Jurnal Ilmu Tanah dan Lingkungan
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Laju Dekomposisi dan Hara Tersedia dari Pangkasan Tumbuhan Bawah Perkebunan Kelapa
Full text linkThe implementation of organic farming in peatland coconut plantations faces challenges such as the low availability of natural nutrients, restrictions on the use of synthetic fertilizers and pesticides, and the demand for soil fertility conservation to ensure sustainable production. One potential solution is the utilization of undergrowth pruning, predominantly composed of Nephrolepis sp., as a source of organic nutrients.This study aimed to determine the decomposition rate and estimate the nutrient release potential from undergrowth pruning in a coconut plantation on peat soil in Riau Province, Indonesia. The litter bag method was employed with an observation period of eight weeks. Results showed that the decomposition rate of the pruned biomass reached 1.92 g per week, with a dry weight reduction of 68%. The most abundant nutrients released during decomposition were potassium (1.79%), phosphorus (0.07%), and copper (5.68 ppm). These findings suggest that undergrowth pruning has the potential to serve as an alternative nutrient source, supporting environmentally friendly coconut cultivation systems on peatlands.Penerapan pertanian organik di perkebunan kelapa lahan gambut menghadapi kendala berupa rendahnya ketersediaan hara alami, pembatasan pemakaian pupuk dan pestisida sintetis, serta tuntutan konservasi kesuburan tanah agar produksi tetap berkelanjutan. Salah satu solusi potensial adalah pemanfaatan pangkasan tumbuhan bawah yang didominasi oleh Nephrolepis sp. sebagai sumber hara organik. Penelitian ini bertujuan untuk mengetahui laju dekomposisi dan menghitung potensi hara yang dilepaskan dari pangkasan tumbuhan bawah di perkebunan kelapa di lahan gambut, Provinsi Riau. Metode yang digunakan adalah litter bag dengan masa pengamatan selama 8 minggu. Hasil penelitian menunjukkan bahwa laju dekomposisi pangkasan tumbuhan bawah mencapai 1.92 g per minggu dengan penurunan bobot sebesar 68%. Hara yang paling banyak dilepaskan selama proses dekomposisi adalah kalium (1.79%), fosfor (0.07%), dan tembaga (5.68 ppm). Hal ini menunjukkan bahwa pangkasan tumbuhan bawah memiliki potensi sebagai alternatif sumber hara alami dalam sistem budidaya kelapa yang ramah lingkungan di lahan gambut
Comparative Analysis of Segmentation Parameters in Object-Based Image Classification for Land Cover/Land Use in Sumedang Regency
Full text linkInformation on land cover and land use plays an important role in biophysical regional analysis, spatial planning, resource management, and the formulation of sustainable development policies. To support these needs, accurate remote sensing image classification is crucial. The Object-Based Image Analysis (OBIA) approach is considered superior to pixel-based classification, as it provides higher accuracy and minimizes the salt-and-pepper effect. The success of object-based classification is influenced by the segmentation method employed. In this study, two segmentation approaches, namely Original Multiresolution Segmentation (OMN) and Region Grow on Object (RGO), were examined based on combinations of segmentation parameters and evaluated for accuracy using the Random Forest (RF) classification algorithm. The segmentation results indicate that the OMN approach produces smaller and more detailed objects, though they tend to be fragmented, whereas the RGO approach generates larger and more generalized objects with greater spatial stability. Based on object-based classification using RGO segmentation with a scale parameter of 0.5, seven land cover and land use classes were identified, with three dominant categories: plantations (50,393 ha), bare land (29,658 ha), and rice fields (27,092 ha). The classification accuracy of RGO was consistently higher than OMN across all parameter configurations, with the rice field class showing close alignment with official BPS data from 2024, which