Maize-soybean Intercropping System Research Articles

Effects of narrow-wide row planting patterns on canopy photosynthetic characteristics, bending resistance and yield of soybean in maize‒soybean intercropping systems

With the improvements in mechanization levels, it is difficult for the traditional intercropping planting patterns to meet the needs of mechanization. In the traditional maize‒soybean intercropping, maize has a shading effect on soybean, which leads to a decrease in soybean photosynthetic capacity and stem bend resistance, resulting in severe lodging, which greatly affects soybean yield. In this study, we investigated the effects of three intercropping ratios (four rows of maize and four rows of soybean; four rows of maize and six rows of soybean; six rows of maize and six rows of soybean) and two planting patterns (narrow-wide row planting pattern of 80–50 cm and uniform-ridges planting pattern of 65 cm) on soybean canopy photosynthesis, stem bending resistance, cellulose, hemicellulose, lignin and related enzyme activities. Compared with the uniform-ridge planting pattern, the narrow-wide row planting pattern significantly increased the LAI, PAR, light transmittance and compound yield by 6.06%, 2.49%, 5.68% and 5.95%, respectively. The stem bending resistance and cellulose, hemicellulose, lignin and PAL, TAL and CAD activities were also significantly increased. Compared with those under the uniform-ridge planting pattern, these values increased by 7.74%, 3.04%, 8.42%, 9.76%, 7.39%, 10.54% and 8.73% respectively. Under the three intercropping ratios, the stem bending resistance, cellulose, hemicellulose, lignin content and PAL, TAL, and CAD activities in the M4S6 treatment were significantly greater than those in the M4S4 and M6S6 treatments. Compared with the M4S4 treatment, these variables increased by 12.05%, 11.09%, 21.56%, 11.91%, 18.46%, 16.1%, and 16.84%, respectively, and compared with the M6S6 treatment, they increased by 2.06%, 2.53%, 2.78%, 2.98%, 8.81%, 4.59%, and 4.36%, respectively. The D-M4S6 treatment significantly improved the lodging resistance of soybean and weakened the negative impact of intercropping on soybean yield. Therefore, based on the planting pattern of narrow-wide row maize‒soybean intercropping planting pattern, four rows of maize and six rows of soybean were more effective at improving the lodging resistance of soybean in the semiarid region of western China.

Shade stress triggers ethylene biosynthesis to accelerate soybean senescence and impede nitrogen remobilization

In gramineae-soybean intercropping systems, shade stress caused by taller plants impacts soybean growth specifically during the reproductive stage. However, the effects of shade stress on soybean senescence remain largely unexplored. In this research, we applied artificial shade treatments with intensities of 75% (S75) and 50% (S50) to soybean plants at the onset of flowering to simulate the shade stress experienced by soybeans in the traditional and optimized maize-soybean intercropping systems, respectively. Compared to the normal light control, both shade treatments led to a rapid decline in the dry matter content of soybean vegetative organs and accelerated their abscission. Moreover, shade treatments triggered the degradation of chlorophyll and soluble proteins in leaves and increased the expression of genes associated with leaf senescence. Metabolic profiling further revealed that ethylene biosynthesis and signal transduction were induced by shade treatment. In addition, the examination of nitrogen content demonstrated that shade treatments impeded the remobilization of nitrogen in vegetative tissues, consequently reducing the seed nitrogen harvest. It's worth noting that these negative effects were less pronounced under the S50 treatment compared to the S75 treatment. Taken together, this research demonstrates that shade stress during the reproductive stage accelerates soybean senescence and impedes nitrogen remobilization, while optimizing the field layout to improve soybean growth light conditions could mitigate these challenges in the maize-soybean intercropping system.

