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 2020

OVERVIEW

Harvesting of lowland 2nd palay and dry season corn has now started in most areas of the country. Good to above normal yield is expected in Tuguegarao, Tayabas, Infanta, Alabat, Calapan, Daet, Legaspi, Virac, Masbate, Catarman, Catbalogan, Tacloban, Surigao del Norte and Surigao del sur while in Ilocos sur, Ilocos Norte, Baler, Casiguran, Ambulong, most parts of MIMAROPA, Panay Island, Mactan, and Dipolog below normal yield is anticipated. Standing late-planted lowland 2nd palay crops is in good crops condition in Casiguran, most of CALABARZON, BIcol Region, Mactan, Catarman, Tacloban, Surigao del Sur and Surigao del Norte. Contrastingly, standing crops in Cagayan Valley, Baler, Ambulong, most parts of MIMAROPA, Panay Island, and Dipolog experienced moisture stress. Land preparation and planting for early-planted wet season corn had just begun in Casiguran, most parts of CALABARZON, Daet, Catarman, Tacloban, Surigao del Norte and Surigao del sur because of adequate rainfall received during the month. While in Baler, most parts of Bicol Region, Catbalogan, Butuan, and ARMM planting activities are hampered due to insufficient moisture available in those areas.

The weather systems that affected the country during the month were the Northeast (NE) Monsoon, Low pressure Areas (LPAs), Tail end of Cold Front (TECF), Easterlies, localized thunderstorm and Inter-tropical convergence zone (ITCZ). No tropical cyclones had developed or entered in the Philippine Area of Responsibility (PAR).

Assessment of rainfall for the month showed that way to below normal rainfall conditions were experienced over Northern Luzon and most areas of Mindanao but Visayas and most parts of Central Southern Luzon received near to above normal rainfall.

REGIONS

Harvesting of lowland 2nd palay in Ilocos sur and Ilocos Norte now started; below normal yield may be anticipated because crops experienced moisture deficiency during its critical stage of growth.
Harvesting of dry season corn now started in Cagayan Valley. Yield is expected to be good despite moisture deficiency occurred during the month. Standing December planted lowland 2nd palay now suffered moisture stress.
Moisture deficiency are still prevalent across the region; currently, any farming activity related to planting rice and corn will not be possible.
Harvesting of lowland 2nd palay as well as dry season corn had just begun in Aurora province; yield is expected to be below normal due to insufficient moisture experienced by the crops during its critical stage of growing down to maturity. The standing late-planted lowland 2nd palay is also affected by moisture deficiency, but in Casiguran crops recovered because of sufficient moisture received during the month. Land preparation and planting of early –planted wet season corn had just started in Casiguran while in Baler planting of corn crops is hampered.
Harvesting of lowland 2nd palay and dry season corn had just begun in most parts of the region; yield is expected to be normal to above normal while in Batangas, below normal yield is expected due to moisture deficiency suffered by the crops during vegetative stage. The standing late-planted lowland 2nd palay in Quezon is faring well but in Batangas, crops suffered moisture stress. Land preparation and planting of early-planted wet season corn in Quezon now started but in Batangas, planting activities are hampered due to insufficient moisture available during the month.
Harvesting of lowland 2nd palay and dry-season had just begun most parts of the region; good to normal yield is projected in Calapan but in other parts, below normal yield is anticipated because crops experienced moisture stress during its critical stage of growth and development. Standing late-planted lowland 2nd palay crops suffered moisture stress in most areas of the region.
Harvesting of lowland 2nd palay as well as dry-season corn had just started all over the region; normal to above normal yield is anticipated because crops experienced sufficient moisture from planting to maturity. The standing December planted lowland 2nd palay continuous to experienced good crops condition. Land preparation and planting of early planted wet season corn now started in Daet but in most parts of the region such activity may be hampered due to insufficient moisture available in those areas.
Harvesting of dry-season corn had just commence in Cebu. Below normal yield is expected this season due to moisture deficiency experienced by the crops during vegetative stage. The standing late-planted lowland 2nd palay planted last December is in good crops condition duet to sufficient moisture available during the month.
Harvesting of dry season had just started in most parts of the region; below normal yield is anticipated because crops experienced negative condition throughout its growing period. On the other hand, standing rice crops experienced moisture deficiency due to very minimal rainfall received during the month.
Good weather and sufficient moisture available during the month favored the harvestable lowland 2nd palay in Catarman; normal to above normal yield is anticipated. Likewise, the harvestable dry-season corn in most parts of the region promises good yield to above normal yield, because crops experienced good condition from planting to maturity. The standing late-planted lowland 2nd palay planted last December experienced good crops condition except in Catbalogan. Land preparation and planting of early-planted wet season had just begun in Catarman and Tacloban, but not in Catbalogan, due to moisture insufficiency available in that particular area.
Harvesting of dry-season corn had just started; below normal yield is expected due to moisture stress experienced by the crops during vegetative stage. The crop condition of the standing late-planted lowland 2nd palay generally getting unfavorable. It is because of very low rainfall received during the month.
Due to insufficient moisture available during the month, any farming activities related to planting rice and corn may not be undertaken in any part of the region.
Any farming activities to be done relative to planting rice and corn may be hampered because of very low rainfall received during the month.
Inadequate moisture available during the month related to planting rice and corn may not possible to done across the region.
Harvesting of lowland 2nd palay as well as dry season corn had just commenced across the region; yield is anticipated to be normal to above normal, because crops experienced good condition from planting down to maturity. The standing late-planted lowland 2nd palay is faring well. Sufficient moisture available during the month favors land preparation and planting early-planted wet season corn.
Rainfall in February is inadequate for any farming activities to be done across the region, that is why planting of early–planted wet season corn may be hampered.

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