Effects of soil physicochemical environment on the plasticity of root growth and land productivity in maize soybean relay strip intercropping system

BACKGROUND

Soil is a key foundation of crop root growth. There are interactions between root system and soil in multiple ways. The present study aimed to further explore the response of root distribution and morphology to soil physical and chemical environment under maize (Zea mays L.) soybean (Glycine Max L. Merr.) relay strip intercropping (MS) An experiment was carried out aiming to examine the effects of nitrogen (N) applications and interspecific distances on root system and soil environment in MS. The two N application levels, referred to as no N application (NN) and conventional N application (CN), were paired with different interspecific distances: 30, 45 and 60 cm (MS30, MS45 and MS60) and 100 cm of monoculture maize and soybean (MM/SS100).

RESULTS

The results demonstrated that MS45 increased the distribution of soil aggregates (> 2 mm) near the crop roots and maize soil nutrients status, which increased by 20.3% and 15.6%. Meanwhile, MS reduced soil bulk density, increased soil porosity and improved soil oxygen content. Optimization of the soil environment facilitated root growth. The MS45 achieved a better result on root distribution and morphology than the other configuration and also increased land productivity.

CONCLUSION

Relay intercropped soybean with maize in interspecific row spacing of 45 cm, improved soil physicochemical environment, reshaped root architecture and optimized root spatial distribution of crops to achieve greater land productivity. © 2024 Society of Chemical Industry.

Grain yield and interspecific competition in an oat-common vetch intercropping system at varying sowing density

Introduction

Oat (Avena nuda L.) and common vetch (Vicia sativa L.) intercropping in the northern regions of China has resulted in substantial production capabilities. However, there is currently a dearth of comprehensive research on whether this intercropping system can enhance productivity through increased sowing densities and underlying interspecies interaction mechanisms.

Methods

A two-year field experiment was conducted in 2022 and 2023 to investigate the yield, biological efficiency, economic efficiency, and competition indicators of oats and common vetch in a high-density intercropping system. Two cropping patterns (monocropping and intercropping) and five sowing densities (D1: 4.5×106 plants ha-1; D2:5.4×106 plants ha-1; D3:6.3×106 plants ha-1; D4: 7.2×106 plants ha-1; and D5: 8.1×106 plants ha-1) were arranged in a randomized block design.

Results

At the same sowing density, the intercropped oats exhibited greater grain yield than the monocultures. Increasing the oat sowing density significantly enhanced oat yield, with the D3 level in intercropping showing the highest yield increase, ranging from 30.98% to 31.85%, compared with the monoculture. The common vetch intercropping grain yield was maximized in the D2 treatment. The land equivalent ratio was maximized at the D2 level in both years and was significantly higher than D1, with the land equivalent coefficient, system productivity index, and percentage yield difference suggesting that increasing oat sowing densities improved the productivity of the intercropping system, with the best performance observed at the D2 level. For both years, the proportionate actual yield loss of oat was the highest at the D3 level; significantly surpassing D1, proportionate actual yield loss of common vetch and actual yield loss were the highest at level D2, both significantly surpassing D1. These indicates that appropriate densification contributes to the realization of the advantages of intercropping. With an increased oat sowing density, the economic benefits of the intercropping system were maximized at the D2 and D3 levels. Regarding intercropping competition, oat was the dominant crop under different sowing densities (Aggressivity for oat (AO)>0, relative crowding coefficient for oat (KO)>1, competition ratio for oat (CRO)>1), whereas common vetch was the inferior crop. Compared with the D1 level, the D2 level harmonized the aggressivity, competitive ratio, and relative crowding coefficients of oat and common vetch, significantly increasing crowding coefficient for common vetch (KV) and competition ratio for common vetch by 19.76% to 21.94% and 4.80% to 7.51%, respectively, while reducing KO and CRO.

Discussion

This result suggests that in the intercropping of common vetch and oat in alpine regions, rational densification can harmonize interspecific competition and thus improve the biological efficiency and economic benefits of intercropping systems.

