•Potato/vetch intercropping is tested as a sustainable cropping system.•Vetch was a stronger competitor for water with partial water equivalent ratio of 0.83.•Land equivalent ratio of 1.30 ...demonstrates high relative land use efficiency compared to sole crops.•Water equivalent ratio of 1.29 demonstrates high relative water use efficiency compared to sole crops.•Spatio-temporal complementarity for water use makes this a productive and resilient cropping system for semi-arid conditions.
Protection from soil erosion and efficient use of water are vital to sustainable dryland potato production in semi-arid regions. Introducing legumes into semi-arid agricultural systems as intercrops improves soil quality due to biological nitrogen fixation and reduced wind erosion as a result of better soil cover, but the consequences of introducing legumes for the water use efficiency of the crop system are less predictable. Here we carried out field experiments from 2014 to 2017 in Inner Mongolia, China. We compared a rotational intercropping system of potato (Solanum tuberosum L.) and hairy vetch (Vicia villosa) with monocultures of potato and hairy vetch and quantified crop yield, water use efficiency and land productivity. While the relative density (the ratio of plant density in intercrop and the density in sole stand) of both crops in the intercropping was 0.5, the average relative yield of the potato over four years was 0.43, but that of the vetch was 0.87, indicating dominance of the vetch in the intercropping system. Land and water equivalent ratios, defined as the area of land or amount of water that would be needed in single cropping to achieve the same yield as in intercropping, averaged to 1.30 and 1.29 over the years, respectively, indicating high relative land and water productivity of potato/hairy vetch intercropping compared to monocultures. Vetch was a stronger competitor for water than potato with a partial water equivalent ratio of 0.83. We conclude that the potato/vetch intercropping system improves land productivity and system level water use efficiency under the rain-fed semi-arid conditions of the study site. These results are useful to optimize cropping systems for regional sustainability with consideration of both arable crop production (potato) and provision of fodder for animal husbandry (vetch).
•Wolfberry/ Gramineae intercropping could improve productivity as evidenced by a significant increase in the land equivalent ratio (LER).•Wolfberry fruit quality was significantly improved under ...intercropping, which shows up in fruits carotenoid, flavonoid, total sugar and ascorbic acid content increased.•Potassium and nitrogen were the nutrients that most affected the bacterial community, and all soil enzymes corelated with bacterial community composition, particularly under intercropping mode.•Wolfberry/ Gramineae intercropping could alter the soil bacterial community composition which reflects changes in soil properties and enzyme activities.
The intercropping of shrubs with Gramineae species has been used widely to increase productivity and sustainability in modern agriculture. However, there have been few studies of intercropping of Wolfberry shrubs (Lycium barbarum) and it is cultivated mostly by clean tillage. In this study, we measured land productivity, crop yield and quality, and soil properties when L. barbarum was intercropped with Gramineae plants compared to when grown in a monoculture with clean tillage. The results showed that Wolfberry/ Gramineae intercropping improved productivity and fruit quality as evidenced by a significant increase in the Land Equivalent Ratio (LER) and the content in the fruit of carotenoid, flavonoid, total sugar and ascorbic acid. The nutrient content and enzyme activity of rhizosphere soils were higher under intercropping. The physical properties of the soil also improved with increased soil moisture, available potassium, available phosphorus and total nitrogen. The effect of intercropping on bacterial diversity was greater than that on fungal diversity, especially alpha diversity as shown by the Shannon Index, although both groups were markedly altered by intercropping. Binding spatial ordination analysis demonstrated that potassium and nitrogen were the nutrients that most affected the bacterial community, and all soil enzymes corelated with bacterial community composition. Collectively, these results suggest that intercropping of L. barbarum with Gramineae plants alters the soil bacterial community composition which reflects changes in soil properties and enzyme activities. Our findings show how to improve Wolfberry productivity and they provide insights into the mechanisms underlying healthy, biodiverse soils in agroecosystems.
