The fertilizer availability as source of N, P, and K nutrient where plant responsif was difficult found by farmer. Thefore, It was needed information about nutrient availability in soil properties to know nutrient deficiency of its by maize as plant indicator. The objective of this research was to study the respons of N, P, and K fertilizers and the best combination of it on the growth and yield of Maize. The research conducted at Udic Pellusterts in North Isimu Tibawa District of Gorontalo Regency. The experi- mental design was following random block design that consist of 5 treatments with 3 replications. The result of this research showing that minus N, P, and K fertilizers have a significantly effect on plant age polination, the percentage of height stem of an ear of corn to plant height and dry straw weight but did not have significantly effect on plant height and the weigh of one hundred grain of Maize. To improve the growth and yield of Maize using fertilizing without P treatment were 250 kg Urea ha-1 and 75 kg KCl ha-1 or completely dosage were 250 kg Urea ha-1, 100 kg TSP ha-1 and 75 kg KCl ha-1 as the best fertilizers combination.

This research aims to describe changes in the use of organic fertilizers in urban communities, both from the point of view of knowledge and behavior. This research was conducted in the period from February to April 2022. The population is urban in Gorontalo Province, with a random sample of 172 people with various professional characteristics. The research variables include people's perceptions, knowledge, and behavior regarding using organic fertilizers. Data were analyzed using descriptive statistics. The results showed that 95.3% of the urban community's perception of a suitable type of fertilizer chose organic fertilizer over non-organic fertilizer, and from the aspect of knowledge, as much as 69.8% knew the benefits of using organic fertilizer, both for plants and the environment and economic benefits. From the behavioral aspect, 83.7% of people are used to using organic fertilizers, and 62.8% prefer to use organic fertilizers compared to other fertilizers. The market potential for organic fertilizer for urban communities in Gorontalo Province based on aspects of knowledge and behavior is relatively high so that marketing can target urban communities. Communities can use agricultural shops with good reputations or images to obtain or trade organic fertilizers.

Coffee is a national strategic commodity that contributes to Indonesia’s foreign exchange, but its productivity remains low due to cultivation on low potential land. This study aimed to determine the land suitability of endemic liberica coffee using two different methods and formulate recommendations for land management in Pinogu Plateau. Thirteen land units were surveyed, and soil samples were collected and analyzed in the laboratory to identify the land characteristics. Land suitability classes (LSCs) were compared by limiting factor and parametric methods. Analysis using the limiting factor method showed that the actual LSCs for liberica coffee consisted of moderately suitable (S2) and marginally suitable (S3) classes. Efforts for improvement could increase the potential of LSC to became very suitable (S1) and S2 classes. Meanwhile, the assessment with the parametric method indicated that the LSC consisted of S1, S2, and S3 classes. These results revealed that the parametric method provides more realistic land characteristics than the limiting factor method. Land management II or the land that had a little limiting factor turned out to be more dominant with the recommendation of adding P and organic fertilizer.

