Effect of zeolite and poultry manure enriched with zinc and copper on agronomical and physiological traits of green bean

Among legumes, green bean (Phaseolus vulgaris L.) has the highest area under cultivation. This legume also has a very high economic value. Today, the application of natural soil amendments such as zeolite to prevent the loss of nitrogen fertilizers has been considered. The zeolite application can reduce the use of chemical fertilizers, increase the soil water holding capacity and also prevent environmental pollution by improving the soil physicochemical characteristics. Addition of poultry manures to the soil also increases soil fertility, decomposition of organic matter and carbon dioxide production in the plant canopy, which ultimately leads to increased grain yield. The aim of this study was to evaluate the effects of fortified zeolite and poultry manure on yield components, yield, photosynthetic pigments and nutrient concentrations in green bean plant.

To study the effect of zeolite and poultry manure enriched with zinc and copper on yield components, yield, photosynthetic pigments and nutrient concentrations in green bean (Phaseolus vulgaris L.), a field experiment was conducted as a factorial based on a randomized complete block design (RCBD) with three replications at the research field of the Islamic Azad University of Amol in 2017. The treatments of this research consisted of five levels of Zeolite (Z1: control or non-use of Zeolite, Z2: application of zeolite alone, Z3: fortified zeolite with zinc, Z4: fortified zeolite with copper and Z5: fortified zeolite with zinc + copper) and five levels of poultry manure (P1: control or non-use of poultry manure, P2: application of poultry manure alone, P3: fortified poultry manure with zinc, P4: fortified poultry manure with copper and P5: fortified poultry manure with zinc + copper). In this experiment, poultry manure and zeolite were used at rates of 1.5 and 1 t.h-1, respectively. Nitrogen, Phosphorus and Potassium fertilizers were applied uniformly in all plots based on the results of soil analysis. At harvest, the yield components, seed yield and nutrient concentrations in the plant were recorded. The concentration of photosynthetic pigments was also measured at the flowering stage. The data were analyzed using SAS software and the means were compared using the least significant difference (LSD) test at the 5% probability level.

The results showed that the differences between different levels of poultry manure were significant in yield components, seed yield, photosynthetic pigments and nutrient concentrations in the plant. The effect of zeolite was significant on all tested traits except for 100-seed weight. The interaction between different levels of poultry manure and zeolite was significant on pod length and anthocyanin. The application of fortified poultry manure and zeolite with zinc and copper increased the evaluated parameters compared to individual application of poultry manure or zeolite and control. The interaction between poultry manure and zeolite revealed that the maximum pod length was obtained by applying P1Z5, P2Z5, P3Z5, P4Z5 and P5Z5 treatments. The maximum anthocyanin concentration was also obtained by applying P4Z5, P5Z1, P5Z2, P5Z3, P5Z4 and P5Z5 treatments. The results of the mean comparison of data for poultry manure showed that the highest seed yield (174 g.m-2) was obtained by application of fortified poultry manure with zinc + copper, which increased by about 27% compared to the control. Under zeolite application, the maximum seed yield (171 g.m-2) was achieved by application of fortified zeolite with zinc + copper, which increased by about 23.3% compared to the control.       

In general, the copper-enriched zeolite and poultry manure treatments showed better impacts than zinc-enriched treatments in terms of studied traits. Application of zeolite and poultry manure increased the yield attributes, seed yield, photosynthetic pigments and nutrient concentration compared to the control, but the highest amount of these traits was obtained under the application of fortified zeolite and poultry manure with zinc and copper. Therefore, the application of fortified poultry manure and zeolite while reducing the amount of chemical fertilizers, can improve the seed yield of green bean.