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 JUNE 2019

OVERVIEW

Harvesting of dry season corn in Catanduanes and Hinatuan had just begun. Normal to above normal yield is expected in Catanduanes due to sufficient moisture experienced by the crops from planting to maturity. However, in Hinatuan, below normal yield is anticipated because crops experienced moisture stress during its critical stage of growth. Land preparation, planting and transplanting activities for delay planted lowland and upland palay in CAR, Region I, Region III, Ambulong, Tayabas, Coron, Cuyo, Pto. Princesa, San Jose, Legaspi, Catanduanes, Masbate, Catarman, Catbalogan, Tacloban, Zamboanga del Norte, Bukidnon, Surigao del norte and Davao region. These were made possible due to sufficient moisture available during the month in those areas. On the other hand, in Region II, Casiguran, Romblon, Region VII, Zamboanga del Sur, Misamis Oriental and General Santos, planting activities were hampered due to inadequate moisture in those areas. Standing crops in CAR, Laoag, Sinait, Baler, Tayabas, Masbate and Davao region are in good condition, but in Iba, Munos, Infanta, Calapan, Romblon, and Daet, crops are suffered from moisture stress.

The weather systems that affected the country during the month were the Southwest (SW) monsoon, tail-end of the cold front (TECF), ridge of high-pressure areas (HPAs), easterlies, low pressure areas (LPAs), and localized thunderstorms. Two tropical cyclones (TCs) entered/developed in the Philippine area of Responsibility (PAR), namely Tropical depression (TD) “Dodong” (June 25-26) and Tropical Depression (TD) “Egay” (June 30-July 01). Those two TCs did not cross the country but enhanced the SW monsoon and brought significant rainfall in most areas of western Luzon and Visayas and increased the water level in dams. Onset of the rainy season associated with the SW monsoon was officially declared on June 14.

Generally, near normal rainfall conditions were experienced in most areas of western Luzon, western and eastern Visayas and most parts of Mindanao; while Bataan, Zambales, Leyte, Southern Leyte and Davao Region received above normal rainfall. In contrast, below normal rainfall was observed over several areas in northern and eastern Luzon, including Bicol Region, Central Visayas and some parts of Mindanao.

REGIONS

Land preparation, planting and transplanting activities for delay-planted, upland 1st palay across the region now commences, made possible by the sufficient rainfall. Standing upland palay and wet season corn in the Ilocos province are now in good crop condition.
Land preparation and other farming activities are hindered by the inadequate rainfall over the region. Standing rice and corn crops were also affected by the moisture deficiency during the month.
Land preparation, planting and transplanting activities for delay-planted, upland 1st palay is on-going in all parts of the region because of the adequate moisture during the month. Standing rice and corn crops are faring well.
Sufficient rainfall received during the month favors land preparation, planting and transplanting activities for planting delay-planted, upland 1st palay throughout the region. Standing rice and corn crops are in good crop condition. However, in Casiguran, crops suffered from moisture stress due to the inadequate moisture during the month.
The ample amount of rainfall received during month is still favorable for land preparation, planting and transplanting activities for the delay-planted upland 1st palay, in Tayabas and Ambulong. In Infanta, however, farming activities related to planting delay- planted, lowland palay is not possible due to the minimal moisture available in June. Standing upland palay as well as wet season corn in Tayabas are faring well.
Land preparation, planting and transplanting activities for delay-planted, upland 1st palay had just begun in most parts of the region except in Romblon. These activities were favored by the sufficient rainfall received during the month. Standing upland palay as well as wet season corn in Romblon suffered moisture stress due to the limited moisture during the month.
Adequate rainfall received in Albay and Catanduanes favors land preparation, planting and transplanting activities for delay-planted, lowland 1st palay. The same is true to delay-planted, upland palay in Masbate. Similarly, standing upland 1st palay as well as wet season corn in Masbate are in good crop condition due to the ample amount of moisture available during the month.
Any farming activity related to planting delay-planted, lowland and upland 1st palay is not possible in any part of the region because of the minimal moisture available during the month.
Due to the insufficient rainfall received during the month, any farming activities related to planting rice and corn will not be possible across the region.
Land preparation, planting and transplanting activities for delay-planted, lowland 1st palay as well as delay-planted, upland 1st palay has begun in eastern Samar. Moisture is sufficient during the month.
Land preparation, planting and transplanting activities for delay-planted, upland 1st palay in Zamboanga del Norte had only recently started due to sufficient moisture available. On the other hand, any farming activity related to planting rice is not possible in Zamboanga del Sur because of the minimal moisture.
Sufficient moisture in Bukidnon, favored land preparation, planting and transplanting activities for delay-planted upland 1st palay. On the other hand, farming activities in Misamis Oriental are hampered by the minimal rainfall received over the area.
Due to sufficient moisture and favorable weather condition available during the month, land preparation, planting, and transplanting activities for delay-planted, upland 1st palay have just started across the region. Likewise, standing upland palay as well as wet season corn planted in May are faring well
Moisture available during the month remains inadequate for planting rice and corn in any part of the region.
Harvesting of dry-season corn has now started in Surigao del Sur; below normal yield is expected because crops experienced moisture deficiency during the critical stage of growth.
In-season fruits and vegetables are in good crop condition due to the sufficient moisture available during the month. Rice and corn crops were not planted all over the region because of the inadequate rainfall received last month.

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