Introduction Agriculture plays an essential role in providing food, and in order to achieve sustainability in the agricultural sector, resources must be used in the best possible way. In order to ...achieve the maximum possible yield, it is necessary for the crop plant to use the environmental factors, water, nutrients, light, and carbon dioxide, with the maximum possible efficiency. The maximum use of the required factors for growth is achieved only when the plant community exerts maximum pressure on these factors. In general, intercropping is one of the ways to achieve sustainable agriculture, with higher yields without increasing agricultural inputs, absorption, and environmental factors productivity. Researchers for the intercropping of corn and mung bean have reported that the mixed cultivation systems used environmental resources more effectively compared to the sole cropping of corn and mung bean. For this reason, nowadays, many plants, especially legumes, are cultivated in an intercropping form due to their ability to fix nitrogen. Due to the lack of resources regarding the effect of planting direction on plant yield, this study was conducted in order to evaluate resources and soil nutrients by changing the planting direction and replacing the intercropping system of the sunflower with cowpea. Materials and Methods This research was conducted in the field of the Agricultural Research Station of Zabol University during 2015-2016. The experiment was performed as a split-plot based on a randomized complete block design with three replications at the Research Farm of the Agricultural Research Institute of Zabol University. The main factor was two levels of planting direction (North-South and East-West), and the secondary factor was intercropping system in five levels, including (100% pure sunflower), (100% pure cowpea ), (50% sunflower + 50% cowpea ) (25% cowpea + 75% sunflower) and (75 % cowpea + 25%sunflower) were considered. Data for studied traits were measured as follows: radiation, temperature, volumetric humidity, calcium, phosphorus, magnesium, potassium, and the land equality ratio. Statistical analysis including, analysis of variance and mean comparisons (least significant difference (LSD) test at the 5% level), were applied to evaluated traits. Results and Discussion The maximum absorption of photosynthetically active radiation (PAR) was in the east-west cultivation direction (77.90%) compared to the north-south treatment, which was 24.6% more than the north-south direction. The analysis of variance indicated that the cultivation direction and intercropping systems on the amount of phosphorus in the soil after harvest were significant at 1% probability level. The comparison of means treatments showed that the amount of phosphorus in the soil in the direction of east-west cultivation was 15% higher compared to the direction of north-south cultivation. The highest amount of soil potassium was obtained in the east-west treatment and the intercropping system of 50% sunflower plus 50% cowpea (24.7 ppm). The lowest amount of soil potassium (16.15 ppm) was obtained in the treatment of east-west cultivation and the intercropping system of 75% sunflower plus 25% cowpea. The relative advantage of intercropping is expressed by the land equivalent ratio. The increase in the ratio of equal land per unit shows the relative usefulness of intercropping compared to sole cropping of each of the mixed components. The comparison of means of the intercropping system showed that among the treatments, the mixture of 75% sunflower plus 25% cowpea had the highest land equivalent ratio (2.54). Conclusion It seems that in order to maintain humidity make maximum use of limited water resources, and obtain high yield, the intercropping system of 75% sunflower plus 25% cowpea and planting direction the prevailing wind of the region (east-west) should be suitable for this region and regions with similar climate and windy conditions. Acknowledgments We would like to thank the chairman and the respected staff of the Agricultural Research Institute of Zabul University, who sincerely accompanied us in the implementation of this thesis.
•Plant Growth-Promoting Rhizobacteria increased the fennel seed yield by 24 %.•Intercropping with common bean improved the fennel essential oil content.•Intercropping increased the amount of ...(E)-anethole and fenchone.•The intercropping ratio of 3:2 and PGPR application improved the land use efficiency.
In order to evaluate the quali-quantitative traits of fennel (Foeniculum vulgare L.) when intercropped with common bean (Phaseolus vulgaris L.) in different cropping patterns and under PGPR application, a two-years field experiment (2015 and 2016) was arranged as factorial design based on randomized complete blocks (RCBD) with three replications. The first factor consisted of six cropping patterns including sole cropping of fennel, sole cropping of common bean, and different intercropping ratios of fennel to common bean (1:1, 2:2, 3:2, 4:2), whereas the second factor included the application and non-application of PGPR. The results showed that the highest seed yields of common bean (2474.83 kg ha−1) and fennel (2730.08 kg ha−1) were produced with sole cropping combined under PGPR application. The fennel essential oil (EO) and seed oil (fixed oil) content in all intercropping patterns were higher than those in sole cropping. Furthermore, under PGPR application, the seed yield, EO content, EO yield, fixed oil content and oil yield of fennel increased by 20.9, 16.4, 39.3, 10.3 and 33.3 %, respectively, compared with control. Based on the chemical analysis of fennel EO, the main constituents were (E)-anethole (73.71–81.10%), fenchone (3.44–6.18%), limonene (3.49–5.82%) and methyl chavicol (4.06–7.22%). The major fatty acids in fennel fixed oil were oleic (77.17–82.90%), linoleic (6.50–8.97%) and palmitic acids (3.25–6.80%). The highest content of unsaturated fatty acids (oleic and linoleic acids) and (E)-anethole were obtained with intercropping ratios (fennel to common bean) of 2:2 and 3:2 under PGPR application, respectively. Furthermore, the highest land equivalent ratio (1.32) was obtained with intercropping ratio of 3:2 under PGPR application. Our findings showed that the intercropping ratio of 2:2 and 3:2 upon PGPR biofertilization may be suggested to farmers instead of sole cropping for enhancing the fennel EO and fixed oil quali-quantitative composition.
