Soil quality degradation associated with resources scarcity is the major concern for the sustainability of conventional rice-wheat system in South Asia. Replacement of conventional management practices with conservation agriculture (CA) is required to improve soil quality. A field experiment was conducted to assess the effect of CA on soil physical (bulk density, penetration resistance, infiltration) and chemical (N, P, K, S, micronutrients) properties after 4 years in North-West India. There were four scenarios (Sc) namely conventional rice-wheat cropping system (Sc1); partial CA-based rice-wheat-mungbean system (RWMS) (Sc2); CA-based RWMS (Sc3); and CA-based maize-wheat-mungbean (Sc4) system. Sc2 (1.52 Mg m−3) showed significantly lower soil bulk density (BD). In Sc3 and Sc4, soil penetration resistance (SPR) was reduced and infiltration was improved compared to Sc1. Soil organic C was significantly higher in Sc4 than Sc1. Available N was 33% and 68% higher at 0–15 cm depth in Sc3 and Sc4, respectively, than Sc1. DTPA extractable Zn and Mn were significantly higher under Sc3 and Sc4 compared to Sc1. Omission study showed 30% saving in N and 50% in K in wheat after four years. Therefore, CA improved soil properties and nutrient availability and have potential to reduce external fertilizer inputs in long run.

No abstract

Cereal cropping productivity in the Indo-Gangetic Plain (IGP) of India is declining, which may be overcome by diversification, alternate crop establishment methods and mulching. This study was conducted to determine whether no-till flat (NTF), permanent raised beds (PRB) and nontraditional ex situ mulching would improve crop and water productivity, economic profitability and soil biological properties in an irrigated maize (Zea mays)-wheat (Triticum aestivum) system (MWS). NTF systems produced 10% higher economic net returns compared with PRBs. Non-traditional mulching (Sesbania, Jatropha and Brassica) increased yields by >10% and net returns by >12% compared with no-mulch. The water saving in PRBs compared with NTF systems was 79, 94 and 173 mm/ha in maize, wheat and MWS, respectively. PRBs saved 29.2% of irrigation water and improved the MWS irrigation water productivity (WP I ) by 24.5% over NTF. On average, mulching saved 23.8 mm/ha irrigation water over no-mulch and improved WP I by 12.0%. PRBs with ex situ mulching produced wheat and maize equivalent system yields lower than NTF but improved WP I and soil biological properties. Jatropha and Sesbania mulching improved yield, water saving, WP I and system profitability. In limited irrigation and no crop residue availability conditions, Sesbania, Jatropha and Brassica vegetation material have potential applications for ex situ mulching under PRBs for water saving and NTF for productivity.

Jatropha (Jatropha curcas L.) is recently introduced in several states as a source of biomass and bioenergy in India. It can withstand and survive on a wide range of soils. However, information related to identification of a genotype tolerant to certain levels of sodicity is lacking. Five Jatropha genotypes (BTP 1-K, BTP 1-N, BTP 1-A, GCC-1, and TNM-5) collected from different ecological regions of the country were screened and evaluated for three years (2007)(2008)(2009)(2010) at Lucknow, India, in sodic soils having four (20, 40, 60, and 80) exchangeable sodium percentage (ESP) levels. A large variation in plant growth, seed yield, and oil content was observed among genotypes owing to sodicity levels. Plant mortality of all the genotypes increased significantly beyond ESP of 40. Among the genotypes screened, BTP 1-A recorded the maximum plant height (240 cm), girth (34·0 cm), biomass yield (14·00 ± 1·43 kg plant À1 ), and number of fruits per plant (14·8) up to ESP 40. The highest seed oil content was found in BTP 1-K and BTP 1-N followed by BTP 1A and the minimum in TMN-5 and GCC-1. Soil amelioration in terms of soil pH, ESP, organic carbon, and microbial biomass was higher under genotype BTP 1-A than BTP 1-K, GCC-1, and TNM-5. Genotype BTP 1-A was found to be suitable for producing more biomass and bioenergy and rehabilitation of degraded lands.

No abstract