recorded an area of 30,038 ha. These findings demonstrate that the RGO approach is more effective in producing representative segmentation and classification for land use mapping.Informasi mengenai penutupan/penggunaan lahan memiliki peran penting dalam analisis biofisik wilayah, perencanaan tata ruang, pengelolaan sumber daya, dan perumusan kebijakan pembangunan berkelanjutan. Untuk mendukung kebutuhan tersebut, klasifikasi citra penginderaan jauh yang akurat menjadi krusial. Pendekatan Object-Based Image Analysis (OBIA) dinilai lebih unggul dibandingkan klasifikasi berbasis piksel karena mampu menghasilkan akurasi yang lebih tinggi serta meminimalkan efek salt and pepper. Keberhasilan klasifikasi berbasis objek dipengaruhi oleh metode segmentasi yang digunakan. Dalam penelitian ini, dua pendekatan segmentasi, yaitu Original Multiresolution Segmentation (OMN) dan Region Grow on Object (RGO), dikaji berdasarkan kombinasi parameter segmentasi dan dievaluasi akurasinya melalui algoritma klasifikasi Random Forest (RF). Hasil segmentasi menunjukkan bahwa pendekatan OMN menghasilkan objek yang lebih kecil dan detail, namun cenderung terfragmentasi, sedangkan pendekatan RGO menghasilkan objek yang lebih besar dan tergeneralisasi dengan kestabilan spasial yang lebih tinggi. Berdasarkan klasifikasi berbasis objek menggunakan segmentasi RGO pada parameter scale 0.5, diperoleh tujuh kelas penutupan/penggunaan lahan, dengan tiga kategori dominan yaitu perkebunan (50,393 ha), tanah terbuka (29,658 ha), dan sawah (27,092 ha). Akurasi klasifikasi RGO tercatat lebih tinggi dibandingkan OMN pada seluruh konfigurasi parameter, dengan nilai kedekatan terhadap data BPS tahun 2024 khususnya pada kelas sawah yang tercatat sebesar 30,038 ha. Temuan ini menunjukkan bahwa pendekatan RGO lebih efektif dalam menghasilkan segmentasi dan klasifikasi yang representatif untuk pemetaan penggunaan lahan
Soil Aggregate Stability Index on Agricultural, Plantation, and Forest Lands
Full text linkThe soil aggregate stability index is one of the critical indicators of soil physical quality, primarily related to the soil\u27s ability to absorb water into the soil and the soil\u27s resistance to rainwater splashing and surface flow erosion in the soil erosion process. The study aimed to determine the soil aggregate stability index class criteria using the dry and wet sieving methods on the OSK 10701 sieve type and to identify the stability of soil aggregates on agricultural land, plantations, and forests around the IPB Dramaga campus. The transformation of the soil aggregate stability class criteria from the conventional sieve to the OSK 10701 sieve types gave excellent results with a coefficient of determination (R2) of 0.89. The soil aggregate stability index differs significantly between soil types and land uses. Podsolic Jasinga has a higher aggregate stability index than Podsolik Dramaga, Regosol Dramaga, and Latosol Dramaga in the upper layer (0-20 cm) and the lower layer (20-40 cm). Forests have a better aggregate stability index than conservation agricultural land, conventional agricultural land, rubber plantations, and oil palm plantations. The difference in stability index between land uses is closely related to soil organic matter contents. Although the soil is denser/more compact, the soil in oil palm and rubber plantations has a lower stability index and is classified as unstable.Indek kestabilan agregat tanah merupakan salah satu indikator kunci kualitas fisik tanah khususnya terkait dengan kemampuan tanah dalam meresapkan air kedalam tanah serta ketahanan tanah terhadap daya percik air hujan dan daya gerus aliran permukaan pada proses erosi tanah. Penelitian ditujukan untuk menentukan kriteria kelas indek kestabilan agregat tanah metoda pengayakan kering dan basah pada tipe ayakan OSK 10701 dan mengidentifikasi kestabilan agregat tanah pada lahan pertanian, kebun dan hutan disekitar kampus IPB Dramaga. Transformasi kriteria kelas kestabilan agregat tanah dari tipe ayakan konvensional kedalam tipe ayakan OSK 