National Environment (Minimum Standards for Management of Soil Quality) Regulations

- Hooding N.F Slight or less - internal drainage Mod. Mod. Rapid Slow to very rapid Slow to very rapid Very slow to - natural drainage Good Good Mod. Imperfect Very poor

- lop soil texture (0-25 cm) SL-CL I.S-C S-C S-C CM to S sub soil texture (25 100 cm) SI.-Cl. LS-C LS-C S-C CM to S ■ suilace sloniness (vol%) <0.01 0.01 -0.1 0.1- 3.0 3-15 >15 - subsurface coarse fragments 0-5 5-15 15-50 20-25 >25 ( voPa )

•1. Salinity /alkalinity ..,-100 cm) - F.c minhos/cm <1 1-4 4-8 8-15 >15 - ESP (0-100 cm) <1 4-10 10-20 20-25 >25

Nl;: No blooding. Mod: Moderate. SL: Sandy Loam. LS: Loamy Sand. CL: Clay Loam. C: Clay Cm: Massive Clay. S: Sand. ESP: Exchangeable Sodium Percentage. EC: Electrical Conductivity. Note: Internal drainage means soil conditions where there is internal impediment of waler How. Natural drainage means downward movement of water within (he soil horizons by gravity.

1 •'!RST SCI IIiD(JLIi Regulations 4,7 and 9

- Flooding 3-4 months 3-4 months <2 months <! months Too short - Drainage Poor Poor to imperfect V.Poor to V. Poor to operate V. Poor moderate

' Physical - .surface text/structure CM to SiCs CM to SCL cm to sr CM to sr CM to Sc - subsurface text CM to LSf CM to Sc •1. Salinity /alkalinity Fc mmho.s/cm <1 <1 <6 <6 <6 - FSP(%) <4 <10 <20 <25 <25

Note: CM: Massive Clay. SiCs: Silly Clay Blocky. SCL: Sandy Clay. Loam. Si*: Fine Sand Sc : Coarse Sand. LSf: Loamy Fine Sand. N.L: Not Limiting. V .P: Very Poor. MO: Months.

FIRST SCHEDULE Regulations 4,8 and 9

- Flooding N.L. N.L. 3-4 months 3-4 months Too short or too long - Drainage Mod. to IP Good lo Poor Good to V.P

- surface lexl/slruclure CM to SiCs CM to SCL CM to SI' cm to sr CM to SC ■ subsuilace tc.xluie/shucluic CM to LSI' CM lo SC

•1. Salinity /alkalinity - lie nuiihos/cni <2 <4 <6 <6 <6 - li.SP(%) <10 <20 ' <35 <35

CM: Massive Clay. SiCs: Silly Clay blocky. SCL: Sandy Clay Loam. SI': Fine Sand. SC: Coarse Sand LSI': Loamy Fine Sand. N.L: Not Limiting. LSI': Loamy Fine Sand. N.L: Not Limiting. V.P: Very Poor I.P: Impermeable.

SECOND SCHEDULE Regulation 9 (2)

GUIDELINES FOR MANAGEMENT OF FRAGILE OR PECULIAR SOILS

PARTI

A. Acid sulphate soils (Sulfaquents) Acid sulphate soils form when the quantity of sulphuric acid, formed by oxidation of reduced sulphur compounds, exceeds the acid neutralizing capacity of absorbed bases and easily weatherable minerals to the extent that the pH drops below 4. Potential acid sulphate soils become acidic as a result of drainage because the reduced sulphur compound (pyrite) is very stable under anaerobic condition.

Pyritic papyrus peats are common in Uganda (e.g. Kabale swamps). Accumulation of ferrous monosulfide (FeS) and ferrous disulphide or pyrite (FeS2) occur in a highly-reducing environment (anoxic). This process is especially prominent in the presence of mobile iron and abundance of organic matter, and under conditions of a ready supply of sulphur.

On drainage (improved aeration) atmospheric and microbiological oxidation convert the iron sulphide into ferric oxide and sulphuric acid, resulting in an extremely acid soil reaction, with pH well below 3-5, and occasionally as low as 1.0.

B Diagnostic field characteristics of (potentially) acid sulphate soils.

The following tests shall be conducted before drainage of any wetland-

that contain sizeable quantities of neutralizing cations, mainly Ca. The presence of Ca (and Mg) carbonate is tested using diluted HC1; the CO2 given off will cause effervescence

rise to the characteristic odour of hydrogen sulphide, indicating the presence of sulphide in the soil

may point to the presence of pyrite

with hydrogen peroxide causes a prominent drop in pH of the soil. This decrease may well be 1 -2 units lower than that which develops under natural oxidation

Reclamation by chemical improvement of acid sulphate soils requires 20-30 tons of lime.per hectare. The cost of purchasing, transporting and application of such large quantities of lime for the reclamation exercise is high and can be justifiable only in few cases. Moreover, large quantities of lime create problems of potash and trace element deficiencies. Leaching is a better solution but no land should be flooded with the drained-off water. Additional measures to be taken include: regular applications of small amounts of lime, together with basic fertilizers (not containing sulphates) and ashes; cultivation of acid-tolerant, shallow rooting crops; mounding of land in the case of more deeply rooting crops and good water table management.

