Soybean Intercropping Research Articles

Optimizing application of biochar, compost and nitrogen fertilizer in soybean intercropping with kayu putih ( Melaleuca cajuputi )

Waste resulted from the distillation of kayu putih leaves is a problem in almost all kayu putih refineries throughout Indonesia due to its enormous availability and un-utilization. It has potential to be used as an organic fertilizer source due to its nutrient content (macro and micro) which is higher than organic fertilizer from animals. The use of kayu putih waste is useful to complement and increase the efficiency of nitrogen fertilizer in soybean intercropping with kayu putih . This [...]

Effects of Multiple Planting Densities on Lignin Metabolism and Lodging Resistance of the Strip Intercropped Soybean Stem

The shading of maize and self-shading are the key factors affecting the stem lignin biosynthesis and lodging resistance of soybean at middle and later growth stages in the strip intercropping system. A study was designed to explore the regulation mechanism of lignin metabolism and different planting densities; PD1, PD2, and PD3 were used having a total number of 17 plants m−2, 20 plants m−2, and 25 plants m−2, respectively, on the lodging resistance of strip intercropped soybean stem. Our results depicted that the lower planting density (PD1) appropriately promoted the leaf photosynthesis activities (Pn), increase the activity of lignin-related enzymes and the accumulation of carbohydrates in stems, and eventually enhanced the lodging resistance of the strip intercropped soybean stem. Correlation analysis also showed that the lodging resistance index of soybean stem was significantly correlated with the available light for soybean canopy and Pn strip intercropped soybean stem characteristics and activities of enzymes related to lignin synthesis among the different planting densities. The findings of our research will be useful in future studies to understand the relationship between different light environment, planting densities, and lodging resistance of intercropped soybean and also guide the optimum planting density in maize–soybean intercropping system.

Soybean-maize intercropping feasibility under drought-prone area in East Java, Indonesia

Abstract. Harsono A, Elisabeth DAA, Muzaiyanah S, Rianto SA. 2020. Soybean-maize intercropping feasibility under drought-prone area in East Java, Indonesia. Biodiversitas 21: 3744-3754. The study aimed to determine the land productivity, economic feasibility, and soybean cultivar which is suitable for intercropped with maize in maize production center on dryland-upland in East Java, Indonesia. The study was conducted in Semanding and Merakurak Sub-districts, Tuban District, East Java, Indonesia at the end of rainy season (March-July 2019). The study used a factorial randomized block design with three replications. The first factor was planting patterns, namely: soybean intercropping with maize, maize monoculture, and soybean monoculture. The second factor was soybean cultivars, namely: Argomulyo, Dena 1, and Dega 1. The maize variety used was NK Hybrid 212. The result of study indicated that by intercropping and selecting appropriate cultivar, soybean could be developed on dryland-upland area. Soybean intercropping with plant spacing of 30 cm x 15 cm and two seeds per-hill and maize in double row with plant spacing of (40 x 20) cm x 200 cm and one seed per-hill was able to produce maize seeds yield as high as maize increase LER by 1.69, and increase farming income. Dena 1 intercropping with maize was able to provide higher benefit, economic feasibility, and land-use efficiency than Argomulyo and Dega 1, even though Dega 1 had the strongest competitiveness, and Argomulyo had the higher soybean yield.

Phenolic Acids Released in Maize Rhizosphere During Maize-Soybean Intercropping Inhibit Phytophthora Blight of Soybean.

