Explain how crop rotation and cover crops are important to sustainable agriculture.

There is a need for the farmers to implement a crop rotation, which builds or maintains soil organic matter, manages and conserves nutrients, works to control pests, and protects against erosion. The cultivators of perennial crops, which are not rotated may use some other kind of approaches like cover crops, in order to sustain the health of the soil.  

The cover crops like hairy vetch or clover, are grown at the time of off-season when the soils may otherwise be left barren. These crops build and safeguard the health of the soil by replenishing soil nutrients, preventing erosion, minimizing the need for herbicides, and keeping the weeds in check.  

calculate how many grams of ammonia can be produced from 4.21 grams of

n2 + 3h2 = 2nh3

my answer:

25.0g n2 x (1 mol/ 28.0gn2) x (2 mol nh3/ 1 mol n2) x (17.0g nh3/ 1 molnh3) = 30.36g n2

25.0g h2 x (1 mol h2/ 2.00g h2) x (2 mol nh3/ 3 mol h2) x (17.0g nh3/ 1 mol nh3) = 141.67g h2

lr = n2

plants need sunlight, water, and carbon dioxide to make food. plants use the raw materials of water, nutrients they absorb from soil, and carbon dioxide to make sugars the plant can use. energy from the sun and chlorophyll are also needed.