Detecting and predicting forest degradation: A comparison of ground surveys and remote sensing in Tanzanian forests

Summary • Tropical forest degradation is widely recognised as a driver of biodiversity loss and a major source of carbon emissions. However, in contrast to deforestation, the more gradual changes from degradation are challenging to detect, quantify, and monitor. Here we present a field protocol for rapid, area-standardised quantifications of forest condition, which can also be done by non-specialists. Using the example of threatened high-biodiversity forests in Tanzania, we analyse and predict degradation based on this method. We also compare the field data to optical and radar remote sensing datasets, thereby conducting a large-scale, independent test of the ability of these products to map degradation in East Africa from space. • Our field data consist of 551 ‘degradation’ transects collected between 1996 and 2010, covering >600 ha across 86 forests in the Eastern Arc Mountains and coastal forests. • Degradation was widespread, with over one third of the study forests – mostly protected areas – having more than 10% of their trees cut. Commonly-used optical remote-sensing maps of complete tree cover loss only detected severe impacts (≥25% of trees cut), i.e. a focus on remotely sensed deforestation would have significantly underestimated carbon emissions and declines in forest quality. Radar-based maps detected even low impacts (<5% of trees cut) in ~90% of cases. The field data additionally allowed to differentiate different types and drivers of harvesting, with spatial patterns suggesting that logging and charcoal production were mainly driven by demand from major cities. • Rapid degradation surveys and radar remote sensing can provide an early warning and guide appropriate conservation and policy responses. This is particularly important in areas where forest degradation is more widespread than deforestation, such as in east and southern Africa

Feasibility study of green harvest technology in the sugarcane farming in Tanzania, under the accompanying measures sugar protocol (2011 – 13)

Report 2017Sugarcane is a tall perennial grass of genus Saccharum. Plant remnants and DNA evidence suggest that sugar cane evolved in South East Asia (Horton et al., 2015), and it was domesticated in Papua New Guinea around 8000 BC (Hartemink and Kuniata 1996). Over the years, the crop has been distributed in other parts of the world including India, China, Europe, Caribbean, Australia, New Zealand, South America, North America and Africa by seafarers, traders, crusaders, colonialists and missionaries (Fischer et al., 2008).Sugar cane performs well in tropical and subtropical climates. The most common cultivated species are S. officinarum L., S. barberi, S. sinense and S. edule. Morphologically, the plant is tall, erecting up to 5 or 6 m with multiple stems, normally branching at the base to make tillers. It is composed of four parts: roots, stalk, leaves and efflorescence (DSD, 2013)

Feasibility study of green harvest technology in the sugarcane farming in Tanzania, under the accompanying measures sugar protocol (2011 – 13)

Report 2017Sugarcane is a tall perennial grass of genus Saccharum. Plant remnants and DNA evidence suggest that sugar cane evolved in South East Asia (Horton et al., 2015), and it was domesticated in Papua New Guinea around 8000 BC (Hartemink and Kuniata 1996). Over the years, the crop has been distributed in other parts of the world including India, China, Europe, Caribbean, Australia, New Zealand, South America, North America and Africa by seafarers, traders, crusaders, colonialists and missionaries (Fischer et al., 2008).Sugar cane performs well in tropical and subtropical climates. The most common cultivated species are S. officinarum L., S. barberi, S. sinense and S. edule. Morphologically, the plant is tall, erecting up to 5 or 6 m with multiple stems, normally branching at the base to make tillers. It is composed of four parts: roots, stalk, leaves and efflorescence (DSD, 2013)

Evaluation of the soil fertility status in relation to crop nutritive quality in the selected physiographic units of Mbeya Region, Tanzania

Second RUFORUM Biennial Meeting 20 - 24 September 2010, Entebbe, UgandaThis study is assessing soil fertility status in Mbeya region of Tanzania in terms of adequacy for crop growth and crop nutrient status in terms of human nutrition. It will examine levels of macro and micronutrient. The study has just been initiated and will run for two years