Interspecies interactions play a key role in soil-borne disease suppression in intercropping systems. However, there are limited data on the underlying mechanisms of soil-borne Phytophthora disease suppression. Here, a field experiment confirmed the effects of maize and soybean intercropping on Phytophthora blight of soybean caused by Phytophthora sojae. Experimentally, the roots and root exudates of maize were found to attract P. sojae zoospores and inhibit their motility and the germination of cystospores. Furthermore, five phenolic acids (p-coumaric acid, cinnamic acid, p-hydroxybenzoic acid, vanillic acid, and ferulic acid) that were consistently identified in the root exudates and rhizosphere soil of maize were found to interfere with the infection behavior of P. sojae. Among them, cinnamic acid was associated with significant chemotaxis in zoospores, and p-coumaric acid and cinnamic acid showed strong antimicrobial activity against P. sojae. However, in the rhizosphere soil of soybean, only p-hydroxybenzoic acid, low concentrations of vanillic acid, and ferulic acid were identified. Importantly, the coexistence of five phenolic acids in the maize rhizosphere compared with three phenolic acids in the soybean rhizosphere showed strong synergistic antimicrobial activity against the infection behavior of P. sojae. In summary, the types and concentrations of phenolic acids in maize and soybean rhizosphere soils were found to be crucial factors for Phytophthora disease suppression in this intercropping system.

Exploring Yield Potential of Pigeonpea and Soybean Intercropping Systems in NEHZ

A field study was conducted on yield potential of Pigeonpea and Soybean intercropping systems at the experimental farm of School of Agriculural Sciences and Rural Development (SASRD) on AICRP on Pigeonpea Nagaland University Medziphema Campus under rainfed conditions during 2016 and 2017. The treatment comprised of different row ratios of Pigeonpea and Soybean i.e 1:1, 1:2, 2:1 and 2:2 respectively with sole Pigeonpea and Soybean. The variety used for Pigeonpea was UPAS 120 and for Soybean was JS-9752 respectively. The experiment was laid in RBD with 3 Replications and 6 Treatments. Sole Pigeonpea performed better with respect to growth and yield. Among the different intercropping systems paired rows (2:2) ratios of Pigeonpea and Soybean performed significantly better in terms of yield (1025.64 Kg/ha) which was at par with (2:1) row ratios. As for economics paired row (2:2) ratios of Pigeonpea and Soybean proved superior to all other treatments in LER (1.89), Net return (Rs 86877/ha), Gross return (Rs 133177.8/ha) and Pigeonpea Equivalent yield (876.9 Kg/ha) which was at par with (1:2) row ratios of Pigeonpea and Soybean.

Effect of Integrated Weed Management on Coffee Growth and Yield at Metu and Haru in South west and West Ethiopia

A field experiment was conducted to evaluate different single and integrated weed management methods on the growth and yield of coffee at Metu and Haru sub centers of Jimma Agricultural Research Center (JARC) between 2014-2018 cropping seasons. At Metu eight treatments were compared in randomized complete block design with three replications. The treatments included the following: (T1) One slash in May + one slash in August,(T2) Three slashing (May+Jully+Augesst), (T3) Roundup 3L/ha. sprayed in may followed by one slashing in July followed by vetivar grass mulching in September , (T4) Roundup 3L/ha.sprayed in May followed by soybean intercropping in July followed by mulching in September , (T5) Roundup 3L/ha. sprayed in May haricot bean intercropping in June followed by mulching in September , (T6) Roundup 3L/ha (only for the first year) Desmodium cover crop all year round permanently , (T7) Vetch cover crop in June followed with one hand weeding , and (T8). Weed free (plots kept weed free all year round). At Haru nine treatments were compared in randomized complete block design with three replications. The treatments included: (T1)one to two times slashing (farmers practice), (T2) three slashing in May, June and July, (T3) four slashing in May, June, July and August, (T4) Round up 3L/ha. sprayed in May followed by slashing followed by mulching followed by slashing and followed by mulching: (T5) slashing followed by Roundup 3L/ha. followed by coffee husk mulching: (T6) Roundup 3L/ha followed by desmodium cover cropping: (T7) Roundup 3L/ha followed by vetch cover cropping: (T8) Roundup 3L/ha followed by soybean intercropping followed by mulching: and (T9) Weed free (plots kept weed free all year round).. The result raveled that at both locations the major weed species included perennial sedges, perennial grasses, and annual broad leaf At Metu herbicide followed by soybean intercropping and followed by mulching in September gave a mean yield of 13.6 quintal clean coffee. Similarly, desmodium cover cropping provided excellent weed control and resulted in mean yield of 13.7 q/ha clean coffee .Desmodium showed a high smothering effect of the highly competitive perennial sedges and grasses by inhibiting the incoming light reaching the soil compared with other treatments and the weed free treatment.. At Haru Roundup 3L/ha followed by slashing followed by mulching followed by slashing and followed by mulching gave consistently very high coffee yield with a mean yield of 21 quintal /ha. compared with other treatments. The weed free treatment gave low yield at both locations. Vetch and desmodium did not well established at Haru compared with Metu. DOI: 10.7176/DCS/10-7-02 Publication date: July 31 st 2020

Diversity of the Seedborne Fungi and Pathogenicity of Fusarium Species Associated with Intercropped Soybean.

