Optimizing soil matric potential and climate based irrigation scheduling to potato under different establishment methods
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Date
2015
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PAU
Abstract
An Investigation under experiment-I was conducted with the objective to determine the most appropriate installation depth of tensiometer with suitable soil matric potential for higher tuber yield and water use efficiency of potato under furrow-ridge irrigation system at Vegetable Research Farm, Punjab Agricultural University, Ludhiana during 2011-12 and 2012-13. Three levels of soil matric suction (S); 20, 35 & 50 kPa at three installation depths (D) of tensiometer; 20, 30 & 40 cm and a control (traditional practice) were replicated thrice in RCBD. The pooled analysis of data showed that treatments S20D20 and S35D20 recorded 86 and 82% higher marketable tuber yield compared to the control. The WUE under S35D20 treatment was upto177% higher than control when data was pooled over two years. Highest dry tuber yield was recorded in S35D20 treatment among all the treatments during both the years. The analysis of pooled data for marketable and graded tuber yield, average tuber weight, discarded percent of tubers, root dry weight, lower content of reducing sugars and higher percent of starch and protein content, plant height at harvest and above ground dry matter accumulation 30, 60 DAP and at harvest also favoured S35D20 and S20D20 treatments. However averaged over two years, WUE and WUEi of S35D20 was more than double as compared to control treatment along with higher marketable tuber yield as 49 % irrigation water was saved. The results revealed that treatment S35D20 was the best treatment for irrigation scheduling in the region. Further, experiment-II was conducted in split plot design with four replications to compare the climatic based irrigation scheduling with S35D20 under ridge-furrow (M1) and bed-furrow planting (M2) system during 2012-13 and 2013-14. Two rows were planted on each bed under furrow-bed planting system. The treatments consisted of five irrigation levels: I1; IWCPE (Irrigation water to cumulative pan evaporation) ratio 1.0, I2; IWCPE ratio 1.25, I3; IWCPE ratio 1.5, I4; S35D20 (tensiometer installed at 20 cm soil depth maintaining SMP of -35 kPa) and I5; control (farmers practice in the region). The ridge-furrow method of planting (M1) showed its advantage over the bed-furrow method of planting (M2) in terms of recording higher WUE, average tuber weight, marketable tuber yield, large and medium sized tuber yield, plant height at 60, 75 DAP and at harvest as well as above ground dry weight accumulation at the time of harvest. Almost three times higher water use efficiency was recorded by S35D20 as compared to control treatment (farmer’s practice) under M1 method of planting. This irrigation treatment was superior in terms of plant height, above ground DMA at 60 DAP and at harvest, graded and marketable tuber yield, starch and protein content and has lower discarded percent of tubers among all other treatments. The results of two experiments suggest that scheduling irrigation based on soil matric potential at -35 kPa SMP with tensiometer installing at soil depth of 20 cm under ridge-furrow irrigation system was better option under North-Western plains of India. Adopting this threshold corresponds to 3 to 4 irrigations of 45 to 45.5 mm each depending on the rainfall during potato growing period. Two separate irrigations of 50 mm each were applied, first as pre-planting irrigation and second irrigation to substantiate emergence. Thus, application of single irrigation two weeks after the complete emergence of crop and remaining 2-3 irrigations at 17 days interval may save irrigation water as compared to the traditional irrigation practice.
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Keywords
irrigation, fungi, planting, yields, potatoes, crops, drying, cultivation, land resources, irrigation water