► Intercrops of pea with wheat, rye, and triticale in two seeding ratios (60:40 and 80:20) were compared with sole crops of pea and each of the three cereals. ► Growth rate of cereals was lower in ...the mixtures than in the sole crops. ► The land equivalent ratio (LER), relative crowding coefficient (K), actual yield loss (AYL) and system productivity index (SPI) values were greater for the pea–triticale mixtures and the pea–wheat and pea–rye mixtures (80:20), indicating an advantage of intercropping. ► In most intercrops, the values of partial
K and AYL, aggressivity, and competitive ratio (CR) indicated that the cereal was more competitive than pea. ► Overall, pea–triticale and pea–wheat mixtures (80:20) were more productive and produced better forage quality than the other mixtures and thus could be adopted by the farmers as alternative options for forage production.
Intercrops of pea (
Pisum arvense L.), a popular legume used in intercropping systems with winter cereals for forage and silage production, with wheat (
Triticum aestivum L.), rye (
Secale cereale L.), and triticale (×
Triticosecale Wittmack) in two seeding ratios (60:40 and 80:20) were compared with monocrops of pea and cereals for two growing seasons. Growth rate, dry matter yield, and N uptake were determined in each intercropping system. Furthermore, several indices were used to evaluate the intercropping systems and analyze the competition and the interrelationships between mixture components. Growth rate of cereals was lower in the mixtures than in the monocrops. Dry matter yield was higher in triticale monocrop, followed by its two intercrops, and the pea–wheat 80:20 intercrop. Moreover, triticale monocrop, pea–triticale intercrops, and pea–wheat 80:20 intercrop showed the highest crude protein yield and N uptake. The land equivalent ratio (LER), relative crowding coefficient (K), actual yield loss (AYL), and system productivity index (SPI) values were greater for the pea–triticale mixtures and the pea–wheat and pea–rye mixtures (80:20), indicating an advantage of intercropping. In most intercrops, the values of partial K, AYL, aggressivity, and competitive ratio (CR) indicated that the cereal was more competitive than pea. The highest values of monetary advantage index (MAI) and intercropping advantage (IA) were recorded for the pea–triticale and the pea–wheat mixtures (80:20). Overall, pea–triticale and pea–wheat mixtures (80:20) were more productive and produced better forage quality than the other mixtures and thus could be adopted by the farmers as alternative options for forage production.
•Productivity and light use of cotton in jujube-cotton intercrop can be increased by optimizing plant density.•Increasing plant density modified the distribution pattern of the light within the ...canopy.•The highest yield and light use efficiency of intercropped cotton were achieved at 18.0plantsm−2.
Tree-crop mixtures may increase yield and revenue especially during the early years of tree plantations. Jujube is grown widely in China for their fruits, and cotton is gaining popularity as an understory crop in young jujube plantations. There is a need for information on productivity and optimal planting densities of cotton in these mixed systems. Field experiments were carried out in 2012 and 2013 in Hetian, Xinjiang, China. Three cotton plant densities (13.5, 18.0 and 22.5plantsm−2) were tested in 6–7 years old jujube plantations, in which the cotton was grown in a 6m-wide space between the tree rows. Cotton leaf area index increased but plant height decreased with plant density. Cotton light interception increased with density, but at early and mid-season, the difference in light interception between 18.0 and 22.5plantsm−2 was only marginal. Increasing plant density modified the distribution pattern of the light within the canopy, thus affected overall cotton light interception and use efficiency. The highest yield and light use efficiency of cotton were achieved at 18.0plantsm−2. Spatial distributions of light intensities and extinction coefficients were affected by the shading of jujube trees within the cotton canopy in the intercrop. Jujube growth, yield and light utilization were not significantly affected by cotton plant density. We conclude that the productivity and light utilization of cotton in jujube-cotton intercropping can be increased by optimizing cotton plant density.
Advantages or disadvantages of intercropping system can estimate through expression of components of yield on the base of values of productive organs (spike, pod). The aim of this work was study of ...variation of spike index in cereals species and pods index in pea of spring intercropping. For investigation included spring species of small grains: wheat, triticale, oat and spring legume pea. The investigation was carried out in field condition in experiment with randomised block design of 5m2 plots, with 4 replications. Each species (cereals and pea) were sown sole and in intercrops wheat+pea, triticale+pea and oat+pea. At the maturity stage used 40 plants (10 plants/replication) for determining harvest index of spike in cereal species and index of pea pods on the base of analysis of spike mass and pod mass and seed mass spike-1 and seed mass pod-1 . Seed mass spike-1 of small grains species genotypes variate in ratio of 0.85 g (wheat+pea) and 1.59 g (oat intercrops) with average 1.19 g for all crops of cereals and variant of cultivation. The spike mass variate in range of 1.37 g (triticale intercrop) and 2.23 g (wheat intercrops) with average 1.72 g for all cereals and variant of cultivation. Harvest index of spike variate between 62.5% (triticale sole) and 89.2% (oat sole). The value of spike mass was the higher in wheat intercrops than in wheat sole, while for triticale and oat spike mass is lower in intercrops. In the same of analyzed small grain species, seed mass was the higher in sole crops than in mixture with pea. The spike index, only in intercrop triticale+pea (63.2%) was slightly higher than in single crop of triticale (62.5%). Pod mass and seed mass pod-1 of pea was the higher in pea intercrops than in pea sole. The highest pod mass was in intercrop pea+triticale (0.72 g) and the least in single crop of pea (0.45 g) with average 0.62 g for all crops. The highest seed mass pod-1 was the highest intercrop pea+triticale (0.56g) and the least in monocrop of pea (0.32 g) with average 0.46 g for all crops. Harvest index of pod variate in ratio 68.0% (pea single) and 77.% in pea/triticale intercrop. Pod index of pea in mixture with each small grains species genotypes was higher than in pea's monocrop. On the base of result we can conclude that intercropping cereals + pea, have positive effect on spike and pod characteristics which values were higher in majority of studied intercrops than in monocrops.