Maize/soybean relay strip intercropping has been widely practiced in Southwest China due to its high productivity and effective application of agricultural resources; however, several seedborne diseases such as seedling blight, pod and seed decay are frequently observed causing severe yield loss and low seed quality. So far, the population and pathogenicity of the seedborne fungi associated with intercropped soybean remain unexplored. In this study, seeds of 12 soybean cultivars screened for intercropping were collected from three growing regions in Sichuan Province of Southwest China, and the seedborne fungi were isolated from the surface-sterilized seeds. Based on sequence analysis of ribosomal DNA internal transcribed spacer (rDNA ITS), 148 isolates were identified into 13 fungal genera, among which Fusarium covered 55.0% as the biggest population followed by Colletotrichum. Furthermore, Fusarium isolates were classified into five distinct species comprising F. fujikuroi, F. proliferatum, F. verticillioides, F. asiaticum and F. incarnatum through sequence analysis of translation elongation factor 1 alpha (EF-1α) and DNA-directed RNA ploymerase II second largest subunit (RPB2). Among them, F. fujikuroi accounted for 51.22% (42/82) and was isolated from 91.7% (11/12) soybean varieties. Pathogenicity assay showed that five Fusarium species were able to infect the seeds of soybean cultivar “Nandou12” and caused water-soaked or rot symptoms, while F. fujikuroi and F. asiaticum had much higher aggressiveness than other species with significant reductions of seed fresh weight and germination percentage. Accordingly, this study indicates that Fusarium species are the dominant seedborne fungi in the intercropped soybean in Sichuan, China, and this provides some useful references for the effective management of seedborne fungal diseases as well as soybean resistance breeding in maize/soybean relay strip intercropping.

Plant architectural responses in simultaneous maize/soybean strip intercropping do not lead to a yield advantage

AbstractMaize/soybean strip intercropping is a commonly used system throughout China with high crop yields at reduced nutrient input compared to sole maize. Maize is the taller crop, and due to its dominance in light capture over soybean in the intercrop, maize is expected to outperform maize in sole cropping. Conversely, soybean is the subordinate crop and intercropped soybean plants are expected to perform worse than sole soybean. Crop plants show plastic responses in plant architecture to their growing conditions to forage for light and avoid shading. There is little knowledge on plant architectural responses to growing conditions in simultaneous (non‐relay) intercropping and their relationship to species yields. A two‐year field experiment with two simultaneous maize/soybean intercropping systems with narrow and wide strips was conducted to characterise architectural traits of maize and soybean plants grown as intercrop and sole crops. Intercropped maize plants, especially those in border rows, had substantially greater leaf area, biomass and yield than maize plants in sole crops. Intercropped soybean plants, especially those in border rows, had lower leaf area, biomass and yield than sole soybean plants. Overall intercrop performance was similar to that of sole crops, with the land equivalent ratio (LER) being only slightly greater than one (1.03–1.08). Soybean displayed typical shade avoidance responses in the intercrop, such as greater internode elongation and changes in specific leaf area, but these responses could not overcome the consequences of the competition with the taller maize plants. Therefore, in contrast to relay intercrop systems, in the studied simultaneous maize/soybean system, plastic responses did not contribute to practically relevant increases in resource capture and yield at whole system (i.e., intercrop) level.

