Irrigation practices and application efficiencies in Pakistan

MOST OF THE DATA PRESENTED IN THIS STUDY WERE COLLECTED IN SCARP AREAS WHERE CANAL SUPPLY IS AUGMENTED BY TUBE? WATER? PROVIDE ABOUT ONE? PER 150 ACRES. FIRST IS A DESCRIPTION OF OBSERVED FARM WATER MANAGEMENT PRACTICES, A SORT OF HYPOTHESIS OF FARMER IRRIGATION PRACTICES, WHICH THEN ARE DOCUMENTED WITH THE DATA COLLECTED. THE METHOD USED WAS TO EVALUATE QUALITATIVELY PRACTICES AND CIRCUMSTANCES THAT CAUSE INEFFECTIVE USE OF IRRIGATION WATER. EFFECTIVENESS OF IRRIGATION WATER USE THEN WAS EVALUATED QUANTITATIVELY IN TERMS OF IRRIGATION APPLICATION EFFICIENCY. FACTORS CONTRIBUTING TO THE INEFFECTIVE USE OF WATER IN PAKISTAN ARE: 1) LACK OF WATER MEASUREMENT AND THE ASSUMPTION BY RESEARCHERS AND FARMERS THAT A CERTAIN DEPTH OF WATER ON THE FIELD MEANS A GIVEN AMOUNT OF WATER HAS BEEN APPLIED. 2) INADEQUATELY LEVELED AND IMPROPERLY DESIGNED FIELDS. 3) INFILTRATION RATES THAT CAUSE EXCESSIVE APPLICATIONS WHEN WATER USE RATES ARE LOW AND UNDER-IRRIGATION WHEN WATER USE RATES ARE HIGH. 4) THE INABILITY TO ADJUST FREQUENCY OF IRRIGATION TO CROP WATER REQUIREMENTS DUE TO THE FIXED WATER-USE SCHEDULE. IRRIGATION APPLICATION EFFICIENCIES MEASURED WAS NEAR 20 PERCENT BASED ON 64 INDIVIDUAL OBSERVATIONS. IMPROVEMENT OF ON-FARM WATER MANAGEMENT HAS A GREAT POTENTIAL FOR INCREASING THE EFFECTIVE IRRIGATION WATER SUPPLY.