Optimum leaf excision increases the biomass accumulation and seed yield of maize plants under different planting patterns

Abstract

Without developing new agronomic practices, present rates of improvement in seed yields of cereal crops globally are insufficient to fulfil the estimated increasing food demand for 2050 and beyond. Intercropping is one of the agricultural practices that can lead to greater crop yields. However, there exists leaf redundancy for maize in intercropping systems, and the top canopy leaves shade more competent leaves at middle strata of maize plants. Therefore, this work aimed to elucidate the effect of leaf excision treatments in maize to understand the optimum leaf area of maize plants under a maize-soybean relay-intercropping system (MS R ) and a sole cropping system (SM). The effects of four-leaf excision treatments (T 1 , 0; T 2 , 2; T 3 , 4; T 4 , 6 leaves excised from the top of maize plants until 7 days after silking) on light interception, leaf area index (LAI), photosynthetic characteristics, total biomass accumulation at blistering stage (BS), dough stage (DS) and physiological maturity (PM), and seed yield of maize were investigated through field experiments for 2 years under MS R and SM. Results showed that, under MS R and SM, as compared to control (T 1 ), optimum excision of leaves (T 2 ) from the top of maize plants significantly improved the light interception (by 25, 18 and 16% at BS, DS and PM, respectively) to lower strata leaves and accelerated the biomass partitioning to maize seeds (by 13 and 12% at DS and PM, respectively). Importantly, plants under T 2 exhibited higher green leaf area than control, that is, excision the top two leaves led to an increase in LAI at PM by 10%, suggesting that leaf senescence under T 2 was delayed which enhanced the photosynthetic rate at PM by 7% in 2017 and 6% in 2018. Relative to T 1 , maize under T 2 produced 19 and 13% higher maize yield under MS R and SM, respectively, and relaycropped maize had 90% of SM seed yield. These results suggest that by manipulating the canopy structure of maize plants we can enhance the biomass accumulation and seed yield of maize crops under MS R and SM. K E Y W O R D Sbiomass, leaf excision, light interception, relay-intercropping, seed yield Muhammad A. Raza and Ling Y. Feng are co-first authors.

Optimized planting time and co‐growth duration reduce the yield difference between intercropped and sole soybean by enhancing soybean resilience toward size‐asymmetric competition

“…The highest crop yields under intercropping systems in each province were used for comparison to estimate the land equivalent ratio, for example, 3,000 kg/ha and 9,000 kg/ha for soybean and maize, respectively, in Shandong, and this method attained the land equivalent ratio of 1.4 in intercropping and 1.8 relay intercropping system, which is considerably higher than the mean values of land equivalent ratio (1.22 ± 0.02 for intercropping and 1.39 for relay intercropping) summarized from the fifty most cited papers and a random sample from the published articles (Yu, Stomph, Makowski, & Van Der Werf, 2015). In the legume-cereal relay intercropping system, cereals usually have yield advantage due to the better growth and edge row effect that achieved equal or higher grain yield as compared to their sole crop yields (Raza, Feng, Khalid, Iqbal, Meraj, et al, 2019;Raza, Feng, Werf, Cai, Khalid, et al, 2019).…”

“…In our experiment, the planting time PT 3 , co-growth duration of 50 days between maize and soybean crops significantly increased the CR S which eventually increases the resilience of relay intercropped soybean toward unequal competition faced from the presence of maize plants in MSRI ( Figure 5), and thus reduces the yield difference of soybean plants between intercropped and sole soybean which evidently enhances the total yield of MSRI (Figure 4). These increment in the yield of maize and soybean might be due to the favorable growing conditions (Liu et al, 2017), decrease competition for nutrients (Raza, Feng, Khalid, Iqbal, Meraj, et al, 2019;Raza, Feng, Werf, Cai, Khalid, et al, 2019), reduce shading conditions (Yang et al, 2014), and adequate water Rahman, Ye, et al, 2017). Significant yield advantage of intercropping was also reported in wheat-maize and wheat-soybean intercropping systems, and accumulated biomass of intercropped maize and soybean was 45%-78% of respective sole crops after wheat harvesting ).…”

“…Intercropping is well-established cropping system in Asia (Liu et al, 2016), Africa (Oseni, 2010), and South America (Echarte et al, 2011) that can enhance the productivity of agricultural land through more efficient utilization of resources with reduced risks of crop failure (Raza, Feng, Iqbal, Ahmed, et al, 2019;Raza, Feng, Khalid, Iqbal, Meraj, et al, 2019). Under intercropping, when crops are grown simultaneously in a mixture of two or more crops, different crop species come into competition for available resources, such as soil nutrients and water in the belowground (Andersen, Hauggaard, Weiner, & Jensen, 2007;Craine & Dybzinski, 2013;Gao et al, 2009;Huang et al, 2018;Yang et al, 2014), and light at the aboveground (Yang, Liao, et al, 2017;Yang, Qing, Chen, Yang, & Yong, 2017;Zhang et al, 2008).…”

Optimum strip width increases dry matter, nutrient accumulation, and seed yield of intercrops under the relay intercropping system

“…In MSR, maize produces higher seed yield due to optimum growth and an edge row-effect, and in some studies, relay-cropped maize produced higher seed yield as compared to maize yield in sole cropping systems (Chen et al, 2017;Raza, Feng, Khalid, Iqbal, Meraj, et al, 2019;Yang et al, 2017). However, soybean in MSR produced lower crop yield than sole soybean because it is planted two months after maize sowing, and the severe competition for available resources with maize plants reduces the initial growth of soybean plants (Fan et al, 2018).…”

The sweet side of misbalanced nutrients in cadmium‐stressed plants

“…Its advantages are limited by the toxicity of high Mn and B concentrations (Carvalho et al, ; Carvalho, Piotto, Franco, et al, ), particularly in leaves (Figures and ). Too high concentrations can damage leaves or their parts, leading to decreased biomass production (Raza et al, ).…”