MAIZE-SOYBEAN INTERCROPPING WITH ORGANIC FERTILIZATION AS A SOLUTION TO ENHANCE CROP AND SOIL PRODUCTIVITY

An ever-increasing population and a decreasing cultivated land are challenging global food security. There is a massive difference between domestic production and demand. It is critical to improve the various index of land in order to secure food for future generations. Intercropping maize and soybeans can be a successful approach for addressing the gap between supply and demand. Due to low crop production per unit area, insufficient crop diversity, a lack of quality seeds and fertilizers, poor crop management, and the unfavorable effects of climate change. The experiment was conducted to understand the relationship of maize-soybean intercropping system with farm yard manure as a source of fertilizer. Our results showed that the farm yard manure has positively affected the overall soil fertility and also improved the crops production. Farm yard manure addition has given more fruitful results under maize-soybean intercropping. Maize-soybean intercropping with farm yard manure had a significant impact on growth and grain yield of both maize and soybean. The agronomic parameters plant height, shoot dry matter yield, grain yield and nitrogen uptake were recorded highest in the farm yard manure treatment under maize-soybean intercropping. Similarly, soil building attributes soil pH, total organic carbon, dissolved organic carbon and soil mineral nitrogen were positively affected by the interaction of farm yard manure and maize-soybean intercropping. Overall, we have concluded that maize-soybean intercropping system is most resilient cropping system with the implementation of farm yard manure to improve the crop productivity, soil health and to overcome the impact of climate change.

Effects of the Host Plants of the Maize-Based Intercropping Systems on the Growth, Development and Preference of Fall Armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae).

In this paper, the effects of maize and its three intercropping plants, sweet potato, soybean and peanut, on the growth and development of FAW, feeding preference of larvae, olfactory response and oviposition preference of adults were studied in the laboratory. The results showed that maize and peanut were suitable for the survival and development of FAW, while sweet potato and soybean were not suitable for multigenerational reproduction. The larvae significantly preferred to feed on maize compared to the other three plants. The olfactory response test indicated that soybean showed a strong deterrent effect against FAW adults. Furthermore, the intercropping plants reduced the host selection rate of adults compared to maize alone. In two-choice tests of the maize vs. the intercropping plants, the female adult preferred to oviposit and lay more eggs on maize rather than on the intercropping plants. The intercropping plants significantly reduced the oviposition selection of FAW adults when the combination (maize + intercropping plant), especially soybean and sweet potato, was compared to maize alone. These may be the reasons for why the maize-soybean intercropping system reduced FAW damage in the field. We also speculated that the maize-sweet potato system may also reduce the FAW damage. This study provided a theoretical basis for the comprehensive management of FAW by utilizing an intercropping system.

Effects of Intercropping on Maize and Soybean Yield Performance, Land Equivalent Ratio, and Maize Leaf Area in Conservation Agriculture

Maize-soybean intercropping systems as a conservation farming practice are receiving increased focus from the scientific community. This is because of the advantages of intercropping, especially nutrient benefits through cereal-legume interactions, alternative sustainable methods to manage biotic stress (pests, diseases, weeds), and crop failure risk management due to erratic weather. In addition, smallholders in developing countries commonly use intercropping to produce crops. In Uganda, 40% of smallholder farmers are practicing intercropping yet no adequate location-specific information is available to inform their practice. Farmers who adopted conservation farming practices did not mulch their maize due to drudgery associated with collecting mulch. This study evaluated the effect of two tillage methods (T1 = Conventional tillage using ox drawn mould board plough, T2 = Minimum tillage using ox drawn ripper) and five soil cover practices (SC1 = Mulched Maize, SC2 = Control no mulch, SC3 = Two rows of soybean in between one row of maize, SC4 = One row of soybean in between one row of maize, SC5 = Sole soybean) on maize and soybean yield performance. The trials were established for 4 rainy seasons on a sandy loam ferrosol at National Agricultural Research Organization Institute in Lira, Uganda. Soil cover practice had a significant effect on maize and soybean crop Yield. Mulching significantly increased maize yield and LAI. The LER for both intercropping partterns were above 1.2. Tillage methods were not significantly different in determining crop performance. The practice of minimum tillage should also be adopted because it enhances the positive effects of soil cover (intercropping). We recommend farmers to adopt the intercropping pattern of one row of soybean in between maize row spaced at 75 × 30 cm for better LER, and crop performance. This intercropping pattern maximizes on available resources to deliver better output in conservation farming. Maize crop generally performed better during first season as compared to second season. We recommend farmers to utilize the first rains as the main maize production season.

