B. Management

B.14 Location
B.15 Water application management
B.16 Pre-harvest farm management
B.17 Harvest and post-harvest conditions
B.18 Mechanization

Management Requirements and Limitations

Land Conditions affecting Management

Some aspects of agronomy impinging on management have already been discussed in section A. In this section, the additional considerations are those associated with location, water application management, pre-harvest farm management, harvest and post-harvest conditions, and mechanization.

B.14 Location

The location of a land unit affects many aspects of the management as follows-

i. closeness to markets or processing facilities;
ii. availability of inputs of fertilizers, pesticides, seeds and planting material;
iii. services provided (roads, electricity, domestic water, etc.);
iv. availability and supply of water for irrigation:
v. time wasted in travel and cost of transport or both;
vi. attention to day-to-day management of crops and irrigation;
vii. accessibility of machinery for land preparation, harvesting, etc.

These are now discussed in turn.

i. Closeness to markets or processing facilities: Fresh vegetables and fruits are often produced on land close to centres of population. The presence of processing facilities, e.g. a rice mill, a sugarcane factory or cotton ginning facilities influences both the cost of transportation and the practicability of growing the crop at a particular location. Time, distance or cost of transportation can be used to define critical limits for factor ratings.

ii. Availability of inputs of fertilizers, pesticides, seeds and planting materials, etc. If the land use depends on such inputs, they must be available at the time and in the amounts they are needed. If they are not available then the land must be classed 'Not Suitable' for this use. The reliability of supply and the timeliness of the supply of inputs may be a descriptor of a land utilization type, or a class-determining factor.

iii. Services provided (roads, electricity, housing, schools, clinics, domestic water, etc.). Land productivity in isolated locations is often less than where close to villages or towns with the above services. In this case, different suitabilities must be given to the land units based on the probable effect in terms of output and costs.

iv. Availability and supply of water for irrigation. Users at the head of irrigation canals generally get more water than tail-enders, to the point where the land values are sometimes very different. The suitabilities in terms of 'location' in the assessment of 'irrigable' lands may be very important. The ability of farmers to pay water charges and taxes are often based on land classes and therefore a careful assessment is important. To avoid double counting under different headings, either the water requirement or the location factor should be used but not both.

The locational and related factors, which are important with regard to water supply, have been studied by Wickham et al. (1977) and IRRI (1974) for run-of-river lowland rice. These are:

a. distance along lateral
b. distance along sub-lateral
c. distance of overland flow
d. elevation of the canal relative to the paddy
e. soil texture
f. number of intervening farms along the overland distance of water movement
g. farm ditch density

The effects of these interact with how adequately the irrigation system services its areas with water, and management factors such as planting date, the control of water upstream from a particular land unit (e.g. the use of checks), the phasing of distribution and scheduling, and gate control. Thus, when water is in short supply, the build-up of drought in certain parts of a system can be attributed to an unfavourable location within the system, and to competition within the system. Farmers nearer the water source are better placed than those further away. In the Philippines irrigation scheme studied by Wickham, the factors highly associated with the duration of crop stress and yields were distance of the farm from the beginning of the lateral, or from the sublateral, and the overland distance of the farm from the point where water was released from the canal system. The main reasons for the increased drought incidence further along major canals were the temporary checks that restricted the amount of water passing along the canals and the lack of control gates. The factors which were not important in Wickham's study were elevation of the canal relative to the paddy, soil texture, number of intervening farms (as distinct from distance of overland flow), or the farm ditch density. The weak association between soil texture and distance along the lateral was due to the fact that heavier soils with greater water-holding capacity were found in the farther reaches of the system, at greater distances overland, and thus tended to compensate.

These locational factors are much more important if water is in short supply than if it is plentiful and this should be taken into account in choosing factor ratings or 'significance' levels for 'location'.

