Development of crop functions for estimating crop and soil management factors of the universal soil loss equation for soil erosion prediction under Tanzanian conditions

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dc.contributor.authorMgina, Christian Alphonce
dc.date.accessioned2026-03-09T10:03:59Z
dc.date.available2026-03-09T10:03:59Z
dc.date.issued2000
dc.descriptionMaster's Dissertation
dc.description.abstractOne of the appropriate tools for predicting soil erosion in planning for soil conservation measures is by the application of soil erosion predictive equations or models. Although many equations do exist for use in soil erosion prediction, they cannot be directly applied to Tanzanian conditions since their developments were done in conditions different from the ones existing in Tanzania. Therefore, it is increasingly acknowledged that such equations are inapplicable for use in predicting soil erosion for Tanzanian conditions. This study was conducted at SUA farm runoff plots with the aim of developing crop functions, as useful data in estimating the crop and soil management factor, C, of the USEE or its revised version (The RUSLE) for its adaptation for use under Tanzanian conditions. Crop height development and canopy curves for maize and sorghum crops were developed using the data collected during the 1998 season and functions relating crop height and crop canopy cover with yield for a three year period (1994, 1995 and 1998) were developed. All the equations developed gave relatively high coefficients of determination (0.72 - 0.99) which were significant at the 95 % level (a = 0.05). The equations developed show that there exists a relationship between crop canopy cover and crop height with yield for both maize and sorghum crops (equations 4.4 to 4.6). Moreover, there exists a relationship between maximum crop height attained by each crop with die final crop canopy cover (equations 4.8 and 4.9). The predicted seasonal crop and soil management factor, C for 1998 season wasestimated using the sub-factor method. The predicted and measured C factor values for maize crop for the 1998 season were 0.147 and 0.086, respectively. For sorghum crop. the values obtained were 0.158 and 0.100. respectively (Table 4.3). Also, a crop development curve was estimated from the developed functions relating yield and crop growth parameters (canopy cover and crop height) and the average curve which related the crop development ratios to crop growth period ratios. This curve was used to estimate the long term C factor value. From the growth curve, the value of 0.136 was estimated (Table 4.4). This value was reasonable when compared to the estimated C factor values for individual years. This suggests that the method can be used to establish average crop growth curves in terms of height and cover for any given crop yield level useful in predicting the crop and soil management factor, C. However, prediction of the crop and soil management factor, C, is appropriate provided that sufficient data bank is available. Thus, research to collect such information is required if soil loss prediction equations are to be locally applicable for their use for practical soil conservation planning in Tanzania.
dc.description.sponsorshipSACCAR/GTZ
dc.identifier.urihttps://www.suaire.sua.ac.tz/handle/20.500.14820/7371
dc.language.isoen
dc.publisherSokoine University of Agriculture
dc.subjectCrop functions
dc.subjectEstimating crop
dc.subjectSoil management factors
dc.subjectUniversal soil loss equation
dc.subjectSoil erosion prediction
dc.subjectTanzanian
dc.titleDevelopment of crop functions for estimating crop and soil management factors of the universal soil loss equation for soil erosion prediction under Tanzanian conditions
dc.typeThesis

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