Asian Research Thesis Index

Abstract

Macronutrients (N, P, and K) along with micronutrients particularly zinc promote successful crop growth under drought stress. Zinc (Zn) is an essential micronutrient involved in photosynthesis and as an enzyme antioxidant-cofactor. Its deficiency may cause severe growth reduction and may also delay the crop maturity. Drought stress is the principal threat to crop productivity worldwide. Approximately, one third of the cultivated area of the world suffers from perpetual drought. Drought stress is an alarming global issue with severe consequence to human well being. In Pakistan, yield of maize (Zea mays L.) is often reduced by drought, and the severity of the problem may increase due to the protected climate change. Therefore, developing different approaches to mitigate drought stress are inevitable to minimize the losses in crop production. This study was conducted at the Agronomic Research Area, University of Agriculture, Faisalabad, Pakistan during spring of 2013/2014. For this, a 2-year field study was conducted to assess the effects of drought on maize hybrid growth, productivity, and yield level changing, etc. It was adjusted as a randomized complete block design to assess the yield variation of the hybrid maize involving a split plot arrangement with three replications. Three soil moisture regimes were maintained as main plot and included: (I1) well-watered treatment, (I2) mild drought with 25 mm of potential soil moisture deficit (PSMD), and (I3) severe drought with 50 mm of PSMD. Nutrients levels were laid out as sub-plots and included:T1 (Control), T2 (200 kg ha-1 N), T3 (300 kg ha-1 N), T4 (12 kg ha-1 Zn), T5 (200 kg ha-1 N + 12 kg ha-1 Zn), T6 (300 kg ha-1 N + 12 kg ha-1 Zn) in first experiment, while in 2nd experiment sub plots treatments were as follows (T1) control, (T2) 100 kg ha-1 K, (T3) 150 kg ha-1 K, (T4) 12 kg ha-1 Zn, (T5) 100 kg ha-1 K + 12 kg ha-1 Zn, and (T6) 150 kg ha-1 K + 12 kg ha-1 Zn.All of the allometric and agronomic parameters like leaf area index, leaf area duration, crop growth rate, plant population, number of grain rows cob-1 and 1000- grain weight were strongly affected by drought. Obtained results were showed that application of Zn with higher doses of N and K strongly improved of the maize root growth, and it was the most cost-effective approach under drought stress conditions. The highest grains yield of (8.57 t ha-1 and 8.12 t ha-1 in 2013 and 8.76 t ha-1 and 8.04 t ha-1 in 2014) were obtained by (I1T6) treatment combination which was resulted in well-watered and fertilized plot with higher doses of nutrients during 2013/2014. Hence, higher rates of N and K with Zn can be used to enhance maize production and net income under well-watered field conditions.

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