Maize-soybean intercropping improved maize growth traits by increasing soil nutrients and reducing plant pathogen abundance

IntroductionMaize (Zea mays L.)–soybean (Glycine max L.) intercropping has been widely utilized in agricultural production due to its effectiveness in improving crop yield and nutrient use efficiency. However, the responses of maize rhizosphere microbial communities and the plant pathogen relative abundance to maize growth traits in maize-soybean intercropping systems with different chemical nitrogen fertilizer application rates remain unclear.MethodsIn this study, a field experiment was conducted, and the bacterial and fungal communities of maize rhizosphere soils in maize-soybean intercropping systems treated with different N fertilization rates were investigated using Illumina NovaSeq sequencing. Maize growth traits, soil physicochemical properties and soil enzyme activities were also examined.Results and discussion:We found that intercropping and N fertilizer treatments strongly influenced soil microbial diversity, structure and function. The PLSPM (partial least squares path modeling) confirmed that soil nutrients directly positively affected maize biomass and that intercropping practices indirectly positively affected maize biomass via soil nutrients, especially NH4+-N. Intercropping agronomic approaches also improved maize growth traits by reducing the plant pathogen abundance, and the relative abundance of the plant pathogen Trichothecium roseum significantly decreased with intercropping treatments compared to monocropping treatments. These results confirmed the benefits of maize-soybean intercropping treatments for agricultural production.

Effects of Soil Physicochemical Properties on Maize, Wheat, and Soybean Yields in Maize-Wheat and Maize-Soybean Intercropping Systems in China: a Meta-analysis

Effects of Soil Physicochemical Properties on Maize, Wheat, and Soybean Yields in Maize-Wheat and Maize-Soybean Intercropping Systems in China: a Meta-analysis

Assessment of molybdenum application on soybean physiological characteristics in maize-soybean intercropping.

Soybean is a leguminous crop known for its efficient nitrogen utilization and ease of cultivation. However, its intercropping with maize may lead to severe reduction in its growth and yield due to shading effect of maize. This issue can be resolved by the appropriate application of essential plant nutrient such as molybdenum (Mo). Aim of this study was to assess the effect of Mo application on the morphological and physiological characteristics of soybean intercropped with maize. A two-year field experiment was conducted for this purpose, and Mo was applied in the form of sodium molybdate (Na2MoO4), and four different levels were maintained i.e., 0, 60, 120 and 180 g ha-1. Soybean exhibited varying responses to different levels of molybdenum (Mo) application. Notably, in both sole and intercropped cropping systems, the application of Mo at a rate of 120 g ha-1 demonstrated the highest level of promise compared to other application levels. However, most significant outcomes were pragmatic in soybean-maize intercropping, as application of Mo @ 120 g ha-1 significantly improved soybean growth and yield attributes, including leaf area index (LAI; 434 and 441%), total plant biomass (430 and 461%), transpiration rate (15 and 18%), stomatal conductance (9 and 11%), and yield (15 and 20%) during year 2020 and 2021 respectively, as compared to control treatment. Similarly, Mo @ 120 g ha-1 application resulted in highest total grain yield (626.0 and 725.3 kg ha-1) during 2020 and 2021 respectively, which exceeded the grain yields of other Mo levels under intercropping. Moreover, under Mo application level (120 g ha-1), grain NPK and Mo contents during years 2020 and 2021 were found to be 1.15, 0.22, 0.83 and 68.94 mg kg-1, and 1.27, 0.25, 0.90 and 72.18 mg kg-1 under intercropping system increased the value as compared to control treatment. Findings of current study highlighted the significance of Mo in enhancing soybean growth, yield, and nutrient uptake efficiency in maize-soybean intercropping systems.