Soybean (Glycine max (L.) Merrill) intercropping with reduced nitrogen input influences rhizosphere phosphorus dynamics and phosphorus acquisition of sugarcane (Saccharum officinarum)

Reducing nitrogen (N) input can improve crop productivity in cereal-legume intercrops, but the impact on phosphorus (P) acquisition is unclear. A 10-year (2009–2018) field experiment was conducted to quantify how P acquisition by sugarcane (Saccharum officinarum) was affected by intercropping with soybean (Glycine max (L.) Merrill at 1:1 and 1:2) with two N inputs (300 kg ha−1 [reduced], 525 kg ha−1 [conventional]). Nitrogen was supplied only to the sugarcane crop, and soybean received no N. There was a significantly higher land-equivalent ratio of sugarcane-soybean intercropping than of the sole cropping, and the intercropping advantage was more pronounced under reduced N input which can be associated with high degree of complementary N use. Furthermore, soybean intercropping with reduced N input stimulated acid phosphomonoesterase activity and depleted organic P in the rhizosphere of sugarcane, resulting in increased sugarcane stem P concentration and system P-use efficiency. The interspecific facilitation of P acquisition could be associated with the increased symbiotic N2 fixation in soybean, soil microbial biomass and activity under reduced N input. In conclusion, soybean intercropping with reduced N input to sugarcane enhanced rhizosphere enzymatic organic P transformation and sugarcane P acquisition, which may contribute to maintaining a sustainable sugarcane production under low N supply. The findings advance our understanding of interactions between N and P cycling and provide new evidence for the value of cereal-legume intercrops in reducing fertilizer input.

Additive intercropping of sunflower and soybean to improve yield and land use efficiency: Effect of thinning interval and nitrogen fertilization

Additive intercropping of sunflower and soybean to improve yield and land use efficiency: Effect of thinning interval and nitrogen fertilization

Response of the arbuscular mycorrhizal fungi diversity and community in maize and soybean rhizosphere soil and roots to intercropping systems with different nitrogen application rates

Maize (Zea mays L.)/soybean (Glycine max L.) intercropping has been widely practiced in China, because of its effectiveness in improving crop yield and nitrogen utilization efficiency. However, the responses of indigenous arbuscular mycorrhizal fungal (AMF) diversity and communities in rhizosphere soil and roots to intercropping systems with different nitrogen application rates remain unclear. In this study, a field experiment was conducted with split-plot design, and AMF communities in crop rhizosphere soil and roots in monoculture and intercropping systems treated with different levels of nitrogen fertilization were investigated using Illumina MiSeq sequencing. Nitrogen fertilization significantly decreased the AMF alpha-diversity in maize rhizosphere soil, and no significant differences were observed between monocultured and intercropped maize. The Shannon index of soybean rhizosphere soil was significantly higher in intercropping treatments than in monoculture treatments for the corresponding nitrogen levels. The AMF diversity in the roots of maize showed different trends to those in the soil. The dominant genera in the present study were Glomus_f_Glomeraceae, Paraglomus, and Gigaspora, which occupied 55.52%, 9.18%, and 8.20% of the rhizosphere soil and 65.35%, 5.32%, and 17.16% of the roots, respectively. Our study showed that the abundance of the dominant genus, Glomus_f_Glomeraceae in maize soil and roots significantly increased in intercropping treatments compared with monoculture treatments, and it also increased with the increase in nitrogen application levels. In soybean soil and roots, the abundance of Glomus_f_Glomeraceae decreased with the increase in nitrogen application levels. The results of the redundancy and correlations analyses indicated that the changes in the AMF diversity and community in intercropping areas were significantly associated with alterations of the soil total nitrogen and alkali-hydrolysable nitrogen due to the interactions between maize and soybeans in intercropping systems with different nitrogen fertilizer application rates.

