Assessing the Efficacy of Wheat-Soybean Based Intercropping System at Different Plant Densities in Bambili, Cameroon

Wheat is one of the most important cereals in the world, serving as a staple for millions globally. In the wake of the geopolitical crisis between Russia and Ukraine, it has become incumbent for many countries to invest in wheat production. Improving cropping systems for wheat production is paramount. Intercropping cereals with legumes has tremendous advantages. Therefore, this study was designed to optimize wheat production by intercropping it with soybean at different densities. Between March and August 2023, a randomized complete block design trial was conducted in Bambili, North West of Cameroon with treatments T1 (wheat monocrop at 200,000 plants ha−1), T2 (soybean monocrop at 250,000 plants ha−1), T3 (200,000 wheat and 125,000 soybean ha−1), T4 (100,000 wheat and 250,000 soybean ha−1), T5 (200,000 wheat and 250,000 soybean ha−1) and T6 (100,000 wheat and 125,000 soybean ha−1). Results revealed that growth parameters of wheat were not significantly influenced by monocrop or intercrop. The yield of wheat was significantly higher in the monocrop than the intercrop treatments, with slight variation amongst the intercrop treatments. Soybean yield was higher in the monocrop than in the intercrop, with no variations amongst the intercrop treatments. Only the land equivalence ratio (LER) for T5 was greater than 1.0. The competitive ratio for T5 was 0.54 for wheat and 1.90 for soybean, comparatively lower than the other monocrop treatments. Intercropping wheat and soybean at 200,000:250,000 ratio is recommended.

Impacts of soil fertility management on productivity and economics of rice and fodder intercropping systems under rainfed conditions in Odisha,India

Under small and marginal farm conditions,allocation of land exclusively for forages is not possible.Hence,integration of forages in existing crop geometry can ensure production of grain and fodder,simultaneously under rainfed conditions.Afield experiment was conducted to study the effect of different nutrient management practices on rice and fodder intercropping systems under rainfed conditions during 2015-2017.The intercropping system comprised(i)sole rice(R),(ii)rice and cowpea(5:2)(CP)and(iii)rice and ricebean(5:2)(RB)whereas the different nutrient management practices comprised(i)application of farm yard manure(FYM)at 5t ha^(-1)(farmers'practice)(N_(1)),(ii)application of inorganic fertilizer(recommended dose of fertilizer(RDF)of rice,60:30:30 kg ha^(-1) of N:P_(2)O_(5):K_(2)O)(N_(2))and(iii)application of both FYM at 5t ha^(-1) and 50%of RDF inorganic fertilizer(N3).The results of the experiment revealed that the growth attribute such as leaf area was influenced significantly when fodder crops were taken as intercrops because rice plant was getting more nitrogen from soil due to nitrogen fixation of leguminous fodder crops.Among the nutrient management practices,significant differences in leaf area were found beween N2 and and between N_(3)and N_(1)treatments.However,regarding total number of effective tillers,significant differences were found neither between nutrient management practices nor between cropping systems.The rice equivalent yield(REY)based on price(REY_(P))was found to be significantly lower in CP(2615 kg ha^(-1);-6.4%)and RB intercropping systems(2571 kg ha^(-1);-8.0%)than in R monocropping system(2794 kg ha^(-1)).However,the REY based on energy(REY_(E))of CP(2999 kg ha^(-1);+7.3%)and RB(2960 kg ha^(-1);+5.9%)were found to be significantly higher than that of R(2794 kg ha^(-1))irrespective of nutrient management practices.Between different nutrient management practices,the N3 treatment recorded the highest REY_(P)and REY_(E)which was at par with the N_(2)treatment and significantly higher than the N1 treatment irrespective of cropping systems.The combined application of both organic and inorganic sources of nutrients helped to supply nutrients throughout the growing season,which led to improved growth parameters and rice yield.The R monocropping system resulted in more income and rain water use efficiency(RWUE)closely followed by rice and fodder intercropping systems.However,the REYe and energy use efficiency(EUE)of rice and fodder intercropping systems were higher than those of R.Also,fodder helped to meet the requirement of cattle feeding in the off-season.Hence,the intercropping system is advocated in the study zone.Further study can be done on ecosystem services and carbon sequestration potential of the intercropping system,as well as the system's coping ability in response to short drought through observing periodic soil moisture regime in root zone.

