Effect of Organic Materials in Agriculture and Forestry
In general, the results of the study showed that the treatment of organic matter significantly affected the various response variables (Table). In certain response variables the effect of organic matter interacts with soil type, and in other variables the effect of organic material does not interact with soil type. Both in response variables that are not affected by their interaction with soil types or those that are affected by interactions with soil types, the provision of organic matter increases the growth and production of sunflower plants, and accelerates the age of flowering and harvesting age.
The results showed that four types of soil used require organic materials.
The addition of organic matter to the four types of soil can be responded to by plants both in their vegetative and generative growth. Organic matter added to the soil can have a positive influence on plants through various effects on changes in overall soil properties.
Addition of organic matter will contribute various nutrients, especially nutrients N, P, and S, plant growth hormones, increase water holding capacity, and increase the activity of soil organisms in all types of soil (Kugedera Andrew Tapiwa Journals, 2019).
Organic matter added to the soil increases the availability of nutrients for plants, especially nutrients N, P, and S. Organic matter provides most of the nitrogen and sulfur and half of the phosphorus absorbed by plants (especially if no artificial fertilizer is added) (Barber, 1984). In most tropical soils, especially in the 4 soil types used in this study, the nutrients N and P are the nutrients that most often limit plant growth (Sanhez, 1992). Plant N needs are high during the growth period, both in the vegetative phase and in the flower growth phase. Phosphorus solubility in FMD soil (Oxisol and Ultisol), Andisol (Andosol), and Vertisol is very low (Fox, 1974 in Sanchez, 1992). In this soil the presence of organic matter with the P nutrients it contains is greatly responded to by plants.
Thus it can be suspected that in the four types of soil that were tried, the addition of nutrients as the influence of organic matter is very useful to meet the needs of plant nutrients.
In Podsolik Merah Putih and Hydromorphic soils with high clay content and low organic matter, the presence of organic material is very helpful in increasing the capacity of available water and loosening the soil. Whereas in Alluvial soils with a relatively coarse texture, the presence of organic matter is very beneficial for increasing the water available to plants and absorbing nutrients from fertilizers. Nutrients which are adsorbed by organic colloids will avoid the process of washing by water and are available to plants gradually (Soepardi, 1983).
Effect of Soil Type. For some of the variables observed, the effect of soil type depends on the presence or absence of organic matter added, but in some of the variables observed, it significantly responds to the effect of soil type without any real interaction with the treatment of organic matter.
Based on the data obtained, it can be concluded that Hydromorphic (T2) and Alluvial (T3) soils for sunflowers have relatively good fertility compared to the other two types of soil (T1 and T4). One of the striking characteristics of Alluvial (T3) soils compared to Andosol and PMK is the availability of higher P nutrients and better porosity. In Andosol and FMD soils plant growth is often limited by P retention (P fixation) and low pH. In both types of soil the availability of P is low, because it is fixed by aluminum cations and oxide minerals. In this experiment P fertilizer was given at the same dose in each pot, and calculated based on the amount of plant needs (6 g TSP / 10 kg of oven dry soil).
Phosphorus fertilizer (TSP) added to the soil will dissolve in water and a complex chemical reaction will take place in the soil.
Saturated acid solution that comes out of the artificial fertilizer will affect the surrounding soil and the solution that comes out pH reaches 0.6-1.5. This highly acidic solution (H3PO4) increases the activity of Al, Fe and Mn ions which can then precipitate P that is soluble in fertilizer, and the P solution in fertilizer can also react with various soil constituents. The amount of P deposited from fertilizers and the amount of P available to plants differ due to different soil properties. In acidic and rich Al, Fe, and Mn soils (such as Andosol and PMK) P that dissolves from fertilizer is actually deposited faster and more than other types of soil, so that the amount of P fertilizer available to plants is only a small fraction of the amount of fertilizer given (Tisdale, et, al; 1985; Sanchez, 1992). Efforts to increase the availability of P and increase the pH and availability of other nutrients in Andosol and PMK (Paleudult) soils are by adding large amounts of organic matter (Uehara and Gilmann, 1981; Stevenson, 1982). In Podsolik Merah Putih, besides the limiting factors described above, there are also other growth limiting factors, namely low nutrient content (low Ca, Mg, and K), low CEC and low available water holding capacity.
To improve this soil in addition to the addition of organic matter also requires the provision of lime and good soil management (Sanchez, 1992).
Hydromorphic soil (Tropaquept) has some relatively better properties compared to Andosol and PMK soils, including a neutral pH, high CEC and high saturation of the base (Soil Survey Staff, 1982).
Effect of Interaction between Organic Material and Soil Type. The results of the study (Tables 1 and 2) show that there is a significant interaction effect between organic matter and soil type on various response variables.
In soil media without added organic matter, there are differences in responses of various variables to different types of soil media. The lowest growth and sunflower production in FMD soil compared to the other three soils, except weight per seed
In the treatment of no added organic matter (B0), sunflower plants in Andosol (T1) soil are shorter at the age of observation 7 mst to 13 mst, have fewer leaves at 5 and 6 mst, and fewer flowering branches at 15 , 16, and 17 mst, with flowering age and harvesting age later than Hydromorphic (T2) and Aluvial (T3) soils.
Research data shows that in Podsolic soil (T4) which is not given organic fertilizer (B0), there is a greater growth inhibiting factor, followed by Andosol soil (T1) and then Alluvial soil (T3).
The addition of organic matter to the four types of soil used significantly reduced the value of the limiting factors for sunflower growth, especially in Podsolic soil (T4) and also in Andosol soils. This can be proved by the fact that the addition of organic matter (B1) results in the difference in the response of the observed variables getting smaller in the four soil types
The addition of organic matter is more responded to by sunflower plants in Podsolic and Andosol soils, compared to Hydromorphic and Alluvial soils. The difference in response given by sunflower plants in Podsolik Merah Putih and Andosol soils compared to the other two types of soil is thought to be due to differences in soil fertility problems, especially the problem of pH, availability of phosphorus, and micro-nutrient problems. In FMD and Andosol soils the pH was lower, the availability of P nutrients was lower and more frequent Al and micro nutrient poisoning (Uehara and Gilmann, 1981) than in Alluvial and Hydromorphic soils.
Effect of Organic Materials in Agriculture and Forestry