Leaf senescence, nitrogen remobilization, and productivity of maize in two semiarid intercropping systems

It is unclear how interspecific resource competition affects crop leaf senescence in association with nitrogen (N) remobilization and overyielding in semiarid intercropping systems. To address this issue, maize intercropped with soybean (weakly competitive species) and wheat (strongly competitive species) was examined across three consecutive years to explore the effects of resource competition on maize relative and absolute yield gain, leaf senescence traits, N remobilization and physiological activities in a typical semiarid site. High yield (171.8 g plant−1), relative yield (0.63) and net effect (0.99 t ha−1) of maize were observed in the maizesoybean intercropping system, while the opposite trend was found in the maizewheat intercropping systems. Overall, maize benefited from intercropping with soybean but was negatively affected by intercropping with wheat. Interestingly, both intercropping systems significantly delayed the onset time of maize leaf senescence by approximately 5–20 days and prolonged the senescence duration by approximately 8–18 days. Intercropping with soybean increased maize leaf dry matter remobilization from 7.3 to 12.5 g per plant−1 and reduced N remobilization from 0.81 to 0.45 g plant−1, respectively. However, when intercropped with wheat, dry matter and N remobilization of maize leaves were decreased, at 4.8 and 0.13 g plant−1, respectively. Therefore, excessive delay and prolonged leaf senescence reduced leaf dry matter translocation and N to the grain which impaired yield formation. Our findings provided novel insights into the physiological mechanism of overyielding from the perspective of leaf senescence traits and remobilization function in the semiarid intercropping systems.

Optimum nitrogen improved stem breaking resistance of intercropped soybean by modifying the stem anatomical structure and lignin metabolism

Excessive use of nitrogen fertilizers enhanced the stem lodging, leading to serious threats to environmental sustainability. As the maize-soybean intercropping system is eco-friendly, however, soybean micro-climate hinders soybean growth and caused lodging. Since the relationship between nitrogen and lodging resistance under the intercropping system is not widely studied. Therefore, a pot experiment was conducted with the application of different nitrogen concentrations referring to low nitrogen (LN) = 0 mg/kg, optimum nitrogen (OpN) = 100 mg/kg, and high nitrogen (HN) = 300 mg/kg. To evaluate the optimum nitrogen fertilization under the maize-soybean intercropping system, two soybean cultivars were selected Tianlong 1 (TL-1), (lodging resistant) and Chuandou 16 (CD-16), (lodging susceptible). The results revealed that under the intercropping system, the OpN concentration significantly improved the lodging resistance of soybean cultivars by reducing the plant height of TL-1 and CD-16 by 4 and 28% as compared to LN, respectively. Following OpN, the lodging resistance index for CD-16 was also increased by 67% and 59% under the respective cropping systems. In addition, we found that OpN concentration prompted the lignin biosynthesis by stimulating the enzymatic activities of lignin biosynthetic enzymes (PAL, 4CL, CAD, and POD), which was reflected at the transcriptional levels (GmPAL, GmPOD, GmCAD, Gm4CL), too. Henceforth, we proposed that optimum nitrogen fertilization boosts soybean stem lodging resistance by modulating the lignin metabolism in the maize-soybean intercropping system.