Effects of Spatial Row Arrangement and Time of Planting Intercrops on Performance of Groundnut (Arachis hypogaea L.) under Maize (Zea mays L.)—Groundnut Intercropping System in Ejura

In monoculture, crop failure due to biotic or abiotic causes can result in partial or total output failure. The yield, socio-economic, and environmental effects of intercropping on the farmer and the environment as a whole have not received much attention. There is a dearth of knowledge on the productivity of maize-groundnut intercrops in Ghana regarding the relative timing of planting and spatial arrangement of component crops. Therefore, the objective of the study was to determine the effects of spatial row arrangement and the time of planting intercrops on the productivity of groundnut under maize-groundnut intercropping. The 5 × 3 factorial field experiment was undertaken at the Miminaso community in the Ejura-Sekyedumase municipality of the Ashanti Region of Ghana during the 2020 cropping seasons. Treatments were evaluated in a Randomized Complete Block Design (RCBD) with three replicates. The levels of row arrangement of intercrops were: one row of maize and one row of groundnut (1M1G), one row of maize and two rows of groundnut (1M2G), two rows of maize and one row of groundnut (2M1G), two rows of maize and two rows of groundnut (2M2G), sole maize and sole groundnut (M/G). The levels of time of introducing groundnut included simultaneous planting of intercrops (0 WAP), planting groundnut one week after planting maize (1 WAP) and planting groundnut two weeks after planting maize (2 WAP). There were significant (P 0.05) treatment interactions for pod and seed yields of groundnut throughout the study. The highest groundnut pod yields of 1815.00 kg/ha and 2359.00 kg/ha were recorded by the 0WAP × 1M2G treatment in the major and minor seasons of 2020, respectively, while the highest groundnut seed yields of 741.00 kg/ha and 726.00 kg/ha were recorded in the major and minor rainy seasons of 2020 by 1WAP × G and 0WAP × G treatments, respectively. The highest seed yields of groundnut (404 kg/ha and 637 kg/ha for major and minor rainy seasons, respectively) were produced by 1WAP × 2M2G.

Performance of Maize (Zea mays L.) and Land Equivalent Ratio under Maize-Groundnut (Arachis hypogea L.) Intercropping System

Soil fertility continues to decline in Ghana due to unsustainable human activities like bush burning, quarrying, improper farming practices, among others. To resolve this challenge, crop farmers resort to continuous use of mineral fertilizers in Ghana, which contaminates the environment and makes crop farming less sustainable and productive. One of the strategies to improve soil fertility and productivity for sustainable crop yields is intercropping. Studies were, therefore, undertaken at Miminaso in the Ejura-Sekyedumase municipality of Ashanti Region of Ghana during the 2020 cropping seasons to determine the effects of spatial row arrangement and time of planting maize and groundnut intercrops on productivity of maize and land equivalent ratio (LER). One row of maize and one row of groundnut (1M1G), one row of maize and two rows of groundnut (1M2G), two rows of maize and one row of groundnut (2M1G), two rows of maize and two rows of groundnut (2M2G), sole maize (M) and sole groundnut (G) were factorially arranged with concurrent planting of intercrops (0 WAP), planting groundnut one week after planting maize (1 WAP) and planting groundnut two weeks after planting maize (2 WAP) in a Randomized Complete Block Design with three replicates. There were significant treatment interaction (P < 0.05) effects for shelling percentage for maize in both seasons of the trial. In the major season of 2020, the highest shelling percentage of 79.30% was associated with 0 WAP × M, while in the minor season of 2020, the highest shelling percentage of 75.02% was recorded by 0 WAP × 2M1G. The treatment interaction effects for maize grain yield were significant only in the minor season of 2020 with the highest maize grain yield of 6341 kg/ha being produced by the sole maize treatment, followed by 1 WAP × 2M2G (6152 kg/ha). The highest LER of 3.05 was associated with 1 WAP × 2M2G in the minor season of 2020. Planting groundnuts within the first week of planting maize (1 WAP) increased maize seed yield and LER in two rows of maize and two rows of groundnut (2M2G) row arrangements.

