Sustainability Of Rice-wheat System Research Articles

Impact of Rice Residue Management Practices on Environment, Productivity and Economics of Wheat: A Review

Rice-Wheat (RW) is a major cropping system followed in Indo-Gangetic Plains of India. This cropping system popularised with mechanisation of both mentioned crops. Increase in mechanisation, particularly use of combined harvesting enables harvesting of rice in a very short span of time but it leaves behind a large amount of crop residue. Ex-situ residue management of this voluminous residue is not feasible and economical to the farmer. Burning of rice residue is a common practise in India to manage the rice residue because of its low economic use, which causes serious air pollution and nutrient losses. Sustainability of RW system is at risk due to soil degradation and poor residue management practices. Proper in-situ residue management is of utmost importance as crop residue contains significant amount of nutrients and it can improve soil physical, chemical and biological health because of huge amount of organic carbon added to the soil. Various soil properties, wheat productivity, economics and the environment are highly influenced by the rice residue management practices adopted. In this review, the authors have discussed impact of different rice residue management practices and wheat sowing methods on wheat productivity, economics, soil properties and the environment.

Incorporation of rice residue and green gram cultivation saves nitrogen, improve soil health and sustainability of rice-wheat system

• Rice residue incorporation and green gram was tested on yield and soil health. • Nitrogen fertilizer up to 75 kg ha −1 was saved by green gram growing before rice. • Sustainability was enhanced by rice residue and green gram incorporation. • Organic C increased by rice residue and green gram incorporation after 7 years. • Saving upto75 Kg N ha −1 in Punjab and Haryana could save $45.1 million yearly. Rice-wheat cropping system and associated residue burning is a major cause of air pollution and soil health depletion in Northern India. This calls for urgent technological interventions to address the issue and improve the profitability of this cropping system. Objective was to study the effect of rice residue incorporation (RRI) and green gram inclusion (GGI) on amount of N applied, productivity and soil health in rice-wheat cropping (RWC) system. Combinations of RRI, nitrogen management and GGI with conventional rice-wheat rotation were tested for 7 years. Eleven treatments with combination of RRI, RR removal, GGI and N management were evaluated. Treatment effects on system productivity, profitability and soil health parameters were measured. Treatment R-W (-RR) - Gg + <25 % N to R and R-W (+RR) - Gg+ <25 % N to R +>25 % N to W produced maximum rice (7677 kg ha −1 ) and wheat yield (5949 kg ha −1 ), though non-significant (P > 0.05) compared to control (Rice = 7508 & Wheat = 5724 kg ha −1 ). Nitrogen fertilizer up to 75 kg ha −1 was saved when GGI was taken up before rice. GGI and RRI was sustainable in terms of higher sustainability value index (SVI = 0.78), wheat equivalent yield (WEY = 20.0 t ha −1 ) and production efficiency (PE = 57.5 kg ha −1 day −1 ). The treatments with GGI + RRI produced 1015$ additional net returns with more than double B:C ratio. Soil health in the form of SOC (0.42 %) and available N (152.6 kg ha −1 ) were also improved with GGI + RRI in treatment R-W (+RR) - Gg+ <25 % N to R +>25 % N to W. Adoption of RRI + GGI over 3.64 m ha area under RWC system of studied ecology may save 45.1 million US $ worth N fertilizer annually in addition to substantial reduction in air pollution.

Effect of tillage and residue management in rice-wheat system

The declining soil health in Indo-Gangetic plains due to intensive tillage practice and residue burning is threatening the sustainability of rice-wheat system (RWS) in this region. Zero tillage (ZT) and residue recycling (incorporation/ mulching) can improve soil health and sustainability of RWS. With this hypothesis an experiment was conducted at ICAR-Central Soil Salinity Research Institute, Karnal (Haryana) to study the effect of ZT and residue recycling in rice and wheat crops on productivity, carbon sequestration, biomass accumulation and physiological growth. The highest grain yield in rice (over varieties) was recorded in PTR+RI (4.71 t/ha) followed by PTR-WR (4.45 t/ha). However, the highest shoot biomass (14.5 t/ha) and carbon sequestration (6.5 t/ha) was recorded in PTR-WR. In wheat crop (over varieties), CTW+RI produced the highest grain yield (5.10 t/ha), shoot biomass (13.6 t/ha), carbon sequestration in above ground parts (4.25 t/ha) and chlorophyll content. Rice variety CSR 36 performed better in terms of grain yield (4.91 t/ha), shoot biomass (14.7 t/ha) and carbon sequestration (6.8 t/ha) while two wheat cultivars produced similar grain yield. So, based on our experiment it can be concluded that residue incorporation in conventional practice in both the crop i.e., conventional tilled puddle transplanted rice and conventional tilled wheat performed better than residue mulched under zero tillage condition.