Lahan kering merupakan salah satu lahan yang potensial untuk pengembangan jagung, tetapi umumnya petani jagung menggunakannya tanpa menerapkan teknik konservasi tanah, sehingga erosi tanah sukar dikendalikan dan produktifitasnya menurun. Penelitian ini bertujuan untuk mendapatkan kombinasi teknik konservasi tanah yang dapat menekan erosi tanah dan meningkatkan hasil jagung. Penelitian ini dilaksanakan di Sub DAS Biyonga Kabupaten Gorontalo. Rancangan penelitian menggunakan rancangan acak kelompok faktorial dengan dua factor, yaitu faktor pertama penanaman menurut kontur dan faktor kedua penanaman dalam strip yang masing-masing factor terdiri dari lima perlakuan pupuk kandang dan mulsa serta masing-masing tiga ulangan. Pengukuran erosi tanah menggunakan petak erosi beserta drum penampung sedimen. Hasil penelitian menunjukkan bahwa penanaman menurut kontur meningkatkan hasil jagung sebanyak ±1,24 kali lebih banyak dibanding penanaman dalam strip, tetapi erosi tanah sebanyak ±1,20 kali lebih banyak dibanding penanaman dalam strip. Hasil jagung tertinggi sebanyak 5,82 ton ha-1 dan erosi tanah sebanyak 1,34 ton ha-1 tahun-1. Sementara, erosi tanah pada penanaman dalam strip hanya 1,08 ton ha-1 tahun-1 dengan hasil jagung sebanyak 4,80 ton ha-1. Dosis pupuk kandang terbaikadalah 10 ton ha-1, sementara untuk mulsa adalah 12 ton ha-1. Kata Kunci: erosi, strip, pertanaman, lahan kering, jagung Abstract Upland is one of land potentials for maize development, but most farmers were using upland without soil conservation, so the soil erosion is difficult controlling and productivity is decreasing. This research was aimed to find of soil conservation technique combinations which can minimize soil erosion and rising of maize yields. This research was carried out in Biyonga Sub-Watershed of Gorontalo Regency. Experimental was conducted in afactorial random block design with2 main factors, where first factor was contour cultivation and the second was strip cropping which each factors consisted of 5 treatments for manure and mulching with 3 replicates. Erosion box and their soil collector were used to measure of soil erosion. Results showed that contour cultivation is ±1.24 higher than strip cropping toincrease maize yields, but soil erosion was ±1.20 higher than strip cropping. The highest of maize yield was 5.82 ha-1 tahun-1 and their soil erosion was 1.34 ton ha-1 tahun-1. Soil erosion on the strip cropping was only 1.08 tonha-1 tahun-1 although maize yields were only 4.80 ton ha-1. The best dosage for manure and mulching were 10 ton ha-1 and 12 ton ha-1.   Keywords: erosion, strip, cropping, upland, maize

Utilization of land resources requires information of the potential and limitations of land use so that the commodity that will be cultivated can achieve optimal yields. The aim of this study was to determine land suitability class of maize (Zea mays L.) of agriculture land in Popayato District, Pohuwato Regensy. This research was conducted from July 2022 to December 2022. Land suitability classes, both actual and potential, were determined based on the matching method between land characteristics of each land unit with the land suitability criteria for maize. The results showed that the actual land suitability class for maize in Popayato District was dominated by marginally suitable (S3 class) respectively at about 95.32% and not suitable (N class) about 4.68% of total area. Limiting factors consisting of class S3 includes: rainfall and humidity, soil depth, base saturation and pH, while the limiting factors in class N was soil depth. After improvement efforts were made, the potential land suitability class for maize plants became S3 class for all land units with an area of 3,587.37 ha.

Black soils store a high amount of soil organic carbon (SOC) and play a crucial role in climate change, food security, and land degradation neutrality. However, data and information regarding black soils in tropical regions, including Indonesia, are limited. This study aimed to characterize and identify the utilization of black soils in Indonesia based on legacy soil survey data. We collated 142 soil pedon samples of Mollisols from articles, technical reports, and existing datasets. The site information (site position, elevation, land use type, parent material) and selected physicochemical properties were stored in a spreadsheet, from which exploratory data analysis was conducted. The result showed that the median SOC content was 1.53%, ranging from 0.6 to 8.2 %; cation exchange capacity was 30 cmol kg-1, ranging from 9 to 95 cmol kg-1; base saturation was 87%, ranging from 11 to 100 %; and bulk density was 1.21 g cm-3, ranging from 1.13 to 1.36 g cm-3. Other soil characteristics (particle size distribution, exchangeable bases, pH, pore, and water retention) varied with horizon type and land use/land cover. The black soils have been used for paddy fields, dryland farming, and gardens with low management intensity. Main cultivated crops include rice (Oryza sativa), corn (Zea mays), cassava (Manihot esculenta), sweet potato (Ipomoea batatas), and nutmeg (Myristica fragrans), clove (Syzygium aromaticum), coconut (Cocos nucifera), and cocoa (Theobroma cocoa). Threats to black soil functions include soil erosion, carbon loss, and nutrient imbalance. Soil and water conservation measures, integrated soil nutrient management, and agroforestry are among the best land management practices for black soils.