Elevation and distance is of great importance in lift-irrigation schemes on account of the cost of pumping. In 'provisionally-irrigable' classifications this may be largely ignored, but it is a major consideration in the selection of 'irrigable' land. Within the irrigable area, once its extent has been determined, there are two main possibilities:

a. If the farmer has to pay the full cost of the water delivered to his farm and this includes costs of pumping, the benefit/cost ratio and suitability of the site will be highly affected by the elevation and distance. This is often the case in groundwater and lift irrigation development.

b. If the project as a whole or the government has responsibility for the cost of the water between the source and the elevated discharge points to farms, all farms may be equally charged for water or the costs may be recovered indirectly or not at all. In this case the elevation and distance need not be a factor in the evaluation once the extent of the irrigable land has been determined. It is important in determining the 'irrigable' area and project development costs. However, most funding agencies require that each land unit supports its own area-specific investment costs (see Chapter 7).

v. Time wasted in travel and cost of travel and transport. The cost in terms of a farmer's time and in labour may be critical in evaluating the 'location'. Transportation costs (as distinct from transportation difficulties) following the construction of the irrigation scheme may significantly affect benefit/cost ratios at different locations. Critical limits may be expressed in relative terms (s1, s2, s3, n1 or n2) or in terms of relative benefit/costs using, for example, cost of transport per tonne/kilometre or per hour. The portrayal of access by the use of isochrons may be necessary to define 'irrigable' land.

There are refined and specialized methods of assessing transport costs which would be used if transportation is a major factor that it is intended to study in detail. Transportation specialists will adopt more sophisticated methods of assessment than the following but the main concept is illustrated below for roads:

a. Classify and map the existing roads; the following basis is suggested;

2 or 4-lane tarmac
single lane tarmac
gravel or improved earth, width >5.5 m
earth, unimproved and/or width <5.5 m

Each divided into:

- level to gently sloping terrain, mean road gradients 1 in 10
- moderately to steeply sloping terrain, mean road gradients 1 in 10

b. Estimate a transport cost for each class of road, per t/km.

c. Identify centres. By measurement from the map of classes of road, multiplied by the unit cost for each class, determine the transport cost to or from centres, per tonne, for intervals along the road systems.

d. Estimate the distance from a road over which it is reasonable to assume that inputs and produce will be carried. Draw limits around the road network at this distance. Areas lying beyond these limits are regarded as inaccessible.

e. For the area with access to roads, draw cost isolines.

vi. Attention to day-to-day management of crops and irrigation: It may not be possible to grow specific crops at distant sites because of theft and crop security. The protection of crops from wild animals, birds, and other pests and diseases may be lacking and the management less than optimum. All these are commonly very important factors. The problem of security also applies to irrigation equipment (e.g. sprinkler pipes, brass nozzles, etc.) which can be stolen for making utensils, parts for motor vehicles, etc. The functioning of the irrigation system may be damaged maliciously.

vii. Accessibility of machinery for land preparation, harvesting, etc. This is a major factor particularly for bulky crops (e.g. sugarcane, sugarbeet) where mechanical cultivation is important to achieve timely sowing or planting. Critical limits depend on the type of equipment to be used, on the rainfall and soil conditions, on topography particularly slope, and other factors. If the land is inaccessible or subject to conditions which hamper access such as wet roads, impassable drains, etc., the opportunities for timely and efficient operations vary according to the severity and location of these constraints.

A combined evaluation of all these factors, taking care not to double count factors which will be considered under other heads can be facilitated with the assistance of Table 46.

Table 46 FACTOR RATINGS FOR LOCATION FOR A SPECIFIED LAND UTILIZATION TYPE AND LAND UNIT

Land Unit No(s): Land Use Type(s)
Factors	Factor ratings 1/				Significance for this assessment	Factor rating selected
	s1	s2	s3	n
Proximity of markets, processing facilities	Ö				Not important	e.g. s1
Inputs availability
Services, house and village proximity
Effect of location on water supply and cost
Transportation and labour costs
Security and day-today management				Ö	Very important	n
Accessibility to machinery
	Factor rating for: LOCATION (Enter n on Format 3)					n

1/ Tick as appropriate.

B.15 Water application management

The land evaluator should assess the land characteristics of the land unit that will affect water application in the field after the land has been developed for irrigation, as discussed below.

To avoid double counting the factors he should assume that the quantity of water specified in Section A.6 (and as affected by location as specified in Section A.14) will be supplied, and that it may or may not meet the full requirement, as appropriate.