Pedological characterization of typical soils of Dodoma Capital City District, Tanzania: soil morphology, physico-chemical properties, classification and soil fertility trends

Journal of Annals of Advanced Agricultural Sciences, 2018; 2 (4): 59-73Pedolological characterization was done in Dodoma Capital City District, Tanzania. Three soil profiles developed from in-situ weathering of granic rocks and designated as HIS-P1, HIS- P2 and HIS-P3 were described. Fifteen samples were taken from genetic horizons and analyzed for physical and chemical characteristics. The soils were generally very deep, with varying textures. Whereas profile HIS-P2 was dominantly loamy, profiles HIS-P1 and HIS-P3 were both clayey but the latter had heavy clay type. In profile HIS-P1, clay eluviation-illuviation was a dominant pedogenic process manifested by presence of clay cutans in the subsoil. Profile HIS-P2 displayed redoximorphic features due to fluctuating water table. Shrinking and swelling, and argilli-pedoturbation were typical pedogenic processes in profile HIS-P3. Profile HIS-P1 had more developed structure (subangular blocky) followed by HIS-P3 and lastly profile HIS-P2 which was structureless massive breaking into weak subangular blocks. Whereas topsoil bulk density values of the soils were within acceptable range, subsoil BD values are likely to cause problems of root penetration particularly for deep rooted crops. Profiles HIS-P1 and HIS-P3 may present limitations to crop growth due to high pH values (> 7.5) in the subsoil which may limit availability of plant nutrients e.g. phosphorus. Organic carbon and nitrogen were generally low and very low in all profiles with most values being < 1.25% and < 0.10%, respectively. Availabe P values were low to very low (< 7 mg/kg) throughout the three profiles. Topsoil base saturation values were high (> 50%) in profiles HIS-P1 and HIS-P2 but very high throughout proflie HIS-P3 (83 - 118%). Zn and Fe levels were rated as inadequate for crop production. According to USDA Soil Taxonomy, the soils were classified as Typic Rhodustults (HIS- P1), Fluventic Dystrustepts (HIS-P2) and Chromic Calcitorrerts (HIS-P3) corresponding to Haplic Cutanic Acrisols, Haplic Cambisols and Calcic Mazic Vertisols in the WRB for Soil Resources. The three soils had different physico-chemical properties, hence the need to characterize soils before fertilizer recommendations is met

Growth and yield responses of rice, wheat and beans to Zn and Cu fertilizers in soils of Mbeya region, Tanzania

Low crop production in most arable lands is associated with soils highly depleted of nutrients. A study was conducted in selected physiographic units of Mbeya Region Tanzania, to investigate the levels of soil macro- and micronutrients effect on crops (rice, wheat and beans) performance. Soils were analyzed in the laboratory. Screen-house experiments with three levels of Zn (0, 7.5 and 15 mg kg -1 soil) and Cu (0, 5 and 10 mg kg -1 soil) in combination with N and P treatment in completely randomized design with three replications was conducted. The results showed that all soils were deficient in N, P and Cu, while 46% of soils had low Ca. Zn was low in 46% of the soils while K and Fe was sufficient in all soils. Application of 15 mg kg -1 Zn and 5 mg kg -1 Cu with N and P fertilizers gave significantly highest grain yield of rice (9.05 g pot -1 ), beans (5.80 g pot -1 ) and wheat (5.58 g pot -1 ). The control gave lowest grain yield in all crops. Zink rate of 15 mg kg -1 and Cu rate of 5 mg kg -1 was sufficient to increase yields in these soils. Field experiments are recommended to confirm Zn and Cu fertilizer recommendations

Evaluation of the soil fertility status in relation to crop nutritive quality in the selected physiographic units of Mbeya Region, Tanzania

This study is assessing soil fertility status in Mbeya region of Tanzania in terms of adequacy for crop growth and crop nutrient status in terms of human nutrition. It will examine levels of macro and micronutrient. The study has just been initiated and will run for two years.RUFORU