Maize–soybean intercropping effect on yield productivity, weed control and diversity in northern Ghana

AbstractThe cereal–legume cropping system is a common practice across the tropical world. However, there are limited quantitative data on the effect of cereal–legume intercropping on weed species diversity. A study was conducted in the Guinea savanna zone of Ghana to evaluate the effect of maize–soybean intercropping on yield productivity and weed species control. The treatments used include three maize maturity types (extra‐early: Abontem, early: Sammaz 27 and medium: Obatanpa) intercropped with soybean at three intraspacing (10, 20 and 30 cm), and their sole crop treatments were laid in a randomized complete block design with three replications. Results showed that the land equivalent ratio (LER) for the intercrops was above 1, indicating better intercrop productivity than the sole crops. An average of 40% land was saved for the intercrops compared with the sole crops. Intercropping Sammaz 27 maize with soybean significantly increased LER by 9% compared to the other types. Intercropping maize with soybean significantly reduced weed biomass at 6 and 9 weeks after planting (WAP) and at harvest relative to the sole maize. The weed biomass at 6 and 9 WAP and harvest increased (p < .05) with increasing soybean intraspacing. The grass and broadleaf weed species count at 6 WAP and harvest from the sole crops were significantly higher than that of the intercrops. The results suggest that intercropping early maize maturity type with soybean at 10 cm intraspacing could be used to increase grain yield, LER and control of grass and broadleaf weeds in a maize‐based cropping system in the Guinea savanna zones of West Africa.

Evaluation of maize-soybean intercropping systems and fertilizer rates on maize grain yield using competitive indices

Field trials were conducted in savanna ecologies of Nigeria during the 2015 and 2016 seasons using maize (PVA8) and soybean (TGX 1448-2E) intercropping systems with different fertilizer rates to evaluate the yield of maize and assess the best intercropping system for resource management. Single plant stands and two plants/stand and 2 arrangements of rows (one row on a ridge and two rows on a ridge) were used to impose maize plant densities evaluated in strip inter-crop with soybean. The trial was factorial, laid out in a randomized complete block design and replicated three times. Thus, 8 maize-soybean strip cropping systems and application of 3 NPK rates were evaluated at Saki-Oyo, Ilorin, and Nasarawa (southern Guinea savanna), Kaduna in the northern Guinea savanna, Funtua (Katsina) and Gusau (Zamfara) located within Sudan savanna ecologies of Nigeria. Data on yields and yield components were collected. The intercropping systems were assessed using existing intercropping indices such as Land Equivalent Ratio (LER), Relative Crowding Coefficient (K), Aggressivity (A), Competitive Ratio (CR), Actual Yield Loss (AYL), Intercropping Advantage (IA) and Monetary Advantage Index (MAI). The result showed that Nasarawa and Kaduna were most ideal locations for maize production in the Nigeria savannas. The highest grain yield of 4.04 tons/ha maize and 1.36 tons/ha soybean were obtained from seeding 1 plant/stand in 2-rows per ridge x 4 ridges of maize alternated with 2 rows of soybean with the application of NPK at 100:50:50. The LER was 1.11, AYL (1.10) and MAI (208) gave a profit of ₦312,102.00 (US$990.80) ha-1 with a benefit-cost ratio of 2.38 and production efficiency of 29.56%. The study concluded that, seeding 80% maize and 20% soybean per ha will lead to sustainable maize crop production with limited use of fertilizer. It can be adopted by the farmers in Nigeria savannas as a relatively profitable intercropping system.
 Keywords: Maize production, Ideal location, Fertilizer rate, Competitive indices, Savanna ecologies, Nigeria

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

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).

The soil carbon cycle determined by GeoChip 5.0 in sugarcane and soybean intercropping systems with reduced nitrogen input in South China

Agricultural soil is the most important carbon (C) pool on the Earth's surface and is also a source or sink of greenhouse gases. The C cycle is one of the important biogeochemical processes in the agroecosystem and requires microorganisms to participate in many of the important C cycling pathways, such as C fixation, C degradation, and methane metabolism. Insight into the functions of microbial communities in the C cycle can provide a better understanding of the response and feedback of soil microbes with respect to global climate change. The microarray GeoChip 5.0 was used in this study to detect the specific genes linking C cycling and soil microbial-mediated processes and to evaluate the abundance, diversity and similarity of the detected genes responding to different nitrogen (N) application levels under intercropping treatment. Our results indicated that compositional changes in soil microbial communities elicited by N input have functional implications for C cycling and storage in agroecosystems. We further identified a sugarcane (Saccharum officinarum) field as a C sink in this intercropping system, in which sugarcane/soybean (Glycine max) (1:2) strip intercropping (SB2) at the N1 application rate (SB2-N1) had the largest C sequestration potential and net C balance among all the treatments. Most of the functional genes involved in C cycling with regards to fixation and degradation were separately identified after 4 years of N fertilization and intercropping treatments, and environmental factors were central in shaping the functional gene structure related to the C cycles. Overall, our results suggested that reduced N application combined with intercropping treatment mediates ecosystem functions and may have profound feedback effects on global climate change.