10701 memberikan hasil yang sangat baik dengan koefisien determinasi (R2) 0.89. Indek kestabilan agregat tanah berbeda nyata antar jenis tanah dan antar penggunaan lahan. Tanah Podsolik Jasinga memiliki kestabilan agregat yang lebih tinggi dibandingkan dengan tanah Podsolik Dramaga, Regosol Dramaga dan Latosol Dramaga baik pada lapisan atas (0-20 cm) maupun lapisan bawah (20-40 cm). Hutan tanaman mempunyai indek kestabilan agregat yang lebih baik dibandingkan dengan lahan pertanian konservasi, lahan pertanian konvensional, kebun karet dan kebun kelapa sawit. Perbedaan indeks kestabilan antar penggunaan lahan berkaitan erat dengan kadar bahan organik tanah. Walaupun tanahnya lebih padat/kompak tanah pada kebun kelapa sawit dan kebun karet mempunyai indek kestabilan yang lebih rendah dan tergolong tidak stabil
Effect of Bio-Organic Fertilizer on Soil Organism in Experimental Oil Palm Plantation Cikabayan, Bogor, Indonesia
Full text linkThe use of chemical-based fertilizer continuously without addition of organic matter may have hazardous effects on the environment. Numerous studies have shown that chemical-based fertilizers may disrupt the balance of soil properties, including physical, chemical, and biological properties. Bio-organic fertilizers have become one of the alternative answers to oil palm sustainability and a replacement for chemical-based fertilizers to promote and provide a better service to the soil and environment. This study aims to analyze the effect of application of biofertilizers combined with different dosages of organic matter (bio-organic fertilizers), i.e. 0 kg tree-1, 6 kg tree-1, and 12 kg tree-1, respectively. The study was conducted in Cikabayan Experimental Oil Palm Plantation, Bogor, West Java with 12 year-old-plant oil palm, from May to November 2023. The study showed an increase in the population density of the soil organisms after application of bio-organic fertilizers, especially with the dose of 6 kg tree-1. The change in the soil fauna community structure was also observed in this study, where Collembola dominated the ecosystem after fertilization. These findings offer practical strategies to mitigate the negative impacts of traditional fertilizers. Moreover, the study highlights the role of bio-organic fertilizers in enhancing soil biodiversity by increasing the populations of beneficial soil organisms.The use of chemical-based fertilizer continuously without addition of organic matter may have hazardous effects on the environment. Numerous studies have shown that chemical-based fertilizers may disrupt the balance of soil properties, including physical, chemical, and biological properties. Bio-organic fertilizers have become one of the alternative answers to oil palm sustainability and a replacement for chemical-based fertilizers to promote and provide a better service to the soil and environment. This study aims to analyze the effect of application of biofertilizers combined with different dosages of organic matter (bio-organic fertilizers), i.e. 0 kg tree-1, 6 kg tree-1, and 12 kg tree-1, respectively. The study was conducted in Cikabayan Experimental Oil Palm Plantation, Bogor, West Java with 12 year-old-plant oil palm, from May to November 2023. The study showed an increase in the population density of the soil organisms after application of bio-organic fertilizers, especially with the dose of 6 kg tree-1. The change in the soil fauna community structure was also observed in this study, where Collembola dominated the ecosystem after fertilization. These findings offer practical strategies to mitigate the negative impacts of traditional fertilizers. Moreover, the study highlights the role of bio-organic fertilizers in enhancing soil biodiversity by increasing the populations of beneficial soil organisms
Monitoring of Ecosystem Services for Water Regulation in the Central and Upper Cisangkuy Watersheds