BACKGROUND AND SCOPE: Multi-cropping approaches in production systems, where more than one crop cultivar or species are grown simultaneously, are gaining increased attention and application. Benefits ...can include increased production, effective pest, disease and weed control, and improved soil health. The effects of such practices on the range of interactions within the plant-soil system are manifest via plant interspecific competition, pest and disease attenuation, soil community composition and structure, nutrient cycling, and soil structural dynamics. Interplant diversity and competition effectively increases the nature and extent of root networks, tending to lead to more efficient resource use in time and space. Increased competitive ability at a system level, and allelopathic interactions, can reduce weed, pest and disease severity. Soil biotic communities are affected by plant diversity, which can increase abundance, diversity and activity of functional groups. Attendant rhizosphere-located processes can facilitate nutrient uptake between component crops. Whilst there are few studies into multi-cropping effects on soil structure, it is hypothesised that such processes are manifest particularly via the role which the belowground biota play in soil structural dynamics. A deeper understanding of eco-physiological processes affecting weed, pest and disease dynamics in the context of multiple cropping scenarios, and breeding cultivars to optimise mutualistic and allelopathic traits of crop mixtures could significantly increase productivity and adoption of more sustainable farming practices. CONCLUSIONS: Wider consideration needs to be given to plant: soil interactions when crop plants are grown in the context of mixtures, i.e. as communities as opposed to monotonous populations. In particular, a better understanding is required of how root systems develop in the context of mixtures and the extent to which resultant interactions with the soil biota are context-dependent. A significant challenge is that crop cultivars or production systems optimised for monocultural circumstances should not be assumed to be most suited for multi-cropping scenarios, and hence alternative strategies for developing new production systems need to take this into account.
Soil nitrogen (N) is one of the most important nutrients for plant productivity and microbial activity in terrestrial ecosystems. However, soil N is also readily affected by land management ...practices, influencing N2O emissions. This study assessed N dynamics in soil from different crop systems including a 1:2 (one row of maize and two rows soybean) and 2:3 (two rows of maize and three rows of soybean) intercrop and a maize and soybean sole crop as a result of residue addition from maize or soybeans. This was achieved through a 140-day incubation study using δ15N natural abundance. The effect of residue addition on soil TN was greater than its influence on crop systems when compared to treatments with no residue addition (Cont). The influence of residue addition on intercrops was most readily observed in the fractionated soil. Light fraction N (LF-N) and soil microbial biomass N (SMB-N) were significantly greater (p<0.05) in the intercrops than in the sole crops. Residue amended treatments were significantly (p<0.05) depleted in δ15N-TN, δ15N-LF and δ15N-SMB compared to Cont treatments. The δ15N-SMB was significantly enriched (p<0.05) compared to that of the residue, TN and LF-N. Residue amended treatments had significantly lower (p<0.05) N2O emissions than Cont treatments. However, N2O emissions were not significantly different (p<0.05) between soybean and maize amended treatments, nor between intercrops and sole crops. Our results demonstrate that the addition of contrasting residue types influenced short-term N dynamics in intercrops differently than sole crops.
•Residue and agroecosystem management type affected short-term N dynamics.•The effect of residue addition on intercrops was most readily observed in soil fractions.•Intercropping is a sustainable land management practice.•Residue addition decreased soil N2O emissions.
The studies were carried out in the Kirov region on sod-podzolic sandy loam soil in a long-time stationary experiment established in 1976. The article provides data (2010-2017) on four ...fallow-grain-grass crop rotations with various types of fallows, annual and perennial legumes (25-50 %), intercrops (12.5-37.5 %). The purpose of the studies is to compare the influence of some biologization techniques in eight-field crop rotations on the change in soil fertility and the balance of nutritional elements of sod-podzolic sandy loam soil. It is found that the application of low doses of mineral fertilizers (N
30
P
30
K
30
) and various types of green manure crops per rotation has significantly increased the content of mobile phosphorus in the arable soil layer (by 39-46 mg/kg). According to grouping the provision of soils with phosphorus, the content of this element passed into the «high provision» group. The content of exchangeable potassium in the soil remained in the «increased» provision group. In the control crop rotation with clean fallow at a minimum supply of nutrients with mineral fertilizers and root-stubble residues, the balance of nitrogen, phosphorus and potassium was created negative at the intensity of less than 100 %. The replacement of clean fallow for cropped and green manure fallows, as well as the introduction of intermediate cruciferous crops into the crop rotation structure contributed to the positive balance of nitrogen (250.2-484.3 kg/ha) with the intensity of 124-150 %. The biologization factors used in crop rotations favored the creation of a positive phosphorus balance (12.5-148.1 kg/ha) with the optimal intensity of 117-163 % and a positive potassium balance (128.9-395.8 kg/ha) with the intensity above the optimal value of 116-148 %. The most advantageous in terms of productivity and ensuring a positive balance of nutritional elements is crop rotation with two green manure fallows and sowing of stubble and hay cruciferous crops in three fields.
