No abstract

This paper discusses the setting up of a multivariate statistical method in selecting the useful soil quality indicators for soil quality assessment under agroforestry pattern. The of soil quality has been recognized as a tool to determine the sustainability of land resources, especially in agroforestry development. The study was carried out at Upper Citarum Watershed of Bandung district, West Java province, Indonesia. The soil samples were taken with purposive sampling under agroforestry pattern. Principal component analysis (PCA) was used as the multivariate statistical method to identify the minimum data set (MDS); scoring of each indicator, and data integration in the index of soil quality. The MDS consisted of four soil chemical indicators and represented 83.6% of the variability of data, i.e., pH, and exchangeable Calcium (exch Ca), organic Carbon (org C), and exchangeable Natrium (exch Na) respectively. The soil quality index (SQI) was categorized under agroforestry pattern as moderate. The artificial agroforestry-based coffee with an intercropping system (timber woods, multi purpose trees and horticultures) provides better soil quality.

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Land conditions in the upper Citarum watershed have been increasingly critical in recent times, causing various problems, especially the high erosion that is considered one of the factors causing river sedimentation and triggering flood. Agroforestry has provided a positive impact on the soil conservation aspect. The dense and critical land in the Upper Citarum watershed has been converted to agroforestry in the last decades. This study aims to estimate the rate of soil erosion of different agroforestry land systems at the Upper Citarum watershed using the MUSLE model. The results show that the surface runoff and soil erosion in forest-based agroforestry systems with intercropping patterns is lower than in farm-based agroforestry.

The Si-available (Siap) content in the soil of paddy fields is decreasing, so it will affect decreasing the productivity of paddy fields. Soil type maps can be used to estimate the potential Siap content in paddy fields. The purpose of this study was to assess the productivity of the paddy field in West Java Province based on the Siap potential in each region using maps of soil types and paddy productivity data. This research was conducted in West Java Province. The research was carried out from February 2021 to March 2021. The research method used was the descriptive research method. This research is secondary data analysis so that no field test is carried out. The validation of the data from the analysis was based on the literature from the previous researchers. The parameters measured in this study were: the distribution of paddy fields, the percentage of soil types in each paddy field, the average productivity of paddy field on each type of soil, the distribution of paddy productivity levels, the potential for Siap to paddy productivity and map of the potential distribution of Siap in West Java Province. Secondary data obtained were then analyzed using spatial analysis and descriptive analysis. The results of the spatial analysis show that 77% of paddy fields in West Java have medium Siap potential, 17% low and 7% high. The results of the correlation analysis show that the productivity of paddy plants has a strong correlation (r = 0.99) to the Siap of paddy soil. The soil maps can be used to estimate the potential of Siap and the productivity of paddy plants. The Si application was recommended in paddy fields in the southern region of West Java Province.

Land use change has long been a problem in West Java, especially in Bandung district (Kabupaten Bandung), a hinterland and buffer area for the Bandung Metropolitan and one of the major crop district in West Java province.  Land use conversion caused the decrease of soil productivity and land availability for agricultural activity especially for food crops, the land reduction is unable to compensate the need of food availability.The research in this study has been done by using descriptive and comparative survey method to study land characteristic and status of land availability in Kabupaten Bandung and its contribution food crop development. The results showed that soil fertility status in Bandung district varies from very low to high. Soil pH conditions ranged from acid to neutral. The actual availability of land for food crops currently stands at 52,790 hectares, with paddy fields as current land use. Availability of potential land for food crops are 64,970 hectares with the current type of land use in the form of bushes and plantations.  Keywords: characteristics, availability, land use conversion, land, district Bandung

Abstrak. Pada sistem hidroponik, pemberian pupuk anorganik dan pupuk hayati dilakukan untuk meningkatkan hasil tanaman karena pupuk anorganik menyediakan unsur hara dan pupuk hayati menghasilkan fitohormon yang meningkatkan pertumbuhan tanaman. Penelitian ini bertujuan untuk mengetahui pengaruh pemberian pupuk hayati yang dikombinasikan dengan pupuk anorganik terhadap populasi bakteri pelarut fosfat, kandungan fosfat (P) dan hasil tanaman tomat. Penelitian ini dilakukan menggunakan rancangan acak kelompok (RAK) dengan 7 perlakuan kombinasi pupuk anorganik (konsentrasi 100%, 75%, dan 50%), pupuk hayati (konsentrasi 100%, 75%, 50%, dan 25%) 4 ulangan. Data yang diperoleh dianalisis secara statistik untuk melihat pengaruh perlakuan. Hasil percobaan menunjukkan bahwa kombinasi pupuk anorganik dan pupuk hayati menunjukkan hasil yang tidak berbeda nyata terhadap populasi bakteri pelarut fosfat, kandungan P, dan hasil tanaman tomat pada sistem hidroponik. Kata kunci : hidroponik, pupuk hayati, tanaman tomat.Abstract. At hydroponic systems, the granting of inorganic fertilizer and biofertilizer is done to increase crop yield due to inorganic fertilizers provide nutrient elements and biofertilizer produce fitohormon that improve plant growth. This research aims to know the effect of biofertilizer on phosphate solubilizing bacteria's population, phosphate (P) content of plant, and yield of tomatoes plant in a hydroponic systems. This research was conducted using Randomized Block Designwith 7 treatments combination consisted of inorganic fertilizer (concentration 100%, 75% and 50%) and biofertilizer (100%, 75%, 50%, and 25%) with 4 replications. The result showed that the combination of inorganic fertilizer and bifertilizer on tomatoes plant in hydroponics system does not show the significant result on phosphatesolubilizing bacteria's population, phosphate content of plant, and yield of tomatoes plant (Lycopersicon esculentum Mill.).

Land resource potential is possessed by Subang regency as valuable capital for regional development. According to the Ministry of Environment, land management and land use overrated for agricultural production and forest production can be caused land degradation that can be lowered soil quality and soil functionality. Soil degradation parameters from Ministerial Regulation Number 07 the year 2006, were minimum standard criteria. Determination of soil degradation by using a score will generate errors was quite large, so it was necessary modified the methods and parameters of the land degradation assessment. The method used was descriptive survey method, sample location was determined by purposive sample using based work map. The observed data and laboratory test results are then analysed using a step-wise discriminant analysis method. The results of discriminant analysis obtained eight parameter of 16 parameters tested, respectively: soil depth (X1), soil permeability (X2), soil acidity or pH (X3), soil potential redox (X4), soil conservation method (X5), rainfall (X6), slope (X7) and C-organic (X8). The resulting discriminant equation D1 = -23.987 + 0.028 X1 + 0.049 X2 - 0.847 X3+ 0.038 X4 - 6,354X5 + 0,007 X6+ 0,033 X7 - 0,206 X8 (r = 0.99; R = 0.98).