Full text linkJasa ekosistem pengaturan air di Daerah Aliran Sungai (DAS) Cisangkuy bagian tengah dan hulu mempunyai peran penting untuk kehidupan manusia dan makhluk hidup lain di wilayah bawahnya. Hal ini terkait dengan kebutuhan air sehari-hari ataupun terkait dengan ancaman bencana, dikarenakan kerusakan ekosistem di wilayah atas dapat mendatangkan bencana banjir seperti yang selama ini terjadi di daerah penelitian. Penelitian ini bertujuan memantau jasa ekosistem pengatur air berdasarkan karakteristik biofisik wilayah. Pendekatan yang digunakan berbasis Multi Criteria Evaluation (MCE) terhadap tiga parameter utama yaitu Topographic Wetness Index (TWI), Normalized Difference Vegetation Index (NDVI), dan kemiringan lereng. Data utama yang digunakan adalah DEM SRTM 30m dan citra satelit Landsat 5 TM dan 8/9 OLI-TIRS periode 2000–2024. Hasil kajian menunjukkan bahwa nilai TWI daerah penelitian secara keluasan didominasi oleh kelas “tinggi” (40,72 %) dan “sangat tinggi” (36,79 %). Adapun untuk kelas lereng didominasi oleh kelas “agak curam” (23,09%) dan “curam” (23,07%). Sementara itu untuk kerapatan vegetasi (NDVI) terjadi perubahan luasan yang cukup dinamis. Kelas “sangat rapat” mengalami penambahan luas cukup signifikan dari 0,43 % (2000) menjadi 1,19 % (2004), dan meningkat tajam menjadi 45,26 % (2024). Sementara itu pada kelas “rapat” sempat naik dari 30,53 % (2000) menjadi 38,58 % (2004), namun mengalami penurunan menjadi 26,16 % (2024). Untuk kelas kerapatan “sedang” sempat naik dari 45,05 % (2000) menjadi 47,43 % (2004) namun turun menjadi 18,47% (2024). Dinamika perubahan luas ini berdampak pada nilai jasa ekosistem pengatur air dimana kelas “tinggi” sempat turun dari 37,95% (2000) menjadi 17,23 % (2004), namun meningkat kembali menjadi 37,76 % (2024). Temuan ini menegaskan bahwa telah terjadi perbaikan ekosistem DAS Cisangkuy bagian tengah dan hulu dalam kurun waktu 20 tahun (2004 ke 2024). Diharapkan kondisi ekosistem tetap terjaga atau membaik sehingga dapat menekan dampak banjir wilayah hilir di masa mendatang. Water regulation ecosystem services in the middle and upper parts of the Cisangkuy watershed play a vital role in the lives of humans and other living beings in the downstream areas. This is related to daily water needs as well as the threat of disasters, given that ecosystem damage in the upstream areas can lead to floods, as has frequently occurred in the research area. This study aims to monitor water regulation ecosystem services based on the biophysical characteristics of the region. The approach used is based on Multi Criteria Evaluation of three main parameters: Topographic Wetness Index, Normalized Difference Vegetation Index, and Slope Gradient. The main data used were 30m SRTM DEM and Landsat 5 TM and 8/9 OLI-TIRS satellite imagery for the period 2000–2024. The results of the study show that the TWI values of the research area are spatially dominated by “high” (40.72%) and “very high” (36.79%) classes. For the slope classes, they are dominated by “moderately steep” (23.09%) and “steep” (23.07%) classes. Meanwhile, for vegetation density (NDVI), there was a dynamic change in area. The “very dense” class experienced a significant increase in area from 0.43% (2000) to 1.19% (2004), and sharply increased to 45.26% (2024). Meanwhile, the “dense” class briefly rose from 30.53% (2000) to 38.58% (2004), but then decreased to 26.16% (2024). For the “medium” density class, it briefly rose from 45.05% (2000) to 47.43% (2004) but then decreased to 18.47% (2024). This dynamic change in area impacted the value of water regulating ecosystem services, where the “high” class initially decreased from 37.95% (2000) to 17.23% (2004), but then increased again to 37.76% (2024). These findings confirm that there has been an improvement in the ecosystem of the upper and middle Cisangkuy Watershed over a 20-year period (2004 to 2024). This ecosystem condition is expected to be maintained or further improved to effectively reduce the incidence of floods and their impacts in downstream areas in the future
Efektivitas Mikoriza dan Fosfor dari Batuan Fosfat pada Pertumbuhan dan Hasil Terong Ungu (Solanum melongena L.)
