Impact of Practice Change on Runoff Water Quality and Vegetable Yield—An On-Farm Case Study

Author

Gunasekhar Nachimuthu (guna.nachimuthu@dpi.nsw.gov.au), Neil V. Halpin (neil.halpin@daf.qld.gov.au) and Michael J. Bell (m.bell4@uq.edu.au)
Additional contact information

Agriculture, 2017, vol. 7, issue 3, 1-22

Abstract: Intensive agricultural practices in farming systems in eastern Australia have been identified as a contributor to the poor runoff water quality entering the Great Barrier Reef (GBR). A field investigation was carried out to measure the off-farm water quality and productivity in a coastal farming system in northeastern Australia. Two vegetable crops (capsicum and zucchini) were grown in summer 2010–2011 and winter 2011 respectively using four different management practices (Conventional—plastic mulch, bare inter-row conventional tillage and commercial fertilizer inputs; Improved—improved practice with plastic mulch, inter-row vegetative mulch, zonal tillage and reduced fertilizer rates; Trash mulch—improved practice with cane-trash or forage-sorghum mulch with reduced fertilizer rates, minimum or zero tillage; and Vegetable only—improved practice with Rhodes grass or forage-sorghum mulch, minimum or zero tillage, reduced fertilizer rates). Results suggest improved and trash mulch systems reduced sediment and nutrient loads by at least 50% compared to conventional systems. The residual nitrate nitrogen in soil accumulated at the end-of-break crop cycle was lost by deep drainage before the subsequent sugarcane crop could utilize it. These results suggest that future research into establishing the linkages between deep drainage, groundwater quality and lateral movement into adjacent streams is needed. The improvement in runoff water quality was accompanied by yield reductions of up to 55% in capsicum and 57% in zucchini under trash mulch systems, suggesting a commercially unacceptable trade-off between water quality and productivity for a practice change. The current study has shown that variations around improved practice (modified nutrient application strategies under plastic mulch, but with an inter-space mulch to minimize runoff and sediment loss) may be the most practical solution to improve water quality and maintain productivity. However, more work is required to optimize this approach and thus reduce the size of any potential productivity and profitability gap that would necessitate an expensive policy intervention to implement.

Keywords: capsicum; zucchini; runoff; nutrients; sediments; GBR (search for similar items in EconPapers)
JEL-codes: Q1 Q10 Q11 Q12 Q13 Q14 Q15 Q16 Q17 Q18 (search for similar items in EconPapers)
Date: 2017
References: View references in EconPapers View complete reference list from CitEc
Citations Track citations by RSS feed

Downloads: (external link)
http://www.mdpi.com/2077-0472/7/3/30/pdf (application/pdf)
http://www.mdpi.com/2077-0472/7/3/30/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: http://EconPapers.repec.org/RePEc:gam:jagris:v:7:y:2017:i:3:p:30-:d:93190

Access Statistics for this article

Agriculture is currently edited by Prof. Dr. Les Copeland

More articles in Agriculture from MDPI, Open Access Journal
Series data maintained by XML Conversion Team (xml-conversion@mdpi.com).

For further details log on website :
http://econpapers.repec.org/article/gamjagris/v_3a7_3ay_3a2017_3ai_3a3_3ap_3a30-_3ad_3a93190.htm