Pedological characterization of typical soils of Dodoma Capital City District, Tanzania: soil morphology, physico-chemical properties, classification and soil fertility trends

Journal of Annals of Advanced Agricultural Sciences, 2018; 2 (4): 59-73Pedolological characterization was done in Dodoma Capital City District, Tanzania. Three soil profiles developed from in-situ weathering of granic rocks and designated as HIS-P1, HIS- P2 and HIS-P3 were described. Fifteen samples were taken from genetic horizons and analyzed for physical and chemical characteristics. The soils were generally very deep, with varying textures. Whereas profile HIS-P2 was dominantly loamy, profiles HIS-P1 and HIS-P3 were both clayey but the latter had heavy clay type. In profile HIS-P1, clay eluviation-illuviation was a dominant pedogenic process manifested by presence of clay cutans in the subsoil. Profile HIS-P2 displayed redoximorphic features due to fluctuating water table. Shrinking and swelling, and argilli-pedoturbation were typical pedogenic processes in profile HIS-P3. Profile HIS-P1 had more developed structure (subangular blocky) followed by HIS-P3 and lastly profile HIS-P2 which was structureless massive breaking into weak subangular blocks. Whereas topsoil bulk density values of the soils were within acceptable range, subsoil BD values are likely to cause problems of root penetration particularly for deep rooted crops. Profiles HIS-P1 and HIS-P3 may present limitations to crop growth due to high pH values (> 7.5) in the subsoil which may limit availability of plant nutrients e.g. phosphorus. Organic carbon and nitrogen were generally low and very low in all profiles with most values being < 1.25% and < 0.10%, respectively. Availabe P values were low to very low (< 7 mg/kg) throughout the three profiles. Topsoil base saturation values were high (> 50%) in profiles HIS-P1 and HIS-P2 but very high throughout proflie HIS-P3 (83 - 118%). Zn and Fe levels were rated as inadequate for crop production. According to USDA Soil Taxonomy, the soils were classified as Typic Rhodustults (HIS- P1), Fluventic Dystrustepts (HIS-P2) and Chromic Calcitorrerts (HIS-P3) corresponding to Haplic Cutanic Acrisols, Haplic Cambisols and Calcic Mazic Vertisols in the WRB for Soil Resources. The three soils had different physico-chemical properties, hence the need to characterize soils before fertilizer recommendations is met

Morphology, genesis, physico-chemical properties, classification and potential of soils derived from volcanic parent materials in selected districts of Mbeya region, Tanzania

This study clarifies the morphology, genesis, physico-chemical properties and classification of soils developed from volcanic parent materials of Mbeya Region, Tanzania. Six typical pedons (MWK 01, IFIG 02, MKY 03, MWZ 04, KYE 01 and NDE 01), were identified, described and 33 soil samples analyzed for physical and chemical characteristics. Results indicate that all pedons were very deep, with textures ranging between fine and coarse. Soil moisture retention ranged between low and medium (78 - 101 mm/m). Some pedons had volcanic ash layers of varying thicknesses and buried 2BC, 2Bwb or 3Bwb horizons, typical of recent volcanic soils. Topsoils had low bulk and particle densities ranging between 0.70 to 1.26 g cm -3 and 1.95 to 2.55 g cm -3 , respectively. Organic carbon (OC) content ranged from medium to very high (1.29 to 5.58%). The studied pedons had extremely acidic to very slightly acidic pH ranging from 4.02 to 6.58. Cation -1 exchange capacity (CEC) ranged from medium to very high (16.8 - 41 cmol(+) kg soil for -1 topsoils and 21 - 42.6 cmol(+) kg for subsoils). All studied pedons had pH NaF > 9.5, reflecting an exchange complex dominated by amorphous Fe and Al oxides and/or humus complexes. Phosphate retention capacity (PRC) ranged from 25 to 97% and one pedon (MWZ 04) met the andic properties requirement of PRC ≥ 85%. SiO 2, Al 2 O 3 and Fe 2 O 3 ranged from 46.5 to 62.1%, 26.3 to 38.4% and 4.0 to 9.8%, respectively. On the basis of computed Chemical Index of Alteration (CIA), the degree of weathering of the studied pedons followed the trend NDE 01>MKY 03>MKW 01>KYE 01>IFIG 02>MWZ 04. According to USDA Soil Taxonomy, the studied pedons were classified as Alfisols (pedons MKW 01, MKY 03 and NDE 01), Inceptisol (pedon IFIG 02), Andisol (pedon MWZ 04) and Entisol (Pedon KYE 01), respectively correlating to Alisols, Cambisol, Andosol and Umbrisol of WRB for Soil Resources. The studied soils were generally rated as having low to medium fertility

