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Residue management is the emerging challenge for sustainable growth of Indian agriculture and environmental protection mainly in Indo-Gangetic Plains (IGP). Out of 620 MT crop residues produced annually in the country, 234 MT is surplus and 30% of it is contributed by rice and wheat. Approximately 16% of total crop residue being burnt, 62% is contributed by rice and wheat. At present, we do not have any viable and systematic approach to deal with crop residues or adoption rate is poor. Therefore, the farmers in majority burn rice residues in the field, which leads to huge nutrient loss besides deteriorating environment and human health. Major forces enforcing residue burning are combinde harvesting, lack of traditional use of crop residues, intensive cropping system and non-availability of buyers for rice straw. Farmers need to get clear fields within short time frame at any cost to ensure the timely sowing of next crop (wheat) without any hindrance in farm operation offered by loose straw. It takes time to manage loose straw by mechanical operation to ensure smooth sowing of next crop in standing stubble which compile farmers to go for straw burning. Field burning of crop residue (FBCR) was not given much attention by policy makers in last two decades because it was at a small scale, but nowadays, it is counted as the serious agricultural pollutant, which is directly impacting environment and human health and causes global warming as burning produces greenhouse gases. In the harvesting season Punjab, Haryana, Western Uttar Pradesh and Delhi face heavy smog problem because of this unhealthy practice and soil fertility is also deprived. In the IGP, rice–wheat is a major cropping system and both crops produce a lot of surplus residues which is ultimately disposed of by burning in the field particularly the rice residues. Nowadays, government and courts have zero tolerance against FBCR. Strict laws including heavy penalties and imprisonment against offenders are already in place. In the absence of suitable and economical viable alternative, farmers are still compelled to follow this practice as it is otherwise a big headache for farmers. We need to manage on-farm and post-harvest management of crop residues either by modification in machineries, educating farmers, adjustment in the cropping system and utilizing rice straw in industry and power generation. In this review, efforts have been made to cover major aspects related to rice residue management in rice–wheat cropping system (RWCS) of India.

In Vietnam, approximately 39 million tons of rice (Oryza sativa) residues accrue every year. In this study, we quantified soil nutrient balances of paddy rice fields under different crop-residue management practices in northern Vietnam. On twelve farms, we calculated nutrient balances for the four prevalent rice-residue management practices, i.e., (1) direct incorporation of rice residues into the soil, (2) application of rice-residue compost, (3) burning of rice residues on the field, and (4) the use of rice residues as fodder for livestock. Soils under practices (1) to (3) showed a positive nutrient balance, which indicates that soil fertility can be maintained under these practices and that the amounts of chemical fertilizers can be considerably reduced. If not, there is a risk of eutrophication in the surrounding surface waterbodies. Practice (4), in contrast, resulted in a negative nutrient balance, which indicates the need for returning nutrients to the soils. From our findings we conclude that knowledge about the effects of rice-residue management practices on nutrient cycles may help to optimize the use of fertilizers, resulting in a more sustainable form of agriculture.

Soil organic matter (SOM), besides influencing carbon (C) transfer between soils and atmosphere, impacts soil functional ability and its response to environmental and anthropogenic influences. We studied the impact of continuous application of rice straw and farmyard manure (FYM) either alone or in conjunction with inorganic fertilizers on aggregate stability and distribution of C and nitrogen (N) in different aggregate fractions after 7 years of rice-wheat cropping on a sandy loam soil. Macroaggregates (>0.25 mm) constituted 32.5-54.5% of total water stable aggregates (WSA) and were linearly related (R ² = 0.69) to soil organic carbon content. The addition of rice straw and FYM significantly (P < 0.05) improved the formation of macroaggregates with a concomitant decrease in the proportion of microaggregates at all the three sampling depths (0-5, 5-10 and 10-15 cm). Macroaggregates had higher C and N density as compared to microaggregates. Application of rice straw and FYM improved C and N density in different aggregate sizes and the improvement was greatest in plots that received both rice straw and FYM each year. Application of FYM along with inorganic fertilizer resulted in a net C sequestration of 0.44 t ha⁻¹ in the plough layer after 7 years of rice-wheat cropping. Carbon sequestration was greater (1.53 t ha⁻¹) when both rice straw and FYM along with inorganic fertilizers were applied annually. It is concluded that addition of rice straw and FYM in rice-wheat system improves soil aggregation and enhances C and N sequestration in macroaggregates. This will help in sustainable rice-wheat productivity in the region.

A laboratory investigation of abrasive waterjet cutting of wheat straws was conducted. The work was aimed at a systematic characterization of the abrasive waterjet cutting capability of wheat straws, as a potential alternative to cutting discs currently adopted in no-till drills and planters for crop residue management. A two level 2IV7−3 fractional factorial design was applied to investigate the influence of abrasive waterjet process parameters on the cutting efficiency of wheat straws. Straw coverage thickness, water pressure, and orifice diameter were found to be the most significant ones. Experimental results suggest that straw cutting mechanism is mostly related to the hydraulic power of the jet. A multiple logistic regression was performed to model the relationship between the cutting efficiency and the jet power. The logistic model was then applied to estimate the average water and power consumption for wheat straw cutting during a no-tillage seeding operation. An average jet hydraulic power of 6400 W would be sufficiently high to guarantee 90% cutting efficiency in presence of heavy residue distribution. The experimental study shows that a small quantity of abrasive powder (50 g·min−1) allows one to increase the jet cutting capability of wheat straws, and to reduce the required maximum hydraulic power, compared to pure waterjet cutting. Results show are potentially relevant for field validation in agriculture based on no-tillage.