Penilaian Komponen Hasil dan Indeks Intercropping 22 Jagung Hibrida Pada Sistem Intercropping Jagung-Kedelai

This study aims to determine the performance of the yield components and the intercropping index of 22 hybrid maize in the maize-soybean intercropping system. This research was carried out in Cikajang, Garut Regency from January 2021 to June 2021. The method used in this research is a quantitative descriptive and experimental method. The experimental design used was a randomized block design with 27 treatments made in 3 replications. The genetic material used was 22 test hybrids from the Padjadjaran University collection and 5 commercial hybrids as comparisons. Assessment of yield components was carried out using The Least Significant Increase (LSI) test assessed for 4 yield components consisting of cob diameter, cob length, number of seeds cobs, and dry seed/plant weight. Intercropping index assessment was analyzed based on the calculation of Land Equivalent Ratio (LER), Area Time Equivalent Ratio (ATER), and Aggressivity (A). The results showed that there were 4 hybrids that had high yields in the maize-soybean intercropping system including DRc6 x DRc7, DRc8 X MDRc18.8.1, DRc8 X MDRc1.1.3 and MDRc3.1.4 X MDRc18.5.1. There are 3 profitable hybrids in the intercropping system of soybean maize based on the intercropping index including DRc4 X MDRc7.2.3, DRc8 x DRc9, and MDRc7.4.3 x MDRc18.8.1.

Quantification of the Cumulative Shading Capacity in a Maize-Soybean Intercropping System Using an Unmanned Aerial Vehicle.

In intercropping systems, higher crops block direct radiation, resulting in inevitable shading on the lower crops. Cumulative shading capacity (CSC), defined as the amount of direct radiation shaded by higher crops during a growth period, affects the light interception and radiation use efficiency of crops. Previous studies investigated the light interception and distribution of intercropping. However, how to directly quantify the CSC and its inter-row heterogeneity is still unclear. Considering the canopy height differences (Hms, obtained using an unmanned aerial vehicle) and solar position, we developed a shading capacity model (SCM) to quantify the shading on soybean in maize-soybean intercropping systems. Our results indicated that the southernmost row of soybean had the highest shading proportion, with variations observed among treatments composed of strip configurations and plant densities (ranging from 52.44% to 57.44%). The maximum overall CSC in our treatments reached 123.77 MJ m-2. There was a quantitative relationship between CSC and the soybean canopy height increment (y = 3.61×10-2×ln(x)+6.80×10-1, P < 0.001). Assuming that the growth status of maize and soybean was consistent under different planting directions and latitudes, we evaluated the effects of factors (i.e., canopy height difference, latitude, and planting direction) on shading to provide insights for optimizing intercropping planting patterns. The simulation showed that increasing canopy height differences and latitude led to increased shading, and the planting direction with the least shading was about 90° to 120° at the experimental site. The newly proposed SCM offers a quantitative approach for better understanding shading in intercropping systems.

Bandwidth Row Ratio Configuration Affect Interspecific Effects and Land Productivity in Maize–Soybean Intercropping System

Intercropping plays an indispensable role in sustainable agriculture. The response of bandwidth row ratio configuration to crop interspecific relationships and land productivity in the maize–soybean intercropping system (MSI) is still unclear. A 2-year field experiment was conducted with sole maize (SM) and sole soybean (SS), two different bandwidths (2.4 m (B1), 2.8 m (B2)), two different maize and soybean row ratios (2:3 (R1), and 2:4 (R2)) for MSI. The results showed that intercropping had advantages for land productivity compared with sole planting. Intercropping cropping had significant differences on crop yield under different intercropping treatments. The 2-yr average land equivalent ratio (LER, 1.59) and group yield under the intercropping patterns of B1R2 were significantly higher than other intercropping treatments (p &lt; 0.05). With a bandwidth of 2.4 m and planting four rows of intercropped soybean, the total LER and group yield increased by 7.57% and 10.42%, respectively, compared to planting three rows of soybean. Intercropped maize was the dominant species and also had a higher nutrient aggressivity than intercropped soybean. The complementarity effect was higher than the select effect in the MSI system, and intercropping advantage was mainly derived from the complementarity effect, which was significantly correlated with intercropped maize yield. Nitrogen and phosphorus nutrient aggressivity in intercropped maize showed significant correlations with group yield and intercropped maize yield. In conclusion, bandwidth 2.4 m, row ratio 2:4 was a reasonable planting pattern because of its superior land productivity, crop nutrients uptake advantage, and harmonious interspecific relationship, which could provide a reference for MSI promotion and application research.

