Integrated approach of crop diversification, soil and rainwater management for enhancing agricultural productivity of rainfed acidic land.

Abstract

Soil acidity is one of the limiting factors which affects crop production adversely in many parts of the India. Nearly 40 percent of the cultivated land in India are acidic in nature and contain soil pH in the range of 4.5 to 6.5. A major portion of the acid soils are grouped as red, laterite as well as mixed red and black or ferruginous red and red yellow soils which come under the classification of Alfisol, Oxisol, Ultisol and Inceptisol. These acidic soils are found in the regions receiving high rainfall where leaching losses of bases are very high. The acid soils are produced in the region of acidic parent material. It is also formed due to application of acid forming fertilizers and removal of basic cations through crop cultivation. The North Eastern states like Arunachal Pradesh, Assam, Manipur, Mizoram, Meghalaya, Nagaland, Tripura and Sikkim have almost entire area having acidic reaction (>95%). Acid soils are also dominant in other Eastern Indian states like Orissa, West Bengal, Bihar, Jharkhand and Chhattisgarh. In Kerala, not only high rainfall and temperature have contributed to the development of acid soils, but soils rich in organic deposits resulting in the formation of peats under marshy conditions have also been responsible for soil acidity. Besides, the acid soils are also found in parts of Tamil Nadu, Karnataka, Maharashtra, Andhra Pradesh, hills of Utter Pradesh and Himachal Pradesh. The major acid soil affected states in India along with the area affected is given in the Table-1. In regard to eastern India, 80% of soils in Orissa (12.5 m ha), 76% in Assam and North Eastern states (20 m ha), 39% in West Bengal (3.5 m ha), 30% in Bihar (5.2 m ha), 20% in eastern M.P. (2.9 m ha) and 10% in eastern U.P. (0.86 m ha) are acidic. In Orissa, out of 15.8 mh a geographical area, 12.8 mha (about 80%) is acidic (pH: 5.0-6.5). Rough estimates show that in Orissa about 12 percent of acid soils are strongly acidic (pH<5.0), 48 percent moderately acidic (pH 5.0-5.5), and 40 percent mildly acidic (pH 5.5-6.5). Agriculturally important districts in Orissa having acid soils pH < 5.5 are Mayurbhanj (80%), Dhenkanal (60%), Angul (60%), Phulbani (60%), Sundargarh (60%) Cuttack, Kendrapada, Jagatsinghpur, Jajpur, Angul, Koraput (33%), Nawarangpur, Khurda, Nayagarh, Puri. Acid soils are low in bases, deficient in organic matter, nitrogen and phosphorous and deficient in secondary nutrients (Ca, Mg), and micronutrients (Mo, B and Zn). Aluminum toxicity, low water retention capacity, high infiltration are also the characteristics of acid soil. Due to these reasons, the crop productivity in acid soil regions is not optimum and far below than that of the potential. Hence it is necessary to ameliorate the acid soils with liming materials along with integrated approach of crop diversification and water management to enhance the productivity of acid soil. Liming materials may be like limestone, dolomite etc. which is costlier and may not be affordable by farmers. But these should be less expensive and available within easy reach of farmers’ beside suitability. In Orissa, locally available huge amount of paper mill sludge may be used as chief source of liming, which will not only raise agricultural production in the state but also reduce environmental pollution in the surrounding areas of the factory. Keeping that above points in view, a project sponsored by TIFAC, New Delhi on “Agricultural diversification for enhancing productivity of acidic uplands of eastern India” was executed by Directorate of Water Management, Bhubaneswar from 2006-07 to 2009-10 in representative acid soil areas of Orissa i.e. Rautrapur village of Durgadevi Panchayat of Remuna Block, Balasore district and Bhimda village of Badasahi block of Mayurbhanj district, Orissa where paper mill sludge of nearby Emmami paper factory, Balgopalpur, Balasore was applied to ameliorate soils. In addition to soil amelioration, efforts were also made to diversify cropping system and to conserve rainwater for its recycling to ensure higher and stable agricultural productivity and cropping intensity of rainfed acidic land.