Safflower Growth as Affected by Cropping Intensity and Micronutrient Foliar Spray

Abstract

ABSTRACTPlant growth analysis is a useful set of quantitative methods that describe the performance of whole plant systems. To evaluate growth changes in safflower (Carthamus tinctorius L.), an experiment was conducted as a split-plot arrangement with three replications at the Urmia University farm in 2011. Cropping systems (main plots) included conventional (high-, medium-, and low-input) and ecological (eco-friendly) systems. Micronutrient treatments [separate and combined use of Zn (2 g/l) and Mn (3 g/l), water spray and control] were the subplots. Leaf area index (LAI), total dry matter (TDM), crop growth rate (CGR), and relative growth rate (RGR) were evaluated and subjected to variance and regression analyses. Leaf area index showed an early increasing trend up to 900 growing degree days (GDDs); afterwards, LAI declined in both cropping systems and micronutrient treatments. In the two sets of treatments, a linear response for TDM and RGR was observed. The trend for CGR in response to treatments was different; except for high-input system, the trend was linear for Zn+Mn and quadratic for other treatments. The LAI and TDM were less in ecological and low-input systems than in medium and high-input systems. Application of micronutrients increased growth parameters, particularly during the early growth stages. Because decreased chemical inputs did not adversely affect safflower growth, farmers should be able to reduce chemical inputs to obtain an acceptable level of safflower production.