Growth performance under intercropping relies heavily on the nitrogen (N), phosphorus (P) and potassium (K) levels of the plants involved. However, few studies on intercropping advantages have ...established a direct link between growth performance and plant nutrient uptake. Using a 3-year field study (2019–2021) with four cotton-based cropping systems (cotton monoculture and garlic/cotton, peanut/cotton, and wheat/cotton intercropping) and three root partitions (no, mesh, and plastic), we measured the biomass and nutrient concentrations of cotton organs to explain differences in nutrient uptake between monoculture and intercropping. Additionally, the contributions of these nutrients to agricultural biomass under monoculture and intercropping were distinguished. Intercropping significantly increased the biomass of cotton aboveground parts by 15.5%, with the peanut/cotton intercropping system showing the greatest improvement. Intercropping also increased aboveground N, P and K concentrations and contents. In terms of cotton partial land equivalent ratio (pLER) values based on aboveground biomass, the root partitions ranked plastic > mesh > no. The relative N, P, and K content totals of intercropped cotton were higher than the pLER for biomass, indicating that the greater biomass under intercropping was accompanied by even greater percentage increases in the pools of N, P and K relative to those under monoculture. In the three intercropping systems, enhanced nutrient uptake was driven similarly by increases in plant nutrient concentration and biomass. Compared with cotton monoculture, intercropping improved the biomass production contributions of N by 46.7%, P by 57.3%, and K by 106%. Thus, intercropping enhanced plant nutritional potential to produce more biomass, and the yield benefit was amplified when belowground competition between intercrops was partially (or fully) diminished by root partitions.
•Cotton-based intercropping outperformed cotton monoculture.•Peanut/cotton intercropping resulted in the greatest improvements for cotton.•Nutrient overyielding of intercropping was co-driven by plant nutrients and biomass.•Cotton yield promotion was amplified when competition was reduced by root partitions.•Intercropping enhanced plant nutritional potential to produce more biomass.
•Crops had lower yields in agroforestry whatever the water regime.•Agroforestry limited crop growth and reduced the number of grains per unit area.•Agroforestry improved individual grain weight but ...not grain yield.•Agroforestry enhances the protein content of grains and straw.•Agroforestry had LER > 1 in most cases but wasn’t clearly affected by water regimes.
Agroforestry systems can be an effective means of stabilizing or even enhancing crop yields under climate change. Although trees compete with crops for soil resources in agroforestry,they can also improve crops' growing conditions, especially, by providing shade under drought. They can promote higher crop yields and higher harvest quality in the drylands. However, the beneficial effect of tree shade may depend on the seasonal pattern of rainfall, which determines the compensation between yield components. In this study, we evaluated two annual crops (durum wheat and faba bean) in olive agroforestry in northern Morocco. We manipulated water supply in a field experiment to span the high inter-annual rainfall variability at the site and tested whether olive trees reduce or improve crop yields. We assessed the effect of water addition on crop growth, yield components, and final yields and estimated the land equivalent ratio of olive agroforestry. Agroforestry limited crop growth and yield whatever the water regime. The magnitude of grain yield reduction was around 50 % for both crops in 2018, probably due to shade. The number of grains per unit area was the most impacted yield component in both 2018 and 2019. In contrast, water addition only had limited effects on faba bean yield, although it enhanced wheat grain yield by 11 % and the number of wheat spikes by 13 %. Agroforestry improved individual grain weight by 39 % for wheat and 17 % for faba bean, and enhanced the protein content of wheat grains and straw by 4 % and 9 %. However, improvements in grain weight and in protein content were not sufficient to compensate for yield loss due to shade. Despite lower crop yields, we show that agroforestry systems are still more land productive than sole crops and trees, even under arid conditions. We show how changing water supply may impact the performance of olive agroforestry in a drier future.
