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Investigating effect of manures sources and application rates on agronomic traits, yield and grain quality of local and improved rice varieties

 

Introduction

The long-term use of chemical inputs has led to environmental contamination and reduced soil fertility. In the past, the use of organic fertilizers has been widespread in paddy soils, but nowadays more chemical inputs are used for many reasons, including ease of preparation, easy use and rapid response of the plant. Traditional rural communities, unlike urban-industrial societies, are not garbage producers. The material cycle in such cultures is not discriminating in nature, and every waste and scum seems to be useless, converted into fertilizers to enter the agricultural cycle and deliver part of the plant nutrients needed and improve the physical and biological conditions of the soil. One of these cases is livestock excrement. According to represented statistics of ministry of agriculture publications annually in Iran more than 20 million tons of manure, produces. It seems that the use of various animal manures can improve the nutritional and moisture content of the soil by improving the physical properties of the soil, and ultimately affect the quantitative and qualitative enhancement of the yield and yield components of rice plant. In view of the high popularity of people about the health and organic rice production in recent years, as well as the abundance and cost of bird poultry, bovine and sheep manures compared to other animal manures, it seems necessary to conduct the project entitled "Effect of different sources and levels of organic fertilizers on agronomic traits, yield, yield components and grain quality of rice cultivars Hashemi and Gilaneh", in order to answer some of the questions and possible ambiguities regarding the use of conventional organic fertilizers and advise and promote their use in the paddy soils.

 

Challenges and necessity

Chemical fertilizers have a significant impact on world food production and are one of the important components in today's agriculture. Predictions indicate that more than 50 percent of agricultural production increases the result of using chemical fertilizers. The conventional agricultural practices in today's world do not have sufficient success in using resource management, and relying excessively on artificial inputs and injecting auxiliary energy such as chemical fertilizers and pesticides have created unsustainable agro-ecosystems. High use of chemical fertilizers can lead to groundwater pollution, decrease in the population of beneficial soil microorganisms and insects, more crops sensitivity to diseases, acidification or alkalization of soil, destruction of soil structure, decline of organic matter and soil fertility. So, for sustainable agriculture development, it is necessary to reduce the use of chemical fertilizers. In recent years, the necessity of the health of products in different agricultural systems has been given particular attention in terms of the presence of pesticides and chemical inputs residues, their impact on human health and environment, led to particular attention to the production methods and inputs. Organic fertilizers, including manures, can increase soil water conservation capacity, reduce tensions, such as drought stress, increase microbial diversity of soil, improve soil physical structure and prevent soil erosion, which, along with supplying part of the plant's nutrients, improves plant growth and yield and increases the quality and health of the product.

 

Research hypotheses

  1. Are the different levels bovine, poultry and sheep manure significantly change the crop characteristics, yield and grain quality of Hashemi and Gilaneh rice varieties?
  2. Are the sources and levels of organic fertilizers affect soil characteristics and chemical composition of grain and straw of Hashemi and Gilaneh rice varieties?

 

Objectives

  1. to investigate the effect of manures sources and application rates on agronomic traits, yield and grain quality of Hashemi and Gilaneh rice varieties.
  2. to investigate the effect of manures sources and application rates on the chemical characteristics of paddy soils.

 

Materials and methods

A randomized complete block design with three replications designed and implementing at Rice Research Institute of Iran, Rasht, during 2018-19. The experimental factors consisted of three sources of completely rotten bovine manure (5, 10 and 20 tons per hectare), processed poultry manure (2.5, 5 and 10 tons per hectare) and sheep manure (10, 20 and 40 tons per hectare), each in three levels, were considered on two rice varieties including Hashemi and Gilaneh. The manures were exposed to free air for a similar period (one week) to reduce the inside moisture content and become uniform. Before using organic manures, the chemical properties of these fertilizers (nitrogen, phosphorus and potassium, and heavy elements including plumbum and cadmium) will be analyzed. The land intended for the implementation of this research project, in cooperation with the Rice Research Institute of Iran, has not even been used for many years, in other words the virginal of the farm is considered to be the main project condition. Morphological traits including plant height, tiller number, number of fertile tillers, number of panicles, panicle length, total number of grains per panicle, number of filled grains panicle, yield, nitrogen and phosphorus and potassium content of seeds and straw of rice plant, soil chemical properties including nitrogen, phosphorus, potassium, organic matter and pH will be investigated. Also, quality traits including amylose content, gel consistency and gelatinization temperature, will be studied.

 

Annual report (until March 2019)

At the first year of experiment A randomized complete block design with three replications implemented at Rice Research Institute of Iran, Rasht. The results of the first year indicated that using higher levels of organic fertilizers led to increase in agronomic trait such as plant height, number of tillers, number of fertile tillers and panicle number of Hashemi and Gilaneh rice varieties. By repeating the experiment in the second year and ANOVA analyzing, it is possible to assess the effect of the environment that has already been included in the experimental factors and to make a more detailed and comprehensive examination of the experimental factors on the studied traits.