OPTIMIZING IRRIGATION AND NITROGEN USE WITH STRAW MULCHING IN POTATO (Solanum tuberosum L.)
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Date
2011
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Abstract
Water and fertilizer are important factors influencing growth, development and tuber yield of potato. Depleting ground water and increasing cost of fertilizers necessitates that these inputs are used efficiently. Straw mulching is likely to enhance tuber yield and conserve irrigation water and fertilizer. A field experiment was conducted at the research farm of the Department of Soil Science, Punjab Agricultural University, Ludhiana on loamy sand soil to optimize irrigation and fertilizer N use of potato with straw mulching. Two rates of rice straw mulch (0 and 6 t ha-1) were imposed in the main plots, three irrigation levels based on IW/PAN-E = 1.0, 1.5 and 2.0 in sub plot and four levels of N @ 0, 135, 180 and 225 kg ha-1 in sub-sub plot. Results revealed that mulching helped to store 5-22 mm more soil moisture in 0-120 cm profile and the differences were larger in top 15 cm layer. Straw mulch lowered maximum soil temperature at 5 cm depth by 0.4 to 7.3°C and raised minimum temperature by 0.4 to 2.9°C. Irrigation water input with IW/PAN-E = 2.0, 1.5 and 1.0 was 24, 16 and 12 cm, respectively. Mulching recorded 25per cent improvement in tuber yield. The WUE improved with N levels and decreasing irrigation water inputs. Mulching also improved irrigation water use efficiency (WUE) by 26.2 kg tuber ha-1 mm-1. Optimum irrigation for maximum tuber yield was at IW/PAN-E =2.0 without mulch and 1.5 with mulch. Tuber yield improved with fertilizer N upto 225 kg ha-1 without mulch but only upto 180 kg N ha-1 in mulched plot. Mulching increased nitrogen use efficiency and it decreased with increasing N rate. Mulching reduced weed infestation and recorded larger size (>50mm) tubers. To conclude, mulching improved tuber yield besides saving irrigation water and fertilizer N.