The Effect of Tree Spacing on Yields of Alley Cropping Systems-A Case Study from Hungary

Alley cropping is a specific agroforestry system, which is regarded as sustainable land use management, that could play a crucial role in climate change adaptation and mitigation. Despite its appealing attributes, farmers' up-take of the system is slow in temperate regions. This study aims to contribute to scaling-up agroforestry through a case study in Hungary and to help to design productive alley cropping systems. We investigated which tree planting pattern of black locust (Robinia pseudoacacia L.) results in the most productive alley cropping system when intercropped with triticale (x Triticosecale W.) by statistically analysing the yields of the intercrop and of the trees in nine different layouts and by calculating land equivalent ratios (LER). There was significant difference between the treatments both in triticale and black locust yields. The more trees planted on a hectare, the higher the volume of the stand, and the less yield of triticale was observed, although the latter correlation was weak and in some cases the triticale was more productive between the trees compared with sole crop control. Eight out of nine treatments had favourable LER (0.94-1.35) when the trees were five years old. Black locust and triticale seem to be a good combination for productive alley cropping systems.

A Comprehensive Approach to Evaluate Durum Wheat-Faba Bean Mixed Crop Performance

Plant breeding for intercropping is lagging because most varieties currently available in the market are selected for sole cropping systems. The present study analyzed the response of durum wheat (12 varieties) and faba bean (3 varieties) in pure and mixed cropping. Field trials were conducted in 2019 and 2020. The performance of each variety in mixed and pure cropping was evaluated using both univariate and multivariate analyses of the grain yield and land equivalent ratio (LER). For durum wheat, grain protein content was also evaluated. Durum wheat varieties were characterized by good performance in both years, whereas faba bean varieties were more affected by the growing season, suggesting that much breeding effort is warranted to improve the latter as a pure and mixed crop. Moreover, the relative performance of all varieties was affected by their combination in mixed cropping, as evaluated based on the ratio (LERratio) between LER for wheat (LERw) and LER for faba bean (LERfb). To further evaluate the overall performance of wheat and faba bean in mixed cropping, total yield, LERtotal (LERw + LERfb), and ln(LERratio) were subjected to principal component and cluster analyses. The first principal component combined the total yield and LERtotal in a single index of the overall performance of each mixed crop combination. The second principal component, based on ln(LERratio), highlighted the relative performance of varieties in each mixed crop combination. The proposed multivariate approach can be applied in the breeding programs for intercropping to identify variety combinations based on crop performance and the relative importance of the proportion of cereal and legume grains in the total harvest.

Suitability and benefits from intercropped sorghum-amaranth under partial root-zone irrigation

BACKGROUND

The production of sufficient animal feed in arid and semi-arid regions plays a significant role in food security in these areas. The present study was conducted based on the hypothesis that intercropping of sorghum and amaranth, comprising relatively drought tolerant forages, will enhance the yield and quality of the feed under limited irrigation water availability.

RESULTS

Implementation of fixed alternate furrow irrigation (FFI) and alternate furrow irrigation (AFI) resulted in a saving of 22.5% and 19.7% of irrigation water, respectively. However, the water saving declined both yield and quality of forage. In conventional furrow irrigation (CFI), the highest dry matter (DM) yield was 15.5 Mg  ha^-1 , obtained from S₅₀ -A₅₀ treatment. In FFI and AFI, sole sorghum produced the highest DM. However, their maximum yields (11.2 and 12.6 Mg ha^-1 , respectively) were not significantly different from yields in S₇₅ -A₂₅ intercropping ratios. Irrigation water use efficiency (IWUE) was similar in CFI and AFI and considerably higher than FFI. Sorghum monoculture and the S₇₅ -A₂₅ intercropping had the highest IWUE (3.4 and 3.3 kg m^-3 ), whereas IWUE of the sole amaranth was 1.7 kg m^-3 . The partial land equivalent ratio and monetary advantage index of amaranth and sorghum indicated that sorghum would benefit from intercropping as long as its ratio in the intercropping is more than 25%.

CONCLUSION

When sufficient irrigation is available, intercropping of sorghum and amaranth can considerably improve yield and quality of emergency feed. However, the benefits from intercropping faded under the two partial root-zone irrigation methods used in the present study. © 2021 Society of Chemical Industry.