Full text linkDalam percobaan ini dilakukan penelitian pengaruh pupuk hayati mikoriza dan batuan fosfat terhadap pertumbuhan dan hasil tanaman terong (Solanum melongena L.) dengan takaran pupuk yang berbeda. Pupuk hayati mikoriza diberikan ke tanah sebesar 0, 10, dan 20 g per lubang tanam, sementara batuan fosfat yang telah dihaluskan diberikan ke tanah sebesar 0, 45, dan 90 kg P2O5/ha. Interaksi antara mikoriza dan batuan fosfat nyata meningkatkan tinggi tanaman terong, bobot rata-rata terong per buah, dan hasil terong dibandingkan dengan tanpa pemberian pupuk. Aplikasi mikoriza nyata meningkatkan tinggi tanaman terong dan bobot rata-rata terong per buah, sedangkan aplikasi batuan fosfat hanya nyata memengaruhi tinggi tanaman terong. Pada perlakuan tanpa batuan fosfat dengan takaran dua kali mikoriza menunjukkan bahwa bobot rata-rata terong per buah nyata lebih tinggi daripada tanpa aplikasi mikoriza. Hal ini menunjukkan bahwa mikoriza mempunyai pengaruh positif terhadap pertumbuhan dan hasil terong dan pada ketersediaan fosfor bagi tanaman terong.In this study, effect of biofertilizer of mycorrhiza and phosphate rock on growth and yield of eggplant (Solanum melongena L.) under different fertilization rates had investigated. Biofertilizer of mycorrhiza were applied to soil as 0, 10, and 20 g per planting hole, meanwhile grinded phosphate rock were added into soil as 0, 45, and 90 kg P2O5 ha-1. Interaction between mycorrhiza and phosphate rock significantly increased the height of eggplant, average weight of an eggplant, and eggplant yield compared to no fertilization treatment. Mycorrhiza application significantly increased the height of eggplant and the average weight of an eggplant, whereas phosphate rock application affected significantly only on the height of eggplant. In the treatment at 0 doses of phosphate rock with double doses of mycorrhiza showed that the average weight of an eggplant were significantly higher than without mycorrhiza application. It was determined that mycorrhiza had positive effect on growth and yield of eggplant and phosphorus bioavailability to eggplant
Land Cover/Use Classification at Landsat 8 with Random Forest and Support Vector Machine Algorithm in Sumedang Regency, West Java
Full text linkKabupaten Sumedang merupakan salah satu kabupaten terpilih dalam proyek strategis nasional, berupa pembangunan Waduk Jatigede dan Jalan Tol Cisumdawu. Pembangunan tersebut menyebabkan alih fungsi lahan pertanian, sehingga dibutuhkan pemantauan penutupan/penggunaan lahan secara terukur. Penelitian ini bertujuan mengidentifikasi pola reflektan setiap penutupan/penggunaan lahan dan membandingkan hasil klasifikasi penutupan/penggunaan lahan di Kabupaten Sumedang pada tahun 2023 dengan pendekatan RF dan SVM. Pola reflektan penutupan/penggunaan lahan bersifat khas, tetapi kemiripan pola reflektan dapat dijumpai pada penggunaan lahan sawah dan ladang/tegalan. Kemiripan pola reflektan tersebut menyebabkan tingginya kerentanan misklasifikasi pada penutupan/penggunaan lahan. Pendekatan RF dan SVM menghasilkan akurasi klasifikasi yang tinggi, yaitu sebesar 93,6% dan 98% masing-masing untuk RF dan SVM. Perbedaan luasan hasil klasifikasi RF dan SVM terjadi sebesar 34,64% karena adanya perbedaan cara kerja klasifikasi. Perbedaan luasan klasifikasi RF dan SVM terbesar terdapat pada penggunaan lahan sawah, yaitu masing-masing sebesar 11.136 hektar dan 31.445 hektar.