Nitrate Leaching from Maize Intercropping Systems with N Fertilizer Over-Dose

A 2-yr field experiment was conducted on a calcareous alluvial soil with four summer maize intercropping systems at Shangzhuang Experiment Station （116.3°E, 39.9°N） in the North China Plain. The objective was to determine nitrate leaching from intercropping systems involving maize （Zea mays L.）： sole maize （CK）, maize ＋ soybean （CST）, maize ＋ groundnut （CGT）, maize ＋ ryegrass （CHM）, and maize ＋ alfalfa （CMX）. Intercropping greatly reduced nitrate accumulation in the 100-200 cm soil layers compared with maize monoculture. Nitrate accumulation under intercropping systems decreased significantly at the 140-200 cm soil depth; the accumulation varied in the order CK〉CST〉CMX〉CHM〉CGT. However, compared to the CK treatment, nitrate leaching losses during the maize growing period were reduced by 20.9- 174.8 （CGT）, 35.2-130.8 （CHM）, 60.4-122.0 （CMX）, and 30.6-82.4 kg ha-1 （CST）. The results also suggested that intereropping is an effective way to reduce nitrogen leaching in fields with N fertilizer over-dose.

Soil Nitrous Oxide Emissions Under Maize-Legume Intercropping System in the North China Plain

Many studies have focused on various agricultural management measures to reduce agricultural nitrous oxide （N2O） emission. However, few studies have investigated soil N2O emissions in intercropping systems in the North China Plain. Thus, we conducted a ifeld experiment to compare N2O emissions under monoculture and maize-legume intercropping systems. In 2010, ifve treatments, including monocultured maize （M）, maize-peanut （MP）, maize-alfalfa （MA）, maize-soybean （MS）, and maize-sweet clover （MSC） intercropping were designed to investigate this issue using the static chamber technique. In 2011, M, MP, and MS remained, and monocultured peanuts （P） and soybean （S） were added to the trial. The results showed that total production of N2O from different treatments ranged from （0.87＆#177;0.12） to （1.17＆#177;0.11） kg ha-1 in 2010, while those ranged from （3.35＆#177;0.30） to （9.10＆#177;2.09） kg ha-1 in 2011. MA and MSC had no signiifcant effect on soil N2O production compared to that of M （P＆lt;0.05）. Cumulative N2O emissions from MP in 2010 were signiifcantly lower than those from M, but the result was the opposite in 2011 （P＆lt;0.05）. MS signiifcantly reduced soil N2O emissions by 25.55 and 48.84%in 2010 and 2011, respectively （P＆lt;0.05）. Soil N2O emissions were signiifcantly correlated with soil water content, soil temperature, nitriifcation potential, soil NH4＋, and soil NO3-content （R2=0.160-0.764, P＆lt;0.01）. A stepwise linear regression analysis indicated that soil N2O release was mainly controlled by the interaction between soil moisture and soil NO3-content （R2=0.828, P＆lt;0.001）. These results indicate that MS had a coincident effect on soil N2O lfux and signiifcantly reduced soil N2O production compared to that of M over two growing seasons.

