Nutrient qualities hydroponic corn green fodder (HCGF) of yellow-maize on different harvest time

The supply of high-quality forage was inhibited by land availability and forage preparation time before it can be used as feed. Hydroponic corn green fodder (HCGF) technology may be a solution to this problem by supplying high-quality forage in short period of time in limited land resources. Yellow-maize is a potential seed for HCGF. The aim of this study was to evaluate the nutrient quality HCGF of yellow-maize harvested at 7th, 9th, 11th, 13th, and 15th day. The design used was completely randomized design with four treatments. The results showed that the linear pattern was observed on dry matter (DM), organic matter (OM), crude fibre (CF), and crude protein (CP) content as the harvest day increased. The DM, OM, and CP content decreased while CF content increased in accordance with the longer HCGF harvest time. The best HCGF profile characterized by high DM content (25.01%) with sufficient CP content (20.09%) was observed in the 7th day harvest. In general, HCGF of yellow-maize harvested at 13th day showed increase in CF content (from 12.09% to 16.27%), and CP content (from 11.70% to 13.23%) compare to its grain.


Introduction
Due to the advancement of the livestock industry, the need for high-quality feed supplies is increasingly crucial.Up until now, the provision of forage has been constrained by land resources and the time required to cultivate these feed crops.An innovation is required to tackle the challenge of limited land and the quality of generated forage.Ideally, high-quality crops should be produced quickly using minimal land.To address this issue, hydroponics is the appropriate technology.Through hydroponics, forage can be grown in a short time for harvesting and to yield excellent quality on restricted land.[1].
Hydroponic fodder technique is a cultivation method for feed crops that utilizes a liquid medium for their growth.This feed can be utilized as ruminant main forage or another nutritious complementary feed for another animal feed.This can minimize various constraints associated with land provision.The advantage of this technique is that it doesn't require extensive land, has a relatively short harvesting time, and yields highly palatable forage [2].This short harvesting time correlates with the quality and quantity of biomass produced, thus it's necessary to determine the appropriate time to harvest these plants.This study evaluates the quality of yellow corn HCGF harvested at different ages.

Materials and Methods
The materials used in this research were selected quality yellow corn seeds to maintain their germination performance.The cultivation of HCGF was carried out on 20 polyethylene trays, each measuring 40 x 60 cm, to accommodate 5 treatments and 4 replications in a Completely Randomized Design.The treatments in this study were harvesting ages: 7, 9, 11, 13, and 15 days.The hydroponic setup adopted a modified type of nutrient film technique [3] for the installation design [4].
Each research unit was planted with 210 grams of selected quality yellow corn seeds.The installation was connected to an automatic irrigation system for watering purposes.Irrigation was carried out daily (until the desired harvesting time) with a total of 5 irrigation sessions at intervals of 07:00, 09:00, 11:00, 13:00, and 16:00.The yellow corn seeds were subjected to proximate analysis to serve as a comparison for the quality of the resulting HCGF (Table 1).The HCGF from yellow corn harvested according to the treatment ages was subsequently subjected to proximate analysis to determine the content of DM, OM, CF, and CP.

Dry matter content
The results of the Analysis of Variance (ANOVA) show that the harvesting age significantly influences (p < 0.05) the dry matter (DM) content of HCGF from yellow corn.There is a linear decrease pattern in the dry matter content as the harvesting age increases.The dry matter content in the study exhibits a significant decrease with the advancing harvesting age.The highest dry matter content was obtained from the 7-day-old harvest (25.01%).The nutrient composition shift of the corn seeds, particularly the dry matter in Table 1 (32.25%),ranges between 25.01% and 13.35%.Plant age can affect the moisture content in plant material, as the dry matter content usually increases with plant age [5].However, in this study, the dry matter content decreases as the HCGF plants mature.This is due to the proportionally higher presence of certain parts of the corn seed when the plant is still young.The dry matter content in the germination of sorghum varieties shows losses that reflect lower values compared to the original sorghum seeds.Most of the dry matter loss during germination is a result of respiration, an energyrequiring process, which explains why there is lower energy based on the dry matter in germination.Original sorghum seeds have higher dry matter values compared to germinated sorghum [6].

