Ecological effect analysis of pumpkin and oil sunflower intercropping in arid area of northwest Hebei Province: I. moisture analysis

Abstract

Experiments were conducted during 2007–2008 at the Zhangbei Agricultural Resource and Ecological Environment Key Field Research Station, Hebei Province, China to study water-efficient pumpkin planting patterns in this area. Four treatments of pumpkin and oil sunflower intercropping were used to study the problem of water resource scarcity and inefficient water use in the plateau of northern Hebei Province. The four treatments were: pumpkin sole cropping (Sp), oil-sunflower sole cropping (So), intercropping one row oil sunflower (IC1) or two rows (IC2) between pumpkin rows. The results showed that oil sunflower competed for soil water with pumpkin during late growth stage of pumpkin in IC2, but there was no water competition in IC1. Total rainfall during the growing season was 201.6 mm and the soil water balance differed between treatments. In all cases the water percolation was low and soil moisture storage always negative. Nearly all water loss was through evapotranspiration, which varied by treatment. The seasonal evapotranspiration of IC1 was less than So, Sp and IC2, 46.57%, 41.22% and 46.73%, respectively. Economic yield of pumpkin decreased from 30.00% (IC1 ) to 71.42% (IC2). However, yield per plant of intercropping oil sunflower increased from 190.71% to 241.26%, as compared with So, because oil sunflower showed remarkably partial advantage. The Land Equivalent Ratio (LER) of pumpkin-oil sunflower was 1.08–1.22, and the Water Equivalent Ratio (WER) of pumpkin-oil sunflower was 1.07–1.26. Economic value of sole pumpkin was greatest but did not differ from treatment IC1. Other treatments had significantly less economic value. In this region of rain-fed dry land farming, a sparse planting of sole pumpkin with high efficiency production could realize water resources most effectively in the Plateau of northern Hebei Province.