D Irrigation The soil suitability for irrigation purposes is considered based on the following qualities-

The qualities mainly relate to irrigation of crops normally grown under rain fed-conditions and give particular attention to soil-water plant relationship. These qualities are not applicable to drip irrigation. The soil chemical qualities are. per earlier recommendation, on the general threshold values for fertility management.

Five classes shall apply: suitable moderately suitable, marginally suitable, potentially suitable, and not suitable for irrigation.

It is important to note that some of the recommended parameters are normally assessed in the field i.e. some parameters have no quantitative values e.g. drainage classes, soil structure etc.

Since most water sources in Uganda are not salt affected, it is assumed that the irrigation water will also be free of salts. Salt content of irrigation water is expressed in one of the parts per million (ppm); milligrammes of salt per litre (mg/I); or as electrical capacity expressed as micro Ohms per centimetre (Ec.xlO'6). High calcium carbonate and gypsum levels occur in very localised areas in Uganda and hence no values are included in the parameters specified in the First Schedule.

Class I - Suitable Class II - Moderately suitable Class III - Marginally suitable Class IV - Potentially suitable Class V - Unsuitable

waterlogged areas; and

The natural flooding or waterlogged system represents the small-scale rice producers in periodically flooded alluvial plains and valleys. These systems depend on flooding from rain events. The irrigated system represents the large-scale systems where irrigation waters are "fairly" well regulated. These rice production systems are adapted to specific hydrologic conditions and specific soil qualities.

The first category is very widespread in eastern Uganda and it is the main cultivation pattern in wetlands.

The following are suitability classifications of soils for natural waterlogged rice production system based on landform, flooding and physical soil properties-

Class I Suitable Class II Moderately suitable Class III Marginally suitable Class IV Potentially suitable Class V Unsuitable

THIRD SCHEDULE. Regulation 10 PARAMETERS AND METHODS OF DETERMINATION OF SOIL QUALITY. There are a variety of soil parameters used for the management of soils:

Chemical parameters

Soil Acidity (pH) The parameter generally denotes soil reaction which expresses the degree of acidity or alkalinity The pH value equals the negative logarithm of the H+ ion concentration (CH+). Conventionally, the soil pH is measured in a soil - water suspension 1:2.5 (10 g soil'in 25 ml water) and is designated pH (water). It could also be determined in suspensions of 1:1 or 1:5.

For the measurement of exchange (reserve or potential) acidity of an acid soil a 1:2.5 suspension should be used to which a neutral salt (KC1) has been added, in order to bring exchangeable H-ions into solution. It is designated pH (KC1). The pH value of soil is most accurately measured with a pH meter in the laboratory method.

Organic matter Organic matter, because of its colloidal nature, contributes to the cation exchange capacity, CEC, and therefore the nutrient retention capability of the soil. Organic matter improves the physical characteristics of the soil through its enhancement of water permeability and retention. Soil organic matter is high in organic carbon and serves as a source of energy for soil micro-organisms. •

Organic carbon should be determined by the modified Walkley and Black method (Nelson, D.W. & Sommers, L.E.)

Sodicity (ESP) Normal soils usually have an exchange complex that is dominated by Ca and Mg and has only minor amounts of K and Na. When excess soluble salts accumulate in such soils, Na frequently becomes the dominant cation in the soil solution, a part of the original Ca and Mg is replaced by the cation. In general, physical properties become increasingly unfavourable with increasing levels of exchangeable Na.

The commonly determined parameter, the exchangeable sodium percentage (ESP) shall be used.

ESP = Exchangeable Na (meq/IOOg soil) xlOO Cation Exchange capacity (meq/IOOg soil)

Salinity (Ec) Saline soils contain soluble salts in concentrations that impair crop growth. Although weathering of primary minerals is the source of nearly all soluble salts, accumulation of these on the spot are seldom concentrated enough to form a saline soil. Invariably, strong salinity is found under semi- arid climatic conditions in soils where salts from other locations have accumulated through the inflow and subsequent concentrations of salt-bearing waters. Most saline soils are characterised by low humus content, no differentiation into horizons and very little structure.

The generally accepted parameter of salinity, the electrical conductivity (Ec) at 25EC shall be used. The Ec can be determined according to the saturated paste extract method and measured with a conductivity bridge.