► Land equivalent ratios were assessed for maize or sunflower intercropped with soybean. ► Sunflower or maize yield response to plant density influenced yield of the intercrop. ► Yield of sunflower ...and maize was reduced from sole to intercrop at each plant density. ► Yield reductions were associated with lower intra-row spacing in the intercrops.
Maize–soybean and sunflower–soybean intercrops have the potential for increasing yield per unit land area and time in fully mechanized farming systems. The objectives of this work were to measure the land equivalent ratio index of maize and sunflower intercropped to soybean, to assess the effects of plant density of its components, and to gain insight into ecophysiological processes affecting their yield determination. Maize–soybean and sunflower–soybean intercrops and their respective sole crops were grown at Balcarce, Argentina during two growing seasons. Treatments included a wide range of plant densities for sole and intercropped sunflower (2–9 plants
m
−2) and maize (4–12 plants
m
−2). Plants were harvested to determine shoot dry matter and grain yield per plot and at the individual plant level. Land equivalent ratio index (LER) increased 11% (mean of the two years) when plant density of sunflower was reduced from 6 to 3 plants
m
−2; and LER increased 5% (year 1) or it was maintained (year 2) when maize plant density was reduced from 8 to 4 plants
m
−2. Yield response to plant density of sunflower and maize influenced LER. The response to plant density of intercropped sunflower and maize grain yield followed the same pattern than that in a sole crop, and grain yield of intercropped sunflower or maize were lower than those for the sole crops at each plant density except at the lowest sunflower plant density. Yield reductions from sole crop to intercrop at each plant density averaged 20% and were associated (i) with lower intra-row spacing in the intercrop and (ii) with a lower shoot production rather than to a change in the dry matter partitioning to reproductive structures; in addition, detrimental effects of soybean over maize or sunflower yield were undetectable.
Grain protein concentration of durum wheat is often too low, particularly in low-N-input systems. The aim of our study was to test whether a durum wheat-winter pea intercrop can improve relative ...yield and durum wheat grain protein concentration in low-N-input systems. A 2-year field experiment was carried out in SW France with different fertilizer-N levels to compare wheat (Triticum turgidum L., cv. Nefer) and pea (winter pea, Pisum sativum L., cv. Lucy) grown as sole crops or intercrops in a row-substitutive design. Without N fertilization or when N was applied late (N available until pea flowering less than about 120 kg N ha⁻¹), intercrops were up to 19% more efficient than sole crops for yield and up to 32% for accumulated N, but were less efficient with large fertilizer N applications. Wheat grain protein concentration was significantly higher in intercrops than in sole crops (14% on average) because more N was remobilized into wheat grain due to: i) fewer ears per square metre in intercrops and ii) a similar amount of available soil N as in sole crops due to the high pea N₂ fixation rate in intercrops (88% compared to 58% in sole crops).
Lepidopteran stemborers and parasitic weeds in the genus Striga are major constraints to efficient production of cereals, the most important staple food crops in Africa. Smallholder farmers are ...resource constrained and unable to afford expensive chemicals for crop protection. Development of a push-pull approach for integrated pest and weed management is reviewed here. Appropriate plants were discovered that naturally emit signalling chemicals (semiochemicals). Plants highly attractive for egg laying by stemborer pests were selected and employed as trap crops (pull), to draw pests away from the main crop. Of these, Napier grass, Pennisetum purpureum (Schumach), despite its attractiveness, supported minimal survival of the pests' immature stages. Plants that repelled stemborer pests, notably molasses grass, Melinis minutiflora P. Beauv., and forage legumes in the genus Desmodium, were selected as intercrops (push). Desmodium intercrops suppress Striga hermonthica (Del.) Benth. through an allelopathic mechanism. Their root exudates contain novel flavonoid compounds, which stimulate suicidal germination of S. hermonthica seeds and dramatically inhibit its attachment to host roots. The companion crops provide valuable forage for farm animals while the leguminous intercrops also improve soil fertility and moisture retention. The system is appropriate as it is based on locally available plants, not expensive external inputs, and fits well with traditional mixed cropping systems in Africa. To date it has been adopted by more than 30 000 smallholder farmers in East Africa where maize yields have increased from ~1 t ha⁻¹ to 3.5 t ha⁻¹. Future directions for semiochemical delivery by plants including biotechnological opportunities are discussed.
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