Optimized nitrogen application methods to improve nitrogen use efficiency and nodule nitrogen fixation in a maize-soybean relay intercropping system

In China, the abuse of chemical nitrogen （N） fertilizer results in decreasing N use efficiency （NUE）, wasting resources and causing serious environmental problems. Cereal-legume intercropping is widely used to enhance crop yield and improve resource use efficiency, especially in Southwest China. To optimize N utilization and increase grain yield, we conducted a two-year field experiment with single-factor randomized block designs of a maize-soybean intercropping system （IMS）. Three N rates, NN （no nitrogen application）, LN （lower N application： 270 kg N ha-1）, and CN （conventional N application： 330 kg N ha-1）, and three topdressing distances of LN （LND）, e.g., 15 cm （LND1）, 30 cm （LND2） and 45 cm （LND3） from maize rows were evaluated. At the beginning seed stage （R5）, the leghemoglobin content and nitrogenase activity of LND3 were 1.86 mg plant-1 and 0.14 mL h-1 plant-1, and those of LND1 and LND2 were increased by 31.4 and 24.5%, 6.4 and 32.9% compared with LND3, respectively. The ureide content and N accumulation of soybean organs in LND1 and LND2 were higher than those of LND3. The N uptake, NUE and N agronomy efficiency （NAE） of IMS under CN were 308.3 kg ha-1, 28.5%, and 5.7 kg grain kg-1 N, respectively; however, those of LN were significantly increased by 12.4, 72.5, and 51.6% compared with CN, respectively. The total yield in LND1 and LND2 was increased by 12.3 and 8.3% compared with CN, respectively. Those results suggested that LN with distances of 15-30 cm from the topdressing strip to the maize row was optimal in maize-soybean intercropping. Lower N input with an optimized fertilization location for IMS increased N fixation and N use efficiency without decreasing grain yield.

Effect of Inoculation with Arbuscular Mycorrhizal Fungus on Nitrogen and Phosphorus Utilization in Upland Rice-Mungbean Intercropping System

The effect of arbuscular mycorrhiza fungi （AMF） on plant growth and nutrition utilization in upland rice and mungbean intercropping system was studied. A pot experiment was conducted in the greenhouse and AMF colonization rates of rice and mungbean roots, plant nutrient contents, the ability of nitrogen fixation, and nutrient contents changed in the soil were analyzed. The results were obtained as follows： the rates of AMF colonization of rice and mungbean roots were reached to 14.47 and 92.2% in intercopping system, and increased by 4.11 and 11.95% compared with that of in monocropping; the nirtrogen contents of mungbean and rice were increased by 83.72 and 64.83% in shoots, and 53.76 and 41.29% in roots, respectively, while the contents of iron in shoot and root of mungbean were increased by 223.08 and 60.19%, respectively. In the intercropping system with inoculation of AMF, the biomass of mungbean increased by 288.8%. However, the biomass of rice was not significantly changed among all treatments with or without inoculation of AMF recorded. The number and dry weight of nodules were significantly increased either when mungbean was intercropped with rice or inoculated with AMF. When compared with that of monocropping without AMF inoculation, the contents of nitrogen, phosphorus and iron in nodules of intercropping mungbean with inoculation increased by 80.14, 69.54 and 39.62%, respectively. Additionally, intercropping with AMF inoculation significantly increased soil nitrogen content, but reduced soil phosphorus content. We concluded that upland rice-mungbean intercropping system and inoculation with AMF improved the nutrient uptake, the ability of nitrogen fixation and the growth of mungbean.

Timing and splitting of nitrogen fertilizer supply to increase crop yield and efficiency of nitrogen utilization in a wheat–peanut relay intercropping system in China

