harvest soybean crop of the third growing season showing very high values based on the criteria of soil properties according to the Soil Research Institute (2009). Not only in the treatment given soil amendment, so also with controls R1, R2 and R3 which were not given soil amendment at all. The high available P value is also based on the initial state of the land before the study, the P content in the soil is already high at 28 ppm (Soil survey staff, 2014). Statistical test results showed a difference in the treatment of R15 which tends 1087 to be higher with the addition of soil amendment doses of cow manure from 5 tons ha -1 plus 50 % NPK fertilizer recommendations in the first planting season to 20 tons ha -1 cow manure plus 50 % NPK fertilizer recommendation with a value of 45,54 ppm, and the lowest is in the R1 control with a value of 36,97 ppm. In the study of Miet al (2018), it produced NPK fertilizer with organic soil amendment (cow manure) at soil depth of 0-10 cm showing the highest level of available P concentration.
In addition to cow manure, increasing the dose of rice husk soil amendment and rice husk biochar can also increase the P value available in the soil. As said by Liu et al (2017), that the administration of rice husk biochar can provide growth effects that are more suitable for soil bacteria and significantly increase the availability of soil phosphorus, biochar has a positive effect on phosphate solubilizing bacteria and contributes to an increase in phosphorus availability. Then, Panditet al (2018) also said that biochar as a soil amendment can significantly increase the content of available P in the soil.

Cation Exchange Capacity (CEC):
Soils with high organic matter content have a higher CEC, as well as younger soils with new weathering starting with soils with advanced weathering having a low CEC value (Tambunan, 2008). The results of the analysis of soil CEC in the third planting season from the provision of soil amendments in the first and second planting seasons can be seen in Table 6.
Some of the results of previous studies such as Gautamet al (2017) said after the application of biochar and manure there was a slight increase in the content of CEC but without statistical differences. Furthermore, in the study of Herlambanget al (2019) also said cow manure can increase CEC within 2 months of the incubation period, because it is biodegradable and contains more cations. Although the value has increased in this third planting season, the CEC value is still at a low criterion of 5 to 16 me 100g -1 (Soil Research Institute, 2009).

Soil C: N Ratio:
Soil C:N ratio is the ratio between C-organic and total Nitrogen content of the soil. Low value of this ratio means decompositition of organic matter run fast or has entered a further phase, and vice versa. Table 7 shows the average 1088 value of C:N ratio. It can be seen that soil C:N ratio of the residues of several soil amendments addition did not show significant differences between treatments.
Based on table 7, C:N values of the treatments residue were categorized as low. Organic matters with low C:N ratio value tend to be decomposed faster than the high value. It is expected can improve soil chemical properties and increase P uptake (Fikdalillahet al., 2016).

Yield Potential of Soybeans:
The results showed that the residual soil amendment did not significantly affect the yield potential of soybeans. The average yield potential of soybean plants can be seen in Table 8.

Protein: Rough Protein Content of Soybean Seed:
Soybean is the main source of protein, even soy is said to be a functional food source when viewed from the nutritional content of the seed. On a dry weight basis, soybeans contain about 40 % protein, 20 % oil, 35 % soluble and insoluble carbohydrates and 5 % ash (Liu, 2004). The results of the analysis of protein in soybean seed in the third planting season due to residues of soil amendment that have been given in the first and second growing seasons can be seen in Table 9. 30,65 Table 9 shows the value of crude protein in soybean seed from the residue of soil amendment administration in the first planting season was highest at R1, that is without giving soil amendment and fertilizer which was 32,2 %. The soybean variety used is Dena I, in general Dena I has a protein content of 36,7 %. The decrease in protein value is thought to be due to the shelf life, because after harvesting soybean seed are not directly analyzed, other than that it is suspected because the very low soil N content is a factor affecting the protein content. There is also no statistically significant difference from the residual soil amendment to the protein content of soybean seed.
Protein is a source of amino acids that contain elements C, H, O and N, in addition, proteins also contain phosphorus and sulfur (Budianto, 2009). There are several elements present in the soil that can affect protein. High and low protein contained in Figure 8 can also be caused by the ability of plants to absorb elements that are in the soil and ascend to the seed of plants running slowly, especially soil amendment which is an organic material that requires a long time to be decomposed in the soil.The protein content of soybean seed is also influenced by the elements nitrogen and phosphorus, as explained by Mitsuhashiet al (2005) states the accumulation of protein in seed is determined by the adequacy of P plants. In addition, Motlaghet al (2012) also reported an increase in protein content also in line with the application of phosphorus fertilizer in the soil. Besides phosphorus, nitrogen also plays a role in influencing protein in soybean seed but its effect is not significant.

Conclusion:-
The conclusions of this study include: 1. Statistical test results can be concluded that there are significant differences in the third growing season due to soil amendment residues in the first and second growing seasons on soil pH and P-available. 1090 2. Potential results show the residual soil amendment of cow manure 20 tons ha -1 tends to be higher than that of other soil amendment residues. 3. Statistical test results can be concluded that there are significant differences in the third growing season due to residual soil amendment in the first and second growing seasons in the protein content of soybean seed.