Effects of Row Spacing and Planting Pattern on Photosynthesis, Chlorophyll Fluorescence, and Related Enzyme Activities of Maize Ear Leaf in Maize–Soybean Intercropping

With the continuous improvement of the mechanization level and the development of new crop varieties, the optimal strip width for intercropping crops is important. In this study, field experiments were conducted to analyze the effects of different row spacings and planting patterns on photosynthesis, chlorophyll fluorescence, and the related enzyme activities of maize ear leaves in a maize–soybean intercropping system using two planting patterns (wide–narrow rows of 80–50 cm and uniform ridges of 65 cm) and two intercropping ratios (four rows of maize and four rows of soybean; six rows of maize and six rows of soybean). The results showed that the pattern of wide–narrow-row spacing significantly improved the photosynthetic capacity of maize compared with the uniform-ridge planting pattern, along with marked elevation in the values of stomatal conductance (Gs), the transpiration rate (Tr), and the photosynthetic rate (Pn). On the other hand, the values of photochemical quenching (qP), actual photochemical efficiency (φPSII), and maximum photochemical efficiency (Fv/Fm) also significantly increased, and the effect of D-M6S6 treatment was the most significant on these parameters. Similarly, the activities of phosphoenolpyruvate carboxylase and ribulose-1,5-bisphosphate carboxylase/oxygenase also increased significantly. Among different treatments, the yield under the D-M6S6 treatment was the highest. Therefore, based on the planting pattern of the wide–narrow-row spacing, the intercropping of six rows of maize and six rows of soybean is the better design in the semi-arid regions of western China.

Nitrogen fertilization coupled with foliar application of iron and molybdenum improves shade tolerance of soybean under maize-soybean intercropping.

Maize-soybean intercropping is practiced worldwide because of some of the anticipated advantages such as high crop yield and better utilization of resources (i.e., water, light, nutrients and land). However, the shade of the maize crop has a detrimental effect on the growth and yield of soybean under the maize-soybean intercropping system. Hence, this experiment was conducted to improve the shade tolerance of such soybean crops with optimal nitrogen (N) fertilization combined with foliar application of iron (Fe) and molybdenum (Mo). The treatments comprised five (5) maize-soybean intercropping practices: without fertilizer application (F0), with N fertilizer application (F1), with N fertilizer combined with foliar application of Fe (F2), with N fertilizer coupled with foliar application of Mo (F3) and with N fertilizer combined with foliar application of Fe and Mo (F4). The findings of this study showed that maize-soybean intercropping under F4 treatment had significantly (p< 0.05) increased growth indices such as leaf area (cm2), plant height (cm), stem diameter (mm), stem strength (g pot-1), and internode length (cm) and yield indices (i.e., No of pods plant-1, grain yield (g plant-1), 100-grain weight (g), and biomass dry matter (g plant-1)) of the soybean crop. Moreover, intercropping under F4 treatment enhanced the chlorophyll SPAD values by 26% and photosynthetic activities such as Pn by 30%, gs by 28%, and Tr by 28% of the soybean crops, but reduced its CO2 by 11%. Furthermore, maize-soybean intercropping under F4 treatment showed improved efficiency of leaf chlorophyll florescence parameters of soybean crops such as Fv/Fm (26%), qp (17%), ϕPSII (20%), and ETR (17%), but reduced NPQ (12%). In addition, the rubisco activity and soluble protein content of the soybean crop increased by 18% in maize-soybean intercropping under F4 treatment. Thus, this suggested that intercropping under optimal N fertilization combined with foliar application of Fe and Mo can improve the shade tolerance of soybean crops by regulating their chlorophyll content, photosynthetic activities, and the associated enzymes, thereby enhancing their yield and yield traits.