Cation Exchange Capacity (CEC) The CEC of a soil often indicates its natural fertility and its ability to supply Ca, Mg, and K for plant growth. It is also a measure of the ability of the soil to store added nutrients (fertilizers). Soils which have a low CEC cannot store large amounts of plant nutrients and must be replenished more regularly.

In the inorganic part of the soil complex only clay particles play a decisive role, since the active total internal surface of silt and sand panicles in comparison to that of clay is very small. Tne CEC of clay depends on the type of clay mineral. The organic matter complex (the humus colloids) has a much higher CEC than clay.

The CEC of a soil shall be determined in the laboratory, either in an exchange medium with pH = 8.2 or in exchange medium with pH = 7.0. The expression T value may be used instead of CEC value.

Exchangeable Bases Tliis is restricted to the cations Ca. Mg. \. one \v <4 these four exchangeable cations (S value) can be related to (lie Cl < '• ■' and expressed as the base saturation percentage (SSP; Tv -<■' values for exchangeable Ca, Mg. and K give certain tMsmmo A. fertility status of the soil (Macro-nutrients). The exchaiwjH'. \< percentage (ESP) is an important criterion for sodiccondiiion'

Exchangeable cations shall be determined in (he laborjtcty by f' <" • photometry- for K and Na, and by atomic absorption spec(rcfh<;i<;tn-»n (AAS) for Ca and Mg using Anderson and Ingram. 1993)

Phosphorous (P) Compounds of P (ADP & ATP) act as energy currency in Energy from photosynthesis and metabolism of carbohydrate:- i-t in these compounds for subsequent use in growth and renodtr.'i e processes. The role of P as a structural component of a wide variety : f biochemical and seed formations are also important.

The following s-» commonlv> used methods shall be arched re calorimetric method (Anderson and Ingram. 1993/: the Olsen f'z extractable P. and Bray II method for available P.

Calcium carbonate The presence of CaC03 affects both the physical and cne .<>- characteristics of a soil. High lime concentrations may no: se-e restrict water movement but may prevent root penera*.o*.. 5 CaCO3 concentration particularly in the very *me tractions or.r.gi r^_' of lime-induced chlorosis for many crops. Tne physical cna"cc.e.^.>~> of calcareous soils change when they are irrigated. It is theretore a soil quality parameter under irrigated agriculture.

Gypsum (CaSO4) Gypsum indirectly affects soil physical properties and theretore influences permeability and infiltration rate. It improves me structure and prevents sodium saturation. A small amount 0: gypsum is favourable for crc-p growth because it serves as a >ource c-t Ca a> a plant nutrient and replaces Na in the exchange Comdex and thus acts to preserve chemical and physical soil degradation.

Coarse Fragments or Stoniness Surface coarse fragments in the top 20 cm will influence tillage conditions as well as the capacity to retain nutrients and water. Coarse fragments can limit the use of agricultural implements and optimum growth of roots. Coarse fragments with a diameter between 2-75 mm are termed gravel: those between 75-250 mm are called cobbles and those more than 250 mm are called stones (Sys et al.. 1991).

Coarse fragments shall be quantified on volume or weight percentage basis.

Rooting Depth Rooting depth is a crucial parameter in soil productivity because it determines soil reserves of water and nutrients. The relationship between rooting depth and productivity is commonly described according to the law of diminishing returns. It is generally defined as the thickness of loose soil above a limiting layer (if anv). Limiting layer is impermeable for roots and percolating water. Soil depth is vital tor the anchoring of plants and provision of a favourable environment for plant root growth.

Soil depth parameter shall be quantified by direct depth (length) measurements.

Water Holding Capacity (WHC) or Available Moisture Content (AMC). This is the amount of water which a given soil horizon can store and is estimated from the difference between field capacity and the lower limit of plant available water (wilting point).

The field capacity (-1/3 bar) and wiltingpoint (-15 bar) shall be determined in the laboratory by the pressure plate method. The field capacity value should also be determined in the field by the ponding method.

Drainage and depth to water table Drainage and depth to water table are vital parameters. The suitability for upland crops decreases when drainage conditions become impeded. Tree crops with a deep root system are more sensitive to poorly drained conditions than annual crops with shallower root systems. Crops like paddy rice react quite differently to drainage conditions; their suitability decreases when drainage conditions improve. For irrigated agriculture, drainage, depth to ground water table and salinity status are critical evaluation parameters.

Drainage classes shall be described in the field as it is normally done. Depth to water table shall be measured in the field.

Slope Slope angle and length are critical parameters for the assessment of erosion potential. It also influences water movement and distribution within the soil profile.

Slope angles or percentages shall be determined in the field.