Agronomically optimizing the timing and rates of nitrogen(N) fertilizer application can increase crop yield and decrease N loss to the environment. Wheat(Triticum aestivum L.)–peanut(Arachis hypogaea L.) relay intercropping systems are a mainstay of economic and food security in China. We performed a field experiment to investigate the effects of N fertilizer on N recovery efficiency, crop yield, and N loss rate in wheat–peanut relay intercropping systems in the Huang-Huai-Hai Plain, China during 2015–2017. The N was applied on the day before sowing, the jointing stage(G30) or the booting stage(G40) of winter wheat, and the anthesis stage(R1) of peanut in the following percentage splits: 50-50-0-0(N1), 35-35-0-30(N2), and 35-0-35-30(N3), using 300 kg N ha-1, with 0 kg N ha-1(N0) as control. ^(15)N-labeled(20.14 atom %) urea was used to trace the fate of N in microplots. The yields of wheat and peanut increased by 12.4% and 15.4% under the N2 and N3 treatments, relative to those under the N1 treatment. The ^(15)N recovery efficiencies( ^(15)NRE) were 64.9% and 58.1% for treatments N2 and N3, significantly greater than that for the N1 treatment(45.3%). The potential N loss rates for the treatments N2 and N3 were23.7% and 7.0%, significantly lower than that for treatment N1(30.1%). Withholding N supply until the booting stage(N3) did not reduce the wheat grain yield; however, it increased the N content derived from ^(15)N-labeled urea in peanuts, promoted the distribution of ^(15)N to pods, and ultimately increased pod yields in comparison with those obtained by topdressing N at jointing stage(N2). In comparison with N2, the N uptake and N recovery efficiency(NRE) of N3 was increased by 12.0% and 24.1%,respectively, while the apparent N loss decreased by 16.7%. In conclusion, applying N fertilizer with three splits and delaying topdressing fertilization until G40 of winter wheat increased total grain yields and NRE and reduced N loss. This practice could be an environment-friendly N management strategy for wheat–peanut relay intercropping systems in China.

Shade adaptive response and yield analysis of different soybean genotypes in relay intercropping systems

Soybean is one of the major oil seed crops,which is usually intercropped with other crops to increase soybean production area and yield.However,soybean is highly sensitive to shading.It is unclear if soybean morphology responds to shading（i.e.,shade tolerance or avoidance）and which features may be suitable as screening materials in relay strip intercropping.Therefore,in this study,various agronomic characteristics of different soybean genotypes were analyzed under relay intercropping conditions.The soybean materials used in this study exhibited genetic diversity,and the coefficient of variations of the agronomic parameters ranged from 13.84 to 72.08%during the shade period and from 6.44 to 52.49%during the maturity period.The ratios of shading to full irradiance in stem mass fraction（SMF）were almost greater than 1,whereas opposite results were found in the leaves.Compared with full irradiance,the average stem length（SL）,leaf area ratio（LAR）and specific leaf area（SLA）for the two years（2013 and 2014）increased by 0.78,0.47 and 0.65 under shady conditions,respectively.However,the stem diameter（SD）,total biomass（TB）,leaf area（LA）,number of nodes（NN）on the main stem,and number of branches（BN）all decreased.During the shady period,the SL and SMF exhibited a significant negative correlation with yield,and the SD exhibited a significant positive correlation with yield.The correlation between the soybean yield and agronomic parameters during the mature period,except for SL,the first pod height（FPH）,100-seed weight（100-SW）,and reproductive growth period（RGP）,were significant（P〈0.01）,especially for seed weight per branch（SWB）,pods per plant（PP）,BN,and vegetative growth period（VGP）.These results provide an insight into screening the shade tolerance of soybean varieties and can be useful in targeted breeding programs of relay intercropped soybeans.

Boosting proso millet yield by altering canopy light distribution in proso millet/mung bean intercropping systems

