A.K. Misra

Legume Effect for Enhancing Productivity and Nutrient Use-Efficiency in Major Cropping Systems–An Indian Perspective: A Review

ABSTRACT Inclusion of legumes in the cropping system has been known since times immemorial. Legume is a natural mini-nitrogen manufacturing factory in the field and the farmers by growing these crops can play a vital role in increasing indigenous nitrogen production. Legume help in solubilizing insoluble P in soil, improving the soil physical environment, increasing soil microbial activity, and restoring organic matter, and also has smothering effect on weed. The carryover of N derived from legume grown, either in crop sequence or in intercropping system for succeeding crops, is also important. In a country like India, where the average consumption of plant nutrients from chemical fertilizers on national basis is very low, the scope for exploiting direct and residual fertility due to legumes has obviously a great potential. This article deals with the beneficial effect of important legumes on increasing productivity and nutrient use-efficiency in various systems. Sorghum, pearl millet, maize, and castor are mainstay in dry lands and marginal and sub-marginal lands. Sorghum yield increased when sown after cowpea, green gram, and groundnut. Grain legumes like groundnut or cowpea provide an equivalent to 60 kg N ha on the subsequent crop of pearl millet. Various studies have shown that among legume/cereal intercropping system, the combination of maize/pigeon pea is considered to be highly suitable with a minimum competition for nutrients, while legume/legume intercropping system, pigeon pea/groundnut system is the most efficient one in terms of resource use-efficiency. In alley cropping system, Leucaena leucocephala (Subabul) prunings provide N to the extent of 75 kg, which benefits the intercrop castor and sorghum. Nitrogen economy through intercropped legume is still a researchable issue because the key point for leguminous crop grown in intercropping system is the problem of nodulation. Incorporation of whole plant of summer green gram/black gram into soil (after picking pods) before transplanting rice resulted in the economizing (40–60 kg N ha−1, 30 kg P2O5, and 15 kg K2O per ha) of rice in rice-wheat system. Similarly, 6–8 weeks old green manure crop of sunhemp or dhaincha accumulates about 3–4 t ha−1 dry matter and 100–120 kg N ha−1 which, when incorporated in situ, supplements up to 50% of the total N requirement of rice. Legumes with indeterminate growth are more efficient in N2 fixation than determinate types. Fodder legumes in general are more potent in increasing the productivity of succeeding cereals. The carryover of N for succeeding crops may be 60–120 kg in berseem, 75 kg in Indian clover, 75 kg in cluster bean, 35–60 kg in fodder cowpea, 68 kg in chickpea, 55 kg in black gram, 54–58 kg in groundnut, 50–51 kg in soybean, 50 kg in Lathyrus, and 36–42 kg per ha in pigeon pea. Direct and residual effect of partially acidulated material and mixture of rock phosphate + single superphosphate were observed to be better when these were applied to green gram in winter season than to rice in rainy season simply because of legume effect.

Long-term continuous cropping, fertilisation, and manuring effects on physical properties and organic carbon content of a sandy loam soil

Effects of continuous cropping, fertilisation, and manuring on soil organic carbon content and physical properties such as particle size distribution, bulk density, aggregation, porosity, and water retention characteristics of a Typic Ustochrept were examined after 31 cycles of maize–wheat–cowpea (fodder) crop rotation. Five contrasting nutrient treatments from a long-term fertiliser experiment were chosen for this study: control (no fertiliser or manure); 100% (optimum dose) nitrogen (N) fertiliser; 100% nitrogen and phosphorus (NP); 100% nitrogen, phosphorus, and potassium (NPK); 100% NPK + farmyard manure (NPK+FYM). The NPK+FYM treatment significantly improved soil organic carbon (SOC) content in 0–0.15 m soil compared with the other 4 treatments; the NPK treatment resulted in significantly more SOC than the control and N treatments (P < 0.05). The SOC in NPK and NPK+FYM treatments was 38.6 and 63.6%, respectively, more than the initial level of SOC (4.4 g/kg) after 31 cycles of cropping. The control and N treatments maintained the SOC status of the soil at the initial value. NPK+FYM significantly improved soil aggregation, soil water retention, microporosity, and available water capacity and reduced bulk density of the soil at 0–0.30 m depth. Greater crop growth under the NPK treatment resulted in increased organic matter content of soil, which improved aggregate stability, water retention capacity, and microporosity compared with the control. The effects were more conspicuous with the NPK+FYM treatment and at the surface soil (0–0.15 m). Application of imbalanced inorganic fertiliser (N and NP treatments) did not have a deleterious effect on the physical properties of the soil compared with the control. SOC content showed a highly significant and positive correlation with mean weight diameter (0.60), % water-stable macro-aggregates (0.61), and soil water retention at –0.033 MPa (0.75) and –1.5 MPa (0.72), and negative correlation with bulk density (–0.70) for the surface 0–0.15 m soil. The study thus suggests that application of balanced mineral fertilisers in combination with organic manure sustains a better soil physical environment and higher crop productivity under intensive cultivation.