He should also assume a water application technique (surface, sprinkler or localized irrigation) as in the description of the land utilization type (but see Chapter 4.2.1). The remaining questions to be answered are:

i. How do the land characteristics affect the operation of the specified water application technique?

ii. Given the location, are there any specific advantages or limitations that will affect yields or costs of water application on the given land?

For the irrigation technique under consideration, the land characteristics used to define critical limits and factor ratings are those that will affect either the cost of water application or the level of crop production on the land. Costs of water application may be affected by:

a. the potential size of management units and subunits (e.g. the size and shape of the fields and farms);

b. different labour requirements and labour availabilities (associated with the specific land area rather than with locational factors already considered);

c. different opportunities and requirements for mechanizing or automating irrigation water application.

The level of crop production may be affected by:

- uniformity of the water application in the field related to soils, topography or other land characteristics;

- the factors concerned with rate, duration and frequency of application specific to the land.

To avoid double counting, the assessment under this heading should not include aspects which have already been considered, nor those which will be considered under the later headings, that is:

1. exclude consideration of land characteristics affecting the water supply or requirements;
2. exclude locational aspects described in B.14;
3. exclude factors affecting land development costs (see Section C).

The following approach can be adopted to select a factor rating for the heading 'Water Application Management' (Table 47).

Table 47 FACTOR RATINGS FOR WATER APPLICATION MANAGEMENT

Land Unit No. Land Use Type Crops Water application technique:
Land characteristics affecting the rating	Factor ratings 1/				Significance	Selected rating
	s1	s2	s3	n
Example:
1. Size and shape of fields				Ö	Important	n
2. Soil intake rate affecting uniformity, leaching	Ö				Less important	s1
3. Costs of moving pipes past an obstruction				Ö	Important	n
	Factor rating for: WATER APPLICATION MANAGEMENT (Enter n on Format 3)					n

1/ Tick as appropriate.

The ways in which land characteristics might affect water application management in different land units where surface, sprinkler and localized irrigation techniques are to be used, are included amongst considerations listed in Table 48. This table describes all the features and requirements of irrigation application techniques, including both those affecting the choice of system and the suitability of the land. This is a comprehensive list and not all the features described are relevant to the assessment of water application management.

Table 48 FEATURES OF IRRIGATION APPLICATION TECHNIQUES FOR EVALUATING CHOICE OF SYSTEM AND SUITABILITY OF LAND A. SURFACE APPLICATION TECHNIQUES

