The Journal of University Grants Commission, Vol. 1, No. 1, 2012

Micronutrient Status of Soils in Western ,

Deepak Dhakal Department of Chemistry, Patan Multiple Campus, Tribhuvan University, Lalitpur, Nepal Email: [email protected]

Abstract: A soil micronutrient status survey was conducted in the western part of Chitwan district where soils from eight cultivated farmer fields were chosen for the purpose. The study to determine the micronutrient status of the farmers’ fields under currently used fertility management practices was conducted in the year 2008. Composite soil samples were collected from each of farmers’ fields to the plow-depth level where most of the soils of the research sites were found to be moderately acidic with pH in the range 5.4-6.7, while mean pH was 6.04. The soil of VDC was strongly acidic, while that of was found to be nearly neutral although both of these VDCs are neighboring each other and farmers also practiced the same cropping pattern. The micronutrients, namely, zinc, copper, manganese, and iron were analyzed by Atomic Absorption Spectroscopy. More than half the samples were noted to be high in Cu and Fe, while all of the soils were low in Zn for most of the crops. The amount of micronutrients such as Zn in the soil was observed to be seriously deficient while Cu, Mn and Fe were of adequate level.

Key words : Atomic absorption spectroscopy, soil micronutrients, pH range, sustainable production.

Introduction Chitwan district, in inner Terai region of Nepal, was initially covered by forest where small Tharu ethnic group- used to cultivate a few parcel of land as shifting cultivation. Chitwan has been recognized as the potential district for agriculture ever since the introduction of the resettlement program in 1958/59. An approximate area of 2128 sq km in Chitwan is associated with two municipality and thirty six Village Development Committees (VDCs). Cultivable land in Chitwan district contains 46894 ha but at present approximately 44391 ha has been used only (Anonymous, 2001). Most of the soils of Chitwan district are developed on sediments deposited by the Narayani, as well as, Rapti rivers, while some of the soils in Chitwan are enriched by decomposition of forest litter. Therefore, soils of the Chitwan are considered as fertile for agriculture purpose. The climate of the district is recognized as the hot, humid and sub-tropical which affects the rock weathering and soil formation processes. The cultivation of high yielding variety of crops and vegetables in the district has led to the suspected nutrient deficiency in the soils of Chitwan district. There are around 18 elements known to be essential for plant growth which are classified as macro and micronutrient on the basis of quantity required by plants. Six elements such as N, P, K (primary nutrients), S, Ca and Mg (secondary nutrients) are required in large quantities for plant growth and are known as macronutrients. Similarly, seven nutrients such as B, Fe, Mn, Zn, Cu, Mo and Cl are needed by plants, animals and

Micronutrient Status of Soils in Western Chitwan 25 human beings in minute quantities and are known as micronutrient, but their presence is essential for soils health. In addition, other beneficial nutrients such as Na, Si, Co, Al and V for some plants (Hoeft, 2004). Following objectives of the survey study was selected: (i) To determine the status of micronutrient in soils of selected farmers’ fields under their present fertility management practice, and (ii) To create awareness among the farmers about micronutrient status of soils in their fields.

Study site The study was carried out in the selected VDCs of Chitwan district. The district lies between 83 °35’ to 84 °55’ longitudes and 27 °21’ to 27 °46’ latitudes covering an area of 2118 sq km. Politically the district has thirty six Village Development Committees (VDC) and two municipalities, Bharatpur and . Bharatpur is the head- quarters of the district. The district is separated into Eastern and Western Chitwan by the Khageri river. Due to the limited budget, the research work was concentrated around certain VDCs of the western part of Chitwan and the study area is clearly indicated as a shaded portion (Fig. 1), where integrated farming system has been practiced by most of the farmers.

Fig. 1. Study site selected for the soil micronutrient status survey

Location Map of Micro Nutrient Status of Soil N W E

S DARE CHOWK

CHANDI BHANJYANG

KABILAS

DAHAKHANI KAULE

SHAKTIKHOR

JUTPANI SIDDHI LOTHAR

MANGALPURBHARATPUR N.P.

SHARDA NAGAR CHAINPUR KORAK PHOOLBARI GUNJA NAGAR BIRENDRA NAGAR DIVYA NAGAR SHIVA NAGAR RATNA NAGAR N.P. GITA NAGAR PARBATIPUR BHANDARA MEGHAULI SHUKRA NAGAR PIPLE BACHHEULI KATHAR JAGATPUR KUMROJ

CHITWAN NATIONAL PARK

GARDI

) I

D

A

M ( BAGHAUDA R

U

P

LEGEND N

A

Y L AYODHYAPUR A National Boundary K District Boundary VDC Boundary Study Area 10 0 10 20 Kilometers

Scale 1 : 400000

Sampling design Different farmer’s fields of research sites were selected by using proportionate stratified random sampling technique. Thus, following VDCs and municipality were selected to represent all types of soils: (i) Meghauli, (ii) , (iii) Gunjanagar, (iv) Jagatpur, (v) Mangalpur, (vi) Dibyanagar, (vii) , and (viii) Bharatpur.