To elucidate the mechanism by which intercropping proso millet(Panicum miliaceum L.)with mung bean(Vigna radiata L.)increases proso millet yield and to determine how this higher yield results from maximization of resources use efficiency,we designed and conducted four strip intercropping row arrangements,including two rows of proso millet alternating with two rows of mung bean(2P2M),four rows of proso millet alternating with two rows of mung bean(4P2M),four rows of proso millet alternating with four rows of mung bean(4P4M),two rows of proso millet alternating with four rows of mung bean(2P4M),sole proso millet(SP,control)and sole mung bean(SM,control)in Yulin,Shaanxi,China.Photosynthetically active radiation(PAR)in the canopy,radiation use efficiency(RUE),leaf photosynthetic characteristics,dry matter accumulation and allocation,and yield of proso millet were investigated.The results showed that the intercropping systems had higher PAR than the monoculture.Mean PAR intensities were increased by respectively 2.2%–23.4%,19.8%–59.7%,and 61.2%–133.3%in the proso millet upper,middle and lower canopies compared with SP.The increase in PAR directly increased RUE,a result attributed mainly to the increase in photosynthetic capacity,including net photosynthetic rate and chlorophyll content.These responses resulted in increased dry matter allocation to plant organs.Yield of intercropped proso millet was 6.8%–37.3%higher than that under monoculture and the land equivalent ratios for the different intercropping patterns were all greater than unity(>1).In general,yield followed a positive linear function of PAR in the intercropping system.The results indicated that intercropping can boost proso millet yield,evidently by altering light distribution within its canopy and consequently increasing RUE,thereby increasing leaf photosynthetic capacity,dry matter accumulation,and allocation to the grain.The optimum combination for improving the growth and yield of proso millet on the Loess Plateau of China was 2P4M.

The Ecological Effects of Young Elm Trees Belt-Pumpkin Strip Intercropping System at the Agro-Pastoral Ecotone in Northern China

Young elm trees belt-pumpkin strip intercropping was studied to solve the actual problem of resource losses in the large barren area resulted from reconverting cultivated land into forest in the agro-pastoral ecotone in northern China. The final objective was to realize effective utilization of the barren land with both ecological improvement and economic development. Field experiments were conducted together with laboratory analysis. The results indicated that the soil moisture level was remarkably increased in young elm trees belt-pumpkin strip intereropping because the pumpkin vines covered the gap between pumpkin planting-furrow and elm trees belt. The water use efficiency of the intercropping system was increased by 23.7-163.3% as compared with the single cropping. Elm trees belt-pumpkin strip intercropping changed the sequential succession trend of the grasses growing in the gap of the pumpkin planting-furrow. The annual grasses become the dominant vegetation. The nutritive value as fodder and yield of the annual grasses were also increased remarkably. The biomass of pumpkin, elm trees and grasses under intercropping increased by 24.4, 28.4 and 144.4%, respectively, as compared with those under single cropping. The land use efficiency was increased by 132%. It was also indicated that the soil erosion from the intercropping land was not increased due to pumpkin plantation. The differences in the soil erosion among intercropped area, elm trees belt and pumpkin strip with single cropping were not remarkable. Therefore, it was concluded that young elm trees belt-pumpkin strip intercropping is an effective way to utilize the barren land between the young elm trees belt and realize synergistic enhancement of ecological benefit and economic profit.

Effects on Agronomic Traits,Yield and Benefit of One-year Triple Cropping "Maize-soybean" Strip Intercropping System Under Reduced Fertilizer Application

[Objectives] This study was conducted to investigate the effects on agronomic traits,yield and benefit of one-year triple cropping " maize-soybean" strip intercropping system under reduced fertilizer application. [Methods]A single factor randomized block design was used,and wide and narrow strip intercropping was adopted. Three different fertilization treatments,namely fertilizers for conventional field fertilization( A1),80% A1( A2) and 60% A1( A3) were applied to the field production. The fertilizing sites were about 25 cm away from maize and repeated three times. [Results]Compared with A1,the change laws of the agronomic traits and yield in the A2 and A3 intercropping systems were described as below. Agronomic traits: The plant height became shorter gradually for the spring soybean,but increased gradually for the summer soybean,the bottom pod height gradually reduced,and the node number,pods per plant and seeds per plant increased;and the plant height,ear length,rows per ear,seeds per row and 1 000-seed weight of the spring maize decreased. Yield: The yield of maize as the main crop decreased but not significant,by 3. 20% and 3. 99%,respectively in A2 and A3,both smaller than 5. 00%;the yield of the spring soybean significantly increased by 9. 70% and 11. 84%,respectively;the yield of the summer soybean increased by 5. 18% and 8. 98%,respectively;and the total yield increased by 0. 20% and 0. 92%,respectively. Benefit: The total output value increased by 2. 97 % and 4. 91 %,respectively,and the total benefit increased by 6. 39% and 11. 22%,respectively. [Conclusions] Under a 40% reduction in fertilizer applied in the field,the one-year triple cropping " maize-soybean" strip intercropping system still met the multi-target requirements of increasing grain production and economic benefits,and thus can be promoted and applied in Guangxi.