[Effects of intercropping on light energy utilization characteristics and productivity of diffe-rent feed crops]

To explore light energy utilization characteristics and yield effect of different legume-gramineae intercropping patterns, we set up five kinds of monocropping patterns including alfalfa, triticale, oats, maize and sorgo as reference in a field experiment. The light energy utilization chara-cteristics and productivity of four kinds of intercropping patterns including alfalfa-triticale, alfalfa-oats, alfalfa-maize and alfalfa-sorgo were examined. The contribution degree of each light energy index to yield formation was analzyed using path analysis method. The results showed that the contribution of each index of light energy to yield from large to small was as follows: leaf area index (LAI)=1.236, net photosynthetic rate (P_n)=0.519, canopy openness (DIFN)=0.302, intercellular CO₂ concentration (C_i)=-0.026, stomatal conductance (g_s)=-0.116, transpiration rate (T_r)=-0.188, PAR interception rate (FIPAR)=-1.708. Light use efficiency (LUE) as a comprehensive indicator of light energy utilization had the largest value (1.367). Compared with monoculture, the values of LAI, P_n, g_s, T_r and FIPAR of four kinds of gramineae grasses increased under intercropping and the values of DIFN and C_i decreased, while alfalfa showed an opposite trend. Compared with monoculture, the LUE of four kinds of gramineae grasses under intercropping was significantly increased. The increase rates of triticale and oats (35.2% and 30.4%) were higher than that of maize and sorgo (28.7% and 26.3%). The decrease rates of alfalfa intercropping with triticale and oats (6.1% and 8.3%) were obviously lower than that of maize and sorgo (21.8% and 24.5%). The values of land equivalent ratio (LER) of four kinds of intercropping patterns was all greater than 1. The LER values of alfalfa-triticale and alfalfa-oat were significantly higher than those of alfalfa-maize and alfalfa-sorgo. It could be seen that LAI had the largest direct contribution to yield, followed by P_n. Among the four intercropping patterns, two patterns, alfalfa-triticale and alfalfa-oats, had greater improvement potential of light energy utilization and yield.

Potential of Legume-Brassica Intercrops for Forage Production and Green Manure: Encouragements from a Temperate Southeast European Environment

Legumes and brassicas have much in common: importance in agricultural history, rich biodiversity, numerous forms of use, high adaptability to diverse farming designs, and various non-food applications. Rare available resources demonstrate intercropping legumes and brassicas as beneficial to both, especially for the latter, profiting from better nitrogen nutrition. Our team aimed at designing a scheme of the intercrops of autumn- and spring-sown annual legumes with brassicas for ruminant feeding and green manure, and has carried out a set of field trials in a temperate Southeast European environment and during the past decade, aimed at assessing their potential for yields of forage dry matter and aboveground biomass nitrogen and their economic reliability via land equivalent ratio. This review provides a cross-view of the most important deliverables of our applied research, including eight annual legume crops and six brassica species, demonstrating that nearly all the intercrops were economically reliable, as well as that those involving hairy vetch, Hungarian vetch, Narbonne vetch and pea on one side, and fodder kale and rapeseed on the other, were most productive in both manners. Feeling encouraged that this pioneering study may stimulate similar analyses in other environments and that intercropping annual legume and brassicas may play a large-scale role in diverse cropping systems, our team is heading a detailed examination of various extended research.

Symbiotic performance of herbaceous legumes in tropical cover cropping systems

Increasing use of herbaceous legumes such as mucuna ( Mucuna pruriens var. utilis [Wright] Bruck) and lablab ( Lablab purpureus [L.] Sweet) in the derived savannas of West Africa can be attributed to their potential to fix atmospheric nitrogen (N2). The effects of management practices on N2 fixation in mucuna and lablab were examined using 15N isotope dilution technique. Dry matter yield of both legumes at 12 weeks was two to five times more in in situ mulch (IM) than live mulch (LM) systems. Land Equivalent Ratios, however, showed 8 to 30% more efficient utilization of resources required for biomass production under LM than IM systems. Live mulching reduced nodule numbers in the legumes by one third compared to values in the IM systems. Similarly, nodule mass was reduced by 34 to 58% under LM compared to the IM systems. The proportion of fixed N2 in the legumes was 18% higher in LM than IM systems. Except for inoculated mucuna, the amounts of N fixed by both legumes were greater in IM than LM systems. Rhizobia inoculation of the legumes did not significantly increase N2 fixation compared to uninoculated plots. Application of N fertilizer reduced N2 fixed in the legumes by 36 to 51% compared to inoculated or uninoculated systems. The implications of cover cropping, N fertilization, and rhizobia inoculation on N contributions of legumes into tropical low-input systems were discussed.