Kata Kunci : proyek strategis nasional, pola reflektan, machine learningSumedang Regency is one of the selected regencies in the national strategic project, in the form of the construction of the Jatigede Reservoir and the Cisumdawu Toll Road. This development has a negative impact on the agricultural sector because it causes a change in the function of agricultural land, so that measurable monitoring of land cover/use is needed. This study aims to identify the pattern of reflectance values for each land cover/use and compare the RF and SVM approaches in the classification of land cover/use in Sumedang Regency in 2023. The pattern of reflectance values for each land cover/use is unique, but the use of rice fields and fields/dry fields has a similar pattern and is more susceptible to misclassification. The RF and SVM approaches produce high classification accuracy, which is 93.6% for RF and 98% for SVM. The difference in RF and SVM classification results is 34.64%. This difference occurs due to differences in the way the classification works.
Keywords : national strategic project, reflectance pattern, machine learnin
Analysis of Soil Quality Index and Its Relation to Fruit Crop Productivity
Full text linkSoil quality is a determining factor for crop production. Therefore, proper assessment of soil quality—by integrating various soil characteristics into a Soil Quality Index (SQI)—is essential to reflect overall soil productivity. This study aimed to determine the SQI and its relationship to fruit crop productivity across seven locations with varying soil characteristics. The research was conducted at SMK PP Saree and SMKN Nisam in Aceh Province; SMKN Gelumbang and SMKN Banyuasin 3 in South Sumatra Province; SMKN Metro and SMKN Gedong Tataan in Lampung Province; and SMKN Kelapa in Bangka Belitung Province. The SQI analysis used eight key soil parameters considered critical for determining and managing crop growth and productivity, namely: effective soil depth, texture, bulk density, pH, organic matter content, cation exchange capacity (CEC), and base saturation. Each parameter was scored on a scale from 0 to 5. The results showed that the Soil Quality Index can effectively assess soil quality using these eight key parameters as a dataset. The studied soils were categorized as having medium to very good quality, with low organic carbon and low CEC identified as the most common limiting factors. Furthermore, the SQI demonstrated a strong positive correlation with fruit crop performance, with a correlation coefficient (r) of 0.832.Kualitas tanah merupakan salah satu faktor krusial yang berpengaruh terhadap produksi tanaman. Oleh karena itu, diperlukan suatu asesmen yang mengintegrasikan karakteristik tanah guna memperoleh gambaran menyeluruh tentang kualitas tanah dalam bentuk Indeks Kualitas Tanah (IKT), yang secara akurat dapat merefleksikan produktivitas tanah. Penelitian yang bertujuan untuk menentukan IKT serta hubungannya dengan produktivitas tanaman buah telah dilaksanakan di tujuh lokasi dengan karakteristik tanah yang berbeda. Ketujuh lokasi tersebut mencakup SMK PP Saree dan SMKN Nisam di Provinsi Aceh, SMKN Gelumbang dan SMKN Banyuasin 3 di Provinsi Sumatera Selatan, SMKN Metro dan SMKN Gedong Tataan di Provinsi Lampung, serta SMKN Kelapa di Provinsi Bangka Belitung. Analisis IKT dilakukan dengan menggunakan delapan karakteristik tanah yang memiliki peran penting dalam menentukan pertumbuhan dan produksi tanaman, yaitu kedalaman efektif, tekstur, bobot isi, pH, kandungan bahan organik, kapasitas tukar kation, serta kejenuhan basa sebagai parameter indikator. Setiap parameter diberikan skor dalam rentang 0 hingga 5. Hasil penelitian menunjukkan bahwa IKT yang diperoleh dari delapan parameter utama secara akurat mencerminkan kualitas tanah. Tanah yang dianalisis memiliki kualitas yang tergolong sedang hingga sangat baik, dengan kandungan bahan organik yang rendah serta kapasitas tukar kation sebagai faktor pembatas utama. Indeks Kualitas Tanah yang diperoleh menunjukkan korelasi yang sangat baik dengan performa tanaman buah, dengan nilai koefisien korelasi (r) sebesar 0,832
