Effect of salinity stress and different levels of potassium fertilizer on yield quantitative and qualitative of Kochia (Bassia scoparia (L.) A.J. Scott)

Today, increasing demand for plant products has been coupled with the reduction of the area of cultivated land due to the limitation of water and soil resources. Water and soil salinity are among the factors that prevent the yield of sufficient yield in crops. Live or non-live-stress tensions can have negative effects on plant production and can even threaten the survival of a plant (Boyer, 1982). Salinity stress is one of the most important factors limiting plant growth and agricultural production, especially in arid and semi-arid regions. However, passionate crops such as kochia can be used as a forage, soil remediation, biofuel and green space and carbon stabilizer (Khan and Ansari, 2008). Potassium is the dominant mineral ion in plant solutions and plays an important role in reducing osmotic potential in plant cells.

This research was carried out at the research farm of Agricultural Research Institute of Zabol University in 2016-17. The experiment was split plot based on randomized complete block design with three replications. Salinity stresses were classified into three levels including: 1, 7 and 14 dS.m-1 as the main plot and potassium sulfate fertilizer at three levels: 100, 200 and 300 kg.ha-1 as a sub plots. Each plot was four rows of cultivation, the distance between rows was 50 cm and the distance between 2 plants per row was 20 cm. Each plot consisted of 4 rows of planting. In this research, quantitative traits included: plant height, number of lateral branches, fresh and dry weight of the plant, leaf weight, leaf to stem ratio. And qualitative traits was measured include DMD, water soluble carbohydrates (WSC), acid soluble fiber (ADF), neutral detergent fiber (NDF), crude protein (CP) and ash ( Ash). For evaluation of forage quality has been used, a NIR device or a near infrared spectrometer, which is the most accurate and, at the same time, the fastest technique for estimating the chemical composition of agricultural products.Analysis of variance of data was performed using SAS software version 9/1. The mean comparison of treatments was done using Duncan test at 5% level. Charts and tables were drawn using Excel and Word software.

According to the results of analysis of variance of data (Table 2), the main effects of salt stress and potassium fertilizer also showed a significant effect on plant height. Comparison of the mean interactions of the investigated factors showed that at all salinity levels, along with increasing potassium fertilizer, the height also increased with the highest altitude with 300 kg.ha-1 potassium sulfate applications in salinity conditions of 1 dS.m-1 (Table 3). Results of analysis of variance of data (Table 4) showed that the effects of salinity stress and potassium fertilizer, as well as their interactions, did not show a significant effect on the DMD of the plant. Comparison of mean of traits showed that salinity stress (1 dsm-1) with 11.49% maximum water soluble carbohydrate and salinity level (14 dsm-1) with 11.44% of the lowest values (Table 5). Also, comparison of mean of traits showed that salinity stress (1 dsm-1) with 12.69% higher and salinity level (14 dsm-1) with the lowest crude protein was 12.34% (Table 5).Comparison of mean of traits showed that salinity stress (1 dsm-1) with 12.69% had the highest crude protein and salinity level (14 dsm-1) with 12.34% of the lowest values (Table 5).

The results of the study on the effect of salinity stress and different levels of potassium on the quantitative characteristics of Kochi showed that all quantitative traits were completely subjected to salt stress and significantly decreased. The highest forage yield belonged to irrigation with salinity of 1 dSm-1 and lowest for irrigation with salinity of 14 dsm-1. It seems that salinity was more effective on the quantitative traits of the plant and did not affect the quality of forage.