Organic matter content
The treatment significantly affects (p < 0.05) the organic matter (OM) content of HCGF from yellow corn.Organic matter linearly decreases with the increasing harvesting age.The organic matter content of the dry matter decreases as the harvesting age increases [7].The organic matter content of HCGF from yellow corn at the 15-day harvest is still in good condition, above 96%.The organic matter content generally experiences an increase when compared to the organic matter content of the corn seeds used in this study (which was 95.75%).As the plant ages, cell walls thicken, forming lignin.Prolonged harvesting age leads to increased ash and mineral content but decreased organic matter.Young plants have active cells, while older plants experience cell wall thickening, resulting in reduced organic matter content.Older plants contain less water and have a higher proportion of cell walls compared to cell contents [8].The loss of organic matter in plants primarily comes from carbohydrates, specifically nonstructural carbohydrates (NSCs) with starch and sugars as the main components, which plants use to fuel metabolic processes for organic matter content formation [9].

Crude fibre content
In this study, the crude fibre content was significantly affected (p < 0.05) by the harvesting age.The fibre content increases as the plant age increases.The increase goes from 3.82% at the 7-day harvest to 19.24% at the 15-day harvest.The longer the harvesting age, the higher the crude fibre content becomes, which is due to the increased number and size of cell walls for carbohydrate synthesis.When plants grow, their cells undergo maturation and the hardening of cell walls.This process involves the accumulation of cellulose, which is the main component of plant fibres.As the plant ages, the increase in coarse fibre content is primarily caused by the accumulation of cellulose in the cell walls.The increase in crude fibre during corn germination can be attributed to the synthesis of structural carbohydrates such as cellulose and hemicellulose [10].

Crude protein content
The research results indicate a significant decrease (p < 0.05) in the crude protein content of HCGF when harvested at older ages.When HCGF is harvested at 15 days of age, there is a decrease of 44.65% (from 20.09 to 11.12%).The high protein content at younger harvest ages can be linked to dry matter loss, particularly carbohydrates, through respiration during germination.Thus, longer germination times might be responsible for greater dry matter loss and the tendency for decreased protein content [6].When plants grow and mature, their cells undergo differentiation, where some cells develop into specialized cells with specific functions.This process of differentiation can lead to a decrease in crude protein content in plants because these cells may be focused on functions and structures that do not require high protein.The alterations in protein levels take place swiftly starting from the fourth day, coinciding with the elongation of the root, enabling the absorption of minerals [11].

Discussion
The decrease in CP and DM content is observed dramatically until the 15th day of harvest.At the beginning of the study (7 days of harvest), the CP and DM content is quite high (25.01 and 20.0%).The decrease in DM can occur due to water soaking during the germination process.Meanwhile, further decrease is related to the conversion of DM into other components as a result of metabolism and photosynthesis.
In order to achieve effective hydroponic fodder production, the crops' fresh yield and DM content hold significance.When the seeds start to sprout, there is a rise in the fresh weight, leading to a subsequent reduction in DM content.This decrease can be primarily linked to water absorption (leaching) and enzymatic processes (oxidation), which diminish the nutritional stores within the seed endosperm.Importantly, the young plant lacks sufficient replenishment from photosynthesis during its brief growing cycle [12].
On the other hand, changes in CP content in maize seeds and the early hydroponic phase (from 11.70 to 20.09%) can occur due to the initiation of leaf formation after maize germination.Leaves contain chlorophyll composed of nitrogen, which is one of the elements readable as CP.However, this CP content will decrease as the plant ages, as cell walls begin to form, which can lower the CP percentage in biomass and increase the percentage of CF.However, sprouting of cereals makes the minerals more available by chelating or merging with the protein [13].

Conclusion
The decrease in CP and DM content is observed dramatically until the 15th day of harvest.At the beginning of the study (7 days of harvest), the CP and DM content is quite high (25.01 and 20.0%).The decrease in DM can occur due to water soaking during the germination process.Meanwhile, further decrease is related to the conversion of DM into other components as a result of metabolism and photosynthesis.

Figure 2 .
Figure 2. The decreasing of HCGF crude protein (CP) and dry matter (DM)

Table 1 .
Nutrient information of yellow-maize seed

Table 2 .
Nutrients quality HCGF of yellow-maize harvested on different age Dry Matter, OM: Organic Matter, CF: Crude Fiber, CP: Crude Protein.Different superscript on same parameter showed significant different (p<0.05)