Intercrops and organic fertilizers can improve the productivity of cropping systems due to increased soil nutrient availability and plant nutrient use efficiency. A 2-year field experiment was conducted to determine the effects of different intercropping ratios and fertilizer types on nitrogen (N) and phosphorus (P) concentrations and yields of fenugreek and buckwheat at the research farm of Shahrekord University, Iran. The treatments consisted of sole cropping of fenugreek (F), buckwheat (B) and three intercropping ratios (F:B = 1:2, 1:1 and 2:1) under three fertilizer types: chemical fertilizer (CF), integrated fertilizer (IF) and broiler litter (BL). At flowering and at harvest, intercropping increased total above-ground dry matter (TAGDM), total seed yield, N and P concentrations (plant) and uptake. The applied N use efficiency and applied N recovery efficiency (ANUE, ANRE) in the intercropped plots were also higher as compared to the sole cropping. The intercropping ratio of F:B (2:1) was the most suitable for improving the tested nutrient variables. The IF and BL showed significant benefits as compared to CF, for TAGDM, total seed yield, N_C and P_C in the plant, as well as N and P uptake in sole and intercrops. For ANUE and ANRE, CF proved to be more effective. This study showed that a 2:1 fenugreek–buckwheat intercropped system with the application of IF and BL can successfully be implemented for improving productivity, N and P contents of fenugreek and buckwheat as well as the nutrient land equivalent ratio (compared with sole cropping with CF) under semi-arid growing conditions.

Cattle manure has a high carbon/nitrogen ratio and may not decompose; therefore, full-dose application of urea fertilizer might improve biological properties by increasing manure decomposition. This study aimed to investigate the effect of combining cattle manure and urea fertilizer on soil CO₂ flux, microbial biomass carbon, and dry matter accumulation during Nigella sativa L. (black cumin) growth under field conditions. The treatments were control, cattle manure, urea, different levels of split and full-dose integrated fertilizer. The results showed that integrated application of cattle manure and chemical fertilizer significantly increased microbial biomass carbon by 10%, soil organic carbon by 2.45%, total N by 3.27%, mineral N at the flowering stage by 7.57%, and CO₂ flux by 9% over solitary urea application. Integrated application increased microbial biomass carbon by 10% over the solitary application and the full-dose application by 5% over the split application. The soil properties and growth parameters of N. sativa L. benefited more from the full-dose application than the split application of urea. Cattle manure combined with chemical fertilizer and the full-dose application of urea increased fertilizer efficiency and improved biological soil parameters and plant growth. This method decreased the cost of top dressing urea fertilizer and proved beneficial for the environment and medicinal plant health.

Antioxidants and flavonoids are beneficial compounds used in the pharmaceutical and food industries that are derived from natural sources. A two-year field experiment was undertaken to investigate the effect of agricultural management practices on the trigonelline content, antioxidant activity measured with DPPH (2,2-Diphenyl-1-Picrylhydrazyl) and FRAP (Fe⁺⁺⁺-Reduction, Ferric reducing antioxidant power), total phenolic content, total flavonoids content, and specific flavonoid contents of fenugreek seeds. The treatments examined were sole fenugreek (Sole F) and three intercropping ratios with buckwheat (B) (F:B = 2:1, 1:1, and 1:2), each with three types of fertilizer (chemical fertilizer, integrated fertilizer, and broiler litter). The highest trigonelline content of fenugreek seeds was obtained in F:B = 2:1 fertilized with broiler litter. Compared to Sole F, the fenugreek seeds harvested in the intercropped treatments had higher antioxidant activity, total phenolic content, vitexin, isovitexin, orientin, and isoorientin. The treatment F:B = 2:1 enhanced the antioxidant activity and the content of bioactive compounds. Overall, the addition of organic manure to fenugreek seeds was highly effective at promoting all compounds analyzed in both the sole and the intercrop systems. Our study found that harvested fenugreek seeds from plants that were intercropped with buckwheat and with the application of organic fertilizer enhanced the seed content of antioxidants and flavonoids.

We present data of a 2 years field experiment on influence of intercropping and N source on yield and yield components of fenugreek (Trigonella foenum-graecum)–buckwheat (Fagopyrum esculentum) intercrops. The experiment was conducted at the research farm, College of Agriculture, Shahrekord, Iran during 2014 and 2015. Treatments included sole cropping of fenugreek (F), sole cropping of buckwheat (B), and three intercropping ratios. Second factor was N fertilizer type: mineral chemical fertilizer (CF) or broiler litter (BL). Intercropping improved yield of fenugreek and buckwheat compared with sole cropping and BL was the more effective fertilizer especially in intercrops. Fenugreek and buckwheat in intercrops used available environmental resources for increasing pods plant⁻¹, seeds pod⁻¹, 1000-seed weight, and harvest index (HI) (for fenugreek) and clusters plant⁻¹ and 1000-seed weight (for buckwheat) compared to the respective sole crops in both years. The resulting land equivalent ratios (LERs) of intercrops varied from 0.99 to 1.72 and the highest LER was observed in F:B = 2:1 treated with BL. This study shows a potential yield benefit of fenugreek–buckwheat intercropping under semiarid growing conditions when planting fenugreek and buckwheat at a ratio of 2:1, respectively, and applying BL compared with sole cropping with inorganic fertilizer application.

Summary: Intercropping can increase crop growth and yield due to improved resource use efficiency. A two-year field experiment was performed in Shahrekord (Iran) to determine the effect of crop stand composition and fertilizer type on the productions of aboveground dry matter and growth parameters of fenugreek-buckwheat intercrops. Sole crops of fenugreek (F) and buckwheat (B) were compared to the three substitutive intercropping ratios (F:B = 2:1, 1:1 and 1:2). Crop stands were fertilized with chemical fertilizer or broiler litter. Fenugreek could produce in intercrops a similar amount of above-ground dry matter compared to its corresponding share on the sowing ratio. Contrary to that, buckwheat could produce in intercrops more above-ground dry matter than its share on the sowing ratio, especially with a low to medium share of buckwheat. Consequently, the intercrops with F:B (2:1) and F:B (1:1) had an above-ground dry matter yield advantage compared to the pure crop stands of both crops. Broiler litter was more effective in increasing the growth rates and thus the above-ground dry matter production compared to the chemical fertilizer. Thus, growing fenugreek and buckwheat in intercrops fertilized with broiler litter can be beneficial for increasing the biomass production in semiarid environments.