Effect of Plastic Mulching and Maize Density on Shoot and Root Allocation
Ibrahim M. Eldoma *
Faculty of Agriculture, University of Zalingei, Zalingei (P.O. Box 6), Sudan.
Feng-Min Li
State Key Laboratory of Grassland Agro-ecosystems, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu Province, China.
Fang Zhang
State Key Laboratory of Grassland Agro-ecosystems, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu Province, China.
Li Ming
State Key Laboratory of Grassland Agro-ecosystems, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu Province, China.
*Author to whom correspondence should be addressed.
Abstract
In rainfed at dry and cool regions, soil moisture and temperature of crop rootzone are possibly managed with effective mulching materials to increase plant biomass production. This study aimed at understanding the effect of maize (Zea mays) planting density in a ridge-furrow system covered with plastic film on the shoot and root biomass. Five treatments were studied during spring 2014 and 2015 in the semi-arid region, northwestern China: medium density planted in bare soil (BMD, with 45×103 plants/ha), lower density in mulched ridge-furrow (MLD), medium density in mulched ridge-furrow (MMD), high density in mulched ridge-furrow (MHD) and extra-high density in mulched ridge-furrow (MXD). Full mulching with a polyethylene film was applied in MLD, MMD, MHD, and MXD with plant populations of 35, 45, 65, and 72 x 103 plants/ha, respectively. Plastic mulching and increased densities increased shoot biomass significantly, so over the two seasons, BMD was lower than MLD, MMD, MHD, and MXD by 28%, 35%, 52%, and 61%, respectively. However, BMD was higher than those treatments in root:shoot ratio (r/s) by 37%, 34%, 48% and 6.0%, respectively. Increased density promoted the growth of shoots more than roots. MMD was, therefore, higher r/s than MHD and MXD by11% and 19%, respectively. Correlations show that the r/s tends to decrease as the crop growth stage advances. During early vegetative stages, growth rates of shoots and roots in BMD were significantly lower. In general, the higher densities showed lower r/s and produced more aboveground biomass and grain yield. Consequently, improving maize grain yield by understanding the increase in plant biomass allocation to the shoots compared to roots and promoting shoot biomass allocated to grain fill is a recommended goal for further research.
Keywords: Tassel, Cool and dryland, Wood, grain yield, Seeding,, Chinese Plateau, epigeal germination, ridge-furrow, soil water conservation