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Ethylene is a potent phytohormone that influences a number of physiological and morphological characters in plants, and its biosynthesis is regulated by several factors, including nutrient availability. This study investigated the effect of using paint-coated calcium carbide (PCC) as a source of ethylene on nitrogen metabolism, photosynthesis and yield in cucumber (Cucumis sativusL.). The application of PCC significantly enhanced plant ethylene production regardless of the addition of nitrogen and there was a concurrent improvement in the morphophysiological attributes of cucumber. PCC application (30 mg kg−1) in combination with N (60 mg kg−1) significantly improved the leaf area, number of primary branches, nitrate reductase activity, nitrogen contents, photosynthetic rate, stomatal conductance, carboxylation efficiency, water use efficiency and fruit yield in cucumber. Therefore, the addition of soil-applied PCC and N could potentially be used to achieve a higher fruit yield in cucumber by improving nitrogen assimilation and photosynthetic characteristics. [ABSTRACT FROM AUTHOR]

Field experiments were conducted in 2006–2007 and 2007–2008 to evaluate the effects of three calcium carbide (CaC2) based formulations (slow release sources of acetylene and ethylene) - matrix-1 [(M-1)(21% CaC2, 58% polyethylene and 21% plaster of paris)], matrix-2 [(M-2)(42% CaC2, 48% polyethylene and 10% plaster of paris)] and paint coated [(PC)(35% CaC2, 44% paint and 21% plaster of paris)] - on nitrification inhibition; growth, yield and nitrogen (N)-uptake of wheat. All the three CaC2formulations (CCF,s) inhibited nitrification, reduced plant height, and improved N-uptake, spike bearing tillers, 1000-grains weight and yield of Inqulab-91 and Bhakhar-02 wheat cultivars. Increase in grain yield was found maximum (22% over the control) with M-1 applied at 30 kg CaC2ha−1; followed by M-2 and PC. Furthermore, CaC2significantly reduced lodging in Bhakhar-02 plots. It is concluded that grain yield of wheat can be enhanced by the application of CaC2formulations particularly M-1 along with NPK fertilizers. [ABSTRACT FROM AUTHOR]

Nitrification inhibition (NI) of applied fertilizer nitrogen (N) is a suitable approach to improve N-use efficiency. Formulated calcium carbide (CaC2), a slow-release origin of acetylene, is a potent nitrification inhibitor; however, its efficacy in relation to different formulations has not been thoroughly investigated. In this study, seven CaC2formulations viz. encapsulated; coated with beeswax, paraffin wax or paint, and matrix-I (21% CaC2, 58% polyethylene and 21% plaster of paris), matrix-II (42% CaC2, 48% polyethylene and 10% plaster of paris) and matrix-III (61% CaC2, 34% polyethylene and 5% paraffin oil) were incubated with soil and their effectiveness in acetylene and ethylene release and NI potential were compared up to 91 days. In CaC2treatments, acetylene flux was decreased, whereas that of ethylene first increased and then decreased with time. During all the time intervals after day 7 of incubation, fluxes of acetylene and ethylene and NI were significantly greater with matrix I, followed by matrix II, paint-coated, and wax-coated CaC2. No acetylene release was noted with encapsulated or matrix III formulations after day 35 of incubation. Among other CaC2formulations, matrix I, matrix II, and paint-coated CaC2were better precursors of acetylene and ethylene, and nitrification inhibitors in the soil. [ABSTRACT FROM PUBLISHER]

Calcium carbide formulations (CCFs) are used for nitrification inhibition and as precursor of ethylene in soil. Their impact on crop growth and yield is thoroughly investigated. However, there is a knowledge gap regarding their influence on seed germination. The present study was planned to study the impact of CCFs on wheat seed germination and early seedling growth. Encapsulated, beeswax coated, paraffin wax coated, paint coated, matrix-1, matrix-2 and matrix-3 CCFs were prepared and applied at 22.5 mg CaC2 kg-1 to sand filled cups. Wheat seeds were sown in sand medium contained in disposable cups. Treatments were allotted according to completely randomized design with three replications. All CCFs except encapsulated and matrix-3 significantly reduced mean emergence time (MET) and increased emergence rate index (ERI) of wheat seedlings. Application of these formulations also improved root growth and increased root: shoot ratio by length; however, influence on root: shoot ratio by weight was found non-significant. Maximum germination and root growth was observed in the treatments of matrix-1 followed by matrix-2, beeswax and paint coated CCFs. To explore the effect of different rates of matrix-1, second experiment was conducted. Its application at 15 mg CaC2 kg-1 was found comparatively better. It is concluded that soil applied CaC2 in some proper formulation can improve wheat seed germination and root and seedling growth. [ABSTRACT FROM AUTHOR]

Calcium carbide (CaC2) is a well-known source of acetylene and ethylene gases. Its use as a plant growth regulator could be an innovative approach for vegetable production if applied in suitable formulation. Different rates of CaC2 (10, 20, 30 and 40 mg plate-1) were evaluated regarding seed germination and morphological characteristics under controlled conditions. The results showed that germination rate was significantly improved by using low rates of CaC2 (10 to 30 mg CaC2 plate-1) while the highest rate of CaC2 (40 mg plate-1) suppressed germination rate of cucumber seeds. Likewise, lower rates of CaC2 were also found effective in enhancing the root and hypocotyl lengths, number of lateral roots and fresh weight of seedling while the highest rate of CaC2 was proved inhibitory. It was recorded that the CaC2 induced improvement in seed germination was significantly correlated (r = 0.75) with magnitude of ethylene production during imbibition. Moreover, a pot experiment was conducted under natural conditions to select optimum rate and coating material of CaC2 regarding growth and yield parameters of cucumber. It was found that all rates of CaC2, irrespective of coating materials, exhibited new primary branches, early female flowering and fruit maturity. Maximum response regarding female flower count, fruit yield and ethylene emission was obtained by the application of paint coated CaC2 at 300 mg pot-1, which resulted in 34% more fruit yield compared to control plants. [ABSTRACT FROM AUTHOR]