**2.3 Research methods**

The approach used is a mixed method with the population pressure analysis method using the Otto Soemarwoto [28] formula and the projected population growth using a geometric formula. The erosion rate calculation is analyzed using the MUSLE method with the support of Geographic Information System tools [29]. To calculate the erosivity of surface runoff as part of the MUSLE method, a modified rational formula is used. The software used is Arc GIS 10.3, and Microsoft Excel 2019. The level of erosion hazard is obtained by overlaying the erosion rate map analysis results with the soil solum map in the Lesti Sub-watershed in Office for Watershed Management and Protection Forest Brantas [27]. The choice of environmentally sound conservation priority areas based on the results of population pressure analysis >1 that intersects with the level of erosion hazard that is heavy/very heavy at the sub-district scale.

The definition of population pressure on land is a comparison of the number of people with a minimum area of land to live properly [28] (**Figure 2**).

Ideal population pressure is one that can still adjust the carrying capacity of the land. Carrying capacity of land itself is the ability of the environment to support life. The higher the percentage of land that can be used for agricultural land, the greater the carrying capacity of the land [28].

Ariani *et al.,* 2012, stated that the Population Pressure value <1 indicates that there was no population pressure or that the area was still able to meet the population's living needs in more than adequate numbers. TP value equal to 1 means that the area is still able to meet the living needs of its inhabitants appropriately. TP value is greater than 1, meaning that there has been a population pressure on the

#### **Figure 2.**

*Flow analysis of population pressure on land in Lesti sub-watershed, Malang District – East Java Province, Republic of Indonesia.*

**61**

*Determination of the Most Priority Conservation Areas Based on Population Pressure…*

land in an area so that it is unable/able to meet the living needs of its residents

Z x

Z = Minimum land area per farmer to be able to live properly

2 1

Z = Minimum land area per farmer to be able to live properly (ha)

LSI1 = The area of irrigated rice field once a year harvest (ha) LSI2 = The area of Irrigated rice field from twice a year harvest (ha)

2 1 0.25 0.5 0.5 0.76 +++ <sup>=</sup> +++

The proportion value of farmers in the population (f) is obtained from the

The population growth rate is calculated using the geometric formula as follows:

In order for calculating the rate of erosion using the formula of the MUSLE

( ) t

f Number of farmers / Total population x 100% = ( ) (3)

Population pressure on land is calculated by the formula Otto Soemarwoto [28]

<sup>+</sup> <sup>=</sup> *Po*

The minimum land area of each farmer to be able to live properly (Z value) is

( ) ( ) ( ) ( ) ( )

*LSI LSI LST LLK*

( ) t

*TP* (1)

*LSI LSI LST LLK* (2)

Pt Po 1 r = + (4)

f 1r

L

*DOI: http://dx.doi.org/10.5772/intechopen.95386*

properly.

as follows:

where

where

where

TP = Population Pressure

T = Time span in years

L = Total area of agricultural land

Po = Total population of the initial year

calculated based on the formula as follows:

LST = The area of rain-fed rice fields (ha)

formula submitted by Soemarwoto [28], namely:

t = The time period, which is stated in years

(Modify Universal Soil Loss Equation) in **Figure 3** and below

*Z*

LLK = Dry land area (ha)

r = Population growth rate

Pt = Total population in the year t Po = Total population of the initial year

F = Proportion of farmers in the population (%)

R = The average population growth rate per year

*Determination of the Most Priority Conservation Areas Based on Population Pressure… DOI: http://dx.doi.org/10.5772/intechopen.95386*

land in an area so that it is unable/able to meet the living needs of its residents properly.

Population pressure on land is calculated by the formula Otto Soemarwoto [28] as follows:

$$\text{TP} = \text{Z} \ge \frac{\text{f} \quad Po \ \text{ (1+r)}^{\text{t}}}{\text{L}} \tag{1}$$

where

*Soil Erosion - Current Challenges and Future Perspectives in a Changing World*

sure in the Lesti Sub-watershed.

heavy/very heavy at the sub-district scale.

greater the carrying capacity of the land [28].