Xanthium Suppression Under Maize||Sunflower Intercropping System

Weed control is one of the major constraint factors in crop production around the world. Field experiments were conducted during 2008-2009 under intercropping systems involving alfalfa （Medicago sativa L.）, sweet potato （lpomoea batatas [L.] Lain.）, peanut （Arachis hypogaea L.）, and sunflower （Helianthus annuus L.） in maize （Zea mays L.） without any weeds control methods taken. The results demonstrate that maizellsunflower is most effective on weed suppression and that it also has a more competitively inhibitory effect on Xanthium compared with the other patterns by evaluating the Xanthium density and dry weight under different intercropping systems with maize. Maizellpeanut, maizellalfalfa and maizel]sweet potato intercrops have no apparent inhibitory effect on weeds. To further investigate the effect of maize]lsunflower on weed control, indoor pot experiments were conducted by determining the effect of extractions on germination rate （GR）, root vigor, MDA （malondialdehyde）, SOD （superoxide dismutase） and POD （peroxidase） content of Xanthium. The results better prove that maizellsunflower extractions have more significant inhibitory effect on GR and young root vigor of Xanthium than maize monocrop extractions.

iTRAQ protein profile analysis of soybean stems reveals new aspects critical for lodging in intercropping systems

Soybean is often intercropped with maize,sugarcane,and sorghum.Because of the shade coming from the latter,the soybean stem lodging is often a very serious problem in intercropping systems.The aim of this study is to characterize the possible mechanisms in the stem of shade-induced promotion of seedling soybean lodging in intercropping systems at the proteome level.We found that the soybean stem became slender and prone to lodging when it was planted with maize in an intercropping system.The inhibition of lignin biosynthesis and lack of photosynthate(soluble sugar)for the biosynthesis of the cell wall led to the lower internode breaking strength.A total of 317 proteins were found to be affected in the soybean stem in response to shade.Under the shade stress,the down-expression of key enzymes involving the phenylpropanoid metabolic pathway inhibited lignin biosynthesis.The up-regulation of expansin and XTHs protein expression relaxed the cell wall and promoted the elongation of internodes.Although the expression of the enzymes involving sucrose synthesis increased in the soybean stem,the lack of a carbon source prevented rapid stem growth.This metabolic deficit is the principal cause of the lower cellulose content in the stem of intercropped soybean,which leads to weakened stems and a propensity for lodging.

Seedling defoliation of cereal crops increases peanut growth and yield in an intercropping system

Intercropping cereals and legumes is practiced widely in the world for improving yields and economic benefits. Shorter legume crops in intercropping are shaded by taller cereals, substantially reducing legume growth and yield. Reducing shade in intercropping by shortening the plant height of cereals by seedling defoliation has been proposed as a practical approach to increase crop yields and land productivity. A two-year field experiment was conducted to investigate the effect of defoliation of cereal crops at seedling stage on the growth and yield of peanut(Arachis hypogaea L.) intercropped with corn(Zea mays L.) or millet(Setaria italica L.). In comparison with non-defoliation controls, defoliation reduced final plant height by 29 cm on average for corn and 18 cm for millet. Photosynthetically active radiation on peanut in intercropping systems with corn or millet intercropping was respectively 27.0% and 22.8% higher than those in controls, significantly improving the light environment of intercropped peanut. Net photosynthetic rates of peanut were on average 25.5% higher in corn and peanut intercropping and 19.6% higher in millet and peanut intercropping than those in non-defoliation controls. Total biomass of intercropped peanut increased owing to increased root growth. Across two years, yield of peanut intercropped with corn was 27.7% and with millet 32.8% higher than those of controls. Defoliation of cereal crops did not affect corn yield but significantly decreased millet yield by 24.5%. Our results suggest that applying seedling defoliation in intercropped corn could increase peanut yield without compromising corn yield in an intercropping system.