Infiltration Infiltration is a very important parameter in irrigated fanning systems. Infiltration is the entry of water into the soil through the soil surface. The rate is dependent on the antecedent moisture, soil structure, pore sizes and their distribution. It is an important parameter in evaluating compacted (physically degraded) soils e.g. degraded rangelands. Rate of water entry is generally very' low in degraded areas and most of the water ends up as runoff, causing considerable soil erosion and siltation problems.

Infiltration rate is determined in the field using the common method of double cylinder infiltrometer (Bouwer. 1986).

Bulk Density This parameter largely depends on the porosity of the soil and is commonly used to evaluate compaction. Loose and porous soils have low values while compacted or physically degraded soils have high values.

Bulk density parameter shall be determined by the core or clod method (Anderson and Ingram, 1993).

Total Porosity Total porosity is the fraction of the soil mass that is occupied by the pores. The pore space is largely determined by the arrangement of the individual solid particles of the soil. The pore space in the soil is partially occupied by the liquid (water) and partly by air.

Porosity shall be computed from the relationship between bulk density and particle density (Anderson and Ingram, 1993).

Flooding S'

Flooding is considered as a serious limitation for most crops apart from paddy rice. Flooding interferes with air entry into the soil.

For paddy rice cultivation, flood evaluation is based on duration and depth of flooding.

Optimal duration, of flooding is 1 10 to 160 days: marginal situations are 90-110 days and more than 180 days. The optimal depth shall be considered as 10-30 cm (Sys et al. 1991).

FOURTH SCHEDULE Regulations 12 and 13 SOIL conservation measures and guidelines Soil conservation is required as a basis for environmentally sound production of food, wood, and other commodities based on sustainable use of land, species and ecosystem. In all these areas, a combination of several conservation practices are recommended and packages will depend on area and crops I livestock/tree species on the land. I. Lowlands and flat areas (Slopes up to 2%) Lowlands are the alluvial plains and the bottom lands of small tributaries in a catchment. The following soil conservation structures and practices are recommended- (a) surface or subsurface drainage: (b) interception and diversion ditches: (c) rows of crops should be laid out at right angles to the contour lines; (cl) crop rotation; and (e) fertility improvement (package will depend on crops and area). Diversion ditches or field ditches should be at a spacing of 100 to 200 metres; depth 30 cm and length not more than 500 metres. These should be laid out slightly off the contour to obtain a gradient of 0.3 to 0.5%. The collecting ditches (depth 60 cm), should drain into main ditches or natural drainage ways and should run in the direction of the greatest slope.

Recommended conservation practices- (a) contour cultivation; (h) contour ridges or absorption banks at a spacing of 30 m: (c) grass strips and strip cropping: width 30 m: (cl) mulching: (e) agro forestry; (/) crop rotation and fertility improvement; and (<>) wind breaks or shelter belts; should be located perpendicular to main erosive wind direction.

Simple conservation practices are insufficient to stop erosion. The following management practices are recommended- (a) terraces; (b) contour cultivation (ploughing and planting along the contour), and absorption banks at a spacing of 10 - 20 m; (c) crop rotation and fertility improvement;

In addition, an optimum stocking rate is required. The following are the recommended stocking rates-

FIFTH SCHEDULE. Regulation 13.

RECOMMENDED FREQUENCY FOR MONITORING OF SOIL QUALITY PARAMETERS FOR ENFORCEMENT PURPOSES.

Soil Parameter Suggested Monitoring Frequency

Bulk density and porosity Annually Structure 2 years Texture 3 years Water holding capacity 3 years Infiltration Annual Coarse fragments and stoniness Every 5 years Soil depth 3 - 5 years Slope, depth to water table, and drainase class Planning phase

Soil organic matter Annually

z pH Annually Exchangeable bases 2 years p 2 *vears CEC 2 *vears Calcium carbonate and gypsum Planning phase Alkalinity, Sodicity (for irrigated agriculture) 3 to 5 years

Form SRO/1 SIXTH SCHEDULE Regulation 13 (2). IMPROVEMENT NOTICE (Issued under section 8 /(i) of the National Environment Statute. 1995 ami regulation 15 of the National Environment (Minimum Standards for Management of Soil Quality) Regulations.2001) TO:

Take notice that on the .................. of an Environmental Inspector(s) from the National Environment . ana=ement Authority earned out an inspection of (he soils and/or land located in village, subcounty of District where it was ound that you or your agents were carryins on the following soil degrading activities:

8 4 (attach more paper if required) ^01 are hereby ordered to stop all the stated illegal activities which are causing or are likely to cause soil degradation on the above mentioned soils or land within a period of days from the date of this Notice. You are also required to restore the soil to its original state. VOL' are notified that in accordance with section 96 of the National Environment Statute 1995. failure to comply with this Notice shall result in criminal prosecutions being instituted against you and/or your agent.

Environmental Inspector. Copy to:

HENRY MUGANWA KAJURA. Mir. ister of Water, Lands and Environment.