FEATURE	SMALL BASINS (MEDIUM) 1/ LARGE BASINS		BORDER STRIPS	SHORT FURROWS (MEDIUM) 1/ LONG FURROWS
1. Land development costs	Low	Often high, precision grading required	Low to medium depending on topography	Low	Often high, precision grading required
2. Capital intensity (field equipment)	Low	Low	Low	Low	Low
3. Labour intensity	High	Low	Medium	High	Low
4. Energy intensity	Low (gravity) High (pumped)	Low (gravity) High (pumped)	Low (gravity) High (pumped)	Low (gravity) High (pumped)	Low (gravity) High (pumped)
5. Size and shape of fields	Very flexible, often small and irregular	Large and regular shaped fields required	Long, rectangular, can be narrow	Very flexible, often small and irregular	Medium to large, regular shape
6. Topography	Important but generally not critical	Often critical if graded or level basin	Suitable slope and absence of cross slopes	Important but generally not critical	Often critical both for graded and dead level furrows
7. Soils	Intake rates often critical for efficient use of water and uniformity of application; influences size of basins, lengths of furrows or border strips in relation to the rate of water delivery, slope and uniformity of microrelief.
8. Management skills	Suitable for small farmers in LDCs	Sophisticated management required	Suitable for middle level management	Suitable for small farmers in LDCs	Sophisticated management required
9. Cropping limitations and mechanization	Wide range of crops, but not mechanized	Suitable field crops planted on the flat or ridges and mechanized	Suitable field crops planted on the flat and mechanized	Wide range of crops, but not mechanized	Row crops, not those planted on the flat; mechanized
10. Scheduling by frequency, rate and duration of the water supply	Continuous (rice); Intermittent, generally fixed by water agency; often 10-30 l/s, limited, fixed duration	Usually intermittent, by arrangement or fixed by water agency; high delivery rates, short duration possible	Intermittent, by arrangement or fixed by water agency; rate must be matched by labour, cutbacks to flow important	Intermittent, by arrangement or fixed by water agency; often 10-30 l/s, limited, fixed duration	Intermittent, by arrangement or fixed by water agency; delivery rate must match labour, cutbacks to flow important
11. Factors affecting uniformity of application	Topography, soils management, size and shape of fields, water supply, labour skills	Levelling and grading of land, soils, management, size and slope of basin, in-field variability	Uniformity of grade, absence of cross slope, rate and duration, cutback stream size, labour skills	Topography, soils, management, size and shape of fields, water supply, labour skills	Uniformity of grade or level, rate and duration, cutbacks to stream flow, or use of return flows, variability
12. Mechanical problems	None	None	None	None	None
13. Security problems	None	None	None	None	None
14. Leaching and salts problems	Salty patches on underwatered high spots	No special problems	No special problems	Salt accumulation on ridges, salty patches on high spots	Salt accumulation on ridges, otherwise no special problems
15. Location	If water in short supply distance from source is important	Usually adequately serviced	No special problems	If water in short supply distance from source is important	No special problems
16. Field water use efficiencies	Inherently low on permeable soil; minimum application is 50 mm per irrigation	Can be very high in very accurately levelled basins	Very dependent on the water control, cross slope, can be high and low	Inherently low on permeable soil? minimum application is 50 mm per irrigation	Very dependent on the water control, rate, duration, slope, high or low
17. Main problems generally encountered	Poor uniformity of application, overwatering, land wasted in bunds and channels	Very high land levelling costs. Exposure of subsoils	Poor uniformity of application, erosion, crop damage	Poor uniformity of application, overwatering, land wasted in channels	Poor uniformity of application, excessive run-off, erosion
18. General remarks	Easily administered water schedules, at expense of efficient water use. Good for third world fanners	Suitable for large mechanized units where labour is costly and energy/water use efficiency is important	Suitable for medium sized farms not growing row crops, especially for forage	Easily administered water schedules at expense of efficient water use Good for third world farmers	Suitable for large mechanized units where labour is skilled

1/ This indicates that there are intermediate conditions to be considered.

Table 48 FEATURES OF IRRIGATION APPLICATION TECHNIQUES FOR EVALUATING CHOICE OF SYSTEM AND SUITABILITY OF LAND B. SPRINKLER AND LOCALIZED IRRIGATION TECHNIQUES

