Optimizing water use between intercropped pea and maize through strip row ratio expansion and N fertilizer reduction in arid areas

Abstract

Abstract Water is the primary limiting factor for crop production in the semi-arid regions. It is imperative to improve water productivity in these water-limited areas. In this research, a field experiment, at Hexi Corridor of northwestern China from 2009 to 2011, was conducted to explore whether changing of strip row ratio and N fertilizer rate will affect water use in maize (Zea mays L.)/pea (Pisum sativum L.) intercropping. Two strip row ratios (i.e. 2 rows of maize and 4 rows of pea, designated as I1; and 3 rows of maize and 4 rows of pea, designated as I2) and three N fertilizer rates (i.e. 0 kg N ha−1, designated as N0; 90 and 300 kg N ha−1 for pea and maize, designated as N1; and 135 and 450 kg N ha−1 for the two crops, designated as N2) were employed in this research. The results showed that I2 improved LAI and reduced soil evaporation across whole growth period, but increased total evapotranspiration by 8.9 % compared to I1. In co-growth period, water competition in I2 was reduced by 19.3 % compared to I1. While in maize independent growth period, water compensation in I2 was improved by 17.2 % compared to I1. For N fertilizer effect, water compensation with N1 and N2 was improved by 16.2 % and 21.1 % compared to N0. The mixed grain yield with I2 was improved by 20.3 % compared to I1; and that with N1 and N2 was improved by 44.0 % and 42.8 % compared to N0. As a result, I2 improved water productivity by 10.5 % compared to I1; and N1 and N2 improved it by 43.8 % and 42.5 % compared to N0, respectively. We concluded that expanding strip row ratio coupled with lower N fertilization could improve water productivity of maize/pea strip intercropping, which is promising in arid areas to save water and achieve the sustainable development goals.