**2.3 Research methods**

Java, Indonesia; 3) contour spatial data (issued by Indonesia Spatial Information Board), soil type, slope and plant management factors and conservation measures. In addition, several tables were agreed upon by experts from previous researchers. Some secondary data related to the agricultural sector and population from agencies such as the Central Statistics Bureau (BPS) of Indonesiaand the Ministry of Agriculture of Indonesia are also needed, particularly to analyze population pres-

The approach used is a mixed method with the population pressure analysis method using the Otto Soemarwoto [28] formula and the projected population growth using a geometric formula. The erosion rate calculation is analyzed using the MUSLE method with the support of Geographic Information System tools [29]. To calculate the erosivity of surface runoff as part of the MUSLE method, a modified rational formula is used. The software used is Arc GIS 10.3, and Microsoft Excel 2019. The level of erosion hazard is obtained by overlaying the erosion rate map analysis results with the soil solum map in the Lesti Sub-watershed in Office for Watershed Management and Protection Forest Brantas [27]. The choice of environmentally sound conservation priority areas based on the results of population

pressure analysis >1 that intersects with the level of erosion hazard that is

people with a minimum area of land to live properly [28] (**Figure 2**).

The definition of population pressure on land is a comparison of the number of

Ideal population pressure is one that can still adjust the carrying capacity of the land. Carrying capacity of land itself is the ability of the environment to support life. The higher the percentage of land that can be used for agricultural land, the

Ariani *et al.,* 2012, stated that the Population Pressure value <1 indicates that there was no population pressure or that the area was still able to meet the population's living needs in more than adequate numbers. TP value equal to 1 means that the area is still able to meet the living needs of its inhabitants appropriately. TP value is greater than 1, meaning that there has been a population pressure on the

*Flow analysis of population pressure on land in Lesti sub-watershed, Malang District – East Java Province,* 

**60**

**Figure 2.**

*Republic of Indonesia.*

TP = Population Pressure

L = Total area of agricultural land

Z = Minimum land area per farmer to be able to live properly

Po = Total population of the initial year

F = Proportion of farmers in the population (%)

T = Time span in years

R = The average population growth rate per year

The minimum land area of each farmer to be able to live properly (Z value) is calculated based on the formula as follows:

$$Z = \frac{\left(0.25\,\mathrm{LSI}\_2\right) + \left(0.5\,\mathrm{LSI}\_1\right) + \left(0.5\,\mathrm{LST}\right) + \left(0.7\,\mathrm{6}\,\mathrm{LLIK}\right)}{\left(L\mathrm{SI}\_2 + L\mathrm{SI}\_1 + L\mathrm{ST} + L\mathrm{LK}\right)}\tag{2}$$

where

Z = Minimum land area per farmer to be able to live properly (ha)

LST = The area of rain-fed rice fields (ha)

LLK = Dry land area (ha)

LSI1 = The area of irrigated rice field once a year harvest (ha)

LSI2 = The area of Irrigated rice field from twice a year harvest (ha)

The proportion value of farmers in the population (f) is obtained from the formula submitted by Soemarwoto [28], namely:

$$\mathbf{f} = \begin{pmatrix} \text{Number of frames/Total population} \end{pmatrix} \mathbf{x} \, \mathbf{100\%} \tag{3}$$

The population growth rate is calculated using the geometric formula as follows:

$$\mathbf{Pt} = \mathbf{Po} \left(\mathbf{1} + \mathbf{r}\right)^{\mathfrak{t}} \tag{4}$$

where

r = Population growth rate

t = The time period, which is stated in years

Pt = Total population in the year t

Po = Total population of the initial year

In order for calculating the rate of erosion using the formula of the MUSLE (Modify Universal Soil Loss Equation) in **Figure 3** and below