Evaluation of the growth characteristics, forage productivity, and feed value of the maize–soybean intercropping system under different fertilization levels

Evaluation of the growth characteristics, forage productivity, and feed value of the maize–soybean intercropping system under different fertilization levels

Impact of Organic and Chemical Nitrogen Fertilizers on the Crop Yield and Fertilizer Use Efficiency of Soybean–Maize Intercropping Systems

The effect of the mixture (1:1) of chemical and organic nitrogen (N) fertilizer on crop yield quality and N fertilizer use efficiency remains elusive. A nitrogen field experiment was conducted in the growing seasons of 2020 and 2021 to investigate the effects of the mixture of chemical and organic N fertilizer on the crop yield, crop quality and nitrogen fertilizer use efficiency in a maize–soybean intercropping system in China. Four treatments applied at 150 kg N ha−1 were used: no nitrogen fertilizer (CK), chemical N fertilizer (ChemF), mixture (1:1) of chemical and organic N fertilizer (ChemF + OrgF) and organic N fertilizer (OrgF). The results showed that the yield and aboveground N accumulation of both soybean and maize increased with the application of fertilizer. The ChemF + OrgF treatment had lower maize and soybean seed yields than for ChemF treatment, but higher than the other two treatments in both years, and the maize yield of the (ChemF + OrgF) treatment was significantly higher (14.9%) in 2021 than 2020. Yields were significantly positively correlated with aboveground N accumulation and fertilizer use efficiency, measured using the nitrogen partial productivity (NPP), nitrogen agronomic efficiency (NAE) and nitrogen fertilizer recovery rate (NFRR). The protein content tended to increase and the oil content tended to decrease under (ChemF + OrgF) applications in soybeans. The (ChemF + OrgF) treatment had the lowest starch content in maize. There was no significant difference in the nitrogen harvest index among treatments, while the NPP, NAE and NFRR were the highest for the application of chemical N fertilizer and significantly decreased with the addition of organic N fertilizer. We conclude that the mixture (1:1) of chemical and organic N fertilizer increased the seed yield and quality of maize, but only the seed yield of soybean.

The effect of strip orientation and width on radiation interception in maize–soybean strip intercropping systems

AbstractMaize–soybean intercropping systems are widely used in developing countries, but few studies have been performed to optimize such systems. The effects of strip width and orientation on photosynthetically active radiation (PAR) distribution characteristics were therefore determined to gain a better understanding of crop productivity in maize–soybean intercropping systems. A series of intercropping experiments incorporating different strip orientations and widths were conducted. In addition, an improved radiation transmission model was used to simulate PAR interception by the maize and soybean crops. We found that more PAR was intercepted by the soybean plants than by the maize plants when the strip orientation angle increased from 0° to 90° in the maize–soybean intercropping systems. This result was obtained in most of the main maize production areas, including those with different latitudes. The effect of strip widths within the intercropping systems also had a significant effect on PAR interception. The relative fraction of PAR intercepted ranged from 39.4% to 86% for soybean and 105.8% to 169.3% for maize. The effect of soybean strip width on leaf PAR interception was greater than that of maize strip width. These results are not only of fundamental biological importance but they also have important implications for agriculture in terms of the optimization of production in intercropping systems.

