Maximizing Land Use Efficiency and Productivity of Soybean and Fodder Maize Intercrops through Manipulating Sowing Schedule and Maize Harvest Regime

Abstract

The incorporation of both food and forage crops in an intercropping system is receiving increasing attention, especially in developing countries with increasing populations and limited resources. In a two-year (2019–2020) field trial, conducted in Northern Egypt, productivity of soybean and fodder maize, as well as the quality of maize herbage, were investigated under three sowing schedules; soybean and maize sown together, and maize sown 15 and 30 days after soybean, in addition to soybean and fodder maize sown in pure stands, with maize harvested at green fodder maturity (GFM), and silage maturity (SM). Harvesting fodder maize at SM resulted in higher herbage yield than harvesting it at GFM, yet it negatively affected the soybean productivity. However, this negative impact was offset when fodder maize sowing was delayed 30 days after soybean sowing. Maize harvested at GFM was characterized by a higher leaf component, which was reflected in its higher crude protein content, yet the decline in quality with advanced maturity was to a great extent, counterbalanced by the presence of high-quality ears in maize harvested at SM. This was clear in its lower fiber and higher non-fiber carbohydrate contents. Land equivalent ratio (LER) demonstrated yield advantage with the delayed sowing of fodder maize (LER > 1), while the dry matter equivalent ratio (DMER) associated the yield advantage with the late harvesting of fodder maize at SM (DMER > 1), across all sowing schedules, which was more realistic for an additive intercropping model where the dry matter is the economic component. In a soybean-fodder maize intercropping system, whether fodder maize will be cultivated for green feeding or for silage production, it is recommended that sowing is delayed until 30 days after the soybean, in order to maximize yield advantage and land use efficiency.

Intercropping Pattern and N Fertilizer Schedule Affect the Performance of Additively Intercropped Maize and Forage Cowpea in the Mediterranean Region

“…In the intercropping practice, competition among the component crops, mainly for light, soil water and nutrients, is among the crucial factors that determines the variations in their productivity [35]. Several previous studies reported lower yields for cereal-legume intercrops compared to sole crops [4,9,24]. They attributed this to the interspecific competition between the different component crops.…”

“…Recently, intercropping has been considered an effective strategy to enhance the resilience of the farming system to climate change hazards [1]. Cereal-legume intercropping is a widely proposed strategy to develop a sustainable food and forage production system [2,3] to replenish the food and feed gaps, especially in developing countries with restricted agricultural inputs [4,5].…”

“…Dramatic reductions in soil moisture content usually accompany sole maize cropping due to increased evapotranspiration, which is distinguishably low in the case of cowpea cropping [2]. Nonetheless, the different root architecture of maize and cowpea allows the crops to capture soil moisture at different depths, and increases the water-use efficiency of the system [4]. Thus, there is evidence that intercropping cowpea with maize is effective in conserving soil's moisture content, which may reach 15.98% during the active period of crop development and 16.70% after crop removal [2,18].…”

Maximizing Land Use Efficiency by Intercropping Some Summer Forage Crops With Maize

“…The superiority of plant height of forage crops associated with dense sowing of maize plants may be explained by high inter specific competition between plants on light which caused an elongation in the internode length. In this concern, many researchers found that the intercropping increased the plant height of millet when intercropped with cowpea (Mohamed et al, 2020) and sorghum when intercropped with cowpea (Chaudhary et al, 2020) as well as fodder maize when intercropped with soybean (Salama and Abdel-Moneim, 2021). Moreover, Omoregie et al (2020) noticed that plant height of millet was increased by increasing the competition among plants especially at the highest plant density of millet.…”

“…These results are in harmony with those obtained by Hassan et al (2017) who found that pearl millet gave the highest values of fresh and dry yields/fed followed by sudan grass and teosinte when they were grown either alone or intercropped with some legume crops. Also, many investigators found that fresh and dry forage yields/unit area of some grass forage crops were decreased when they were intercropped with some crops such as maize (Samarappuli and Berti, 2018), cowpea (Shahwan et al, 2013, Pal et al, 2014, Iqbal et al, 2017, Ginwal et al 2019and Qadir et al, 2021 and soybean (Salama andAbdel-Moneim, 2021 andSoe Htet et al, 2021).…”