Ridge-furrow planting with biodegradable film mulching over ridges for rain harvesting improving root growth and yield of maize

Abstract: Plastic film mulching can reduce soil evaporation and improve water use efficiency, thereby relieving water shortage and steadily increasing crop productivity in arid and semi-arid region of China. For such reasons, plastic mulching film has been increasingly used, which leads to many negative effects such as environment pollution and land degeneration. Biodegradable film is considered to be a promising way to solve such problems caused by plastic film without compromising its positive effects. Many studies focus on the effects of biodegradable film mulch on soil water storage and maize growth, but few has dedicated to the effect of biodegradable film mulching combined with planting patterns on maize growth. Therefore, this study aimed to investigate the effects of biodegradable film with plating patterns on soil water storage, maize root growth and maize yield. A field experiment was carried out from June to November in 2013 and 2014, respectively. Four kinds of treatments were designed using complete randomized block design with three replicates, respectively: flat planting without mulching (CK), flat planting with biodegradable film mulching (M1), ridge-furrow planting with biodegradable film mulching over ridge only (M2) and ridge-furrow planting with biodegradable film mulching over ridges (M3). The maize variety was Luodan 9 for the two-year experiments. Soil moisture of 0-200 cm depth during different growth stage and before and after a rainfall, maize yield and root growth (including root length, root surface area, root volume and total root dry weight) in the maize mature stage under different mulching patterns were measured. The correlation between soil water storage capacity and root indicators, water use efficiency and yield was analyzed. Results showed that degradation of films under different plating patterns was similar. The mulching treatments all played an important role in rainfall harvesting. With the degradation of biodegradable film, the capacity of rainwater harvesting under all mulching treatments reduced. Average soil water storage of two years under M1, M2 and M3 was significantly (P<0.05) higher than that under CK in 2013 and 2014, and increased by 7.40%, 9.54% and 13.21% than CK respectively. Water consumption under three mulching treatments in 2013 and 2014 was significantly (P<0.05) lower than that of CK, mainly due to the fact that biodegradable mulching film reduces land surface evaporation effectively. The root length, root surface area, root volume and total root dry weight under three mulching treatments were all significantly (P<0.05) higher than those under CK，and root length density for maize in mature periods under M1, M2 and M3 were improved by 9.23%, 13.85% and 16.92% compared to CK, respectively. The reason of such a difference between CK and three treatments might be the improvement of water storage capacity and root growth of maize under three mulching treatments. The correlation coefficient between water storage capacity and total root length was 0.83, while the correlation coefficient between water storage capacity and root surface area was 0.77. Compared to CK, the average yield in 2013 and 2014 under treatments of M1, M2 and M3 increased by 16.03%, 18.53%, 40.22%, average water use efficiency in the two years increased by 21.29%, 26.57%, 57.27%, and average rainfall use efficiency increased by 13.98%, 19.57%, 35.65%, respectively. Water storage capacity had significant positive correlation with grain yield and water use efficiency and the correlation coefficient was 0.91 and 0.86 respectively. Evapotranspiration had significant negative correlation with grain yield and water use efficiency and the correlation coefficient was 0.77 and 0.86, respectively. Comparably, M3 was best among the three treatments in improving soil water storage, root growth and yield of maize, and ridge-furrow planting with biodegradable film mulching over ridges could be an effective method for maize cultivation in drought area.