D. V. Singh

Influence of straw mulching on fertilizer nitrogen use efficiency, moisture conservation and herb and essential oil yield in Japanese mint (Mentha arvensis L.)

In a field study, the influence of organic mulches viz. paddy straw and citronella (Cymbopogon winterianus Jowitt) distillation waste on herb and essential oil yield and fertilizer N use efficiency in Japanese mint (Mentha arvensis L.) were examined for two years. Herb yield (dry weight) increased by 17 and 31% with paddy straw and citronella distillation waste, respectively over the use of no mulch. Essential oil yield also significantly increased due to mulching. A significant response to N was observed with 200 kg N ha−1 in unmulched plots as against 150 kg N ha−1 in mulched plots. Mulched soils have been observed to contain 2 to 4% higher moisture as compared to unmulched soils. Nitrogen uptake by plants increased by 18 and 25% over no mulch with using paddy straw and citronella distillation waste, respectively.

Effect of residual sodium carbonate in irrigation water on the soil sodication and yield of palmarosa (Cymbopogon martinni) and lemongrass (Cymbopogon flexuosus)

The effects of residual sodium carbonate (RSC) in irrigation water on soil sodication and yield and cation composition of palmarosa (Cymbopogon martinii Roxb. Wats) and lemongrass (Cymbopogon flexuosus Steud Wats) were studied in the open bottom reinforced concrete cemented (RCC) cylindrical barrels embedded in the field and filled with sandy loam soils. The results indicated that the increasing RSC in irrigation water significantly increased the pH, electrolyte conductivity (ECe) and SARe of the soil and, hence, considerably decreased the herb and oil yield of both the palmarosa and lemongrass. The reduction in total herb yield was 14.5, 18.3, 28.8 and 32.0% in palmarosa and 38.6, 46.0, 57.7 and 62.6% in the lemongrass over control at 4.0, 8.0, 12.0 and 16.0 meq/l of RSC, respectively. The total oil yield of palmarosa increased by 22.6% with the increase in RSC from 2.0 (control) to 4.0 meq/l and further increase in RSC decreased the oil yield by 13.0, 22.4 and 22.9% over control at 8,12 and 16 meq/l of RSC, respectively. The total oil yield of lemongrass was decreased by 27.0, 39.4, 47.7 and 50.8% over control at 4, 8, 12 and 16 meq/l, respectively. The concentration of Na increased significantly and K and Ca decreased with increase in RSC of irrigation water in vegetative tissues of both species. The lemongrass accumulates significantly greater amount of Na in shoot tissues as compared to palmarosa and it failed to survive at high RSC after 21 months of transplanting. The results suggests that palmarosa is more tolerant to irrigation water sodicity than the lemongrass.

Recycling of nutrients in Japanese mint - assessment of soil fertility and crop yield

The efficiency of mint-residue, composted alone and amended with starter nutrients, microbial culture and soil suspension (hereafter termed amended compost) was compared with farm yard manure and inorganic fertilizer on the yield of Japanese mint (Mentha arvensis L.) and improvement of soil fertility. Herbage, essential oil yield, nutrient uptake of Japanese mint and soil available nutrients were significantly enhanced due to application of amended compost as compared to nonamended compost, farm yard manure and inorganic fertilizer. Organic fertilized soils maintained significantly higher available nutrients throughout the crop growth period as compared to inorganic fertilized soils. No additional improvement in yields and soil fertility was recorded with combined application of compost and inorganic fertilizer in 1:1 ratio as against addition of compost alone. Advantage of such combinations was recorded in case of farm yard manure. Results of the study suggested possibilities for nutrient recycling through composted mint-residue for supplementing the fertilizers requirement of Japanese mint.

