Analysis of soil physico-chemical properties of guava orchard in multi zones of district Larkana, Sindh, Pakistan

This study was an effort to assess the soil physico-chemical properties of guava orchards in four Taluka of district Larkanaduring 2014-15. Composite soil samples were collected from three (4x4 each) blocks (16 tress) of each orchard at three soil depths (0-15, 15-30 and 30-45 cm).The soil samples were analyzed for some physical and chemical properties of the soil. Analytical results of this study described that soils of taluka Bakrani and Dokri orchards were classified as silty clay and Larkana and Ratodero orchards had silty clay loam texture. Electrical conductivity ofsoil samples of guava orchards in four taluka of district Larkana, showed that 100% of the soils of study area has an average value of (<1 dsm ). For pH, however, all soil samples were found medium alkaline (pH7.6-8.3). In Pakistan, guava is grown on an area of 64.0 hectares with a total production of 546.6 tons. Sindh contributes 9.8 hectares of area under guava with a total production of 75.4 tons (GOP, 2012). In case of organic matter, results of this study revealed that all soil samples were found poor (<0.86) in OM content except surface soil (015cm) of Bakrani guava orchards. All the guava orchard soils were put in the categorization of very marginal calcareous (5-10 %). Results regarding soluble Nashowed that average soluble Na contents ranged between 0.30-0.45 meq L across the four taluka’s of Larkana. Overall results showed that 100% soil samples were found marginal in soluble Na. Soluble Ca ranged between 5.37 to 8.74 meq L. Ratodero guava orchard soils have more Ca content than other taluka’s followed by Larkana. Further study revealed that 100% of the samples were found marginal in Ca content. Similarly, 100 % of the soil samples were marginal in Mg content. In this study K ranged between 302-403 with an average K of 351 meq L across four taluka.


Introduction
Orchard soils under semiarid/arid subtropical regions have low organic carbon content and inherent low soil fertility status [1]. Poor soil fertility seems to be one of the most important reasons for low fruit productivity [2]. Restoration of the soils are important if tree crops are planted from view point of orchard sustainability and productivity as millions of farmers are engaged in fruit production, sustaining their livelihood and nutritional security [3]. The environmental condition of Pakistan is good for the cultivation of different varieties of vegetables and fruits. Fruits contribute for the production of drinks [4]. Among fruits guava has importance in Pakistan fruit industry and it is ranked as 4 th place on the basis of area (62.5 thousand ha) and production (555 thousand tons) [5]. Sindh contributes 9.8 hectares of area under guava with a total production of 75.4 tons [6]. It has a high nutritional importance. It produces the fruit two times in a year i.e. Kharif (summer) and Rabi (winter) however the most excellent fruit is obtained in winter [7,8] conducted experiment based on the nutrient requirement of guava trees. [9] determined guava leaves samples and observed NPK and Mg and Zn deficiency in the orchards. Guava is very good source of vitamin C when compared with citrus and apple [10]. Punjab province shares 77% of guava production in the Pakistan [11]. The taking away of nutrients from guava orchards happens because of the harvested fruit, as was stated earlier, and also by pruning the trees. In adult guava orchards, very much pruning is practiced, which may greatly cause in decrease aboveground biomass to 40 to 60%. The scraped material consists of about 24.5 kg of green material per plant (7.8 kg of leaves; 2 kg of boughs and 14.7 kg of branches, twigs and small fruits [12]. Locally, number of guava trees is found unhealthy and premature death is common problem. As a result very little knowledge is available about phyicochemical properties of the soil of guava orchard's [13]. Therefore soil should be analyzed for macro and micro nutrients for improving tree health, fruit yield and quality [14]. Soil fertility is decreasing on daily basis because of intensive cropping to fulfill the needs of rapidly rising population [14]. Therefore, this study is proposed to explore orchards of district Larkana, Sindh for their physico-chemical properties.

Materials and methods
This study was conducted to investigate soil physico-chemical properties of guava orchards soil of district Larkana, Sindh. Soil sampling was done to collect samples. The collected soil samples were analyzed for particle size distribution by Hydrometer method, EC and pH were determined by digital EC and pH meter, calcium carbonate, and organic matter was determined by Walkley and Black method, soluble Na + , K + were analyzed by ammonium acetate method, extractable Ca + and Mg + were analyzed by ammonium acetate and soluble Clwas determined by Mohar's titration.

Results and discussion
The result of particle size distribution analysis of guava orchard soils of all Taluka at different soil depths is presented in Figure  1. The data showed a sand percent of 8  Results regarding pH is presented in Table  2. The average soil pH of all taluka was recorded as (8.21), whereas minimum pH value was found (7.78) and maximum pH of (8.88).As compared to other larkana taluka orchards soil has more average pH (8.74). Whereas, Bakrani (7.92) and Ratodero (7.96) has lowest pH among all four studied talukas.

Soluble Na + (meqL -1 ) in Soil
Results regarding soluble Na + (Table 5) showed that a slightly variation was found at different soil depths in all selected Talukas of district Larkana. Average soluble Na + contents ranged between 0.30-0.45 meqL -1 across the four taluka's of Larkana. The orchard of Taluka Dokri contained more Na + than other Taluka orchard soils. Overall results showed that 100% soil samples were found marginal in soluble Na + .

Soluble calcium (meqL -1 )
The result of soluble Ca has been given in

Conclusions
It is concluded from above results that the soils of guava orchards of district Larkana are generally heavy in texture, non-saline, strongly alkaline and poor in organic matter, moderately to medium calcareous in nature. The soil was found marginal in soluble Na, Ca, Mg. The available potassium was quite adequate. Therefore, the application of organic matterand the macro nutrients fertilizers are suggested to maintain soil fertility as well as yield of the guava in the guava orchards.