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Materials and methods The survey area covered seven VDCs and one Municipality Bharatpur of the Western part of Chitwan district with an elevation ranging around 125-140 masl. The farmers’ fields were selected randomly from each VDC to represent all soil types of the command area. Eight farmers’ fields were chosen for the study and, sampling locations are indicated in Fig. 1. Field procedure: Field survey for sampling out was done in May 2008 and eight soil samples were taken from different cultivated fields of the survey sites. Composite soil samples were taken from the depth of 0-15 cm where cropping history of the field was also noted. Laboratory procedure: Analysis was carried out on soils that were air dried, ground and sieved through a 2 mm mesh sieve. Determination of soils pH: 1:1 soil/water (20 g Soils + 20 ml distilled Water, stirred 2/3 times in an hour, set aside for 30 min to settle down the suspension before the pH measurement (Marten and Lindsay, 1990). Determination of micronutrients: The micronutrients such as Cu, Mn, Zn, and Fe were extracted with DTPA (Diethylene Triamine Penta Aceticacid), and analyzed by AAS (Marten and Lindsay, 1990). DTPA : Fifteen gram soil in 30 cc DTPA (0.005 M) solution, shaking 2 h and filter by using Whatman no. 42; the filtrate was analyzed for Cu, Mn, Zn, and Fe by AAS.

Results and discussion Soils of Chitwan district are developed from alluvial deposits, and the soils studied were found to be of sandy loam texture. Most of the soils were acidic in nature with the mean pH was 6.04. Samples were collected from farmers’ fields where different cropping pattern were practiced. The dominant cropping pattern were rice based followed by maize, wheat and vegetables. Chloride, copper, iron, manganese, molybdenum and zinc are the seven nutrients known to be needed for crop production. Monitoring of B, Cl and Mo has been excluded in this report. All of the collected samples were found to be adequate in Cu, Mn and Fe, while these soils were observed to be all low in Zn. Similar results have also been observed by Tuladhar et al . (2004), Khatri - and Schulte (1984) who found that Zn was the most limiting nutrient for the soils of . Thus, deficiency of Zn has been confirmed on one of these four micronutrients around the research sites of Chitwan district. Guidelines for interpreting some of the micronutrient tests are provided in Table 1.

Soil pH: Most of the soils of the research sites were found to be moderately acidic in nature with the pH range of 5.4-6.7, and the mean pH 6.04 was obtained. Among them

Micronutrient Status of Soils in Western Chitwan 27 the soils of Meghauli VDC were strongly acidic, while those of Dibyanagar were found to be nearly neutral although both of these VDCs are neighboring each other, and the farmers also grow nearly same crops in both of the research sites. Soil pH affects the mineral dissolution, precipitation and thereby affects plant availability of certain elements, since soils pH usually determines availability of nutrients on the soils (Hoeft, 2004).

Table 1. Micronutrient status of soils in research sites of Chitwan district - 2008 Micronutrient Variable (ppm) Critical level Nutritional status of (ppm) soils (%) Mean Range Low Adequate Zinc (Zn) 0.68 0.43 – 1.00 0.2 – 2.0 100 - Copper (Cu) 2.30 0.76 – 3.62 0.1 – 2.5 20 80 Manganese (Mn) 8.55 6.46 – 11.50 1.0 – 5.0 - 100 Iron (Fe) 47.20 10.20 – 82.42 2.5 – 5.0 - 100

Thus, Table 1 clearly indicates that more than 50% samples were found high in Cu, and 100% samples were high in Mn and Fe, while all of the soils were low in Zn. The amount of micronutrients in the soils, especially Zn, was seriously deficient whereas, and micronutrients like Cu, Mn and Fe were at an adequate level for most of the crops. So, among the analyzed micronutrients Cu, Mn and Fe were adequate in most of the soils in the study sites, but Zn needed proper attention especially in the areas where intensive cropping is practiced since Zn has become a serious problem for rice cultivation in the research area. Field experiments on the basis of micronutrient content of the soils are needed in order to verify critical levels of micronutrient with respect to various crops for integrating farming system. The importance of micronutrients such as Zn in rice, vegetables, as well as, other sensitive crops should be conveyed to local farmers where deficiency is more prominent. Farmers should be encouraged to test their soil health regularly for correcting micronutrient deficiencies and other soils health problems for sustainable integrating farming system in the area. Since, balanced application of fertilizers is essential to avoid crop yield decline and to supplement nutrient losses from the soils. Therefore, regular soil testing and monitoring of fertility status of not only the major nutrients like N, P and K, but also micro-nutrients, is important for achieving sustainable agriculture; this practice would insure high productivity in accordance with nutrient demand by crops and would also be environmentally friendly.

Acknowledgements The author would like to thank the University Grants Commission, Nepal and Soil Science Division, NARC, Khumaltar for providing the financial support and technical support, respectively.

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References

Anonymous. (2001). Nepal district profile - 2001 . : Central Bureau of Statistics.

Hoeft, R. (2004). http//www.cropsci.uiuc.edu/classic/2004/article2

Khatri-Chhetri, T.B. & Schulte, E.E. (1984). An assessment of the secondary and micronutrients status of selected soils and crops of the Chitwan valley, Nepal. Nepalese Journal of Agriculture , 15, pp. 1-10.

Khatri-Chhetri, T.B. & Schulte, E.E. (1985). Response of maize to the application of secondary and micronutrients on the soils of the Chitwan valley, Nepal, II; results of multi-location trials. Journal of Institute of Agriculture and Animal Science, 6, pp. 59-76.

Marten, D.C. & Lindsay, W.L. (1990). Testing for copper, iron, manganese and zinc. In R.C. Westhernman (Ed.), Soil testing and plant analysis ; 3 rd edition, SSSA, GNC. No. 3 in the SSSA Book Series, USA.

Tuladhar, J., Sah, K. & Lauren, J.G. (2004). Nutrient status in soils of Chitwan district. Proceedings of the 4 th national conference on science and technology , March 23-26, 2004 (pp. 616- 623). Kathmandu: Nepal Academy of Science and Technology.