Science Letters

Impacts of Residual Boron on Wheat Applied to Previous Cotton Crop under Alkaline Calcareous Soils of Punjab

Abid Niaz 1*, Allah Nawaz 1, Shabana Ehsan 1, Ifra Saleem 1, Muhammad Ilyas 1, Abdul Majeed 1, Atif Muhmood 1, Atta Muhammad Ranjha 2, Rahmatullah 2, Nazir Ahmed 2

1 Soil Chemistry Section, Institute of Soil Chemistry and Environmental Sciences, Ayub Agricultural Research Institute, Faisalabad, Pakistan

2 Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad, Pakistan

Abstract

Cotton and wheat are two most important crops of Pakistan. Food and Agriculture Organization of the United Nations reported that boron deficiency occurred widely in Pakistan, especially under cotton-wheat cropping system. High soil pH and CaCO3 content are the major factors of low boron (B) availability in alkaline calcareous soils; therefore, this study was conducted to assess the leftover effects of B on wheat in these soils. For this purpose ten B treatments (0, 0.25, 0.50, 0.75, 1, 1.25, 1.50, 1.75, 2 and 3 kg B/ha) as boric acid were applied to cotton. After the harvesting of cotton, wheat was sown in the same plots as a test crop without B application, but all other nutrients were applied at recommended rates. Soil analysis showed that B concentration gradually increased from 0.17 mg/kg (at control) to 0.36 mg/kg (at 3 kg B/ha) after the cotton harvest in B application plots. The average highest soil B concentration of 0.24 mg/kg was obtained after first year cotton harvest followed by second year (0.21 mg B/kg) whilst the lowest soil B concentration of 0.19 mg/kg was obtained after the third season of cotton. This study revealed that residual B applied to previous cotton crop has a significant effect on wheat crop in terms of yield and growth. No toxic effect of residual B was observed in wheat. The highest grain yields of 4.70 t/ha and 4.58 t/h were obtained from 1.50 kg B/ha treated plots during first and second years, respectively while the minimum was obtained from control. There was a highly significant linear relationship (P<0.05) between residual B levels and plant B content of the first wheat crop (R�= 0.96**) and second wheat crop (R�= 0.93**) seasons.

Keywords Alkaline, boron, calcareous, residual effect, Pakistan.

Received December 16, 2015 Accepted February 25, 2016 Abstract Published March 15, 2016 Manuscript Published April 15, 2016

*Corresponding author Abid Niaz Email draniazch@gmail.com