Cropping Systems of Central India: An Energy and Economic Analysis

ABSTRACT The study attempts to analyze the energy input-output relationship and economic returns of the cropping systems in central India. The data collected from farmers through multistage random sampling techniques, were subjected to descriptive analysis of simple proportions and percentages. Findings reveal that total energy involved in soybean-wheat system (19817 MJ ha−1; renewable 5507 MJ ha−1 and non-renewable 14310 MJ ha−1) is much greater than soybean-chickpea (11239 MJ ha−1; renewable 4883 MJ ha−1 and non-renewable 6356 MJ ha−1), pigeonpea monocropping (2329 MJ ha−1; renewable 714 MJ ha−1 and non-renewable 1616 MJ ha−1), fallow-wheat (13716 MJ ha−1; renewable 2810 MJ ha−1 and non-renewable 10906 MJ ha−1) and fallow-chickpea (4445 MJ ha−1; renewable 2526 MJ ha−1 and non-renewable 1919 MJ ha−1). The percentage of non-renewable energy is higher than renewable energy inputs. Soybean-wheat (70%) and fallow-wheat (78%) systems resorted to more use of non-renewable energy than renewable energy. In soybean-chickpea system share of non-renewable energy is 52%. The energy outputs follow the order: soybean-wheat (70495 MJ ha−1) > fallow-wheat (52084 MJ ha−1) > soybean-chickpea (44485 MJ ha−1) > pigeonpea monocropping (20427 MJ ha−1) > fallow-chickpea (20357 MJ ha−1); energy efficiency is the highest in pigeonpea mono-cropping (8.76); for other systems it ranged from 3.67 in soybean-wheat to 4.63 in fallow-chickpea system. The net energy of the systems is 50678 MJ ha−1 in soybean-wheat, 38368 MJ ha−1 in fallow-wheat, 33246 MJ ha−1 in soybean-chickpea, 18098 MJ ha−1 in pigeonpea monocropping and 15912 MJ ha−1 in fallow-chickpea. Though the soybean-wheat system results in highest net energy, its energy productivity (0.269 kg MJ−1) is the lowest and that of fallow-wheat system is 0.288 kg MJ−1. It is comparatively higher for other systems, viz., soybean-chickpea (0.307 kg MJ−1), pigeonpea monocropping (0.643 kg MJ−1) and fallow-chickpea (0.342 kg MJ−1). Further, energy intensity is 3.84 MJ kg−1 and 0.887 MJ Rs.−1 in physical and economic terms, respectively, in the soybean-wheat system, and are greater than other systems, viz., soybean-chickpea (3.43 MJ kg−1 and 0.577 MJ Rs.−1), pigeonpea monocropping (1.55 MJ kg−1 and 0.243 MJ Rs.−1), fallow-wheat (3.59 MJ kg−1 and 1.408 MJ Rs.−1) and fallow-chickpea (2.96 MJ kg−1 and 0.569 MJ Rs.−1). But the soybean-wheat cropping system has been found more remunerative in terms of benefit-cost ratio (1.27) owing to its ability to generate the highest return per rupee investment than soybean-chickpea (1.23) and pigeonpea monocropping (1.23). The fallow-based systems are having comparatively better benefit/cost ratio. The investment requirement and also net return is highest for soybean-wheat system, thus is preferred by the large farmers. Farmers are forced to use soybean-chickpea crop rotation whenever there is lack of adequate rainfall during rainy season and irrigation facilities in succeeding winter season. Thus, fallow-chickpea rotation is suitable for extremely poor farmers with no irrigation facilities.