IMPROVEMENT IN FOOD RESOURCES: WORKSHEET IV I. Answer briefly: ( 3 marks each) Which factors affect grain during storage? How do they affect them? Why should preventive measures and biological control methods be preferred for protecting crops? What are the advantages of practicing crop rotation? Weeds affect the growth of crops. What advice would you give a farmer to control the growth of weeds? II. Read the paragraph given below and answer the questions that follow. (4 marks) Fertilizers are commercially produced plant nutrients. Fertilizers supply nitrogen, phosphorus and potassium. Fertilizers are a factor in the higher yields of high-cost farming. Fertilizers should be applied carefully in terms of proper dose, time, and observing pre and post-application precautions for their complete utilisation. For example, sometimes fertilizers get washed away due to excessive irrigation and are not fully absorbed by the plants. This excess fertilizer then leads to water pollution. Also continuous use of fertilizers in an area can destroy soil fertility because the organic matter in the soil is not replenished and micro-organisms in the soil are harmed by the fertilizers used. Short-term benefits of using fertilizers and long-term benefits of using manure for maintaining soil fertility have to be considered while aiming for optimum yields in crop production. What would be the short term benefit of using fertilizers? What would be the long term benefit of using manure? What harm does long term use of fertilizers cause to the soil? How do fertilizers lead to water pollution? Pls solve as many questions as possible I will mark most ans as brainliest
Answers
Answer:
Compare the use of manure and fertilizers in maintaining soil fertility.
Ans. Effects of using manures on soil quality:
(i) The manures enrich the soil with nutrients.
(ii) They provide a lot of organic matter (humus) to the soil and thus restores water retention capacity of sandy soils and drainage in clayey soil.
(iii) The addition of manures reduces soil erosion.
(iv) They provide food for soil organisms, like soil friendly bacteria.
Effects of using fertilizers on soil quality:
(i) By the continuous use of fertilizers, the soil becomes powdery, dry and rate of soil erosion increases.
(ii) By the use of fertilizers, the organic matter decreases which further decreases the porosity of soil and the plant roots do not get oxygen properly.
(iii) The nature of soil changes to acidic or basic.
NCERT Textbook Page 208
1. Which of the following conditions will give the most benefits? Why?
(a) Farmers use high-quality seeds, do not adopt irrigation or use fertilizer.
(c) Farmers use quality seeds, adopt irrigation, use fertilizer and use crop protection measures.
Ans. In this, (c) Farmers use quality seeds, adopt irrigation, use fertilizer and use crop protection measures.
Use of any quality seeds is not sufficient until they are properly irrigated, enriched with fertilizers and protected from biotic factors. Hence, option (c) will give the most benefits.
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