Growth responses of maize-soybean intercropping system and its potential for cattle feed in Bali

There had been a 2.145 ha fields transition in Bali which had a major impact on the loss of food production. However, there was raise in the population annually, therefore it disrupts local food security. Effort to raise the effectiveness and agricultural productivity areas through changing cropping system from monoculture to intercropping. This study aimed to find out the growth responses of maize and soybean crops cultivated by monoculture and intercropping planting systems and its carrying capacity for cattle feed. The study was arranged using a randomized block design with 3 treatments and 3 replications, namely: T1: Bima 20 URI VUB maize seeds in monoculture (40cm x 20cm x 80cm; 1 seed/hole or 70cm x 40cm x 100cm; 2 seeds/hole); T2: Anjasmoro, Deja 2 and Devon soybean VUB seeds in monoculture system (40cm x 20cm; 2-3 seeds/hole); T3: maize-soybean intercropping; Maize (2 rows; 40cm x 12.5; 2 seeds/hole); Soybeans (4 rows; 30cm x 10cm; 2-3 seeds/hole); both distance: 40cm. Data collected were growth performance, yield components and yield capacity of both maize and soybean crops also competition and profit value of maize and soybeans crops cultivated by intercropping planting system. The results showed that monoculture maize crops cultivated by monoculture planting system were better than it intercropped with soybean crops in terms of growth parameters. However, intercropping maize and soybean were produced greater yield components on cobs number, cobs and grains weight than monoculture (P<0.05), except grains weight per cobs. The monoculture soybean plant in growth, components and yield parameters were greater than intercropping (P>0.05). The ATER, LER, RCC, CR, and AYL values were 3.24; 1.28; -2.69; 4.58; -0.098 on maize and 2.52; 0.84; 1.82; 0.21; -0.158 on soybean. Those result was followed by carrying capacity in intercropping system by 30% usage can be used for 1.804 AU meanwhile 40% usage was sufficient for 1.353 AU. Intercropping system can be recommended to farmers to increase growth responses of maize-soybean and its potential carrying capacity for cattle feed.

Film mulching affects root growth and function in dryland maize-soybean intercropping

• Maize roots morphological behaviors respond to soybean roots presence in dry and wet conditions. • Intercropped maize roots were shallower compared to sole maize. • More active root-diameter strategy for intercropped maize to adapt to varied water conditions. • Film mulching improved the overlap of interspecific roots. • Film mulching greatly increased maize grain yield with a lesser decline of soybean grain yield relative to sole soybean. Understanding the morphological response of maize roots in the presence of soybeans in fields under varied water conditions is vital for identifying maize-dominant intercropping systems suitable for climate change. In this study, two maize-soybean intercropping systems (maize with and without film mulching) were compared with maize and soybean sole crops in rainfed farmland on the Loess Plateau. Different features, including the maize root morphological traits, root vertical distribution, shoot traits, interspecific root overlap, and grain yield of intercrops, were determined after silking in 2017 (dry year) and 2018 (wet year). The intercropped maize (without film mulching) employed a thin root system under dry conditions and a profuse root system under wet conditions, with shallow roots and active root-diameter strategy to adapt to varied water conditions. These features resulted in higher grain yield in per unit area for the intercropped maize (16.97 % overyielding) than sole maize without film mulching. Film mulching of intercropped maize modified the roots with confined growth under dry conditions and inhibited the roots with excessive growth under wet conditions; as a consequence, the two morphologies of intercropped maize root system were reshaped into the optimal one (less profuse but not thin), with S-type vertical distribution (1 m soil profile) for root length and more beneficial root-diameter strategy. Besides, film mulching improved interspecific root interaction through an evident increase in root length or mass in the interspecific overlap regions. Finally, film mulching improved the maize overyielding dramatically (84 %) due to high leaf adaptability and efficient root-shoot synergy in maize plants. Importantly, the maize mulching did not decrease intercropped soybean yield significantly when compared with sole soybean due to the benefits from interspecific facilitation, while it enhanced total grain yield (10.67 %) for the intercropping system. Thus, film mulching improved maize root morphology and balanced soil resource exploitation and shoot development, consequently strengthening the attainable grain yield in the intercropping system. To conclude, the research elucidates the plant root mechanisms (root morphological changes) underlying overyielding of intercropped maize in varied water conditions. It identifies film mulching of maize as a strategy to optimize root growth and function for higher intercropping yield advantage in dryland.