A review: System of crop intensification on field crops
Dr. Hannah Krujia
ACTO Agronomy, KVK Phek
With the ever increasing demand for food accompanied by the constraints of climate change and the availability and quality of soil and water, the farmers are challenged to produce more food per hectare with less water and with fewer agrochemical inputs if possible. The ideas and methods of the system of rice intensification which is improving irrigated rice production are now being extended and adapted to many other crops viz., wheat, maize, finger millet, sugarcane, legumes, vegetables, and even spices. Promoting better root growth and enhancing the soil’s fertility with organic materials are being found effective means for raising the yields of many crop plants with less water, less fertilizer, reduced seeds, fewer agrochemicals, and greater climate resilience. The principles and practices that improve the productivity and resilience of these varied crops are broadly referred to as the system of crop intensification (SCI).
System of crop intensification principles and practices build upon the productive potentials that derive from plants having larger, more efficient, longer-lived root systems and from their symbiotic relationships with a more abundant, diverse, and active soil biota. The main elements of System of crop intensification include:
- High-quality seeds or seedlings, well selected and carefully handled, to establish plants that have vigorous early growth, particularly of their root systems.
- Providing optimally wide spacing of plants to minimize competition between plants for available nutrients, water, air, and sunlight. This enables each plant to attain close to its maximum genetic potential.
- Keeping the topsoil around the plants well-aerated through appropriate implements or tools so that soil systems can absorb and circulate both air and water. It is usually done as part of weeding operations, this practice can stimulate beneficial soil organisms, from earthworms to microbes, at the same time that it reduces weed competition.
- If irrigation facilities are available, these should be used but sparingly, keeping the soil from becoming waterlogged. A combination of air and water in the soil is critical for plants growth and health, sustaining both better root systems and a larger soil biota.
- Amending the soil with organic matter, as much as possible to enhance its fertility and structure and to support the soil biota. Soil with high organic content can retain and provide water in the root zone on a more continuous basis, reducing crops need for irrigation water.
- Reducing reliance on inorganic fertilizers and pesticides, and to the extent possible, eliminating them. This will minimize environmental and health hazards and avoids adverse impacts on beneficial soil organisms.
System of crop intensification as a concept and strategy can be said to have begun with farmers modifications of their usual methods for cultivating crops. Some examples are as below:
- Finger millet (Eleusine coracana) - About 40 years ago, millet farmers in Haveri district of northern Karnataka, developed a system of cultivation that they called guli ragi (‘holeplanted millet’) This food crop is traditionally established by broadcasting seed which gave a yield of 1.25 – 2.5 tonnes/ha, with a maximum of 3.75 tonnes. In guli ragi cultivation, young millet seedlings 20 –25 days old are transplanted two seedlings per hole spaced at 45 × 45 cm in a square grid pattern. Guli ragi includes putting a handful of compost or manure into each hole along with the seedlings to boost soil fertility. When the plants are established in a square grid, intercultivation between rows is possible in perpendicular directions, not just between rows. Millet crop acquires more resistance to lodging, especially when traditional varieties are planted and their crop is less susceptible to pests and diseases, particularly to stem borers and aphids, according to the farmers (Uphoff, 2006).
- Wheat (Triticum spp.) - The system of wheat intensification (SWI) adapts SRI ideas and methods for production of wheat. Farmers working with NGO guidance made further increases in yield averaging 4.6 tonnes/ha instead of 2 tonnes/ha (PRADAN, 2012). The Jeevika programme reported that average SWI yield increased to 72% in 2012, with households net income/ha from wheat production raised by 86% under SWI (Behera et al., 2013). Farmers there traditionally sowed their wheat crop quite densely, using about 175 kg of seed per hectare. With wider plant spacing, the seed rate under SWI was reduced by 95%, to just 7.5 kg/ha while giving a much higher yield.
- Maize (Zea mays) Together with rice and wheat, maize is the third major cereal crop in the world. In the first trials in Himachal Pradesh in 2009, farmers sowed 1–2 seeds per hill, adding compost and other organic matter to the soil with three soil-aerating weedings. Their average yield of 3.5 tonnes/ha was 75% more than it is produced with conventional methods. Trials were laid out to measure the effects of having different spacings between hills. These trials showed best results by sowing seeds in a grid pattern with 40 × 40 cm spacing. In Assam, where maize yields are usually 3.75–4.5 tonnes/ha, farmers versions of system of crop intensification have given yields of 6.0–7.5 tonnes, with spacing as wide as 30 × 60 cm and with their seed rate reduced by 50% (SeSTA, 2015).
Behera, D., Chaudhury, A., Vutukutu, V.K., Gupta, A., Machiraju, S.,& Shah, P. (2013). Enhancing agricultural livelihoods through community institutions in Bihar, India. New Delhi: World Bank.
PRADAN. (2012). Cultivating rapeseed/mustard with SRI principles: A training manual. Gaya: Professional Assistance for Development Action.
SeSTA. (2015). SRI Experience, 2013–14. Unpublished report, Seven Sisters Development Assistance, Bongaigaon, Assam.
Uphoff, N. (2006). Report on SRI status in the Indian States of Andhra Pradesh and Karnataka(pp. 26–29). Ithaca, NY: Cornell International Institute for Food, Agriculture and Development.