Alternate or equal ridge-furrow pattern: Which is better for maize production in the rain-fed semi-arid Loess Plateau of China?

Ridge-furrow with plastic film mulch is a key method now used by local farmers to overcome the challenges of cooling and low rainfall in a production of major food grains in the semi-arid Loess Plateau of China. Field experiments were conducted over two consecutive seasons, 2014 and 2015, to determine if alternating or equal ridge-furrow patterns would increase maize (Zea mays L.) growth and grain yield. The experiment comprised five treatments: (1) flat-bare plot (CK); (2) ridge-furrow with equal ridge widths of 55 cm (RFE); (3) ridge-furrow with alternating wide (0.7 m) and narrow (0.4m) ridges (RFA); (4) ridge-furrow with equal ridge widths and completely mulched by plastic (colorless and transparent polyethylene) film (RFME); and (5) ridge-furrow alternating wide and narrow ridges, completely mulched with the film (RFMA). Grain yields for RFE, RFA, RFME and RFMA were -23.3%, -18%, 185% and 177% in 2014, respectively, and -22.3%, -6.7%, 207% and 215% in 2015, respectively, less/more than CK. Correspondingly 100-seed weights of grain were -12.6%, -4.6%, 79% and 63% different than CK CK in 2014, and -6%, -1.2%, 78% and 86% in 2015. Corresponding total plant dry mass (DM) was 4.6%, -0.4%, 53.4% and 51.3% less/more than Cl( in 2015; and maximum leaf area index (LAI) differed from CK by -0.15, -0.15, 0.42 and 0.45 m(2) m(-2) in 2015. The yield was highest for RFME in 2014 (6780 kg ha(-1)) and for RFMA treatment in 2015 (6250 kg ha(-1)). There were no significant differences in grain yield, 100-seed weight, DM and LAI among CK, RFE and RFA or between RFME and RFMA; however, there were significant differences between each of CK, RFE or RFA and either RFME or RFMA due to the effect of plastic mulch. This effect was associated with significant increases in both soil moisture and temperature: in the first half of the season in 2014, topsoil temperatures (at 10 cm depth) of RFE, RFA, RFME and RFMA treatments were 0 degrees C, 0 degrees C, 1.7 degrees C and 1.6 degrees C higher compared with CK, respectively; and correspondingly in 2015, soil water storage (SWS) within 0-140 cm depth was 1.3, 1.7, 9.2 and 7.2% higher. Without film mulch, the patterns of equal and alternate ridge widths had no significant effect on yield components, LAI, DM, SWS and soil temperature during both seasons. Nevertheless, the alternate pattern with film mulch is useful and necessary for labor to pass through crop rows during crop tending, as well as being a better method for maize production in this semi-arid rain-fed area. (C) 2016 Elsevier B.V. All rights reserved.