any planning for the future requires estimates of future conditions. it is possible to study changes over time series. in this study, changes of production and cultivated area of 17 field crops of khorasan razavi province in a 25-year period were determined with mann - kendall test, sen’s estimator slope and linear regression. analysis of the three tests showed that performance of 76.5% from yi...

leach into groundwater after crop harvest in the fall, and depending on the species, can sequester atmospheric C Biculture legume–cereal cover cropping may enhance aboveand and/or N, thereby reducing the amount of N fertilizer belowground biomass yields and C and N contents. The increase in C and N supply to the soil has the potential to improve soil quality required for summer crops (Hargrove,...

Improper tillage with no manure may cause a range of undesirable processes (destruction of soil structure, accelerate erosion, depletion of organic matter and fertility). A field experiment was conducted to observe the change in soil properties after incorporation of green manure crops and to find out the residual effect of green manure crops along with tillage on maize and rice yields during 2...

Sustainable soil and crop management practices that reduce soil erosion and nitrogen (N) leaching, conserve soil organic matter, and optimize otton and sorghum yields still remain a challenge. We examined the influence of three tillage practices (no-till, strip till and chisel till), four cover rops {legume [hairy vetch (Vicia villosa Roth)], nonlegume [rye (Secaele cereale L.)], vetch/rye bicu...

The origins of agriculture, 10 000 years ago, led to profound changes in the biology of plants exploited as grain crops, through the process of domestication. This special case of evolution under cultivation led to domesticated cereals and pulses requiring humans for their dispersal, but the accompanying mechanisms causing higher productivity in these plants remain unknown. The classical view o...

Field plots in Tifton loamy sand were treated with various soil pesticides in 1973 and 1974 and either left exposed or covered with biodegradable flint mulch. Test crops were cantaloup, slicing and pickling cucumber, squash, and sweet corn. Overhead sprinkler irrigation was used in 1973, and trickle irrigation under the film mulch was used on sweet corn in 1974. Soil was assayed for nematodes, ...

The conservation of water is crucial to sustainable agricultural production in areas of low rainfall or uneven precipitation distribution. Under such circumstances, drip irrigation methods offer a useful option for economic production of vegetable crops. This preliminary study examined the efficacy and performance of two drip irrigation methods on cucumber and tomato crops grown out of season. ...