Complementarity in acquisition of nitrogen (N) from soil and N₂-fixation within pea and barley intercrops was studied in organic field experiments across Western Europe (Denmark, United Kingdom, ...France, Germany and Italy). Spring pea and barley were sown either as sole crops, at the recommended plant density (P100 and B100, respectively) or in replacement (P50B50) or additive (P100B50) intercropping designs, in each of three cropping seasons (2003-2005). Irrespective of site and intercrop design, Land Equivalent Ratios (LER) between 1.4 at flowering and 1.3 at maturity showed that total N recovery was greater in the pea-barley intercrops than in the sole crops suggesting a high degree of complementarity over a wide range of growing conditions. Complementarity was partly attributed to greater soil mineral N acquisition by barley, forcing pea to rely more on N₂-fixation. At all sites the proportion of total aboveground pea N that was derived from N₂-fixation was greater when intercropped with barley than when grown as a sole crop. No consistent differences were found between the two intercropping designs. Simultaneously, the accumulation of phosphorous (P), potassium (K) and sulphur (S) in Danish and German experiments was 20% higher in the intercrop (P50B50) than in the respective sole crops, possibly influencing general crop yields and thereby competitive ability for other resources. Comparing all sites and seasons, the benefits of organic pea-barley intercropping for N acquisition were highly resilient. It is concluded that pea-barley intercropping is a relevant cropping strategy to adopt when trying to optimize N₂-fixation inputs to the cropping system.
Intercropping maize and soybean is renowned for improving crop production and resource use efficiencies. Interspecific competition and complementarity with respect to root plasticity is essential ...knowledge for understanding the mechanisms of overyielding and optimizing intercropping species selection. We conducted a three-year field experiment (2017–2019) to quantify land and water productivities in relation to above- and below-ground interspecific interactions, root growth and distribution under different nitrogen rates in maize/soybean intercropping. The land productivity in terms of land equivalent ratio (LER) in maize/soybean intercropping was 1.10 across all years and N rates. The yield increase in intercropped maize was mainly gained from an 45% increase in kernel numbers, while the yield loss of intercropped soybean was caused mainly by an 35% decrease in the pod numbers compared to sole cropping. The system level water use efficiency, defined as water equivalent ratio (WER) was also 1.10. Compared with sole stands, intercropped maize consumed more water during the vegetative stage, but intercropped soybean took up more during the reproductive stage. That indicated a temporal complementarity of water use in the intercrop, which benefited maize kernel formation and partially offset the negative shading effect of soybean grain filling. Soybean showed a marked increase in root length density (RLD). Compared to the produced aboveground biomass (DM) in the intercrop, the intercropped soybean invested more assimilates into root than shoot, as defined as root plasticity, the RLD/DM ratio of soybean in the intercrop was 76% more than sole system. However, the intercrop did not change root plasticity of maize. The overlap of maize and soybean roots, i.e. interspecific interaction interface, occurred mainly within the position between two border rows and at first soybean row. Under interspecific competition, soybean in the intercropping created both temporal and spatial differentiation for water uptake, which might be a key reason for enhancing intercropping land and water productivities. Our results contribute to understanding the mechanism of interspecific interaction for maximizing land and water productivities in rain-fed intercropping.
•Maize/soybean intercrop enhanced land and water productivities in rainfed conditions.•The yield increase of intercropped maize was due to an 45% increase in kernel number.•The yield loss of intercropped soybean was caused by an 35% decrease in pod number.•Shaded soybean in intercrop produced more roots than aboveground biomass.•Interspecific complementarity enhanced crops water use efficiencies in intercrop.
•Two years on-farm trials on intercropping in poor soils in low inputs systems.•Land productivity increased by maize-cowpea intercropping.•Same proportion of N derived from the atmosphere for sole or ...intercropped cowpea.•Maize and cowpea grain mineral contents not impacted by treatment but by season.•Cowpea grain mineral contents (Fe, Zn, Mn, Cu, Ca, Mg, P, K) higher than for maize.
