Changes in land use will impact on the characteristics of humic acid in the soil due to biotic and abiotic factors. The study aimed to characterize humic acid in soil from various land uses in Tutur District, Pasuruan Regency of East Java. Soil sampling was carried out on six land uses, namely mixed garden, coffee plantation, apple orchard, vegetable garden, pine forest, and conservation forest. Analysis of soil samples included soil chemical characteristics (pH, redox, organic-C, and total-N) and characterization of humic acid included colour ratio of E4/E6, total acidity, carboxyl groups, and phenolic groups. The results showed that the land use of coffee plantation provided the best soil fertility indicated by the contents of humic acid, total-N, organic-C in the soil that were higher than that of other land-uses. The highest humification index was obtained for coffee plantation land use with the measurement of the E4/E6 colour ratio of 4.56 index value. The best characteristics based on the total value of acidity, the -COOH group and the phenolic -OH group were observed in the coffee plantation. This was supported by the characteristic of humic acid through the humification index or E4/E6 colour ratio, as well as the low phenolic -OH value which is a characteristic of fulvic acid.

Sandy loam soils contain low organic carbon and have low ion adsorption capacity. Under certain conditions, the soils contain heavy metals that are harmful to plants. Soil amendments such as biosilica and humic acid from natural sources are expected to increase the soil adsorption capacity to heavy metals. A simulation experiment consisting of two factors was conducted to explore the effectiveness of humic and biosilica, as soil amendments, in adsorbing heavy metals from soils. The first factor was biosilica dose composing 0 t ha^-1 (S0), 0.5 t ha^-1(S1), 1 t ha^-1(S2), and 1.5 t ha^-1(S3). The second factor was the humic acid dose composing 0 kg ha^-1 (H0), 20 kg ha^-1 (H1), 40 kg ha^-1 (H2), and 60 kg ha^-1 (H3). The humic acid and biosilica were applied to soil contaminated with Pb and Cd. The results showed that the combination of 0.5 t biosilica ha^-1 (S1) and 20 kg humic acid ha^-1 (H1) significantly increased soil pH, organic C content, cation exchange capacity, and reduced the availability of Pb and Cd at 90 days after treatment. The Pb and Cd contents in plant tissue decreased from roots to grains. Humic acid treatment was more effective in absorbing Pb of 86.89-90.49% and Cd of 71.47-76.33% than other treatments.

Pakan ternak ayam sangat penting untuk meningkatkan produktivitas maupun kualitas ayam, Pemberian pakan secara manual kurang efektif dan kurang efisien, baik dari sisi efisiensi jumlah pakan maupun kebutuhannya akan tenaga kerja. IoT merupakan teknologi yang dapat mengakses data kapan saja dan dimana saja dengan menggunakan perangkat ponsel. Salah satu pemanfaatan IoT adalah monitoring di bidang lingkungan, termasuk diantaranya adalah di bidang peternakan. Pemanfaatan Internet of Things (IoT) dalam pemberian pakan merupakan terobosan dan solusi tepat dalam mengatur jadwal pemberian dan jumlah pakan ternak ayam. Jumlah pakan disesuaikan dengan usia dan jumlah ayam dalam kandang. Prototype dengan memanfaatkan internet dan sensor, mikrokontroller, modul RTC, serta NodeMCU merupakan terobosan penting mengendalikan dan mengatur pemberian pakan. Sensor merupakan pendeteksi pakan dalam wadah pakan ternak, sedang modul RTC untuk menjadwal pakan, serta mikrokontroller merupakan pengendali utama. Data yang diperoleh dari sensor akan dikirimkan ke cloud data server yang kemudian diteruskan ke ponsel sehingga peternak dapat memantau ketersediaan pakan dan status pemberian pakan dari jarak jauh. Selain itu pemberian pakan juga dapat dilakukan dari jarak jauh melalui aplikasi yang sudah disediakan dalam ponsel. Hasil uji dan implementasi di kandang ternak ayam memperlihatkan bahwa penggunaan alat pakan ternak otomotis berbasis IoT sangat efektif untuk memantau ketersediaan pakan