Yield increases of cucumber following cover crops in a rotation system have been previously reported for intensive Chinese agricultural production. However, little information is available as to how this system affects soil microbial properties and nematodes. A 4-year field experiment on a greenhouse cucumber double-cropping system was conducted to investigate the effects of four different summer cover crops on cucumber yield, soil nutrients, microbial properties and nematodes. After 4 years, six cover crop and residue management rotational cropping systems that included sweet corn residue removed (SR), sweet corn residue incorporated (SI), and garland chrysanthemum and edible amaranth (GR) significantly (P < 0.05) increased cucumber fruit yields summed for the years 2005-2008 by 22%, 32% and 26%, compared to the control (CONTROL), while cropping systems that included common bean residue removed (CR) and common bean residue incorporated (CI) significantly (P < 0.05) decreased yields by 30% and 22%, respectively. Plant available N losses and P, K accumulation in soil were efficiently reduced by planting cover crops. Soil microbial biomass, population and diversity were higher under summer cover crop-related treatments than under the control. The dominant plant-parasitic nematodes found in our experiment field were Meloidogyne sp. and Helicotylenchus sp, which were all parasites of both common bean and cucumber. A strong relationship between cucumber yields and the non-plant-parasitic: plant-parasitic nematode ratio (NPR) (r = 0.703, p < 0.001) was found in the break-host systems (SR, SI and GR). These results suggested that on the nutrient rich soils of our study, cucumber yield increases for the SR, SI and GR treatments, compared with the control, could be explained by higher microbial biomass, population and diversity and NPR.

A laboratory incubation experiment is conducted for 90 days under controlled conditions where either pruning residue or its biochar is applied to determine which application generates the lowest amount of greenhouse gas from tea plantation soil. To study the effect of incorporation depth on soil N2O and CO2 emissions, experiment 1 is performed with three treatments: (1) control; (2) tea pruning residue; and (3) residue biochar mixed with soil from two different depths (0–5 cm and 0–10 cm layers). In experiment 2, only the 0–10 cm soil layer is used to study the effect of surface application of tea pruning residue or its biochar on soil N2O and CO2 emissions compared with the control. The results show that biochar significantly increases soil pH, total C and C/N ratio in both experiments. The addition of pruning residue significantly increases soil total C content, cumulative N2O and CO2 emissions after 90 days of incubation. Converting pruning residue to biochar and its application significantly decreases cumulative N2O emission by 17.7% and 74.2% from the 0–5 cm and 0–10 cm soil layers, respectively, compared to their respective controls. However, biochar addition increases soil CO2 emissions for both the soil layers in experiment 1. Surface application of biochar to soil significantly reduces both N2O and CO2 emissions compared to residue treatment and the control in experiment 2. Our results suggest that converting pruning residue to biochar and its addition to soil has the potential to mitigate soil N2O emissions from tea plantation.

Nitrogen nutrient management is crucially important in shallow-rooted vegetable production systems characterized by high input and high environmental risk. To investigate the effects of summer catch crop (sweet corn, common bean, garland chrysanthemum and edible amaranth), residue management, and soil temperature and water on the succeeding cucumber rhizosphere nitrogen mineralization in intensive production systems, we determined the rates of net nitrogen mineralization and nitrification in a 4-year field experiment on greenhouse cucumber double-cropping systems. Summer catch crop and its residue significantly increased the succeeding cucumber rhizosphere mineral nitrogen contents, when compared to conventional practices. In general, summer catch crop and its residue significantly increased the rates of both net nitrogen mineralization and net nitrogen nitrification at 4 or 40°C, and increased the rates of net nitrogen immobilization (negative mineralization) and net nitrogen nitrification at 15 or 28°C, in succeeding cucumber rhizosphere after four-year treatment. Soil temperature and water had more influence than catch crops and residue management on N mineralization. The effect of carbon on nitrogen mineralization was more pronounced than that of nitrogen, and the effect of microbial carbon on the different forms of inorganic N was more pronounced than that of organic carbon. When the effects of soil temperature and water content were eliminated, cumulative net nitrogen mineralization and nitrification in catch crop and residue management plots were 296-784 and 57-84% higher, respectively, than conventional practices plots. Catch crops and residue management influenced change of ammonium-N more significantly than that of nitrate-N. Additionally, there were complex relationships between fruit yield and soil N mineralization in catch crop- and residue management-induced systems.

