Land management practices for improved water conservation

Water conservation is important, especially in areas where water is limited or not enough for crop production.

Land management practices that aim to conserve water in upland farms are based on the understanding of water cycle and its component processes.

THE WATER CYCLE

· Upland farms receive water mainly from rainfall.

· Some of these water enter the soil (infiltration).

· Some run over the land surface and flow out to the streams, rivers and seas (runoff).

· Water in the soil is used by crops.

· Some water in the soil move downward (percolation) and sideward (seepage) into the ground water and then also to the streams, rivers and seas.

· Water is resumed to the air directly from water surfaces, ground surfaces, etc., (evaporation) and thru plants (transpiration).

· Water vapors in the air join together to form clouds and condense to form rain.

Water cycle

TABLE 3. CYCLE SUMMARY.

GAINS	PATHS	STORES
Rain	Infiltration	Soil (temporary)
	Uptake	Plants (temporary)
	Percolation/	Groundwater
	seepage
	Runoff/percolation/	Rivers, seas, etc.
	seepage
	Evaporation/transpiration	Air clouds

The goals of water conservation strategies are to store more rain water, increase infiltration, decrease runoff, percolation and seepage and minimize evaporation. Early land preparation, cultivation along the contours, deep cultivation and addition of organic matter increase the capacity of the soil to hold water by improving the soil structure. They are best done before the onset of the rainy season. Other practices like mulching, terracing, maintenance of vegetative groundcover minimize runoff by giving more time for the rainwater to infiltrate the soil. Minimum tillage and zero tillage decreases evaporation and are more effective in storing residual soil moisture for dry-season cropping.

Organic matter sources include compost, animal manure, green manure and other organic fertilizers. Leaf litters and crop residues such as rice straws, corn stovers, rice hulls, etc., are some examples of good mulching materials.

In some areas, networks of small water holes, small farm ponds or water-impounding structures are established to conserve more water.

TABLE 4. WATER CONSERVING LAND MANAGEMENT PRACTICES.

EFFECTS ON PROCESSES

PRACTICES	Rain Water Storage	Infiltration	Runoff	Percolation Seepage	Evaporation/Transpiration
Addition of organic matter	+	+	-	+	o
Contour cultivation	o	+	-*	o	o
Deep cultivation	+*	+*.	-	+	o
Terracing	o	+	-	o	o
Maintenance of vegetative groundcover	+	+	-	+	+
Mulching	o	+	-	+	-
Minimum/Zero tillage+	+	+	-	o	-
Fallowing	+	+	-	o	-
Early land preparation	+	+	-	+	+

Note: + (increase); - (decrease); o (no effect); '(short-temm effect)

ALLEY CROPPING

Alley cropping is a system of intercropping rows of food crops with rows of fast-growing trees or shrubs. Generally, it is practiced in areas with flat to gently rolling topography. The crop rows are oriented in an east-west direction.

Alley croping

PROCEDURE

1. Site Selection. The area to be devoted to alley cropping should have a flat to gently sloping topography and should be less productive for purely food crop production.

2. Land Preparation. After clearing and weeding the area, layout the rows of trees or shrubs and food crops in an east-west direction with the following distances: in between rows of tree crops, 5 meters; in between rows of tree and food crops, 1 meter; in between individual tree plants, 25 to 150 centimeters. Distances between rows and individual food crops shall depend on the type of plant to be grown. With use of a harrow or hoe, cultivate only the rows where tree and food crops will be planted.

3. Planting of trees and food crops. Plant trees with food crops during the planting season. Allow the tree crops to grow one full year while conducting normal farming operations on the food crops.

4. Maintenance. Conduct pruning of the tree crops in the second year, twice or every three months at 0.5 meter height. Leaves and small stems should be used as mulching materials for food crops.

BENEFITS

1. increases soil nitrogen.
2. Helps control weeds.
3. Serves as windbreaks, controls soil erosion.
4. Provides livestock feed and firewood.
5. increases available moisture by improving infiltration and reducing runoff.
6. Helps achieve higher yields over conventional cropping system.

TROUBLE-SHOOTING PROBLEMS

Common problems encountered in alley cropping are competition between trees/shrubs and food crops for sunlight, space, water and nutrients.

