Abstract:
Degraded soils in Northwest China are mostly nonproductive due to imbalanced
nutrient and inadequate water supply. The effects of manure application at three
different rates (7.5, 15.0, and 22.5 t ha–1) combined with chemical fertilizers on soil water
and Water-Use Efficiency in maize [compared with chemical fertilizers (control)], under
semi-arid conditions in dark Loessial soil and over a period of four years were studied to
provide scientific support for water management. High manure application significantly
reduced soil water evaporation throughout the fallow period as compared with control. It
significantly increased soil water storage capacity at the big trumpet growth stage of the
crop, and with the fertilization application years continued (P< 0.05). Manure application
improved soil water holding capacity at the tasseling and grain filling stages. It decreased
evapotranspiration at the jointing–big trumpet and tasseling–grain filling stages. It as
well improved Water-Use Efficiency by 16.67 to 295.42% at the jointing–big trumpet
stage vs. 9.38-68.96% at the tasseling-grain filling stage and 8.51 to 36.58% for the whole
growth period of the crop maize. With a continuation of the fertilizer application years,
water-use efficiency at the tasseling-grain filling stage was significantly improved with
increasing manure application rates (P< 0.05). Medium and High Manure application
rates significantly increased water-use efficiency at the big trumpet–tasseling and grain
filling-maturity stages as compared with control (P< 0.05). With manure application
years continued, soil nutrient was no longer the major factor limiting the crop’s water-use
efficiency. The most promising manure application rate adopted to improve water-use
efficiency was recorded as 15.0 t ha–1
.
Keywords: Dry land, Farmyard manure, Soil water storage, Water use efficiency.