Pedological characteristics and implication on soil fertility of selected soils of Mbeya Region, Tanzania

Understanding the soil origin and its fertility in a given climatic conditions is important for efficient and sustainable utilization of soils. The composition of parent material determines the mineral nutrient content (Nube and Voortman, 2006), and sorption of nutrients, other chemicals and soil organic matter. A recent study in China demonstrated that available Fe and Zn in Xichang city soils differed depending on the nature of the parent rock (Zhang et al., 2012). Time is also essential in determining the stage of weathering, and hence soil properties. The soils of the surveyed areas are derived from volcanic tephra deposits of which are reported to be from relatively old (Upper Miocene to Lower Pleistocene Kitulo and Ngozi volcanoes) to most recent eruptions (Middle Pleistocene to Holocene Rungwe and Kyejo Volcano) (Fontijn et al., 2010). Information on the differences in chemical and other characteristics of the soils derived from these chronologically variable deposits of the area is limited. Mbeya region is among the four regions of Southern Highlands of Tanzania with high agricultural production, supplying major staple food in the country. However, crop yields are still low despite use of NPK fertilizers, contributing to food insecurity in Tanzania. Copper and Zn deficiencies were reported in this area’s volcanic soils about three decades ago, which was associated with nutrient mining (Kamasho, 1980). Yet, to date there is no follow-up studies on the status of these micronutrients in soils. Therefore, there is a need to determine the properties of soils of Mbeya region in relation to their origin and genesis. Mineral malnutrition is also wide spread and it is estimated that about 66% of world population is Fe deficient, over 30% is Zn deficient, 30% is iodine deficient and 15% is selenium deficient (White and Broadley, 2009). In Tanzania about 65% of children under 5 years of age are iron deficient (Fortifying African’s Future, 2009), 58.2% of pregnant women are anemic and 23% of the population are at risk of Zn deficiency (TFNC, 2009). These nutritional health problems can be attributed to low soil mineral content and/or availability to crops (Welch and Graham, 2002). Adequate levels of essential minerals in food crops to satisfy human health requirement is referred to as crop nutritive quality. One way to curb mineral malnutrition is fortification of some staple food with these essential minerals. However, food fortification cannot be expected to reach all populations deficient in essential micronutrients, especially in developing countries, and have challenge of low bioavailability (Hurrell, 1997; Mehasho, 2006). Therefore, there is a need to investigate, systematically, the relationship between soil nutrient contents (both macro- and micro-nutrients) and crop quality as might be related to the potential for agronomic biofortification to improve human nutrition and health. This study was therefore conducted as a contribution to efforts by national and international programs and strategies to attain not only high yields but also nutritional health for poverty alleviation. Therefore, the objective of this study was to determine and assess the pedologicalcharacteristics of soils and their influence on soil fertility and crop quality in selected physiographic units of Mbeya region. Specifically, i) to determine the morphological and physico-chemical characteristics of the soils ii) to determine the mineralogical composition of the soils iii) to determine the extent of weathering, and iv) to determine the implication of soil characteristics on nutrient availability, agricultural productivity and crop nutritive quality.RUFORU