Alternate cotton-peanut intercropping:a new approach to increasing productivity and minimizing environmental impact

Recent publications have highlighted the development of an alternate cotton-peanut intercropping as a novel strat-egy to enhance agricultural productivity.In this article,we provide an overview of the progress made in the alternate cotton-peanut intercropping,specifically focusing on its yield benefits,environmental impacts,and the underlying mechanisms.In addition,we advocate for future investigations into the selection or development of appropriate crop varieties and agricultural equipment,pest management options,and the mechanisms of root-canopy interactions.This review is intended to provide a valuable reference for understanding and adopting an alternate intercropping system for sustainable cotton production.

THE WATERMELON-CHINESE FIR INTERCROPPING SYSTEM

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Profitability Level and Determinants of Tea Intercropping in Taraba State

Intercropping involves the cultivation of more than one crop on a plot of land at a particular time.Tea intercropping with other crops can increase the profitability of farmers and the development of tea plants.The study estimated the profitability level of intercropped tea farms and determined the factors affecting the profitability of tea intercropping systems in the study area.Information was obtained from two hundred and four tea farmers using a well-structured questionnaire.The analytical techniques used in the study were descriptive analysis and linear regression.The results revealed that the majority(95.6%)of the farmers are from Kakara and Nyiwa towns.There are few(2.9%)women involved in tea farming in Taraba State.29%of the tea farmers are young less than 30 years and old above 60 years.Fifteen percent of the farmers are single,83.8%are married and 1.5%are divorced.About 40%of the tea farmers had no formal education,21%have between 1-6 years of education,19%had 7-12 years of education and 21%had greater than 12 years of education.The gross margin is N289,900,581.9 and the gross margin per farmer is N1,421,081.28.The net income is N2,879,055,533.3 and the net income per farmer is N1,411,301.63.The amount of profit tea farmers make in Taraba State is N1,425,001 and the profit per farmer is N6,985.30.Labour costs(weeding,pruning,application of insecticide,watering)and cost of materials(cutlass,file,chemical,bag and others)are significant determinants of the profit level of the tea intercropping system in Taraba State.Tea intercropping farming is profitable in Taraba State Nigeria.

Root Length Density in Maize/Cowpea Intercropping under a Basin Tillage System in a Semi-Arid Area of Zimbabwe

A study to assess the effect of intercropping maize (Zea mays L.) and cowpea (Vigna unguiculata L.) within the same basin or outside the basin on root length density (RLD) was conducted at the International Crop Research Institute for Semi-Arid Tropics (ICRISAT) Matopos Research Station from December 2009 to April 2010. The experiment was laid out in a Randomised Complete Block Design (RCBD) with four treatments replicated four times namely;sole maize, sole cowpea, maize-cowpea intercrop with cowpea and maize planted within the same basin and maize-cowpea intercrop with cowpea planted 20 cm outside the maize basin. There was significant difference (P < 0.001) in RLD, grain yield and stover yield. Maize-cowpea intercropped within the same basin achieved higher RLD, grain yield and stover yield than cowpea that was intercropped outside the basin and the sole crops. The land equivalent ratio (LER) in both intercrop designs showed that intercropping had better grain yield performance when compared to sole cropping. It can be concluded that intercropping maize and cowpeas within the same basin can result in an environment around the crop achieving higher RLD which translates to better grain yield compared to the sole cropping and intercropping cowpeas outside the basin.