Impact Assessment for Agriculture
Preface

The Impact Assessment and Applications Section (IAAS) of Climatology and Agrometeorology Division (CAD) regularly issue this monthly/bulletin which will provide users such as food security managers, economic policy makers, agricultural statisticians and agricultural extension officials with qualitative information on the current and potential effects of climate and weather variability on rainfed crops, particularly rice and corn. This bulletin, entitled “Climate Impact Assessment for Agriculture in the Philippines”, represents a method for converting meteorological data into economic information that can be used as supplement to information from other available sources.

For example, an agricultural statistician or economist involved in crop production and yield forecast problems can combine the assessment with analysis from area survey results, reports on the occurrence of pests and diseases, farmers’ reports and other data sources.

The impact assessments are based on agroclimatic indices derived from historical rainfall data recorded for the period 1951 to the present. The indices, expressed in raw values percent of normals and percentile ranks, together with real time meteorological data (monthly rainfall, in percent of normal), percent of normal cumulative rainfall, as well as the occurrence of significant event such as typhoons, floods and droughts are the tools used in the assessment of crop performance. Crop reports from PAGASA field stations are also helpful.


The narrative impact assessment included in the bulletin depicts the regional performance of upland, 1st lowland and 2nd lowland palay; and dry and wet season corn crops, depending on the period or the season. Tabulated values of normal rainfall and generalized monsoon and yield moisture indices are provided for ready reference. Spatial analysis of rainfall, percent of normal rainfall and the generalized monsoon indices in percentile ranks are also presented on maps to help users visualize any unusual weather occurring during the period. The generalized monsoon indices in particular, are drought indicators; hence, the tables (see Appendices) together with the threshold values can be used in assessing drought impact, if there are any. It also helps assess any probable crop failure.

It is hoped therefore that this bulletin would help provide the decision-makers, planners and economist with timely and reliable early warning/information on climatic impact including the potential for subsistence food shortfalls, thereby enabling them to plan alternate cropping, if possible, food assistance strategies/mitigation measures to reduce the adverse impact of climate and eventually improve disaster preparedness.

Impact assessment for other principal crops such as sugarcane and coconut, for energy and for water resources management, are from time to time will be included in the forthcoming issues of this bulletin.


The IAAS of CAD will appreciate suggestions/comments from end-users and interested parties for the improvement of this bulletin.

Definition of Terms
The Generalized Monsoon Index (GMI) helps determine the performance of the rains during the season and serves as a good indicator of potential irrigation supplies. It is a tool used to assess rainfed crops.

The GMI for the southwest monsoon (GMIsw) in an area during June to September is defined as follows:
GMIsw = W6P6 + W7P7 + W8P8 + W9P9

The GMI for the northeast monsoon (GMIne) in an area during October to January is defined as:
GMIne = W10P10 + W11P11 + W12P12 + W1P1

where:

W = weight coefficient of monthly rainfall for the season;
P = rainfall amount in the ith month
(i = 1 for January, 2 = for February, etc.)

The Yield Moisture Index (YMI) is a simple index that helps the users assess agroclimatic crop conditions during the crop season. The YMI for a particular crop is defined as follows:
n YMI =  [Pi Ki] i

where:

i = crop stage (1 = planting/transplanting,
2 = vegetative, 3 = flowering, 4 = maturity, etc.)
n = total no. of crop stages;
P = rainfall during the ith crop stage; and
K = appropriate crop coefficient for the ith crop stage.

Tentatively, the threshold values of categories of indices for interpretation being adopted for both YMI and GMI are as follows:


PERCINTELE RANK INTERPRETATION
> 80 Potential for Flood Damage
41 - 80 Near normal to above-normal crop condition
21 - 40 Moderate drought impact with reduced yield
11 - 20 Drought impact with major yield losses
< 10 Severe drought impact with crop failure and potential food shortages

Agroclimatic / AGROCLIMATIC / CROP CONDITION ASSESSMENT FOR FEBRUARY 2019

OVERVIEW

In some parts of the country, harvesting of dry season corn and lowland 2nd palay had just begun; good to normal yield is expected in Baler, Casiguran, Quezon province, and CARAGA region because of sufficient moisture available to the crops during the critical stage of growth and development. Due to moisture stress, below normal yield is anticipated in Aparri, Basco, Calapan, Romblon, Cuyo, Bicol region, Panay Island, Mactan, Bahol, Catarman, Catbalogan, Zamboanga del norte, and Davao region. Because of the insufficient moisture available last November, all planting activities were hampered in Ilocos Region, CAR, Tuguegarao, Dumaguete, Zamboanga del Sur, Misamis Occidental, Bukidnon, General Santos and ARMM. Standing crops were found to be in good to normal crop condition in Baler, Casiguran, Quezon Province, and CARAGA Region, while those in Cagayan Valley, some of MIMAROPA, Panay Island, Mactan, Negros Oriental and Davao Region have moderate to poor crop condition attributed to moisture stress.