How to minimize competition for sunlight:

1. Orient the rows in an east-west direction to avoid shading.

2. Use of trees/shrubs that are self-pruning or can withstand frequent pruning.

3. Use of trees/shrubs that have small crown and light branching characteristics.

4. Use of trees/shrubs with leaf arrangements that permit penetration of light or those that have leafless periods.

5. Use of trees/shrubs that are shade-tolerant during their establishment stage.

6. Use of food crops that do not cast too much shade and/or are not climbers that affect the growth of trees in the establishment stage.

Figure

How to minimize competition for space:

1. Use of multipurpose trees/shrubs that produce either fodder, fueiwood or food.

2. Proper spacing of the rows of trees/shrubs to allow sufficient space for food crops.

3. With the use of plow or spade, cut the lateral roots of trees that expand to the area of food crops.

How to minimize competition for water and nutrients:

1. Use of trees/shrubs and food crops whose litter fall is easily decomposed.
2. Use of trees/shrubs and food crops that fix atmospheric nitrogen.
3. Use of trees/shrubs with root systems deeper than those of food crops.
4. Avoid using food crops whose nutrient requirements rapidly exhaust the soil.
5. Practice crop rotation and mulching.

Figure

TABLE 5. SUGGESTED TREE SPECIES FOR ALLEY CROPPING.

		CHARACTERISTICS.
SCIENTIFIC NAME	COMMON NAME	1	2	3	4	5	6	7	8	9	10	11	12
Albizia lebbek	Langil	x	-	x	x	x	x	x	-	-	x	x	-
Albizia lebbekoides	Kariskis	-	-	x	-	x	x	-	-	-	x	-	-
Albeia procera	Akleng parang	x	x	x	-	x	x	-	-	-	x	x	-
A/nus japonica	Alnus	x	-	-	x	x	x	-	-		-	-	-
Alnus nepalensis	Alnus		x	-	-	x	x	x	-	x	-	-	x
Azadirachta indica	Neem	-	-	x	x	x	-	-	x	-	x	x	x
Cajanus cajan	Kadios	x	x	-	-	x	x	-	x	x	x	-	-
Calliandra calothyrsus	Calliandra	x	x	-	x	x	x	x	x	-	x	-	-
Cassia siamea	Thailand shower	-	-	x	x	-	-	x	-	-	x	x	-
Desmodium gyroides	Karikut-rikut	x	-	-	x	x	x	x	x	-	-	-	-
Desmodium rensonli	Rensonii	x	x	-	x	x	x	x	x	-	x	-	-

CHARACTERISTICS

SCIENTIFIC NAME

COMMON NAME

1

2

3

4

5

6

7

8

9

10

11

12

Erythrina onentalis

Dapdap

x

-

x

x

x

x

x

x

x

-

-

-

Flemingia macrophylla

Malabalatong

x

-

-

x

x

x

x

-

-

-

-

-

Gliricidia septum

Kakauate

x

x

x

x

x

x

x

x

x

x

-

-

Gmelina arborea

Gmelina

-

-

x

-

x

-

x

x

x

x

x

-

Leucaena diversifolia

Acid Ipil-ipil

x

x

x

-

x

x

x

x

x

x

x

-

Leucaena

Ipil-ipil

x

x

x

x

x

x

x

x

x

x

leucocephala

Moringa oleffera

Malunggay

x

x

x

-

x

-

-

x

x

x

-

-

Pithecellobium dulce

Kamachile

x

-

-

x

x

x

-

-

-

x

x

x

Psidium guajava

Bayabas

-

-

x

x

x

-

-

-

x

x

-

x

Sesbania grandiflora

Katuray

x

x

x

x

x

x

-

x

x

x

-

-

Spondias purpurea

Sineguelas

-

x

x

x

x

-

-

-

x

-

-

x

		CHARACTERISTICS
SCIENTIFIC NAME	COMMON NAME	1	2	3	4	5	6	7	8	9	10	11	12
Swietenia macrophylla	M a hog a n y	x	x	x	x	x	-	x	-	-	-	x	-
Syzygium cumini	Duhat	x	-	-	x	-	-	x	-	x	x	x	x

Legend:

1 Self-pruning and/or withstand frequent pruning
2 Small crown, light branching
3 With leafless period, leaf pemmit sunlight penetration
4 Shade-tolerant at establishment stage
5 Litterfall easily decomposed
6 Nitrogen-fixing
7 Deep-rooted
8 Fodder/forage
9 Food
10 Fuelwood
11 Lumber and other wood products
12 Medicinal