Poor soil fertility and erratic rainfall constrain crop production in rain-fed smallholder farming systems in sub-Saharan Africa. Integration of drought tolerant and N2-fixing crops into maize-based cropping systems is a risk-averse strategy that also improves nitrogen cycling. A field experiment was carried out during the 2017/18 and 2018/19 cropping seasons in Goromonzi district in Zimbabwe. The trials were established on 14 farms, and on two field types (homefields and outfields), with eight treatments from a combination of cropping systems (maize and cowpea monocrops or maize/cowpea intercrops) and with or without nitrogen fertilizer (+N; -N). The trials were implemented on the same field plots for the two consecutive seasons. An improved cowpea variety and a landrace were used. The objectives were to determine 1) the productivity of the different cropping systems under variable soil fertility conditions, 2) N2-fixation of the two cowpea types when planted as monocrops or intercrops, and 3) mineral composition of maize and cowpea grains from intercrops and sole crops. Contrary to expected results, soil properties were not significantly different (P > 0.05) between field types. The land equivalent ratios (LER) were >1 for both seasons, implying improved land productivity under intercropping. Intercropping significantly reduced cowpea nodulation and active nodules, but not the total nodule weight, resulting in similar proportion of nitrogen derived from the atmosphere (%Ndfa) for cowpea grown as monocrop or in intercropping with maize. However, the total amount of fixed nitrogen was reduced in intercropping systems due to the smaller cowpea biomass compared to monocropping. Maize and cowpea grain mineral contents (Fe, Zn, Mn, Cu, Ca, Mg, P, K) were significantly affected by the cropping season only. We showed that intercropping maize with cowpea generally increases system productivity, in addition to substantial amounts of nitrogen being added to the system through N2-fixation. However, intercropping was not an agronomic biofortification option in these nutrient-depleted soils. Finally, annual variation in grain mineral quality can be larger than the annual variation in grain yield, potentially posing serious challenges to human nutrition.
•Rainfed wheat/maize intercropping provided land equivalent ratios above 1.•Wheat in first border rows and second border rows showed major yield increase.•The yield components resulted in ...intercropped wheat yield increase were different.•The SPAD and Pn in border rows of intercropped wheat were significantly improved.•The SPAD and Pn of intercropped maize showed growth recovery after wheat harvest.
Intercropping has been widely adopted by farmers for higher yield compared to monoculture, and the border effect was responsible for the yield advantage in irrigated areas. However, few studies have investigated the border effect based on photosynthesis, especially under rainfed conditions. Here, we evaluated the yield in rainfed wheat/maize strip relay intercropping, and explored the associated differences in yield components and physiological process compared to sole crops. A two-year field experiments was conducted including three treatments (sole wheat, sole maize and wheat/maize intercropping) in Yangling, located in the semi-humid region of northwest China. Grain yield, yield components, chlorophyll relative content (SPAD) and photosynthetic parameters in different rows were measured for wheat and maize. Results showed that wheat/maize intercropping increased the land use efficiency and total yield of wheat and maize under rainfed conditions. The yield of intercropped wheat was significantly (p < 0.05) increased by 35% on average over two years, resulting not only from the first border rows but also from the second border rows. The yield improvement in the first border rows relative to sole wheat was attributed to the increase of ear number (56%, p < 0.05), kernel number per ear (14%, p < 0.05) and thousand kernel weight (12%, p < 0.05), but the yield improvement in the second border rows was only attributed to the ear number (22%, p < 0.05). The yield of intercropped maize was not significantly (p > 0.05) decreased (6%), mainly attributed to the border rows (19% lower than in sole maize), in which the kernel number per cob and thousand kernel weight were 14% and 8% (p < 0.05) lower than that in sole maize. This was because that the SPAD and photosynthetic rate of maize in intercropping was suppressed during the co-growth period (about 62 days). Although the two had a partly growth recovery after wheat harvest, the growth recovery was not complete, and this was responsible for the reduction of maize yield in intercropping. This study demonstrates that the importance of yield components and the photosynthesis basis for yield advantage in intercropping systems, and reducing the adverse effect of dominate crop on subordinate crops could better exert the advantages of intercropping.
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