	SPRINKLERS				MINI-SPRINKLERS	ORIFICE AND LONG PATHWAY EMITTERS (ON-LINE OR IN-LINE)	BIWALL TUBING
	LOW OUTPUT	MEDIUM 1/		HIGH OUTPUT
1. Land development costs	Low or nil		Low or nil		Low or nil	Low or nil	Low or nil
2. Capital intensity (field equipment)	High		High		High	High	High
3. Labour intensity	Hand move systems, high labour need, mechanized and mobile systems low.				High need for labour in laying and removing tubing, low labour need during period of irrigation and/or automatic control of water supply		High labour for installation, low for operating, often ploughed in
4. Energy intensity	Medium-high water pressures required		Medium to very high pressures		Low pressures (losses on filtration)	Low pressures (no advantage if pressure for filtration is high)	Low pressures but losses over filters
5. Size and shape of fields	Not suitable for very small fields. Hand move systems are flexible; and mobile, mechanized systems inflexible requiring large, regular shaped fields.				Very adaptable; limited length of laterals	Very adaptable; limited length of laterals	Very adaptable; Limited length of laterals
6. Topography	Not suitable for very steep land. Some limitations for mobile and mechanized systems but less so than for surface irrigation systems				Very adaptable	Very adaptable	Very adaptable
7. Soils	Suitable for soils with high intake rates. Sometimes problems with low intake soils. Problems with high rate of application, mobile systems and rainguns				No intake problems. Some lateral water spreading	No intake problems. Lateral spread is limited especially on sandy soils	No intake problems. Lateral spread is limited especially on sandy soils
8. Management skills	Not suitable for farmers in the third world who cannot get spares or manage the operation effectively				Intermediate level of management but fairly simple	Sophisticated management to prevent malfunction	Sophisticated management to prevent malfunction
9. Cropping limitations and mechanization	Apart from some tall crops and rice no problems. Highly mechanized wheel mounted laterals, centre pivots, cable systems, or permanent systems reduce labour requirements				Better for tree crops and widely spaced row crops; automated control possible	Intensive high value crops; unsuited for seedbed irrigation, reel-in systems, automation	Wide row crops, can be subsurface (e.g. sugarcane), mechanized laying
10. Scheduling by frequency, rake or duration of the water supply	Usually on demand. Intervals are days or weeks, medium to high rates, 3-15 mm per hour		Usually on demand. Intervals are days or weeks, medium to high rates, 3-15 mm per hour		Usually on demand. 1-3 day intervals. Low-medium rate, medium-long duration	Usually on demand. 1-3 day intervals or continuous. Low rate, long duration	Usually on demand. 1-3 day intervals or continuous. Low rate, long duration
11. Factors affecting uniformity of application	Wind is the major problem of hand-mover sprinkler systems. Drop in pressures along lines, distances of throw and spacing between sprinklers				Not uniform when used as localized irrigation; pressure regulators can be used to improve uniformity	Not uniform when used as localized irrigation, variation along laterals is a design factor	Not uniform when used as localized irrigation, variation along laterals is a design factor
12. Mechanical problems	Moving parts wear, nozzles may block, some filtration and servicing needs				Nozzle blockages	Filtration critical aspect to stop clogging; a major limitation
13. Security problems	Not vandal proof; pipe and metal fittings must be removed from field at night in some countries				Not very vulnerable to damage or theft. Needs attention	Not particularly vulnerable and equipment can be left operating in field for long periods unattended
14. Leaching and salt problems	Under-watering can be a problem on very impermeable soils; uniformity problems; scorch on wetted leaves especially important e.g. citrus				No special problem. Low level avoids leaf scorch in tree crops	The major advantage is better yields with salty water due to the soil never drying out, frequent irrigations. Salt encrustations on soil surface
15. Location	Distance and elevation major cost factors in pressure head losses and requirements				Intermediate costs for pressurizing	Long duration irrigation results in smaller head losses but note pressure head loss across filters
16. Field water use efficiency	Much affected by wind and distribution uniformity, can be high or low				Very high	Very high	Very high
17. Main problems generally encountered	Costly equipment, high pumping costs, operational difficulties, hand move problems on wetted land, application rates too high with moving systems, wind drift and uneven application				Excessive lengths of piping, especially for closely spaced crops. High labour for unblocking nozzles	Clogging, installation and removing long lengths of tubing. Weeding. High cost. No use for seedbeds	Clogging, installation, no use for seedbed irrigation and therefore may need sprinklers as well
18. General remarks	Suitable for high intake soils and uneven topography for a wide range of crops and extensive fanning or intensive systems				Low pressure requirements suitable for small to medium-scale farmers	Better yields and water use efficiency justifies high capital costs on unintensive farms	Better yields and water use efficiency can justify high capital costs

1/ Indicates there are intermediate conditions to be considered.

B.16 Pre-harvest farm management

The most important factor to evaluate under this heading is the effect of land characteristics on the timing of farm activities. Timeliness is often a class-determining factor as affected by soil workability and other characteristics that vary from place to place. It can therefore have an important influence on overall farm production and on costs of production.

The following farm activities may be helped along or hindered by specific land characteristics such as soil workability in association with labour, power and water availability:

i. land preparation (starting date, duration in days or weeks);
ii. nursery preparation and sowing (water availability);
iii. direct seeding or transplanting in the field;
iv. irrigation (timing of, hold-ups due to wet soil, etc.);
v. weeding (rainy spells and intractable soil conditions);
vi. top dressing of fertilizer applications (delays result in yield losses);
vii. spraying for pest and disease control, or weed control;
viii. others (e.g. interrow cultivations) specific to certain crops.

