Nagraj Rao Statistician Asian Development Bank CROP CUTTING: AN INTRODUCTION

INTRODUCTION Importance of timely and reliable crop production statistics  Relevance to mitigating food security issues  Planning government interventions in the agriculture sector Usual methods to estimate rice crop area and production estimates  Administrative reporting systems  Satellite data  Household surveys: Recall based or Crop Cutting

ADMINISTRATIVE REPORTING SYSTEM ADVANTAGES Inexpensive Time efficient DISADVANTAGES Measurement errors Biased Unreliable Overestimated

SATELLITE BASED TECHNOLOGY Can also be combined with administrative records or survey data ADVANTAGES Can provide forecasts for better policy planning Time efficient and allows for multiple estimates a year Potentially cost efficient DISADVANTAGES Quality of estimates still needs to be explored Requires ground-truthing and validation activities for tune up

HOUSEHOLD SURVEYS Two methods : Farmer recall and Crop-cutting ADVANTAGES (if objectively designed) Unbiased Reliable Estimates within an acceptable confidence interval Measurement errors minimized DISADVANTAGES Large budgets needed Long time taken to collect data, clean and analyze

CROP CUTTING Implemented on plots where rice are grown to obtain objective estimates of rice yield. Requires the identification of randomly selected sub-plots where crop cutting will be performed. NOTE: A PLOT IS A CONTINUOUS PIECE OF LAND ON WHICH 1) A UNIQUE CROP OR A MIXTURE OF CROPS IS GROWN, UNDER A UNIFORM, CONSISTENT CROP MANAGEMENT SYSTEM. 2) IT MUST BE CONTINUOUS AND SHOULD NOT BE SPLIT BY AN OBSTRUCTION (E.G. RIVER OR PATH ETC.) OF MORE THAN ONE METRE IN WIDTH. 3) FARM BOUNDARIES ARE DEFINED ACCORDING TO THE CROPS GROWN AND THE OPERATOR.

KEY DIFFERENCE BETWEEN STANDARD CROP CUTTING AND TA 8369 CROP CUTTING METHOD List Sampling Frame versus Area Sampling Frame  List frame: Uses census sampling frame to identify a random selection of households  farms owned by households  obtain crop cutting from farms owned by household  Area Frame: Using remotely sensed data, classify land into different land uses (in our case rice)  selected a random number of areas where rice is grown (in our case 200m x 200m)  do a complete enumeration of all plots within these random number of areas.

AREA SAMPLING FRAME CLOSED SEGMENT APPROACH  Only ask about portion of the plot within the 200m x 200m area  Farmers will find it hard to respond for a portion of their plot MIXED SEGMENT APPROACH  Ask about the full plot even if only part of it falls within the 200m x 200m area  Adjust values for what lies within the 200m x 200m.

200 m

FARMER’S PLOT

AREA TO BE ASKED ABOUT IN CLOSED SEGMENT APPROACH

FARMER’S PLOT AREA TO BE ASKED ABOUT IN MIXED SEGMENT APPROACH

CLOSED SEGMENT APPROACH VERSUS MIXED SEGMENT APPROACH CLOSED SEGMENT APPROACH  Difficult to implement – farmer’s don’t know about a portion of their farm MIXED SEGMENT APPROACH  More practical, and adjustments are easy to make from the statistical point of view.

METHODOLOGY FOR CROP CUTTING FOR TA 8369 Step 1: Design a questionnaire and manual for crop- cutting. Step 2: Identify all 200m x 200m meshes where rice is grown  This will be done during ground-truthing Step 3: Within the 200m x 200m meshes where rice is being grown, identify the different plots and owners.

METHODOLOGY FOR CROP CUTTING FOR TA 8369 Step 4: Perform crop cutting on all plots identified  Utilization of mixed segment approach (similar to US NASS)  Selection of crop cutting sub plots should be randomized

PLOT 1 PLOT 2 PLOT 3 PLOT 4 PLOT 5 PLOT 6 PLOT 7 PLOT 8 PLOT 9

PLOT 1 PLOT 2 PLOT 3 PLOT 4 PLOT 5 PLOT 6 PLOT 7 PLOT 8 PLOT 9

METHODOLOGY FOR CROP CUTTING FOR TA 8369 Step 5: Measurement Procedure  With the consent of the farmer, harvest all of the rice contained within the sub plot area.  The fresh weight of the crop cut rice harvested will be weighed at this time to get total weight. p/what-is-harvesting/cutting-the-rice-crop

METHODOLOGY FOR CROP CUTTING FOR TA 8369 Step 5: Measurement Procedure  Haul the rice to a safe place – make sure there are no losses. harvesting/cutting-the-rice-crop

METHODOLOGY FOR CROP CUTTING FOR TA 8369 Step 5: Measurement Procedure  Next, thresh the rice into the grain that is in paddy form (with the shell) and weigh this threshed rice after checking the moisture. All pictures taken from : rse/index.php/what-is-harvesting/cutting-the-rice-crop

METHODOLOGY FOR CROP CUTTING FOR TA 8369 Step 5: Measurement Procedure  Then, dry the threshed rice and then take the dry weight using the scales provided to you. This rice will still be in paddy form (with the shell).

METHODOLOGY FOR CROP CUTTING FOR TA 8369 Step 5: Measurement Procedure  Next, clean the grain. Cleaning means removing all the materials other than the grain. This could be sand, stones, straw, weeds and so on. This includes the chaff. ncourse/index.php/what-is-harvesting/cutting- the-rice-crop

METHODOLOGY FOR CROP CUTTING FOR TA

METHODOLOGY FOR CROP CUTTING FOR TA 8369 Step 5: Measurement Procedure  Take the dry weight of the shelled rice using the scales provided to you.  This dry weight is the most critical piece for yield calculations.

QUESTIONS?? For More Information: (Community for Agricultural and Rural Statistics)

AFTER CROP CUTTING FIELD ACTIVITY Double data entry of the data collected for data verification. Creation of database for storing the data. Data cleaning and analysis for calculation of yield and production information. Conduct of farmer recall survey to facilitate comparison with crop cutting (Q1 2016).

YIELD/PRODUCTION CALCULATIONS For each subplot, we measure the quantity of rice harvested. Let us say this is q1 for sub-plot 1, q2 for subplot 2 etc. Calculate the area that falls within the 200m x 200m mesh for each plot. Use unitary method to calculate production for each plot, accounting for rice area rate within the 200m x 200m. Aggregate production information within each plot to the 200m x 200m. Aggregate production information for the full province using sampling weights.