Performance of lemongrass cultivars intercropped with chamomile under sodic soils with different levels of gypsum application

Field experiments were conducted in sodic soils (pH 9.8, ESP 60) with different levels of chemical amendment (gypsum) to evaluate the performance of three cultivars of lemongrass (Cymbopogon flexuosus), i.e., Praman, Pragati, and CKP-25. Lemongrass was planted in mid July and three harvests of fresh herbs were taken in a year. The three levels of gypsum were a control (no gypsum), GR25 (25% of the gypsum requirement) and GR50 (50% of the gypsum requirement). Praman was observed to be the most and CKP-25 the least suitable variety for sodic soils. A gypsum level of GR25 (25% of gypsum requirement) was found to be optimum for higher production of lemongrass in such soil. Gypsum application significantly influenced the herb and oil yield and accumulation of major as well as trace elements. Seedlings of chamomile (Matricaria chamomila) were planted in between the rows of lemongrass. Chamomile (Matricaria chamomila) grown as an intercrop produced flowers equivalent to 75–104 kg lemongrass oil. Use of amendments (gypsum) and cropping had significant influence on the physico-chemical characteristics of the soil.

Ameliorative potential of Palmarosa for reclamation of sodic soils

Abstract To evaluate the ameliorative potential of the high value crop, Palmarosa, for reclamation of sodic soils, an experiment was conducted in glazed pots with artificially prepared sodic soils having different ESP levels at the Central Institute of Medicinal and Aromatic Plants, Lucknow, India during 1994–95 and 1995–96. The results revealed that plant height, number of tillers per plant, and herb yield decreased significantly with increase in soil ESP. However, oil yield increased significantly (24.5%) at ESP-55 over ESP-16 (control). Further increases in soil ESP up to 85 decreased the oil yield compared to the yield obtained under ESP-55. The growth of Palmarosa in sodic soils of varying ESP reduced the soil ESP from 2 to 20 units during the two years of experimentation. The sodium (Na) concentration in the plant tissue increased significantly with increasing levels of soil ESP, whereas concentrations of calcium (Ca), magnesium (Mg), and potassium (K), in general, decreased with increases in soil ESP. The highest uptake of Na and K was noted at ESP-55 and brought down the soil ESP by 20 units during the course of investigation. However, the highest uptake of Ca and Mg was noted at ESP-16 (control). It may be concluded that growing of Palmarosa in sodic soils would bring down the soil ESP substantially without the use of chemical amendments for reclamation. The crop would also give high return from its cultivation in sodic soils.

Effect of nitrification inhibitors on herb and essential oil yield of Japanese mint on sandy soil

Pyrethrum (Chrysanthemum cinerariefolium) flowers have been observed to have insecticidal properties and could be used as an indigenous nitrification inhibitor for increasing N-use efficiency. A field experiment was conducted at the Central Institute of Medicinal and Aromatic Plants, Lucknow, India during 1988 and 1989 to evaluate the relative performance of pyrethrum flower waste and Dicyandiamide (DCD) as nitrification inhibitors applied with prilled urea (PU) to Japanese mint (Mentha arvensis L.). The results revealed that application of the nitrification inhibitors with prilled urea significantly increased the herb and essential oil yield of the crop compared to that of prilled urea alone. Addition of Dicyandiamide and pyrethrum flower waste gave 30 and 23% more herb yield than prilled urea alone, the corresponding increase in oil yield being 27 and 22%, respectively. Application of nitrogen at 200 kg ha−1 in dicayndiamide or pyrethrum flower waste treated soil significantly enhanced the herb and essential oil yields and N-uptake by the crop to more than that for 300 kg N ha−1 with prilled urea. Both the materials improved the N use efficiency by one and half time as compared to that with PU at 100 kg N ha−1. The results indicate pyrethrum flower dust can be effectively used as a potential nitrification inhibitor.