REGIONS

Persistence of low moisture across the region made it impossible to perform any farming activity.
Harvesting of dry-season corn had recently started. Below normal yield is expected because crops were under moisture stress during the critical stage of growth and development. Same is true with the vegetating late-planted, lowland palay, which are now suffering from moisture deficiency due to the minimal rainfall during the month.
Scarcity of moisture still prevailed all over the region, thus any farming activity may not be performed.
Good to normal yield is anticipated from the harvestable, dry season corn as well as lowland 2nd palay since these crops remained in good condition from planting to maturity. Likewise, the vegetating late-planted, lowland 2nd palay in Baler and Casiguran are in good condition due to the sufficient moisture available during the month.
Harvesting of dry season corn across the region and lowland 2nd palay in Quezon has started; good yield is anticipated because crops were in good condition during the critical stage of growth and development. Likewise, the vegetating late-planted, lowland 2nd palay are in good condition. The favorable crop conditions are attributed to the sufficient amount of moisture available during the month.
Harvesting of dry season corn had just begun in Calapan and Romblon, as well as the harvesting of lowland 2nd palay in Cuyo. Below normal yield is expected because crops were under moisture stress during the critical stage of growth to maturity. Similarly, the standing late-planted, lowland 2nd palay in Calapan and Romblon also experience moisture stress due to the minimal moisture available during the month.
Harvesting of dry season corn and late-planted, lowland 2nd palay across the region had just begun; below normal yield is expected because crops experienced moisture stress during the critical stage of growth. The minimal amount of moisture available during the month brought moisture stress to the standing late-planted lowland 2nd palay.
In Bohol and Mactan, the harvestable dry season is anticipated to be below normal because crops suffered moisture stress during the critical stage of growth. Likewise, the vegetating, lowland 2nd palay In those areas suffered moisture stress due to lesser amount of moisture available during the month.
Harvesting of dry-season corn had recently started; below normal yield is expected because of the inadequate moisture available to the crops during the critical stage of growth. The amount of rainfall received during the month was very low, and it stressed the standing lowland 2nd palay across the region.
Harvesting of dry season corn as well as lowland 2nd palay had just begun; below normal yield is expected because crops suffered from moisture stress during the grain filling stage.
Standing late-planted, lowland 2nd palay were affected by moisture deficiency.
Harvesting of dry season corn had just started in Zamboanga del Norte; below normal yield is expected due to moisture deficiency suffered by the crops during the critical stage of growth. The standing lowland 2nd palay are also affected by the same.
Because of insufficient rainfall received during the month since November, farming activities are hindered in all parts of the region.
Harvesting of dry season corn had just started across the region; below normal yield is anticipated because of the inadequate moisture avaiIable during the month which stressed such crops. Similarly, the vegetating late-planted lowland 2nd palay are also affected.
Rainfall amount is still minimal across the region; hence, any farming activity related to planting rice and corn cannot be performed.
Harvesting of lowland 2nd palay as well as dry season corn had just begun across the region; normal to above normal yield is anticipated because crops were maintained in good condition from planting to maturity. Similarly, the standing late-planted, lowland 2nd palay benefited from sufficient moisture available during the month.
The available moisture remains to be insufficient across the region, farming activities related to planting rice and corn are not be possible.

Ten Day Rainfall Distribution

Monthly Rainfall Distribution

Generalized Moonsoon Index

Tropical Cyclone

No Active Tropical Cyclone

Actual Rainfall and Potential Evapotranspiration

Stations

For Particulars, please contact:

THELMA A. CINCO


Impact Assessment and Applications Section (IAAS)

Climatology and Agrometeorology Division (CAD)

PAGASA-DOST

Telefax No.: 434-58-82