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Upland has potential uses for agriculture practices in indonesia. However there are some problems to manage, one of them is many existing upland in sloping areas and high risk to erosion and runoff. Indonesian Soil Research Institute developed a recommendation model for the land management information system (SILAHAN) based on the study of criteria for soil conservation indicators with calculation of erosion hazard index and surface runoff. The aim of this study was to validation SILAHAN prediction models from surface runoff aspects on a plot scale as the basis for formulating recommendations for the most complex land management technology. Validation of the prediction results of surface runoff in SILAHAN model is done by comparing surface runoff results of real measurements in field with the results of predicted by SILAHAN with three simulation. The results of statistical tests with r pearson correlation coefficient is 0,31, 0,31, and 0,32, PBias is -90,6, -86,6 and -83,5, and NSE is -0,76, -0,68, and -0,63. The results of the prediction of plot scale surface runoff in the SILAHAN model were not same as the measurements result on the field observations. it is suggested to determine the correction factors and development capabilities of the SILAHAN model to assess the effectiveness of a land management system in reducing the amount of surface runoff.

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Low inputs of smallholder plantation in drained peatland causes the low oil palm yield. Extreme environmental factors in tropics, such as excessive rainfall, may also reduce the yield. The research objective was to evaluate the effect of the amount of rainfall on oil palm fresh fruit bunch (FFB) yield. Two study sites with different drainage condition of well (WD) and fair (FD) drained oil palm plantations on peatland was carried out from 2018 to 2019 in Jambi Province, Indonesia. The daily rainfall was monitored using a manual rain gauge. FFB yield was monitored every two weeks, following the farmer’s practice. This study showed that the excessive amount of rainfall in WD plantation site decreased FFB yield in the subsequent weeks after the rainfall events. The higher the amount of rainfall the longer the recovery of FFB yield occurs. The lowering FFB yield was possibly affected by nutrient deficiency due to nutrient transportation through water movement during the event of high rainfall amount. The FFB yield in the FD site was not affected by rainfall, reflected the higher nutrient availability of FD compared to that of WD. Based on these findings, it is confirmed that well-drained agricultural peatland is a fragile ecosystem in terms of nutrient loss.