The suitability can be rated in terms of how the land characteristics affect farm operations. It is often necessary to take account of labour supply and peak requirements, on-farm power in the form of human, animal and tractor facilities, and the availability of water. For example, in wetland rice, the farm operations on a soil that is difficult to cultivate when dry by animal-drawn implements may produce less yield, because the farmer has to delay sowing or planting until sufficient water is available to soften it, than where tractor cultivation is possible. The delay in planting date may be more, or less, depending on the particular soil and might result in larger or smaller yields, or the growing of only one crop per year rather than two.

Continuing with the examples, the same farmer may have land which is more easily weeded (e.g. sandy soil) than other land (e.g. clay). One area of rice may be readily drained for spraying and another may be impossible to drain with differences resulting in variations in pest and disease control and therefore yields.

The choice of factor ratings for 'pre-harvest farm management' can be facilitated by the use of Table 49, or a modification of it.

Table 49 FACTOR RATING FOR PRE-HARVEST FARM MANAGEMENT

Land Unit No. Land Use Type: Crops Other relevant descriptors:
Land characteristics or factors	Activity that is affected	Factor ratings 1/				Significance	Selected ratings
		s1	s2	s3	n
Example:
1. Soil workability	Land preparation Nursery Direct seeding Transplanting Fertilizer application Irrigation Weeding Spraying Other
2. Access to water for an early nursery	Date of planting Number of crops per year Yields
Factor rating for: PRE-HARVEST FARM MANAGEMENT (Enter () on Format 3)							()

1/Tick as appropriate.

B.17 Harvest and post-harvest conditions

This assessment concerns harvest and post-harvest conditions that affect:

i. the carrying out of harvest and post harvest operations in an efficient and timely manner;
ii. the spoilage of the crop produce in the field or during later drying and processing.

Land characteristics that might affect either of these are generally those associated with wetness, dryness or wind. It may be impossible to harvest a crop on time, or the land may be damaged by machinery compacting some soils more than others, or the quality of product may be better on some soils than others. For example, some crops, notably root crops and groundnuts are of better final quality if grown on non-adhesive soils rather than on adhesive soils and they are more difficult to harvest on the latter. The yield is affected because some of the crop is lost in the soil during harvest. Soil adhering to roots such as sugarbeet may lead to lower acceptability and prices, or penalties at the processing plant.

Product quality is often affected by excessive air humidity or rainfall and this may lead to diseases and losses in storage. Produce from land that dries out well before harvest may be of better final quality than from that which does not. For example, the milling quality of sugarcane will produce more sugar per tonne of cane on land which has allowed the cane to ripen and concentrate the juice, than on wetter land.

Red soil on potatoes so enhances the export prices from one particular country, that production of this crop is confined to soil of that colour.

Wind may be a favourable or unfavourable factor, assisting in the drying of some crops (e.g. grain) and increasing the perishability of others (e.g. vegetables).

For any given crop and land combination, the characteristics that are class-determining can be readily identified.

B.18 Mechanization

This assessment concerns conditions of the land that specifically affect mechanized agricultural operations, excluding those already discussed (e.g. soil workability for pre-harvest farm operations). The conditions which act as limitations to mechanization are slope angle, rock hindrances, stoniness or extreme shallowness of the soil, and the presence of heavy clays. Table 50 suggests some critical limits for certain of these limitations.

This is an important assessment if heavy harvesting machinery has to be used in the field and if bulky harvest products have to be transported out of the field to some central point. Limitations to mechanization can arise from a number of different features of land that are not necessarily related.

Table 50 CRITICAL LIMITS FOR MECHANIZATION AND ON-FARM TRANSPORTATION 1/

Land characteristic	Critical limits
	s1	s2	s3	n1	n2
Slope angle (degree)	5	10	18	35	- 2/
(percent)	9	18	32	70	-
Rock hindrances % (outcrops and boulders)	1	4	10	25
Stones, topsoil %	1	5	15	40	-
Plastic heavy clay	absent	absent	present	present	present

1/ Values given are the maximum permitted at each suitability level.
2/ Must be specified for each individual case.