Evaluation and Tradeoff Analysis of Ecosystem Service for Typical Land-Use Patterns in the Karst Region of Southwest China

Although many land-use patterns have been established to restore vegetation and eliminate poverty in the karst area in southwest China, the ecosystem services (ESs) of these patterns are still not fully understood. To compare the differences in seven typical monoculture patterns and three agroforestry patterns, their ESs and tradeoffs were analyzed within the Millennium Ecosystem Assessment Framework. Compared with the local traditional corn pattern, the marigold pattern improved provisioning, regulating, and cultural services by >100%. The pomegranate pattern provided far more provisioning services than the other patterns. The apple + soybean intercropping pattern reduced regulating services, and eventually, its Total ESs (TES) and ecosystem multifunctionality index (EMF) also decreased. Cultural services will be enhanced by the introduction of fruit trees, as well as intercropping. Orange + peach had the greatest negative tradeoffs between provisioning and regulating services (P-R), provisioning and supporting services (P-S), and provisioning and cultural services (P-C), which indicates that the provisioning services urgently require improvement. Peach + pumpkin intercropping decreased the negative tradeoffs of P-R, P-S, and P-C (all > 10%), while pomegranate + grass intercropping increased the negative tradeoffs of R-S and R-C (all > 100%). Our results suggest that all six of these patterns are worthy of promotion but the pomegranate pattern should be given priority. Among the three intercropping patterns studied herein, the apple + soybean pattern should be redesigned to improve performance.

Effects of intercropping sugar beet (Beta vulgaris L.) with millet, soybean and Moldavian balm on yield and quality in an organic production system

ABSTRACT To study the effects of intercropping different sugar beet cultivars with soybean, Moldavian balm and proso millet in an organic production system on the yield and quality of sugar beet, a factorial experiment was conducted in 2016 and 2017 in West Azarbayjan, Iran. In 2016, the sugar beet-soybean intercropping resulted in the highest Na and α-amino-N concentrations in the sugar beet (2.384 and 2.879 meq. 100 g−1 beet respectively), but in 2017 the concentrations of these compounds were not significantly different between the intercropping patterns. For all intercropping patterns the land equivalent ratio (LER) was greater than one. In 2016, the highest LERT, based on white sugar yield, was obtained in the sugar beet–soybean intercropping system (1.27 for cv. Vaclav), but in 2017 the highest LERT based on white sugar yield, was obtained in sugar beet–Moldavian balm intercropping (1.24 for cv. Vaclav). Among the sugar beet cultivars, Ghazira had the highest sugar concentration and white sugar yield. It was concluded that the sugar beet–Moldavian balm intercropping system could be used in organic production systems to achieve high land productivity.

Utilization of Thinned Sunflower and Soybean Intercrops as Forage: A Useful Strategy for Small Scale Farms in Intensive Agricultural Systems