Conservation agriculture effects on crop and water productivity, profitability and soil organic carbon accumulation under a maize-wheat cropping system in the North-western Indo-Gangetic Plains

The Indo-Gangetic Plains (IGP) of India is dominated with rice − wheat cropping system that occupies almost 10.5 million ha area. The sustainability of rice-wheat system is under threat due to numerous water-, nutrients-, weeds- and environment-related problems, mainly, due to the cultivation of rice. Suitable crop and soil management practices with a bias to conservation agriculture (CA) that can sustain soil and environmental health as well as improve crop and water productivity, are required for the Indian IGP. Maize can be a viable alternative to rice and a potential driver for diversification of rice-wheat system. The acreage of maize is on the increase in conventional and conservation agriculture-based cereal systems of India in recent years. Therefore, a field experiment, involving a maize (Zea mays L.)-wheat cropping system was undertaken on a sandy clay loam soil for three years (2010–11 to 2012-13) in New Delhi to evaluate the impacts of CA on crop and water productivity, profitability and soil organic carbon (SOC) accumulation. There were five CA-based treatments in first year, and two treatments were introduced in second year (2011-12) onwards. The experiment was laid out in a randomized complete block design with three replications. In all the residue retention plots, wheat residue was retained in maize crop and maize residue was retained in wheat crop under zero till conditions. Results showed that the plots under permanent broad bed with residue (PBB+R) and without residue (PBB) resulted in ∼29 and ∼26% higher maize grain yield, respectively than conventional tillage (CT) (2.6tha−1), but wheat grain yields were comparable in all the treatments in first year. Maize grain yield in second year under PBB+R and zero tillage with residue (ZT+R) were 55 and 43% higher than CT plots (2.8tha−1). Three-year mean maize yields due to PBB+R and permanent narrow bed with residue (PNB+R) were 28 and 15% higher than that in CT plots (3.3tha−1). The PBB+R resulted in 11% higher two-year mean water productivity in maize than PBB (∼without residue), but both these treatments were comparable in this regard in wheat. The ZT+R plots resulted in 14% and 22% higher two-year mean water productivity, respectively in maize and wheat than ZT plots. Overall, the plots under PBB+R had 57% and 19% higher mean water productivities in maize and wheat, respectively compared with CT plots. Again, the PBB+R plots gave 12% higher two-year mean net returns compared with CT plots. With regard to net returns, the plots under permanent narrow bed with and without residue (PNB+R; PNB) were inferior to PBB, PBB+R, ZT and ZT+R plots. Retention of both-season crop residues could significantly improve SOC concentration in surface (0–5cm) soil. The PBB+R resulted in highest SOC pool at 0–30cm soil layer, which was significantly higher than that in CT. This system showed maximum carbon sequestration potential. Thus, this CA practice, which involves PBB+R is superior to other practice. This would save water through higher water-use efficiency, and lead to accumulation of more carbon in soil with higher sequestration potential, besides giving sustainable production through maize-wheat system over the years. This can be adopted across the IGP regions of India, where irrigated rice-wheat system is in practice, and in similar agro-ecologies of the tropics and sub-tropics under irrigated conditions.

Productivity and Sustainability of Rice-Wheat System in Indo-Gangetic Plains

Recent studies indicate that Rice-Wheat System in the Indo-Gangetic Plains is now facing a number of stresses resulting in slowdown in productivity growth. It is now important to study and empirically verify through in depth analysis the observed trend, yield growth, instability, total factor productivity and sustainability of yield. In this context, the present study has been carried out with following specific objectives; (a) to estimate total factor productivity in rice and wheat to calculate sustainability (b) to study the yield trend and instability in rice and wheat in IGP region. Major changes in yield was observed in UP and Punjab. Bihar had no significant changes during the period under reference. There is a scope to increase in all districts of Bihar.