Residual Effects of Red Gram [Cajanus cajan (L.) Millsp.] on Growth, Yield and Quality of Fodder Maize (Zea mays L.)

Background: Bio-recycling of crop residues is contemplated as an environment friendly soil enrichment and conservation practice that sustains agricultural productivity in the long run. Legume residues are privileged by the unique nitrogen fixing capacity and rhizospheric properties that enhance soil fertility, thereby reducing the need for chemical nutrient inputs. The present study was conducted to evaluate the residual effect of red gram on fodder maize cultivated as succeeding crop in the southern laterites of Thiruvananthapuram district, Kerala, India. Methods: The field experiment to assess the effect of red gram residue incorporation on the growth and yield of fodder maize was carried out in the Instructional Farm, College of Agriculture, Vellayani, Kerala during June - August 2019. Fodder maize (African tall) was sown in the plots after incorporation of crop residues of red gram varieties (APK 1 and Vamban (Rg) 3) grown under different planting geometry (40 cm x 20 cm and 60 cm x 30 cm) and NPK doses (40:80:40, 30:60:30 and 20:40:20 kg NPK ha-1) and compared with the package of practices recommendation and in randomized block design (RBD) replicated thrice. Result: Significantly higher quantities of red gram residues were realised and incorporated in the treatments involving a planting geometry of 40 cm x 20 cm and an NPK dose of 40:80:40 kg NPK ha-1 in both varieties used, Vamban (Rg) 3 and APK 1 (T7 and T1). Nutrient contents in the residues and decomposition in T1 and T7 resulted in the maximum additions in soil, available N, P and K status and dehydrogenase activity. Evaluation of the residual effects of the legume on fodder maize revealed the significantly highest growth and yields in maize raised with chemical fertilizers as per package recommendation and, among the residue incorporated treatments, maximum plant height and fodder yields were recorded in the treatment in which residues of Vamban (Rg) 3 raised at 40 cm x 20 cm spacing and fertilised with 40:80:40 kg NPK ha-1 were incorporated, on par with variety APK 1 raised under same management practice. The green fodder yield with residue incorporation was 80-90 per cent that under chemical fertilizer managed treatment. Among the quality parameters, crude protein (9.30%) was the highest with chemical fertilizer application while carbohydrate content (66.23%) was the lowest.

Field Investigation of Straw Length, Stubble Height and Rotary Speed Effect on the Dispersion and Burying of Residue

High-yielding agriculture leads to plenty of residues left in the field after harvest, which not only makes seeding operations difficult, but also decreases residue decomposition rate. Thus, it is necessary to incorporate some residue into the soil by tillage operations. Providing the relation between tillage operations and residue incorporation, and establishing a mathematical model plays an important role in residue management and the design of tillage machinery. In order to obtain detailed data on the interaction between crop residue and tillage operations, an electric and multi-functional field testing bench with precise parameter control was developed to perform residue incorporation characteristics of rotary tillage, and investigated straw length, rotary speed and stubble height effect on the dispersion and burying of residue. Three experimental factors affecting residue incorporation performance were studied, i.e. six lengths of straw (30-150 mm), four heights of stubble (50-200 mm), and three rotary speeds (240-320 rpm). Chopped straw and stubble with certain sizes were prepared for the test, and measure the dispersion uniformity and burying rate of residue after rotary tillage. The results indicated that straw length, stubble height, and rotary speed all impact residue incorporation quality. The dispersion uniformity and burying rate of residue decreased with the increase of straw length and stubble height; Lower rotary speed parameter buried lesser residue and dispersed worse uniformity than higher one; It is suggested that farmers determine the straw length and stubble height at the stage of harvest according to the burying rate and dispersion uniformity of residue.

Return of crop residues to arable land stimulates N2O emission but mitigates NO3− leaching: a meta-analysis

Incorporation of crop residues into the soil has been widely recommended as an effective method to sustain soil fertility and improve soil carbon sequestration in arable lands. However, it may lead to an increase in the emission of nitrous oxide (N2O) and leaching of nitrate (NO3−) to groundwater due to higher nitrogen (N) availability after crop residue incorporation. Here, we conducted a meta-analysis based on 345 observations from 90 peer-reviewed studies to evaluate the effects of crop residue return on soil N2O emissions and NO3− leaching for different locations, climatic and soil conditions, and agricultural management strategies. On average, crop residue incorporation significantly stimulated N2O emissions by 29.7%, but decreased NO3− leaching by 14.4%. The increase in N2O emissions was negatively and significantly correlated with mean annual temperature and mean annual precipitation, and with the most significant changes occurring in the temperate climate zone. Crop residues stimulated N2O emission mainly in soils with pH ranging between 5.5 and 6.5, or above 7.5 in soils with low clay content. In addition, crop residue application decreased NO3− leaching significantly in soils with sandy loam, silty clay loam, and silt loam textures. Our analysis reveals that an appropriate crop residue management adapted to the site-specific soil and environmental conditions is critical for increasing soil organic carbon stocks and decreasing nitrogen losses. The most important novel finding is that residue return, despite stimulation of N2O emissions, is particularly effective in reducing NO3− leaching in soils with loamy texture, which are generally among the most productive arable soils.