Multipurpose intercropping, as a way of agricultural intensification, would contribute to solving the food and feed shortage problems facing the developing countries. In Northern Egypt, a 2-year field study was conducted to investigate the forage potential, in terms of productivity and quality, of thinned sunflower and soybean intercrops, that were subjected to three nitrogen (N) fertilizer rates (70, 105, 140 kg N ha−1) and three ages at forage removal (thinning); 15, 30, and 45 days after sowing (DAS) for sunflower, and 30, 45, and 60 DAS, for soybean. Altering N rate exerted limited effect on the studied sunflower and soybean forage parameters. Dry matter (DM) content of sunflower (157.14 g kg−1) and crude protein (CP) content of sunflower (120.48 g kg−1) and soybean (162.49 g kg−1) were significantly increased, while soybean NDF content significantly decreased, with increasing the N rate. The effect of age at forage removal was more pronounced as it is a direct reflection to the crop’s stage of maturity at cutting. Older sunflower and soybean plants were characterized by higher herbage yield, DM and fiber contents, yet lower CP than younger plants. Maximum herbage yield achieved with late cutting of sunflower and soybean amounted to 9.82 and 10.81 t ha−1, respectively. Relative feed value of sunflower and soybean herbage was less stable in response to the variations in the studied treatments, while, relative forage quality resulting from all treatments was graded as “premium”, making them suitable for high-producing dairy cows and young calves in intensive dairy production systems.

Sugarcane/soybean intercropping with reduced nitrogen input improves crop productivity and reduces carbon footprint in China

Global climate change and decreases in available land are significant challenges that humans are currently facing. Alternative management approaches for sugarcane fields have great potential to help mitigate these problems in China. We hypothesized that soybean intercropping with reduced nitrogen input could increase crop productivity and reduce the carbon footprint (CF) of sugarcane fields in China. Therefore, a long-term field experiment from 2009 to 2017 in the Pearl River Delta of China was chosen to test this hypothesis. The results showed that the energy yields of sugarcane/soybean intercropping systems were 17.8%–39.4% higher than those of sugarcane monocropping systems. The energy yields of the same cropping systems using conventional and reduced N inputs (525 kg ha−1 and 300 kg ha−1) did not show a significant difference. Additionally, the CF values of the unit yield (CFY) for sugarcane/soybean intercropping were 3.2%–30.4% lower than those of the monocropping systems, showing the higher CF efficiency of the intercropping pattern, although the difference was not significant. The CF of the unit area (CFA) and the CFY of all the cropping patterns at the conventional N level were 19.5%–62.0% higher than that at the reduced N level, demonstrating that reducing the nitrogen input could significantly lower the CF of the sugarcane fields. In addition, the high N level cased negative effects in terms of increasing the crop productivity and reducing the CF of the soybean/sugarcane intercropping pattern. In conclusion, sugarcane/soybean intercropping with reduced N input improved crop productivity while lowering the CF of sugarcane fields in China. The sugarcane/soybean (1:2) intercropping with 300 kg N ha−1 system showed the best benefits in the Pearl River Delta of China. These advanced agricultural practices contributed to improved farmland use efficiency and clean production in an agricultural system.

Analysis of Grain Yield Differences Among Soybean Cultivars under Maize–Soybean Intercropping

Shading created by intercropping reduces the photosynthetic capacity of soybean plants but also directly affects the pod setting process of soybean. However, which of the changed aspects induce the yield differences in intercropped soybean cultivars is still unknown. Four soybean cultivars with similar yield and growth and development processes in monoculture were selected by a pre-experiment. Field experiments were carried out from 2015 to 2017 to investigate the leaf photosynthetic parameters, total biomass, reproductive characteristics, yield and yield components of soybean. The yield of soybean cultivars was significantly decreased in intercropping systems and the yield of cultivars (cvs.) ZH39 and QH34 were considerably higher than those of cvs. HD19 and HD20. Besides, the pod and seed number and harvest index were also reduced by intercropping and the yield components of cvs. ZH39 and QH34 in intercropping were significantly higher than those of cvs. HD19 and HD20, other than the seed size. Although the parameters of leaf photosynthetic capacity (leaf area index, net photosynthetic rate, and chlorophyll content) of soybean were changed by intercropping, there was no significant difference among cultivars. Additionally, the CGRR1–R5 (crop growth rate between R1 and R5) of intercropped soybean was lower than that of monoculture, while no significant differences were observed in different cultivars. The reproductive biomass at R5 was significantly different among soybean cultivars, and the reproductive partitioning and seed set efficiency of different cultivars were varied by the reproductive biomass at R5. Therefore, high-yielding cultivars in intercropping can achieve higher yield due to more reproductive structures survived at R5.