Determination of the Critical Limit of Phosphorus for Shallot Growth in Brebes Regency, Central Java
Full text linkIntensifikasi pemupukan yang berimbang merupakan salah satu cara untuk meningkatkan mutu bawang merah dan produksi guna memenuhi permintaan pasar. Guna mencapai hasil panen yang optimal, ketersediaan fosfor (P) tanah harus berada di atas tingkat kritis. Penelitian ini bertujuan untuk menentukan batas kritis hara P dan menentukan pengekstrak terbaik di antara Bray 1, Olsen, Mehlich I, dan HCl 25% serta mengevaluasi pengaruh pemupukan P terhadap pertumbuhan tanaman bawang merah di Kabupaten Brebes, Jawa Tengah. Penentuan batas kritis P di tanah dilakukan dengan mengekstrak P tanah dari 16 lokasi yang tersebar di Kabupaten Brebes. Pemupukan P dilakukan dengan pemberian larutan KH2PO4 sebanyak 0, ½X, X, dan 2X dimana X adalah dosis pupuk P anjuran dalam bentuk P2O5sebesar 120 kg ha-1. Tanaman dipanen biomasanya berumur enam minggu setelah tanam. Batas kritis P tanah ditetapkan menggunakan metode Cate dan Nelson. Hasil penelitian menunjukkan bahwa setiap ekstraksi P memiliki nilai koefisien korelasi berbeda yang dipengaruhi oleh pengekstraknya. Koefisien korelasi antara kandungan hara P tanah yang diekstrak menggunakan metode Bray 1, Olsen, Mehlich I, dan HCl 25% dengan bobot kering tanaman berturut-turut adalah 0,630, 0,341, 0,821, dan -0.089. Nilai korelasi untuk metode Bray 1 dan Mehlich 1 dengan bobot kering tanaman secara statistik berturut-turut nyata dan sangat nyata. Batas kritis kandungan P tanah untuk mencapai 90% produksi relatif bawang merah di kabupaten Brebes tersebut berdasarkan metode Bray 1 dan Mehlich 1 yaitu 40 ppm P. Pengekstrak P tanah di Brebes yang paling baik adalah Mehlich 1. Pemupukan disarankan pada tanah-tanah dengan kadar P tanah kurang atau sama dengan 40 ppm P.Intensification of balanced fertilization is one way to improve shallot quality and production to meet market demand. In order to achieve optimal crop yields, soil phosphorus (P) availability must be above a critical level. This study aimed to determine the critical limit of the P nutrient and determine the best extractor between Bray 1, Olsen, Mehlich I, and 25% HCl and evaluate the effect of P fertilization on the growth of shallot plants in Brebes Regency, Central Java. Determination of the critical level of P in the soil was determined by extracting soil P from 16 locations spread across Brebes Regency. P fertilization was carried out by applying KH2PO4 solution as much as 0, ½X, X, and 2X where X is the recommended dose of P fertilization in the form of P2O5 of 120 kg ha-1. The plants were harvested six weeks after planting. The critical level of soil P is determined using the Cate and Nelson method. The results showed that each P extraction had different correlation coefficient values influenced by the type of extractants. The correlation coefficients between soil P nutrient content extracted by Bray 1, Olsen, Mehlich 1, and HCl 25% methods and plant dry weight were 0.630, 0.341, 0.821, and -0.089, respectively. The correlation values for Bray 1 and Mehlich 1 methods with plant dry weight were statistically significant and highly significant, respectively. The critical limit of soil P content to achieve 90% of relative yield of shallots in Brebes district based on Bray I, and Mehlich I methods were 40 ppm P. The best soil P extractant in Brebes was Mehlich 1. Fertilization was recommended on soils with soil P content less or equal to 40 ppm P
The Spectral trends of cabbage (Brassica oleracea L.) at different fertilization levels
