Nutrient Accumulation and Distribution Assessment in Response to Potassium Application under Maize–Soybean Intercropping System

Aftab Ahmed,Feng Yang,Hafsa Nazir Cheema,Samina Aftab,Sadam Hussain,Weigou Liu,Wenyu Yang

doi:10.3390/agronomy10050725

Aftab Ahmed, Feng Yang + Show 5 more

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https://doi.org/10.3390/agronomy10050725

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Abstract

Intercropping is an intensive agricultural cropping system widely practiced for enhanced yield and nutrient acquisition advantages. A two-year maize–soybean intercropping (MSI) field study was performed in 2018 and 2019 to assess the effects of potassium (K) fertilizer application on biomass accumulation and distribution of essential nutrients in the various plant parts (root, green biomass and seed) of maize–soybean intercropping (MSI). Three different treatments of K fertilizer applications (T0: no potassium application; T1: maize 40, soybeans 30 and T2: maize 80, soybeans 60 kg ha−1) were designed with 2 rows of maize by wide, narrow row planting in row arrangements of 160 cm + 40 cm. Soybeans were grown in 2 wide rows at a width of 40 cm and a row spacing of 60 cm between the rows of maize and soybeans, while the sole maize (SM) and sole soybean (SS) were grown with 70-cm and 50-cm row spacing, respectively. The results of the two-year study confirmed that, as compared to T0, T2 significantly increased nitrogen, phosphate and potassium (NPK) accumulation in all maize parts by 27%, 16% and 20% grain, 23%, 22% and 14% green biomass and 30%, 17% and 15% root, respectively. In soybean treatments, T2 significantly increased NPK accumulation by 23%, 22% and 24% grain, 16%, 15% and 12% green biomass and 18%, 19% and 20% root, respectively. The increased accumulation of nutrients under T2 raised the overall biomass and its distribution to root, green biomass and grain in maize and soybeans by 11% and 18% and 16% and 19%, 20% and 12%, respectively, compared to T0. On average, after two years of experiments, the T2 intercropped maize and the soybeans showed 103% and 64% of the sole yield and attained the maximum LER of 1.66 and 1.68, respectively. Our results reveal that managing optimum K level application (80:60 kg ha−1) can accelerate biomass accumulation and distribution of other essential nutrients in the plant parts of intercropped maize and soybeans. Therefore, it is immensely important to concern potassium application levels in developing a sustainable maize–soybean intercropping systems for achieving higher productivity and land equivalent ratio (LER).

Highlights

With population expansions, intensification of urbanization, climate change, the worldwide food crises have been observed recently in the world [1,2]
The results of the present study suggests that potassium has a profound effect on the total biomass production of maize and soybeans under the maize–soybean intercropping (MSI) (Table 1)
Maximum phosphorus concentrations in MSI were measured in T2 with 0.25 g plant−1 and 0.54 g plant−1 and minimum total phosphate accumulation (TPA) in T0 treatment

Summary

Introduction

Intensification of urbanization, climate change, the worldwide food crises have been observed recently in the world [1,2]. Developing countries like China, Ethiopia, India and Indonesia have committed extensive attention to intercropping to enhance sustainable agriculture productivity [3,4]. Various benefits of a cereal legume intercropping system—mainly intercropping legumes (soybeans) with cereals (maize or wheat)—make better use of nutrients, available resources and sunlight [5], enhance yield [6] and the improve land equivalent ratios [7]. In intercropping, both crops have a co-growth period requiring more resources to produce higher yields simultaneously [8,9]

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