Growth and Cation Accumulation of Mint Genotypes in Response to Soil Sodicity

Growth and cation accumulation of four mint species and four Japanese mint (Mentha arvensis) cultivars in response to soil sodicity was studied in pot experiments. The sprouting of all cultivars of Japanese mint was significantly inhibited by soil sodicity. The extent of inhibition in sprouting was greater in the cultivars Kalka and Himalaya than in the Shivalik and Koshi. A severe shoot injury symptom was exhibited in M. citrata, M. cardiaca, and M. arvensis after 50 days of transplanting at the soil ESP level 54.0 and in M. piperita after 50 and 70 days of transplanting at the soils ESP levels 25.0 and 54.0, respectively. Mentha piperita, grown on soils ESP of 25.0 and above, failed to survive after developing the shoot injury symptoms. Soil sodicity significantly restricted the herb yield of mint genotypes. At the ESP level of 54.0, the decrease in herb yield was 83.1, 92.2, 89.6, and 98.2% over control in M. citrata, M. cardiaca, M. arvensis, and M. piperita, respectively. The reduction in the yield of Japanese mint at the soil ESP level of 45.0 was 53.8, 81.4, 53.2, and 71.4 per cent over control in the cultivars Shivalik, Kalka, Himalaya, and Koshi, respectively. The oil yield of mint species was not significantly affected with increases in soil ESP level from 1.5 (control) to 25.0. Increases in soil sodicity enhanced the concentration of sodium (Na) and decreased that of potassium (K), calcium (Ca), and magnesium (Mg) in shoot tissues of mint genotypes as compared with control. The Na induced Ca nutrition imbalance had a greater impact on growth inhibition and shoot injury in M. piperita than K and Mg nutrition imbalance. Decreases in K/Na, and Ca/Na ratios in shoot tissues of Japanese mint were significantly and positively correlated with decrease in herb yield. The relatively lower increase in Na and the capacity to maintain high K/Na, Ca/Na and Mg/Na ratios in the cultivars Shivalik and Himalaya showed their greater tolerance to sodicity than that of Kalka and Koshi.

Fate of Fertilizer15N applied as urea and ammonium sulphate in opium poppy (Papaver somniferum L.) grown under greenhouse conditions

Laboratory incubation and greenhouse experiments were conducted to investigate the comparative effectiveness of urea and ammonium sulphate in opium poppy (Papaver somniferum L.) using15N dilution techniques. Fertilizer treatments were control (no N), 600 mg N pot−1 and 1200 mg N pot−1 (12 kg oven dry soil) applied as aqueous solution of urea or ammonium sulphate. Fertilizer rates, under laboratory incubation study were similar to that under greenhouse conditions. A fertilizer15N balance sheet reveals that N recovery by plants was 28–39% with urea and 35–45% with ammonium sulphate. Total recovery of15N in soil-plant system was 77–82% in urea. The corresponding estimates for ammonium sulphate were 89–91%. Consequently the unaccounted fertilizer N was higher under urea (18–23%) as compared to that in ammonium sulphate (9–11%). The soil pH increased from 8.2 to 9.4 with urea whereas in ammonium sulphate treated soil pH decreased to 7.3 during 30 days after fertilizer application. The rate of NH3 volatilization, measured under laboratory conditions, was higher with urea as compared to the same level of ammonium sulphate. The changes in pH of soil followed the identical trend both under laboratory and greenhouse conditions.

Relationship of manganese with iron and zinc with respect to latex yield and composition in opium poppy (Papaver somniferum Linn) under two fertility conditions

Two different field experiments were conducted for two years during 1985–86 and 1986–87 to study the relationship of Mn (0, 15 and 30 kg ha−1) with Fe (0, 15 and 30 kg ha−1) and Zn (0, 10 and 20 kg ha−1) under two fertility (NPK) conditions on yield and quality of opium poppy. The main effect of these micronutrients with respect to latex yield was highest at 15 kg ha−1 of Mn or Fe and 10 kg ha−1 Zn. Increasing the level beyond that resulted in reduction in latex yield. Highest response was observed when 15 kg ha−1 Mn was applied with either 15 kg ha−1 Fe or 10 kg ha−1 Zn. Morphine, codeine, narcotine and thebaine content of the latex was highest with 15 kg Mn, 15 kg Fe or 10 kg ha−1 Zn or the combined application of 15 kg Mn with 15 kg Fe or 10 kg Zn ha−1.