Full text linkSayuran kubis merupakan salah satu komoditas hortikultura penting yang banyak disukai sebagai lalapan atau olahan lainnya karena memiliki rasa manis yang ringan. Untuk memenuhi kebutuhan nutrisi tanaman kubis selama proses pertumbuhan pemberian pupuk merupakan praktek umum di masyakat. Mengidentifikasi, mengkarakterisasi, dan memantau tanaman sayuran campuran di lahan menggunakan menggunakan metode tradisional merupakan suatu tantangan. Pengamatan dengan data satelit optik multispektral, hiperspektral atau proximal sensing seperti spektroradiometer telah banyak digunakan untuk indetifikasi, karakterisasi dan memantau tanaman di lahan pertanian. Akan tetapi, penelitian identifikasi, diskriminasi dan pemetaan kuantitatif profil spektral kubis di Indonesia menggunakan spektroradiometer masih terbatas. Penelitian ini bertujuan untuk mengidentifikasi profil respon spektral tanaman kubis yang ditanam di lahan sempit menggunakan spektroradiometer dan untuk menganalisis respon spektral kubis terhadap perlakuan tingkat pemupukan yang berbeda. Hasil penelitian menunjukkan tren spektral tanaman kubis pada semua fase pertumbuhan memiliki tren yang mirip dengan perubahan spektral dari vegetasi hijau. Reflektansi kubis rendah pada panjang gelombang cahaya tampak dan tinggi pada panjang gelombang tepi merah dan infra merah dekat. Perlakuan pemupukan berpengaruh nyata terhadap spektral kubis pada taraf 5%. Pada fase tumbuh yang sama dengan semakin tinggi dosis pemupukan, semakin tinggi reflektansi gelombang cahaya tampak (biru, hijau dan merah), tepi merah dan infra merah dekat. Variasi nilai reflektan yang stabil meningkat pada gelombang cahaya tampak, tepi merah dan infra merah dekat ini diinterpretasi menunjukkan status pertumbuhan kubis yang baik. Pada tahapan fase tumbuh, dengan bertambahnya umur tanaman terlepas dari tingkat pemupukan, reflektansi kubis pada gelombang biru dan merah sedikit menurun, sebaliknya reflektansi kubis pada tepi merah dan infra merah dekat semakin meningkat hingga mencapai puncaknya pada 45 hari setelah tanam dan menurun setelah 63 hari setelah tanam.Cabbage is one of the important horticultural commodities that are widely preferred as fresh vegetables or other processed foods because it has a mild sweet taste. To meet the nutritional needs of cabbage plants during the growth process, fertilizer application is a common practice in the community. Identifying, characterizing, and monitoring mixed vegetable crops in fields using traditional methods is a challenge. Observations with multispectral, hyperspectral or proximal sensing optical satellite data such as spectroradiometers have been widely used for identification, characterization and monitoring of plants in agricultural land. However, research on identification, discrimination and quantitative mapping of cabbage spectral profiles in Indonesia using spectroradiometers is still limited. This study aims to identify the spectral response profile of cabbage plants planted in narrow land using the spectroradiometer and to analyze the spectral response of cabbage to different fertilization level treatments. The results showed that the spectral trend of cabbage plants at all growth phases had a trend similar to the spectral changes of green vegetation. Cabbage reflectance is low at visible light wavelengths and high at red edge and near infrared wavelengths. Fertilization treatment significantly affected the cabbage spectral at the 5% level. At the same growth phase with the higher dose of fertilizer, the higher the reflectance of visible light (blue, green and red), red edge and near infrared. Variation of stable reflectance values increased in visible light waves, red edge and near infrared is interpreted to indicate good growth status of cabbage. At the growth phase stage, with increasing age of plants regardless of fertilization level, the reflectance of cabbage in blue and red waves decreased slightly, on the contrary the reflectance of cabbage in red edge and near infrared increased until it reached its peak at 45 days after planting and decreased after 63 days after planting