Integrated plant nutrient supply in rice (Oryza sativa)–wheat (Ttriticum aestivum) system

Abstract

A field experiment was conducted at Karnal during 2005–07 to evaluate the effect of 13 different combinations of integrated plant nutrient supply including crop residues, farmyard manure, pressmud, neem-coated urea and biofertilizers on productivity and soil health of rice (Oryza sativa L.)–wheat (Triticum aestivum L. emend Fiori & Paol.) system under integrated nutrient supply. Growth and yield attributes of rice, viz tillers/m2, panicle length, number of grains/ panicle and 1 000-grain weight were statistically similar under organic, inorganic and integrated plant nutrient supply. The number of days to heading was significantly less with the 100% organic application. Although the highest system productivity (9.88 tonnes/ha) was observed in treatment 100% inorganic nutrient supply to rice–125% inorganic nutrient supply wheat but taking soil fertility improvement in consideration, the treatments, viz 75% inorganic to rice–100% inorganic+25% through farmyard manure in wheat (9.22 tonnes/ha), 75% inorganic + 50% through farmyard manure in rice–100% inorganic + biofertilizer in wheat (9.36 tonnes/ha), 50% inorganic + 50% through pressmud in rice–100% inorganic in wheat (9.39 tonnes/ha), 50% inorganic + 50% through farmyard manure to rice–50% inorganic + 50% through farmyard manure + biofertilizer in wheat (9.13 t/ha), 75% neem-coated urea in rice–100% neem coated urea + 25% through rice residue in wheat (9.08 tonnes/ha) were found significantly superior than 100% organic supply through farmyard manure in rice–wheat (6.82 tonnes/ha) and at par with 100% recommended inorganic nutrient supply in rice– wheat (9.43 tonnes/ha). Slight improvement in organic carbon status was observed in all treatments even in conventional cropping of rice–wheat system. NPK balance sheet shows that nitrogen (4–206 kg/ha) and phosphorus (20.6–185.0 kg/ ha) have the positive balance, whereas K shows highly negative balance (–130 to –416 kg/ha). K balance was less negative (–130 to –405 kg/ha) where organic source of nutrient was applied in parts or full.