The effect of sole and intercropping of field pea (Pisum sativum L.) and spring barley (Hordeum vulgare L.) and of crop residue management on crop yield, NO3(-) leaching and N balance in the cropping system was tested in a 2-year lysimeter experiment on a temperate sandy loam soil. The crop rotation was pea and barley sole and intercrops followed by winter-rye and a fallow period. The Land Equivalent Ratio (LER), which is defined as the relative land area under sole crops that is required to produce the yields achieved in intercropping, was used to compare intercropping performance relative to sole cropping. Crops received no fertilizer in the experimental period. Natural 15N abundance techniques were used to determine pea N2 fixation. The pea–barley intercrop yielded 4.0 Mg grain ha-1, which was about 0.5 Mg lower than the yields of sole cropped pea but about 1.5 Mg greater than harvested in sole cropped barley. Calculation of the LER showed that plant growth resources were used from 17 to 31% more efficiently by the intercrop than by the sole crops. Pea increased the N derived from N2 fixation from 70% when sole cropped to 99% of the total aboveground N accumulation when intercropped. 21 However, based upon aboveground N accumulation the pea–barley intercrop yielded about 85 kg N ha-1, which was about 65 kg lower than sole cropped pea but about three times greater than harvested in sole cropped barley. Despite different preceding crops and removal or incorporation of straw, there was no significant difference between the subsequent non-fertilized winter-rye grain yields averaging 2.8 Mg ha-1, indicating an equalization of the quality of incorporated residue by the NO3(-) leaching pattern. NO3(-) leaching throughout the experimental period was 61 to 76 kg N ha-1. Leaching dynamics indicated differences in the temporal N mineralization comparing lysimeters previously cropped with pea or with barley. The major part of this N was leached during autumn and winter. Leaching tended to be smaller in the lysimeters originally cropped with the pea–barley intercrops, although not significantly different from the sole cropped pea and barley lysimeters. Soil N balances indicated depletion of N in the soil–plant system during the experimental period, independent of cropping system and residue management. N complementarity in the cropping system and the synchrony between residual N availability and crop N uptake is discussed.

Soil degradation in the savannah-derived agroecosystems of West Africa is often associated with rapid depletion of organic carbon stocks in soils of coarse texture. Field experiments were conducted over a period of more than 30 years at two sites in semiarid Togo to test the impact of agricultural management practices on soil C stocks and crop productivity. The resulting datasets were analysed using dynamic simulation models of varying complexity, to study the impact of crop rotation, fertiliser use and crop residue management on soil C dynamics. The models were then used to calculate the size of the annual C inputs necessary to restore C stocks to thresholds that would allow positive crop responses to fertilisers under continuous cultivation. Yields of all crops declined over the 30 years irrespective of crop rotation, fertiliser use or crop residue management. Both seed-cotton and cereal grain yields with fertiliser fluctuated around 1 t ha⁻¹ after 20 years. Rotations that included early maturing sorghum varieties provided larger C inputs to the soil through residue biomass; around 2.5 t C ha⁻¹ year⁻¹. Soil C stocks, originally of 15 t ha⁻¹ after woodland clearance, decreased by around 3 t ha⁻¹ at both sites and for virtually all treatments, reaching lower equilibrium levels after 5-10 years of cultivation. Soil C dynamics were well described with a two-pool SOM model running on an annual time step, with parameter values of 0.25 for the fraction of resistant plant material (K₁), 0.15-0.20 for the decomposition rate of labile soil C (K₂) and 8-10 t C ha⁻¹ for the fraction of stable C in the soil. Simulated addition of organic matter to the soil 30 years after woodland clearance indicated that additions of 3 t C ha⁻¹ year⁻¹ for 15-20 years would be necessary to build ‘threshold' soil C stocks of around 13 t ha⁻¹, compatible with positive crop response to fertiliser. The simulated soil C increases of 0.5 to 1.6% per year are comparable with results from long-term experiments in the region. However, the amounts of organic matter necessary to build these soil C stocks are not readily available to resource-poor farmers. These experimental results question the assumption that crop residue removal and lack of fertiliser input are responsible for soil C decline in these soils. Even when residues were incorporated and fertilisers used at high rates, crop C inputs were insufficient to compensate for C losses from these sandy soils under continuous cultivation.

Crop residues, the byproduct of crop production, are valuable natural resources that can be managed to maximize different input use efficiencies. Crop residue management is a well-known and widely accepted practice, and is a key component of conservation agriculture. The rapid shift from conventional agriculture to input-intensive modern agricultural practices often leads to an increase in the production of crop residues. Growing more food for an ever-increasing population brings the chance of fast residue generation. Ecosystem services from crop residues improve soil health status and supplement necessary elements in plants. However, this is just one side of the shield. Indecorous crop residue management, including in-situ residue burning, often causes serious environmental hazards. This happens to be one of the most serious environmental hazard issues witnessed by the agricultural sector. Moreover, improper management of these residues often restrains them from imparting their beneficial effects. In this paper, we have reviewed all recent findings to understand and summarize the different aspects of crop residue management, like the impact of the residues on crop and soil health, natural resource recycling, and strategies related to residue retention in farming systems, which are linked to the environment and ecology. This comprehensive review paper may be helpful for different stakeholders to formulate suitable residue management techniques that will fit well under existing farming system practices without compromising the systems’ productivity and environmental sustainability.