Effect of residue and nutrient management on productivity, nutrient uptake, economics and greenhouse gas emission of rice in intensified rice-based cropping systems

A long-term field experiment was conducted at Institute research farm, ICAR-National Rice Research Institute, Cuttack, Odisha since 2012-13. The experiment was conducted in a split plot design involving two cropping systems i.e., rice-maize-cowpea (R-M-C) and rice-groundnut-cowpea (R-G-C) covering three crops in three seasons i.e., kharif, rabi and summer, respectively in main plots and five nutrient management treatments i.e., control control - control (C-C-C), RDF-RDF - RDF (R-R-R), Residue Incorporation (RI) +75% of RDF-RDF - RDF (RI+R75-R-R), RI+ 75 % of RDF-Straw Mulching (SM) + RDF - RDF (RI+R75-SM+R-R) and RI+75 % of RDF - SM+RDF - 50 % of RDF (RI+R75-SM+R-R50) in sub-plots; where control indicates no fertilizer application to each crop of the system, RDF indicates recommended dose of fertilizers for respective crops, RI indicates cowpea residue incorporation in succeeding rice crop before transplanting and SM indicates rice straw mulching @ 6 t ha-1 in succeeding groundnut and maize. Significant improvement in growth parameters of rice i.e., plant height, tillers plant-1, leaf area index, dry matter accumulation, yield i.e., grain yield, straw yield, harvest index, nutrient uptake, economic gain i.e., gross return, net return and B:C ratio, CH4 flux in cowpea residue incorporated treatments than the residue removal treatments. Cowpea residue incorporation with 75% of recommended dose of fertilizer to rice followed by straw mulching with recommended dose of fertilizer to rabi season crops i.e., maize and groundnut and recommended dose of fertilizer to summer season crops i.e., RI+R75-SM+R-R recorded 10.2% higher number of tillers hill-1, 17.1% higher LAI, 10.9% higher DMA, 8.5% higher panicles m-2 and 8.8% higher filled grains panicle-1 than recommended dose of fertilization to each crop i.e., R-R-R. RI+R75-SM + R-R also recorded 11.3% higher grain yield, 9.7% higher straw yield, 13.7% higher N uptake, 15.8% higher P uptake, 11.9% higher K uptake, 11.3% higher gross return, 15.1% higher net return and 25.6% less N2O emission than recommended dose of fertilization to each crop i.e., R-R-R. Cowpea residue incorporation with 25% reduction in RDF, straw mulching with RDF to rabi season crops i.e., maize and groundnut and RDF to summer season crops (RI+R75-SM+R-R) however recorded at par growth, yield, nutrient uptake and economic return to that of RI+R75-SM+R-R50. Thus, RI+R75-SM+R-R50 could be useful in achieving higher productivity and profitability from rice in an intensified rice-based cropping system.

Improvement of Soil Health and System Productivity through Crop Diversification and Residue Incorporation under Jute-Based Different Cropping Systems

Crop diversity through residue incorporation is the most important method for sustaining soil health. A field study was conducted over five consecutive years (2012–2017) to see the impact of residue incorporartions in Inceptisol of eastern India. The main plot treatments had five cropping systems (CS), namely, fallow−rice−rice (FRR), jute−rice−wheat (JRW), jute−rice−baby corn (JRBc), jute−rice−vegetable pea (JRGp), jute−rice−mustard−mungbean/green gram (JRMMu), which cinsisted of four sub-plots with varied nutrient and crop residue management (NCRM) levels, namely crops with no residue +75% of the recommended dose of fertilizers (RDF) (F1R0), crops with the residue of the previous crops +75% RDF (F1R1), crops with no resiude +100% RDF (F2R0), and crops with residue +100% RDF (F2R1). The highest system productivity was obtained for JRBc (15.3 Mg·ha−1), followed by JRGp (8.81 Mg·ha−1) and JRMMu (7.61 Mg·ha−1); however, the highest sustainability index was found with the JRGp cropping system (0.88), followed by JRMMu (0.82). Among the NCRMs, the highest productivity (8.78 Mg·ha−1) and sustainability index (0.83) were recorded in F2R1. Five soil parameters, namely, bulk density, available K, urease activity, dehydrogenase activity, and soil microbial biomass carbon (SMBC), were used in the minimum data-set (MDS) for the calculation of the soil quality index (SQI). The best attainment of SQI was found in the JRGp system (0.63), closely followed by the JRMMu (0.61) cropping system.

On Farm Testing of Rice Residue Management Techniques for Wheat (Triticum aestivum L.) Establishment in Punjab

Rice residue management (RRM) has been the key component of systems’ sustainability. The paper reports the effect of different RRM and wheat (Triticum aestivum L.) establishment methods on productivity and yield contributing attributes through farmer participatory mode in south-western Punjab. Different RRM technologies including rice residue removal, residue incorporation and residue retention on soil as surface mulch were evaluated. Wheat grain yield was significantly (p<0.05) higher with happy seeder method of wheat establishment following chopping of loose rice stubble, which acts as surface mulch, compared with the other RRM technologies. Wheat grain yield in other RRM technologies viz. rice residue incorporation and removal did not differ significantly. The yield contributing attributes viz. plant height, number of effective tillers m-1 row length, 1000-grain weight, ear length and the number of grains ear-1 were significantly higher in happy seeder method of wheat establishment. The weed count (Phalaris minor) was significantly lower than the other compared methods of RRM. The correlation matrix exhibited a linear positive relationship between the grain yield and plant height (r=0.951*; p<0.05), ear length (r=0.941*), 1000-grain weight (r=0.853*) and number of grains ear-1 (r=0.771*). All economic indices viz. average net (Rs. 74, 840/- ha-1), gross returns (Rs. 1,00,620/- ha-1) and benefit-cost (B:C; 3.9) ratio were significantly enhanced because of low cost of cultivation (Rs. 25,780/- ha-1) under happy seeder method of wheat establishment.