Criteria Determining Harvesting a Crop and Preparation for Marketing
Harvesting: It is the removal of entire plants or economic parts (grain, seed, leaf, root, or entire plant) after maturity from the field.
Time of harvesting: If the crop is harvested early the produce contains high moisture and more immature grains. Higher moisture results shriveling of seed and infestation of pests. The immature grains lead to low yields and reduce quality as well as germination %. Late harvesting results in shattering of grains, germination when it rains and breaking during processing. Hence, harvesting at correct time essential to get good quality grains & higher yield. Crops can be harvested at physiological or harvest maturity. Crop is considered to be at physiological maturity when the translocation of photosynthates is stopped to economic part. Physiological maturity refers to a developmental stage after which no further increase in dry matter occurs in the economical part. This is important only when a field is to be vacated for sowing another crop otherwise, one should go for harvesting the crop at harvest maturity. Harvest maturity generally occurs 7 dates after physiological maturity with following symptoms:
1. Loss of moisture in grains up to 12 to 14%.
2. Yellowing and dropping of leaves.
3. Drying and change in colour of grains or pods.
4. Life cycle completes which vary with crop to crop and variety.
5. General symptoms in various crops are:
1) Lower leaves turn to yellow straw.
2) Lower & other leaves fall down.
3) Stem turn to straw colour.
4) Pith formation in stem takes place.
5) Grains become hard & fully developed.
6) Moisture % in grain becomes less than 20% on total weight basis.
7) In maize, drying of cob sheath and fibers take place.
B) COTTON: Picking of fully opened & bursted bolls is done in 3 – 4 stages.
1) Pods turn to brown,
2) Grains become hard,
3) Shedding of lower older leaves take place.
4) Yellowing of leaves.
1) Yellowish colour to crop,
2) Flowers, if flowering variety is planted.
3) Swelling of eye buds,
4) Sweetness of juice,
5) Reads 21 to 24 Bricks Saccharometer reading.
1) Drying of vines.
2) Black colouring to the inner side of pods
3) Reddening or dark colouration to the seed coat,
4) Prominent margins on pod.
1) Dropping of leaves and drying,
2) Hardening of tuber.
Determination of harvesting date is easier for determinate crops and difficult for indeterminate crops as it contains flower, immature & mature pods. Therefore, such crop should be harvested when 75% maturity is achieved or periodical harvesting should be done.