Root-shoot regulation and yield of mulched drip irrigated maize on sandy soil

Document Type: Research Paper

Authors

1 College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling 712100, Shaanxi Province, China.

2 Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, Shaanxi Province, China.

3 College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, Shaanxi Province, China.

4 Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, Shaanxi Province, China

Abstract

Sandy fields have been reclaimed to exploit the grain production potential in northwest
China. A 2-year statistically replicated field study was conducted to determine the effects of
mulched drip irrigation on soil water, soil nitrate, shoot root growth and yields of maize on a
sandy field in the Hetao irrigation district. Treatments included border irrigation (BI), fully
mulched drip irrigation (FMDI) and partially mulched drip irrigation (PMDI). Low frequency
fertigation and high frequency fertigation were applied in 2014 and 2015, respectively. The
results showed that high frequency mulched drip irrigation (MDI) maintained soil moisture and
NO
3--N at suitable levels and improved soil water uniformity (Cus). Soil NO3--N was adequate
for the FMDI treatment of both high and low frequency fertigations, but it was insufficient for
the PMDI treatment under low frequency fertigation. Soil water and C
us regulated root-shoot
via leaf areas and surface root areas were described well by the ratio of root surface area to leaf
area (S
r/l). Higher Cus tended to cause a lower Sr/l. Compared with the BI treatment, a higher
yield and harvest index (HI) was obtained under the MDI treatments primarily due to the high
number of grains per spike. The FMDI and PMDI treatments resulted in no yield differences
under high frequency fertigation. Therefore, high frequency PMDI management with irrigation
amounts based on the reference evapotranspiration after the jointing stage were recommended in
the sandy maize field based on economic considerations. Under low frequency fertigation, the
FMDI treatment was recommended for a higher yield, which was attributable to the higher dry
matter of the vegetative organs and maintaining higher levels of soil NO
3--N in the upper sand
layer when compared to the PMDI treatment.

Keywords